32d305783171b9bc505926a6fb45cf6e8b1ec14f
[ffmpeg.git] / libavcodec / mpeg12.c
1 /*
2  * MPEG1 codec / MPEG2 decoder
3  * Copyright (c) 2000,2001 Fabrice Bellard.
4  *
5  * This library is free software; you can redistribute it and/or
6  * modify it under the terms of the GNU Lesser General Public
7  * License as published by the Free Software Foundation; either
8  * version 2 of the License, or (at your option) any later version.
9  *
10  * This library is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13  * Lesser General Public License for more details.
14  *
15  * You should have received a copy of the GNU Lesser General Public
16  * License along with this library; if not, write to the Free Software
17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
18  */
19  
20 /**
21  * @file mpeg12.c
22  * MPEG1 codec / MPEG2 decoder.
23  */
24  
25 //#define DEBUG
26 #include "avcodec.h"
27 #include "dsputil.h"
28 #include "mpegvideo.h"
29
30 #include "mpeg12data.h"
31
32
33 /* Start codes. */
34 #define SEQ_END_CODE            0x000001b7
35 #define SEQ_START_CODE          0x000001b3
36 #define GOP_START_CODE          0x000001b8
37 #define PICTURE_START_CODE      0x00000100
38 #define SLICE_MIN_START_CODE    0x00000101
39 #define SLICE_MAX_START_CODE    0x000001af
40 #define EXT_START_CODE          0x000001b5
41 #define USER_START_CODE         0x000001b2
42
43 #define DC_VLC_BITS 9
44 #define MV_VLC_BITS 9
45 #define MBINCR_VLC_BITS 9
46 #define MB_PAT_VLC_BITS 9
47 #define MB_PTYPE_VLC_BITS 6
48 #define MB_BTYPE_VLC_BITS 6
49 #define TEX_VLC_BITS 9
50
51 static void mpeg1_encode_block(MpegEncContext *s, 
52                          DCTELEM *block, 
53                          int component);
54 static void mpeg1_encode_motion(MpegEncContext *s, int val, int f_or_b_code);    // RAL: f_code parameter added
55 static void mpeg1_skip_picture(MpegEncContext *s, int pict_num);
56 static inline int mpeg1_decode_block_inter(MpegEncContext *s, 
57                               DCTELEM *block, 
58                               int n);
59 static inline int mpeg1_decode_block_intra(MpegEncContext *s, 
60                               DCTELEM *block, 
61                               int n);
62 static inline int mpeg2_decode_block_non_intra(MpegEncContext *s, 
63                                         DCTELEM *block, 
64                                         int n);
65 static inline int mpeg2_decode_block_intra(MpegEncContext *s, 
66                                     DCTELEM *block, 
67                                     int n);
68 static int mpeg_decode_motion(MpegEncContext *s, int fcode, int pred);
69
70 #ifdef CONFIG_ENCODERS
71 static uint8_t (*mv_penalty)[MAX_MV*2+1]= NULL;
72 static uint8_t fcode_tab[MAX_MV*2+1];
73
74 static uint32_t uni_mpeg1_ac_vlc_bits[64*64*2];
75 static uint8_t  uni_mpeg1_ac_vlc_len [64*64*2];
76 #endif
77
78 static void init_2d_vlc_rl(RLTable *rl)
79 {
80     int i;
81     
82     init_vlc(&rl->vlc, TEX_VLC_BITS, rl->n + 2, 
83              &rl->table_vlc[0][1], 4, 2,
84              &rl->table_vlc[0][0], 4, 2);
85
86     
87     rl->rl_vlc[0]= av_malloc(rl->vlc.table_size*sizeof(RL_VLC_ELEM));
88     for(i=0; i<rl->vlc.table_size; i++){
89         int code= rl->vlc.table[i][0];
90         int len = rl->vlc.table[i][1];
91         int level, run;
92     
93         if(len==0){ // illegal code
94             run= 65;
95             level= MAX_LEVEL;
96         }else if(len<0){ //more bits needed
97             run= 0;
98             level= code;
99         }else{
100             if(code==rl->n){ //esc
101                 run= 65;
102                 level= 0;
103             }else if(code==rl->n+1){ //eob
104                 run= 0;
105                 level= 127;
106             }else{
107                 run=   rl->table_run  [code] + 1;
108                 level= rl->table_level[code];
109             }
110         }
111         rl->rl_vlc[0][i].len= len;
112         rl->rl_vlc[0][i].level= level;
113         rl->rl_vlc[0][i].run= run;
114     }
115 }
116
117 static void init_uni_ac_vlc(RLTable *rl, uint32_t *uni_ac_vlc_bits, uint8_t *uni_ac_vlc_len){
118     int i;
119
120     for(i=0; i<128; i++){
121         int level= i-64;
122         int run;
123         for(run=0; run<64; run++){
124             int len, bits, code;
125             
126             int alevel= ABS(level);
127             int sign= (level>>31)&1;
128
129             if (alevel > rl->max_level[0][run])
130                 code= 111; /*rl->n*/
131             else
132                 code= rl->index_run[0][run] + alevel - 1;
133
134             if (code < 111 /* rl->n */) {
135                 /* store the vlc & sign at once */
136                 len=   mpeg1_vlc[code][1]+1;
137                 bits= (mpeg1_vlc[code][0]<<1) + sign;
138             } else {
139                 len=  mpeg1_vlc[111/*rl->n*/][1]+6;
140                 bits= mpeg1_vlc[111/*rl->n*/][0]<<6;
141
142                 bits|= run;
143                 if (alevel < 128) {
144                     bits<<=8; len+=8;
145                     bits|= level & 0xff;
146                 } else {
147                     bits<<=16; len+=16;
148                     bits|= level & 0xff;
149                     if (level < 0) {
150                         bits|= 0x8001 + level + 255;
151                     } else {
152                         bits|= level & 0xffff;
153                     }
154                 }
155             }
156
157             uni_ac_vlc_bits[UNI_AC_ENC_INDEX(run, i)]= bits;
158             uni_ac_vlc_len [UNI_AC_ENC_INDEX(run, i)]= len;
159         }
160     }
161 }
162
163 static void put_header(MpegEncContext *s, int header)
164 {
165     align_put_bits(&s->pb);
166     put_bits(&s->pb, 16, header>>16);
167     put_bits(&s->pb, 16, header&0xFFFF);
168 }
169
170 /* put sequence header if needed */
171 static void mpeg1_encode_sequence_header(MpegEncContext *s)
172 {
173         unsigned int vbv_buffer_size;
174         unsigned int fps, v;
175         int n, i;
176         uint64_t time_code;
177         float best_aspect_error= 1E10;
178         float aspect_ratio= s->avctx->aspect_ratio;
179         
180         if(aspect_ratio==0.0) aspect_ratio= s->width / (float)s->height; //pixel aspect 1:1 (VGA)
181         
182         if (s->current_picture.key_frame) {
183             /* mpeg1 header repeated every gop */
184             put_header(s, SEQ_START_CODE);
185             
186             /* search closest frame rate */
187             {
188                 int i, dmin, d;
189                 s->frame_rate_index = 0;
190                 dmin = 0x7fffffff;
191                 for(i=1;i<14;i++) {
192                     if(s->avctx->strict_std_compliance >= 0 && i>=9) break;
193                      
194                     d = abs(MPEG1_FRAME_RATE_BASE*(int64_t)s->avctx->frame_rate/s->avctx->frame_rate_base - frame_rate_tab[i]);
195                     if (d < dmin) {
196                         dmin = d;
197                         s->frame_rate_index = i;
198                     }
199                 }
200             }
201  
202             put_bits(&s->pb, 12, s->width);
203             put_bits(&s->pb, 12, s->height);
204             
205             for(i=1; i<15; i++){
206                 float error= mpeg1_aspect[i] - s->width/(s->height*aspect_ratio);
207                 error= ABS(error);
208                 
209                 if(error < best_aspect_error){
210                     best_aspect_error= error;
211                     s->aspect_ratio_info= i;
212                 }
213             }
214             
215             put_bits(&s->pb, 4, s->aspect_ratio_info);
216             put_bits(&s->pb, 4, s->frame_rate_index);
217             v = (s->bit_rate + 399) / 400;
218             if (v > 0x3ffff)
219                 v = 0x3ffff;
220             put_bits(&s->pb, 18, v);
221             put_bits(&s->pb, 1, 1); /* marker */
222
223             if(s->avctx->rc_buffer_size)
224                 vbv_buffer_size = s->avctx->rc_buffer_size;
225             else
226                 /* VBV calculation: Scaled so that a VCD has the proper VBV size of 40 kilobytes */
227                 vbv_buffer_size = (( 20 * s->bit_rate) / (1151929 / 2)) * 8 * 1024;      
228             put_bits(&s->pb, 10, (vbv_buffer_size + 16383) / 16384); 
229             put_bits(&s->pb, 1, 1); /* constrained parameter flag */
230             put_bits(&s->pb, 1, 0); /* no custom intra matrix */
231             put_bits(&s->pb, 1, 0); /* no custom non intra matrix */
232
233             put_header(s, GOP_START_CODE);
234             put_bits(&s->pb, 1, 0); /* do drop frame */
235             /* time code : we must convert from the real frame rate to a
236                fake mpeg frame rate in case of low frame rate */
237             fps = frame_rate_tab[s->frame_rate_index];
238             time_code = (int64_t)s->fake_picture_number * MPEG1_FRAME_RATE_BASE;
239             s->gop_picture_number = s->fake_picture_number;
240             put_bits(&s->pb, 5, (uint32_t)((time_code / (fps * 3600)) % 24));
241             put_bits(&s->pb, 6, (uint32_t)((time_code / (fps * 60)) % 60));
242             put_bits(&s->pb, 1, 1);
243             put_bits(&s->pb, 6, (uint32_t)((time_code / fps) % 60));
244             put_bits(&s->pb, 6, (uint32_t)((time_code % fps) / MPEG1_FRAME_RATE_BASE));
245             put_bits(&s->pb, 1, 1); /* closed gop */
246             put_bits(&s->pb, 1, 0); /* broken link */
247         }
248
249         if (s->avctx->frame_rate < (24 * s->avctx->frame_rate_base) && s->picture_number > 0) {
250             /* insert empty P pictures to slow down to the desired
251                frame rate. Each fake pictures takes about 20 bytes */
252             fps = frame_rate_tab[s->frame_rate_index];
253             n = av_rescale((int64_t)s->picture_number * s->avctx->frame_rate_base, fps, s->avctx->frame_rate) / MPEG1_FRAME_RATE_BASE - 1;
254             while (s->fake_picture_number < n) {
255                 mpeg1_skip_picture(s, s->fake_picture_number - 
256                                    s->gop_picture_number); 
257                 s->fake_picture_number++;
258             }
259
260         }
261 }
262
263 static inline void encode_mb_skip_run(MpegEncContext *s, int run){
264     while (run >= 33) {
265         put_bits(&s->pb, 11, 0x008);
266         run -= 33;
267     }
268     put_bits(&s->pb, mbAddrIncrTable[run][1], 
269              mbAddrIncrTable[run][0]);
270 }
271
272 /* insert a fake P picture */
273 static void mpeg1_skip_picture(MpegEncContext *s, int pict_num)
274 {
275     /* mpeg1 picture header */
276     put_header(s, PICTURE_START_CODE);
277     /* temporal reference */
278     put_bits(&s->pb, 10, pict_num & 0x3ff); 
279     
280     put_bits(&s->pb, 3, P_TYPE);
281     put_bits(&s->pb, 16, 0xffff); /* non constant bit rate */
282     
283     put_bits(&s->pb, 1, 1); /* integer coordinates */
284     put_bits(&s->pb, 3, 1); /* forward_f_code */
285     
286     put_bits(&s->pb, 1, 0); /* extra bit picture */
287     
288     /* only one slice */
289     put_header(s, SLICE_MIN_START_CODE);
290     put_bits(&s->pb, 5, 1); /* quantizer scale */
291     put_bits(&s->pb, 1, 0); /* slice extra information */
292     
293     encode_mb_skip_run(s, 0);
294     
295     /* empty macroblock */
296     put_bits(&s->pb, 3, 1); /* motion only */
297     
298     /* zero motion x & y */
299     put_bits(&s->pb, 1, 1); 
300     put_bits(&s->pb, 1, 1); 
301
302     /* output a number of empty slice */
303     encode_mb_skip_run(s, s->mb_width * s->mb_height - 2);
304     
305     /* empty macroblock */
306     put_bits(&s->pb, 3, 1); /* motion only */
307     
308     /* zero motion x & y */
309     put_bits(&s->pb, 1, 1); 
310     put_bits(&s->pb, 1, 1); 
311 }
312
313 static void common_init(MpegEncContext *s)
314 {
315     s->y_dc_scale_table=
316     s->c_dc_scale_table= ff_mpeg1_dc_scale_table;
317 }
318
319 #ifdef CONFIG_ENCODERS
320
321 void ff_mpeg1_encode_slice_header(MpegEncContext *s){
322     put_header(s, SLICE_MIN_START_CODE + s->mb_y);
323     put_bits(&s->pb, 5, s->qscale); /* quantizer scale */
324     put_bits(&s->pb, 1, 0); /* slice extra information */
325 }
326
327 void ff_mpeg1_clean_buffers(MpegEncContext *s){
328     s->last_dc[0] = 1 << (7 + s->intra_dc_precision);
329     s->last_dc[1] = s->last_dc[0];
330     s->last_dc[2] = s->last_dc[0];
331     memset(s->last_mv, 0, sizeof(s->last_mv));
332 }
333
334 void mpeg1_encode_picture_header(MpegEncContext *s, int picture_number)
335 {
336     mpeg1_encode_sequence_header(s);
337
338     /* mpeg1 picture header */
339     put_header(s, PICTURE_START_CODE);
340     /* temporal reference */
341
342     // RAL: s->picture_number instead of s->fake_picture_number
343     put_bits(&s->pb, 10, (s->picture_number - 
344                           s->gop_picture_number) & 0x3ff); 
345     s->fake_picture_number++;
346     
347     put_bits(&s->pb, 3, s->pict_type);
348     put_bits(&s->pb, 16, 0xffff); /* non constant bit rate */
349     
350     // RAL: Forward f_code also needed for B frames
351     if (s->pict_type == P_TYPE || s->pict_type == B_TYPE) {
352         put_bits(&s->pb, 1, 0); /* half pel coordinates */
353         put_bits(&s->pb, 3, s->f_code); /* forward_f_code */
354     }
355     
356     // RAL: Backward f_code necessary for B frames
357     if (s->pict_type == B_TYPE) {
358         put_bits(&s->pb, 1, 0); /* half pel coordinates */
359         put_bits(&s->pb, 3, s->b_code); /* backward_f_code */
360         }
361
362     put_bits(&s->pb, 1, 0); /* extra bit picture */
363     
364     s->mb_y=0;
365     ff_mpeg1_encode_slice_header(s);
366 }
367
368 void mpeg1_encode_mb(MpegEncContext *s,
369                      DCTELEM block[6][64],
370                      int motion_x, int motion_y)
371 {
372     int i, cbp;
373     const int mb_x = s->mb_x;
374     const int mb_y = s->mb_y;
375     const int first_mb= mb_x == s->resync_mb_x && mb_y == s->resync_mb_y;
376
377     /* compute cbp */
378     cbp = 0;
379     for(i=0;i<6;i++) {
380         if (s->block_last_index[i] >= 0)
381             cbp |= 1 << (5 - i);
382     }
383
384     if (cbp == 0 && !first_mb && (mb_x != s->mb_width - 1 || mb_y != s->mb_height - 1) && 
385         ((s->pict_type == P_TYPE && (motion_x | motion_y) == 0) ||
386         (s->pict_type == B_TYPE && s->mv_dir == s->last_mv_dir && (((s->mv_dir & MV_DIR_FORWARD) ? ((s->mv[0][0][0] - s->last_mv[0][0][0])|(s->mv[0][0][1] - s->last_mv[0][0][1])) : 0) |
387         ((s->mv_dir & MV_DIR_BACKWARD) ? ((s->mv[1][0][0] - s->last_mv[1][0][0])|(s->mv[1][0][1] - s->last_mv[1][0][1])) : 0)) == 0))) {
388         s->mb_skip_run++;
389         s->qscale -= s->dquant;
390         s->skip_count++;
391         s->misc_bits++;
392         s->last_bits++;
393     } else {
394         if(first_mb){
395             assert(s->mb_skip_run == 0);
396             encode_mb_skip_run(s, s->mb_x);
397         }else{
398             encode_mb_skip_run(s, s->mb_skip_run);
399         }
400         
401         if (s->pict_type == I_TYPE) {
402             if(s->dquant && cbp){
403                 put_bits(&s->pb, 2, 1); /* macroblock_type : macroblock_quant = 1 */
404                 put_bits(&s->pb, 5, s->qscale);
405             }else{
406                 put_bits(&s->pb, 1, 1); /* macroblock_type : macroblock_quant = 0 */
407                 s->qscale -= s->dquant;
408             }
409             s->misc_bits+= get_bits_diff(s);
410             s->i_count++;
411         } else if (s->mb_intra) {
412             if(s->dquant && cbp){
413                 put_bits(&s->pb, 6, 0x01);
414                 put_bits(&s->pb, 5, s->qscale);
415             }else{
416                 put_bits(&s->pb, 5, 0x03);
417                 s->qscale -= s->dquant;
418             }
419             s->misc_bits+= get_bits_diff(s);
420             s->i_count++;
421             s->last_mv[0][0][0] = 
422             s->last_mv[0][0][1] = 0;
423         } else if (s->pict_type == P_TYPE) { 
424                 if (cbp != 0) {
425                     if (motion_x == 0 && motion_y == 0) {
426                         if(s->dquant){
427                             put_bits(&s->pb, 5, 1); /* macroblock_pattern & quant */
428                             put_bits(&s->pb, 5, s->qscale);
429                         }else{
430                             put_bits(&s->pb, 2, 1); /* macroblock_pattern only */
431                         }
432                         s->misc_bits+= get_bits_diff(s);
433                         put_bits(&s->pb, mbPatTable[cbp - 1][1], mbPatTable[cbp - 1][0]);
434                     } else {
435                         if(s->dquant){
436                             put_bits(&s->pb, 5, 2); /* motion + cbp */
437                             put_bits(&s->pb, 5, s->qscale);
438                         }else{
439                             put_bits(&s->pb, 1, 1); /* motion + cbp */
440                         }
441                         s->misc_bits+= get_bits_diff(s);
442                         mpeg1_encode_motion(s, motion_x - s->last_mv[0][0][0], s->f_code);    // RAL: f_code parameter added
443                         mpeg1_encode_motion(s, motion_y - s->last_mv[0][0][1], s->f_code);    // RAL: f_code parameter added
444                         s->mv_bits+= get_bits_diff(s);
445                         put_bits(&s->pb, mbPatTable[cbp - 1][1], mbPatTable[cbp - 1][0]);
446                     }
447                 } else {
448                     put_bits(&s->pb, 3, 1); /* motion only */
449                     mpeg1_encode_motion(s, motion_x - s->last_mv[0][0][0], s->f_code);    // RAL: f_code parameter added
450                     mpeg1_encode_motion(s, motion_y - s->last_mv[0][0][1], s->f_code);    // RAL: f_code parameter added
451                     s->qscale -= s->dquant;
452                     s->mv_bits+= get_bits_diff(s);
453                 }
454                 s->f_count++;
455         } else
456             {    // RAL: All the following bloc added for B frames:
457                 if (cbp != 0)
458                     {    // With coded bloc pattern
459                     if (s->mv_dir == (MV_DIR_FORWARD | MV_DIR_BACKWARD))
460                         {    // Bi-directional motion
461                         if (s->dquant)
462                             {    // With QScale
463                             put_bits(&s->pb, 5, 2);
464                             put_bits(&s->pb, 5, s->qscale);
465                             }
466                         else    // Without QScale
467                             put_bits(&s->pb, 2, 3);
468                         s->misc_bits += get_bits_diff(s);
469                         mpeg1_encode_motion(s, s->mv[0][0][0] - s->last_mv[0][0][0], s->f_code);
470                         mpeg1_encode_motion(s, s->mv[0][0][1] - s->last_mv[0][0][1], s->f_code);
471                         mpeg1_encode_motion(s, s->mv[1][0][0] - s->last_mv[1][0][0], s->b_code);
472                         mpeg1_encode_motion(s, s->mv[1][0][1] - s->last_mv[1][0][1], s->b_code);
473                         s->b_count++;
474                         s->f_count++;
475                         s->mv_bits += get_bits_diff(s);
476                         put_bits(&s->pb, mbPatTable[cbp - 1][1], mbPatTable[cbp - 1][0]);
477                         }
478                     else if (s->mv_dir == MV_DIR_BACKWARD)
479                         {    // Backward motion
480                         if (s->dquant)
481                             {    // With QScale
482                             put_bits(&s->pb, 6, 2);
483                             put_bits(&s->pb, 5, s->qscale);
484                             }
485                         else    // Without QScale
486                             put_bits(&s->pb, 3, 3);
487                         s->misc_bits += get_bits_diff(s);
488                         mpeg1_encode_motion(s, motion_x - s->last_mv[1][0][0], s->b_code); 
489                         mpeg1_encode_motion(s, motion_y - s->last_mv[1][0][1], s->b_code); 
490                         s->b_count++;
491                         s->mv_bits += get_bits_diff(s);
492                         put_bits(&s->pb, mbPatTable[cbp - 1][1], mbPatTable[cbp - 1][0]);
493                         }
494                     else if (s->mv_dir == MV_DIR_FORWARD)
495                         {    // Forward motion
496                         if (s->dquant)
497                             {    // With QScale
498                             put_bits(&s->pb, 6, 3);
499                             put_bits(&s->pb, 5, s->qscale);
500                             }
501                         else    // Without QScale
502                             put_bits(&s->pb, 4, 3);
503                         s->misc_bits += get_bits_diff(s);
504                         mpeg1_encode_motion(s, motion_x - s->last_mv[0][0][0], s->f_code); 
505                         mpeg1_encode_motion(s, motion_y - s->last_mv[0][0][1], s->f_code); 
506                         s->f_count++;
507                         s->mv_bits += get_bits_diff(s);
508                         put_bits(&s->pb, mbPatTable[cbp - 1][1], mbPatTable[cbp - 1][0]);
509                         }
510                     }
511                 else
512                     {    // No coded bloc pattern
513                     if (s->mv_dir == (MV_DIR_FORWARD | MV_DIR_BACKWARD))
514                         {    // Bi-directional motion 
515                         put_bits(&s->pb, 2, 2); /* backward & forward motion */
516                         mpeg1_encode_motion(s, s->mv[0][0][0] - s->last_mv[0][0][0], s->f_code);
517                         mpeg1_encode_motion(s, s->mv[0][0][1] - s->last_mv[0][0][1], s->f_code);
518                         mpeg1_encode_motion(s, s->mv[1][0][0] - s->last_mv[1][0][0], s->b_code);
519                         mpeg1_encode_motion(s, s->mv[1][0][1] - s->last_mv[1][0][1], s->b_code);
520                         s->b_count++;
521                         s->f_count++;
522                         }
523                     else if (s->mv_dir == MV_DIR_BACKWARD)
524                         {    // Backward motion
525                         put_bits(&s->pb, 3, 2); /* backward motion only */
526                         mpeg1_encode_motion(s, motion_x - s->last_mv[1][0][0], s->b_code); 
527                         mpeg1_encode_motion(s, motion_y - s->last_mv[1][0][1], s->b_code); 
528                         s->b_count++;
529                         }
530                     else if (s->mv_dir == MV_DIR_FORWARD)
531                         {    // Forward motion
532                         put_bits(&s->pb, 4, 2); /* forward motion only */
533                         mpeg1_encode_motion(s, motion_x - s->last_mv[0][0][0], s->f_code); 
534                         mpeg1_encode_motion(s, motion_y - s->last_mv[0][0][1], s->f_code); 
535                         s->f_count++;
536                         }
537                     s->qscale -= s->dquant;
538                     s->mv_bits += get_bits_diff(s);
539                     }
540             // End of bloc from RAL
541             }
542         for(i=0;i<6;i++) {
543             if (cbp & (1 << (5 - i))) {
544                 mpeg1_encode_block(s, block[i], i);
545             }
546         }
547         s->mb_skip_run = 0;
548         if(s->mb_intra)
549             s->i_tex_bits+= get_bits_diff(s);
550         else
551             s->p_tex_bits+= get_bits_diff(s);
552     }
553
554     // RAL: By this:
555     if (s->mv_dir & MV_DIR_FORWARD)
556         {
557         s->last_mv[0][0][0]= s->mv[0][0][0];
558         s->last_mv[0][0][1]= s->mv[0][0][1];
559         }
560     if (s->mv_dir & MV_DIR_BACKWARD)
561         {
562         s->last_mv[1][0][0]= s->mv[1][0][0];
563         s->last_mv[1][0][1]= s->mv[1][0][1];
564         }
565 }
566
567 // RAL: Parameter added: f_or_b_code
568 static void mpeg1_encode_motion(MpegEncContext *s, int val, int f_or_b_code)
569 {
570     int code, bit_size, l, m, bits, range, sign;
571
572     if (val == 0) {
573         /* zero vector */
574         code = 0;
575         put_bits(&s->pb,
576                  mbMotionVectorTable[0][1], 
577                  mbMotionVectorTable[0][0]); 
578     } else {
579         bit_size = f_or_b_code - 1;
580         range = 1 << bit_size;
581         /* modulo encoding */
582         l = 16 * range;
583         m = 2 * l;
584         if (val < -l) {
585             val += m;
586         } else if (val >= l) {
587             val -= m;
588         }
589
590         if (val >= 0) {
591             val--;
592             code = (val >> bit_size) + 1;
593             bits = val & (range - 1);
594             sign = 0;
595         } else {
596             val = -val;
597             val--;
598             code = (val >> bit_size) + 1;
599             bits = val & (range - 1);
600             sign = 1;
601         }
602
603         assert(code > 0 && code <= 16);
604
605         put_bits(&s->pb,
606                  mbMotionVectorTable[code][1], 
607                  mbMotionVectorTable[code][0]); 
608
609         put_bits(&s->pb, 1, sign);
610         if (bit_size > 0) {
611             put_bits(&s->pb, bit_size, bits);
612         }
613     }
614 }
615
616 void ff_mpeg1_encode_init(MpegEncContext *s)
617 {
618     static int done=0;
619
620     common_init(s);
621
622     if(!done){
623         int f_code;
624         int mv;
625         int i;
626
627         done=1;
628         init_rl(&rl_mpeg1);
629
630         for(i=0; i<64; i++)
631         {
632                 mpeg1_max_level[0][i]= rl_mpeg1.max_level[0][i];
633                 mpeg1_index_run[0][i]= rl_mpeg1.index_run[0][i];
634         }
635         
636         init_uni_ac_vlc(&rl_mpeg1, uni_mpeg1_ac_vlc_bits, uni_mpeg1_ac_vlc_len);
637
638         /* build unified dc encoding tables */
639         for(i=-255; i<256; i++)
640         {
641                 int adiff, index;
642                 int bits, code;
643                 int diff=i;
644
645                 adiff = ABS(diff);
646                 if(diff<0) diff--;
647                 index = vlc_dc_table[adiff];
648
649                 bits= vlc_dc_lum_bits[index] + index;
650                 code= (vlc_dc_lum_code[index]<<index) + (diff & ((1 << index) - 1));
651                 mpeg1_lum_dc_uni[i+255]= bits + (code<<8);
652                 
653                 bits= vlc_dc_chroma_bits[index] + index;
654                 code= (vlc_dc_chroma_code[index]<<index) + (diff & ((1 << index) - 1));
655                 mpeg1_chr_dc_uni[i+255]= bits + (code<<8);
656         }
657
658         mv_penalty= av_mallocz( sizeof(uint8_t)*(MAX_FCODE+1)*(2*MAX_MV+1) );
659
660         for(f_code=1; f_code<=MAX_FCODE; f_code++){
661             for(mv=-MAX_MV; mv<=MAX_MV; mv++){
662                 int len;
663
664                 if(mv==0) len= mbMotionVectorTable[0][1];
665                 else{
666                     int val, bit_size, range, code;
667
668                     bit_size = s->f_code - 1;
669                     range = 1 << bit_size;
670
671                     val=mv;
672                     if (val < 0) 
673                         val = -val;
674                     val--;
675                     code = (val >> bit_size) + 1;
676                     if(code<17){
677                         len= mbMotionVectorTable[code][1] + 1 + bit_size;
678                     }else{
679                         len= mbMotionVectorTable[16][1] + 2 + bit_size;
680                     }
681                 }
682
683                 mv_penalty[f_code][mv+MAX_MV]= len;
684             }
685         }
686         
687
688         for(f_code=MAX_FCODE; f_code>0; f_code--){
689             for(mv=-(8<<f_code); mv<(8<<f_code); mv++){
690                 fcode_tab[mv+MAX_MV]= f_code;
691             }
692         }
693     }
694     s->me.mv_penalty= mv_penalty;
695     s->fcode_tab= fcode_tab;
696     s->min_qcoeff=-255;
697     s->max_qcoeff= 255;
698     s->intra_ac_vlc_length=
699     s->inter_ac_vlc_length= uni_mpeg1_ac_vlc_len;
700 }
701
702 static inline void encode_dc(MpegEncContext *s, int diff, int component)
703 {
704     if (component == 0) {
705         put_bits(
706             &s->pb, 
707             mpeg1_lum_dc_uni[diff+255]&0xFF,
708             mpeg1_lum_dc_uni[diff+255]>>8);
709     } else {
710         put_bits(
711             &s->pb, 
712             mpeg1_chr_dc_uni[diff+255]&0xFF,
713             mpeg1_chr_dc_uni[diff+255]>>8);
714     }
715 }
716
717 static void mpeg1_encode_block(MpegEncContext *s, 
718                                DCTELEM *block, 
719                                int n)
720 {
721     int alevel, level, last_non_zero, dc, diff, i, j, run, last_index, sign;
722     int code, component;
723 //    RLTable *rl = &rl_mpeg1;
724
725     last_index = s->block_last_index[n];
726
727     /* DC coef */
728     if (s->mb_intra) {
729         component = (n <= 3 ? 0 : n - 4 + 1);
730         dc = block[0]; /* overflow is impossible */
731         diff = dc - s->last_dc[component];
732         encode_dc(s, diff, component);
733         s->last_dc[component] = dc;
734         i = 1;
735     } else {
736         /* encode the first coefficient : needs to be done here because
737            it is handled slightly differently */
738         level = block[0];
739         if (abs(level) == 1) {
740                 code = ((uint32_t)level >> 31); /* the sign bit */
741                 put_bits(&s->pb, 2, code | 0x02);
742                 i = 1;
743         } else {
744             i = 0;
745             last_non_zero = -1;
746             goto next_coef;
747         }
748     }
749
750     /* now quantify & encode AC coefs */
751     last_non_zero = i - 1;
752
753     for(;i<=last_index;i++) {
754         j = s->intra_scantable.permutated[i];
755         level = block[j];
756     next_coef:
757 #if 0
758         if (level != 0)
759             dprintf("level[%d]=%d\n", i, level);
760 #endif            
761         /* encode using VLC */
762         if (level != 0) {
763             run = i - last_non_zero - 1;
764             
765             alevel= level;
766             MASK_ABS(sign, alevel)
767             sign&=1;
768
769 //            code = get_rl_index(rl, 0, run, alevel);
770             if (alevel <= mpeg1_max_level[0][run]){
771                 code= mpeg1_index_run[0][run] + alevel - 1;
772                 /* store the vlc & sign at once */
773                 put_bits(&s->pb, mpeg1_vlc[code][1]+1, (mpeg1_vlc[code][0]<<1) + sign);
774             } else {
775                 /* escape seems to be pretty rare <5% so i dont optimize it */
776                 put_bits(&s->pb, mpeg1_vlc[111/*rl->n*/][1], mpeg1_vlc[111/*rl->n*/][0]);
777                 /* escape: only clip in this case */
778                 put_bits(&s->pb, 6, run);
779                 if (alevel < 128) {
780                     put_bits(&s->pb, 8, level & 0xff);
781                 } else {
782                     if (level < 0) {
783                         put_bits(&s->pb, 16, 0x8001 + level + 255);
784                     } else {
785                         put_bits(&s->pb, 16, level & 0xffff);
786                     }
787                 }
788             }
789             last_non_zero = i;
790         }
791     }
792     /* end of block */
793     put_bits(&s->pb, 2, 0x2);
794 }
795 #endif //CONFIG_ENCODERS
796
797 /******************************************/
798 /* decoding */
799
800 static VLC dc_lum_vlc;
801 static VLC dc_chroma_vlc;
802 static VLC mv_vlc;
803 static VLC mbincr_vlc;
804 static VLC mb_ptype_vlc;
805 static VLC mb_btype_vlc;
806 static VLC mb_pat_vlc;
807
808 static void init_vlcs(MpegEncContext *s)
809 {
810     static int done = 0;
811
812     if (!done) {
813         done = 1;
814
815         init_vlc(&dc_lum_vlc, DC_VLC_BITS, 12, 
816                  vlc_dc_lum_bits, 1, 1,
817                  vlc_dc_lum_code, 2, 2);
818         init_vlc(&dc_chroma_vlc,  DC_VLC_BITS, 12, 
819                  vlc_dc_chroma_bits, 1, 1,
820                  vlc_dc_chroma_code, 2, 2);
821         init_vlc(&mv_vlc, MV_VLC_BITS, 17, 
822                  &mbMotionVectorTable[0][1], 2, 1,
823                  &mbMotionVectorTable[0][0], 2, 1);
824         init_vlc(&mbincr_vlc, MBINCR_VLC_BITS, 36, 
825                  &mbAddrIncrTable[0][1], 2, 1,
826                  &mbAddrIncrTable[0][0], 2, 1);
827         init_vlc(&mb_pat_vlc, MB_PAT_VLC_BITS, 63, 
828                  &mbPatTable[0][1], 2, 1,
829                  &mbPatTable[0][0], 2, 1);
830         
831         init_vlc(&mb_ptype_vlc, MB_PTYPE_VLC_BITS, 7, 
832                  &table_mb_ptype[0][1], 2, 1,
833                  &table_mb_ptype[0][0], 2, 1);
834         init_vlc(&mb_btype_vlc, MB_BTYPE_VLC_BITS, 11, 
835                  &table_mb_btype[0][1], 2, 1,
836                  &table_mb_btype[0][0], 2, 1);
837         init_rl(&rl_mpeg1);
838         init_rl(&rl_mpeg2);
839
840         init_2d_vlc_rl(&rl_mpeg1);
841         init_2d_vlc_rl(&rl_mpeg2);
842     }
843 }
844
845 static inline int get_dmv(MpegEncContext *s)
846 {
847     if(get_bits1(&s->gb)) 
848         return 1 - (get_bits1(&s->gb) << 1);
849     else
850         return 0;
851 }
852
853 static inline int get_qscale(MpegEncContext *s)
854 {
855     int qscale = get_bits(&s->gb, 5);
856     if (s->mpeg2) {
857         if (s->q_scale_type) {
858             return non_linear_qscale[qscale];
859         } else {
860             return qscale << 1;
861         }
862     }
863     return qscale;
864 }
865
866 /* motion type (for mpeg2) */
867 #define MT_FIELD 1
868 #define MT_FRAME 2
869 #define MT_16X8  2
870 #define MT_DMV   3
871
872 static int mpeg_decode_mb(MpegEncContext *s,
873                           DCTELEM block[6][64])
874 {
875     int i, j, k, cbp, val, mb_type, motion_type;
876     
877     dprintf("decode_mb: x=%d y=%d\n", s->mb_x, s->mb_y);
878
879     assert(s->mb_skiped==0);
880
881     if (s->mb_skip_run-- != 0) {
882         if(s->pict_type == I_TYPE){
883             fprintf(stderr, "skiped MB in I frame at %d %d\n", s->mb_x, s->mb_y);
884             return -1;
885         }
886     
887         /* skip mb */
888         s->mb_intra = 0;
889         for(i=0;i<6;i++)
890             s->block_last_index[i] = -1;
891         s->mv_type = MV_TYPE_16X16;
892         if (s->pict_type == P_TYPE) {
893             /* if P type, zero motion vector is implied */
894             s->mv_dir = MV_DIR_FORWARD;
895             s->mv[0][0][0] = s->mv[0][0][1] = 0;
896             s->last_mv[0][0][0] = s->last_mv[0][0][1] = 0;
897             s->last_mv[0][1][0] = s->last_mv[0][1][1] = 0;
898             s->mb_skiped = 1;
899             s->current_picture.mb_type[ s->mb_x + s->mb_y*s->mb_stride ]= MB_TYPE_SKIP | MB_TYPE_L0 | MB_TYPE_16x16;
900         } else {
901             /* if B type, reuse previous vectors and directions */
902             s->mv[0][0][0] = s->last_mv[0][0][0];
903             s->mv[0][0][1] = s->last_mv[0][0][1];
904             s->mv[1][0][0] = s->last_mv[1][0][0];
905             s->mv[1][0][1] = s->last_mv[1][0][1];
906
907             s->current_picture.mb_type[ s->mb_x + s->mb_y*s->mb_stride ]= 
908                 s->current_picture.mb_type[ s->mb_x + s->mb_y*s->mb_stride - 1] | MB_TYPE_SKIP;
909 //            assert(s->current_picture.mb_type[ s->mb_x + s->mb_y*s->mb_stride - 1]&(MB_TYPE_16x16|MB_TYPE_16x8));
910
911             if((s->mv[0][0][0]|s->mv[0][0][1]|s->mv[1][0][0]|s->mv[1][0][1])==0) 
912                 s->mb_skiped = 1;
913         }
914
915         return 0;
916     }
917
918     switch(s->pict_type) {
919     default:
920     case I_TYPE:
921         if (get_bits1(&s->gb) == 0) {
922             if (get_bits1(&s->gb) == 0)
923                 return -1;
924             mb_type = MB_TYPE_QUANT | MB_TYPE_INTRA;
925         } else {
926             mb_type = MB_TYPE_INTRA;
927         }
928         break;
929     case P_TYPE:
930         mb_type = get_vlc2(&s->gb, mb_ptype_vlc.table, MB_PTYPE_VLC_BITS, 1);
931         if (mb_type < 0){
932             fprintf(stderr, "invalid mb type in P Frame at %d %d\n", s->mb_x, s->mb_y);
933             return -1;
934         }
935         mb_type = ptype2mb_type[ mb_type ];
936         break;
937     case B_TYPE:
938         mb_type = get_vlc2(&s->gb, mb_btype_vlc.table, MB_BTYPE_VLC_BITS, 1);
939         if (mb_type < 0){
940             fprintf(stderr, "invalid mb type in B Frame at %d %d\n", s->mb_x, s->mb_y);
941             return -1;
942         }
943         mb_type = btype2mb_type[ mb_type ];
944         break;
945     }
946     dprintf("mb_type=%x\n", mb_type);
947 //    motion_type = 0; /* avoid warning */
948     if (IS_INTRA(mb_type)) {
949         /* compute dct type */
950         if (s->picture_structure == PICT_FRAME && //FIXME add a interlaced_dct coded var?
951             !s->frame_pred_frame_dct) {
952             s->interlaced_dct = get_bits1(&s->gb);
953         }
954
955         if (IS_QUANT(mb_type))
956             s->qscale = get_qscale(s);
957         
958         if (s->concealment_motion_vectors) {
959             /* just parse them */
960             if (s->picture_structure != PICT_FRAME) 
961                 skip_bits1(&s->gb); /* field select */
962             mpeg_decode_motion(s, s->mpeg_f_code[0][0], 0);
963             mpeg_decode_motion(s, s->mpeg_f_code[0][1], 0);
964             skip_bits1(&s->gb); /* marker */
965         }
966         s->mb_intra = 1;
967         memset(s->last_mv, 0, sizeof(s->last_mv)); /* reset mv prediction */
968
969         if (s->mpeg2) {
970             for(i=0;i<6;i++) {
971                 if (mpeg2_decode_block_intra(s, block[i], i) < 0)
972                     return -1;
973             }
974         } else {
975             for(i=0;i<6;i++) {
976                 if (mpeg1_decode_block_intra(s, block[i], i) < 0)
977                     return -1;
978             }
979         }
980     } else {
981         if (mb_type & MB_TYPE_ZERO_MV){
982             assert(mb_type & MB_TYPE_PAT);
983
984             /* compute dct type */
985             if (s->picture_structure == PICT_FRAME && //FIXME add a interlaced_dct coded var?
986                 !s->frame_pred_frame_dct) {
987                 s->interlaced_dct = get_bits1(&s->gb);
988             }
989
990             if (IS_QUANT(mb_type))
991                 s->qscale = get_qscale(s);
992
993             s->mv_dir = MV_DIR_FORWARD;
994             s->mv_type = MV_TYPE_16X16;
995             s->last_mv[0][0][0] = 0;
996             s->last_mv[0][0][1] = 0;
997             s->last_mv[0][1][0] = 0;
998             s->last_mv[0][1][1] = 0;
999             s->mv[0][0][0] = 0;
1000             s->mv[0][0][1] = 0;
1001         }else{
1002             assert(mb_type & MB_TYPE_L0L1);
1003 //FIXME decide if MBs in field pictures are MB_TYPE_INTERLACED
1004             /* get additionnal motion vector type */
1005             if (s->frame_pred_frame_dct) 
1006                 motion_type = MT_FRAME;
1007             else{
1008                 motion_type = get_bits(&s->gb, 2);
1009             }
1010
1011             /* compute dct type */
1012             if (s->picture_structure == PICT_FRAME && //FIXME add a interlaced_dct coded var?
1013                 !s->frame_pred_frame_dct && IS_PAT(mb_type)) {
1014                 s->interlaced_dct = get_bits1(&s->gb);
1015             }
1016
1017             if (IS_QUANT(mb_type))
1018                 s->qscale = get_qscale(s);
1019
1020             /* motion vectors */
1021             s->mv_dir = 0;
1022             for(i=0;i<2;i++) {
1023                 if (USES_LIST(mb_type, i)) {
1024                     s->mv_dir |= (MV_DIR_FORWARD >> i);
1025                     dprintf("motion_type=%d\n", motion_type);
1026                     switch(motion_type) {
1027                     case MT_FRAME: /* or MT_16X8 */
1028                         if (s->picture_structure == PICT_FRAME) {
1029                             /* MT_FRAME */
1030                             mb_type |= MB_TYPE_16x16; 
1031                             s->mv_type = MV_TYPE_16X16;
1032                             s->mv[i][0][0]= s->last_mv[i][0][0]= s->last_mv[i][1][0] = 
1033                                 mpeg_decode_motion(s, s->mpeg_f_code[i][0], s->last_mv[i][0][0]);
1034                             s->mv[i][0][1]= s->last_mv[i][0][1]= s->last_mv[i][1][1] = 
1035                                 mpeg_decode_motion(s, s->mpeg_f_code[i][1], s->last_mv[i][0][1]);
1036                             /* full_pel: only for mpeg1 */
1037                             if (s->full_pel[i]){
1038                                 s->mv[i][0][0] <<= 1;
1039                                 s->mv[i][0][1] <<= 1;
1040                             }
1041                         } else {
1042                             /* MT_16X8 */
1043                             mb_type |= MB_TYPE_16x8; 
1044                             s->mv_type = MV_TYPE_16X8;
1045                             for(j=0;j<2;j++) {
1046                                 s->field_select[i][j] = get_bits1(&s->gb);
1047                                 for(k=0;k<2;k++) {
1048                                     val = mpeg_decode_motion(s, s->mpeg_f_code[i][k],
1049                                                              s->last_mv[i][j][k]);
1050                                     s->last_mv[i][j][k] = val;
1051                                     s->mv[i][j][k] = val;
1052                                 }
1053                             }
1054                         }
1055                         break;
1056                     case MT_FIELD:
1057                         s->mv_type = MV_TYPE_FIELD;
1058                         if (s->picture_structure == PICT_FRAME) {
1059                             mb_type |= MB_TYPE_16x8 | MB_TYPE_INTERLACED; 
1060                             for(j=0;j<2;j++) {
1061                                 s->field_select[i][j] = get_bits1(&s->gb);
1062                                 val = mpeg_decode_motion(s, s->mpeg_f_code[i][0],
1063                                                          s->last_mv[i][j][0]);
1064                                 s->last_mv[i][j][0] = val;
1065                                 s->mv[i][j][0] = val;
1066                                 dprintf("fmx=%d\n", val);
1067                                 val = mpeg_decode_motion(s, s->mpeg_f_code[i][1],
1068                                                          s->last_mv[i][j][1] >> 1);
1069                                 s->last_mv[i][j][1] = val << 1;
1070                                 s->mv[i][j][1] = val;
1071                                 dprintf("fmy=%d\n", val);
1072                             }
1073                         } else {
1074                             mb_type |= MB_TYPE_16x16; 
1075                             s->field_select[i][0] = get_bits1(&s->gb);
1076                             for(k=0;k<2;k++) {
1077                                 val = mpeg_decode_motion(s, s->mpeg_f_code[i][k],
1078                                                          s->last_mv[i][0][k]);
1079                                 s->last_mv[i][0][k] = val;
1080                                 s->last_mv[i][1][k] = val;
1081                                 s->mv[i][0][k] = val;
1082                             }
1083                         }
1084                         break;
1085                     case MT_DMV:
1086                         {
1087                             int dmx, dmy, mx, my, m;
1088
1089                             mx = mpeg_decode_motion(s, s->mpeg_f_code[i][0], 
1090                                                     s->last_mv[i][0][0]);
1091                             s->last_mv[i][0][0] = mx;
1092                             s->last_mv[i][1][0] = mx;
1093                             dmx = get_dmv(s);
1094                             my = mpeg_decode_motion(s, s->mpeg_f_code[i][1], 
1095                                                     s->last_mv[i][0][1] >> 1);
1096                             dmy = get_dmv(s);
1097                             s->mv_type = MV_TYPE_DMV;
1098                             /* XXX: totally broken */
1099                             if (s->picture_structure == PICT_FRAME) {
1100                                 mb_type |= MB_TYPE_16x16 | MB_TYPE_INTERLACED; 
1101
1102                                 s->last_mv[i][0][1] = my << 1;
1103                                 s->last_mv[i][1][1] = my << 1;
1104
1105                                 m = s->top_field_first ? 1 : 3;
1106                                 /* top -> top pred */
1107                                 s->mv[i][0][0] = mx; 
1108                                 s->mv[i][0][1] = my << 1;
1109                                 s->mv[i][1][0] = ((mx * m + (mx > 0)) >> 1) + dmx;
1110                                 s->mv[i][1][1] = ((my * m + (my > 0)) >> 1) + dmy - 1;
1111                                 m = 4 - m;
1112                                 s->mv[i][2][0] = mx;
1113                                 s->mv[i][2][1] = my << 1;
1114                                 s->mv[i][3][0] = ((mx * m + (mx > 0)) >> 1) + dmx;
1115                                 s->mv[i][3][1] = ((my * m + (my > 0)) >> 1) + dmy + 1;
1116                             } else {
1117                                 mb_type |= MB_TYPE_16x16;
1118
1119                                 s->last_mv[i][0][1] = my;
1120                                 s->last_mv[i][1][1] = my;
1121                                 s->mv[i][0][0] = mx;
1122                                 s->mv[i][0][1] = my;
1123                                 s->mv[i][1][0] = ((mx + (mx > 0)) >> 1) + dmx;
1124                                 s->mv[i][1][1] = ((my + (my > 0)) >> 1) + dmy - 1 
1125                                     /* + 2 * cur_field */;
1126                             }
1127                         }
1128                         break;
1129                     }
1130                 }
1131             }
1132         }
1133         
1134         s->mb_intra = 0;
1135
1136         if (IS_PAT(mb_type)) {
1137             cbp = get_vlc2(&s->gb, mb_pat_vlc.table, MB_PAT_VLC_BITS, 1);
1138             if (cbp < 0){
1139                 fprintf(stderr, "invalid cbp at %d %d\n", s->mb_x, s->mb_y);
1140                 return -1;
1141             }
1142             cbp++;
1143
1144             if (s->mpeg2) {
1145                 for(i=0;i<6;i++) {
1146                     if (cbp & 32) {
1147                         if (mpeg2_decode_block_non_intra(s, block[i], i) < 0)
1148                             return -1;
1149                     } else {
1150                         s->block_last_index[i] = -1;
1151                     }
1152                     cbp+=cbp;
1153                 }
1154             } else {
1155                 for(i=0;i<6;i++) {
1156                     if (cbp & 32) {
1157                         if (mpeg1_decode_block_inter(s, block[i], i) < 0)
1158                             return -1;
1159                     } else {
1160                         s->block_last_index[i] = -1;
1161                     }
1162                     cbp+=cbp;
1163                 }
1164             }
1165         }else{
1166             for(i=0;i<6;i++)
1167                 s->block_last_index[i] = -1;
1168         }
1169     }
1170
1171     s->current_picture.mb_type[ s->mb_x + s->mb_y*s->mb_stride ]= mb_type;
1172
1173     return 0;
1174 }
1175
1176 /* as h263, but only 17 codes */
1177 static int mpeg_decode_motion(MpegEncContext *s, int fcode, int pred)
1178 {
1179     int code, sign, val, m, l, shift;
1180
1181     code = get_vlc2(&s->gb, mv_vlc.table, MV_VLC_BITS, 2);
1182     if (code == 0) {
1183         return pred;
1184     }
1185     if (code < 0) {
1186         return 0xffff;
1187     }
1188
1189     sign = get_bits1(&s->gb);
1190     shift = fcode - 1;
1191     val = (code - 1) << shift;
1192     if (shift > 0)
1193         val |= get_bits(&s->gb, shift);
1194     val++;
1195     if (sign)
1196         val = -val;
1197     val += pred;
1198     
1199     /* modulo decoding */
1200     l = 1 << (shift+4);
1201     m = 2 * l;
1202     if (val < -l) {
1203         val += m;
1204     } else if (val >= l) {
1205         val -= m;
1206     }
1207     return val;
1208 }
1209
1210 static inline int decode_dc(MpegEncContext *s, int component)
1211 {
1212     int code, diff;
1213
1214     if (component == 0) {
1215         code = get_vlc2(&s->gb, dc_lum_vlc.table, DC_VLC_BITS, 2);
1216     } else {
1217         code = get_vlc2(&s->gb, dc_chroma_vlc.table, DC_VLC_BITS, 2);
1218     }
1219     if (code < 0){
1220         fprintf(stderr, "invalid dc code at %d %d\n", s->mb_x, s->mb_y);
1221         return 0xffff;
1222     }
1223     if (code == 0) {
1224         diff = 0;
1225     } else {
1226         diff = get_xbits(&s->gb, code);
1227     }
1228     return diff;
1229 }
1230
1231 static inline int mpeg1_decode_block_intra(MpegEncContext *s, 
1232                                DCTELEM *block, 
1233                                int n)
1234 {
1235     int level, dc, diff, i, j, run;
1236     int component;
1237     RLTable *rl = &rl_mpeg1;
1238     uint8_t * const scantable= s->intra_scantable.permutated;
1239     const uint16_t *quant_matrix= s->intra_matrix;
1240     const int qscale= s->qscale;
1241
1242     /* DC coef */
1243     component = (n <= 3 ? 0 : n - 4 + 1);
1244     diff = decode_dc(s, component);
1245     if (diff >= 0xffff)
1246         return -1;
1247     dc = s->last_dc[component];
1248     dc += diff;
1249     s->last_dc[component] = dc;
1250     block[0] = dc<<3;
1251     dprintf("dc=%d diff=%d\n", dc, diff);
1252     i = 0;
1253     {
1254         OPEN_READER(re, &s->gb);    
1255         /* now quantify & encode AC coefs */
1256         for(;;) {
1257             UPDATE_CACHE(re, &s->gb);
1258             GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2);
1259             
1260             if(level == 127){
1261                 break;
1262             } else if(level != 0) {
1263                 i += run;
1264                 j = scantable[i];
1265                 level= (level*qscale*quant_matrix[j])>>3;
1266                 level= (level-1)|1;
1267                 level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
1268                 LAST_SKIP_BITS(re, &s->gb, 1);
1269             } else {
1270                 /* escape */
1271                 run = SHOW_UBITS(re, &s->gb, 6)+1; LAST_SKIP_BITS(re, &s->gb, 6);
1272                 UPDATE_CACHE(re, &s->gb);
1273                 level = SHOW_SBITS(re, &s->gb, 8); SKIP_BITS(re, &s->gb, 8);
1274                 if (level == -128) {
1275                     level = SHOW_UBITS(re, &s->gb, 8) - 256; LAST_SKIP_BITS(re, &s->gb, 8);
1276                 } else if (level == 0) {
1277                     level = SHOW_UBITS(re, &s->gb, 8)      ; LAST_SKIP_BITS(re, &s->gb, 8);
1278                 }
1279                 i += run;
1280                 j = scantable[i];
1281                 if(level<0){
1282                     level= -level;
1283                     level= (level*qscale*quant_matrix[j])>>3;
1284                     level= (level-1)|1;
1285                     level= -level;
1286                 }else{
1287                     level= (level*qscale*quant_matrix[j])>>3;
1288                     level= (level-1)|1;
1289                 }
1290             }
1291             if (i > 63){
1292                 fprintf(stderr, "ac-tex damaged at %d %d\n", s->mb_x, s->mb_y);
1293                 return -1;
1294             }
1295
1296             block[j] = level;
1297         }
1298         CLOSE_READER(re, &s->gb);
1299     }
1300     s->block_last_index[n] = i;
1301    return 0;
1302 }
1303
1304 static inline int mpeg1_decode_block_inter(MpegEncContext *s, 
1305                                DCTELEM *block, 
1306                                int n)
1307 {
1308     int level, i, j, run;
1309     RLTable *rl = &rl_mpeg1;
1310     uint8_t * const scantable= s->intra_scantable.permutated;
1311     const uint16_t *quant_matrix= s->inter_matrix;
1312     const int qscale= s->qscale;
1313
1314     {
1315         int v;
1316         OPEN_READER(re, &s->gb);
1317         i = -1;
1318         /* special case for the first coef. no need to add a second vlc table */
1319         UPDATE_CACHE(re, &s->gb);
1320         v= SHOW_UBITS(re, &s->gb, 2);
1321         if (v & 2) {
1322             LAST_SKIP_BITS(re, &s->gb, 2);
1323             level= (3*qscale*quant_matrix[0])>>4;
1324             level= (level-1)|1;
1325             if(v&1)
1326                 level= -level;
1327             block[0] = level;
1328             i++;
1329         }
1330
1331         /* now quantify & encode AC coefs */
1332         for(;;) {
1333             UPDATE_CACHE(re, &s->gb);
1334             GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2);
1335             
1336             if(level == 127){
1337                 break;
1338             } else if(level != 0) {
1339                 i += run;
1340                 j = scantable[i];
1341                 level= ((level*2+1)*qscale*quant_matrix[j])>>4;
1342                 level= (level-1)|1;
1343                 level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
1344                 LAST_SKIP_BITS(re, &s->gb, 1);
1345             } else {
1346                 /* escape */
1347                 run = SHOW_UBITS(re, &s->gb, 6)+1; LAST_SKIP_BITS(re, &s->gb, 6);
1348                 UPDATE_CACHE(re, &s->gb);
1349                 level = SHOW_SBITS(re, &s->gb, 8); SKIP_BITS(re, &s->gb, 8);
1350                 if (level == -128) {
1351                     level = SHOW_UBITS(re, &s->gb, 8) - 256; LAST_SKIP_BITS(re, &s->gb, 8);
1352                 } else if (level == 0) {
1353                     level = SHOW_UBITS(re, &s->gb, 8)      ; LAST_SKIP_BITS(re, &s->gb, 8);
1354                 }
1355                 i += run;
1356                 j = scantable[i];
1357                 if(level<0){
1358                     level= -level;
1359                     level= ((level*2+1)*qscale*quant_matrix[j])>>4;
1360                     level= (level-1)|1;
1361                     level= -level;
1362                 }else{
1363                     level= ((level*2+1)*qscale*quant_matrix[j])>>4;
1364                     level= (level-1)|1;
1365                 }
1366             }
1367             if (i > 63){
1368                 fprintf(stderr, "ac-tex damaged at %d %d\n", s->mb_x, s->mb_y);
1369                 return -1;
1370             }
1371
1372             block[j] = level;
1373         }
1374         CLOSE_READER(re, &s->gb);
1375     }
1376     s->block_last_index[n] = i;
1377     return 0;
1378 }
1379
1380 /* Also does unquantization here, since I will never support mpeg2
1381    encoding */
1382 static inline int mpeg2_decode_block_non_intra(MpegEncContext *s, 
1383                                DCTELEM *block, 
1384                                int n)
1385 {
1386     int level, i, j, run;
1387     RLTable *rl = &rl_mpeg1;
1388     uint8_t * const scantable= s->intra_scantable.permutated;
1389     const uint16_t *quant_matrix;
1390     const int qscale= s->qscale;
1391     int mismatch;
1392
1393     mismatch = 1;
1394
1395     {
1396         int v;
1397         OPEN_READER(re, &s->gb);
1398         i = -1;
1399         if (n < 4)
1400             quant_matrix = s->inter_matrix;
1401         else
1402             quant_matrix = s->chroma_inter_matrix;
1403
1404         /* special case for the first coef. no need to add a second vlc table */
1405         UPDATE_CACHE(re, &s->gb);
1406         v= SHOW_UBITS(re, &s->gb, 2);
1407         if (v & 2) {
1408             LAST_SKIP_BITS(re, &s->gb, 2);
1409             level= (3*qscale*quant_matrix[0])>>5;
1410             if(v&1)
1411                 level= -level;
1412             block[0] = level;
1413             mismatch ^= level;
1414             i++;
1415         }
1416
1417         /* now quantify & encode AC coefs */
1418         for(;;) {
1419             UPDATE_CACHE(re, &s->gb);
1420             GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2);
1421             
1422             if(level == 127){
1423                 break;
1424             } else if(level != 0) {
1425                 i += run;
1426                 j = scantable[i];
1427                 level= ((level*2+1)*qscale*quant_matrix[j])>>5;
1428                 level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
1429                 LAST_SKIP_BITS(re, &s->gb, 1);
1430             } else {
1431                 /* escape */
1432                 run = SHOW_UBITS(re, &s->gb, 6)+1; LAST_SKIP_BITS(re, &s->gb, 6);
1433                 UPDATE_CACHE(re, &s->gb);
1434                 level = SHOW_SBITS(re, &s->gb, 12); SKIP_BITS(re, &s->gb, 12);
1435
1436                 i += run;
1437                 j = scantable[i];
1438                 if(level<0){
1439                     level= ((-level*2+1)*qscale*quant_matrix[j])>>5;
1440                     level= -level;
1441                 }else{
1442                     level= ((level*2+1)*qscale*quant_matrix[j])>>5;
1443                 }
1444             }
1445             if (i > 63){
1446                 fprintf(stderr, "ac-tex damaged at %d %d\n", s->mb_x, s->mb_y);
1447                 return -1;
1448             }
1449             
1450             mismatch ^= level;
1451             block[j] = level;
1452         }
1453         CLOSE_READER(re, &s->gb);
1454     }
1455     block[63] ^= (mismatch & 1);
1456     
1457     s->block_last_index[n] = i;
1458     return 0;
1459 }
1460
1461 static inline int mpeg2_decode_block_intra(MpegEncContext *s, 
1462                                DCTELEM *block, 
1463                                int n)
1464 {
1465     int level, dc, diff, i, j, run;
1466     int component;
1467     RLTable *rl;
1468     uint8_t * const scantable= s->intra_scantable.permutated;
1469     const uint16_t *quant_matrix;
1470     const int qscale= s->qscale;
1471     int mismatch;
1472
1473     /* DC coef */
1474     if (n < 4){
1475         quant_matrix = s->intra_matrix;
1476         component = 0; 
1477     }else{
1478         quant_matrix = s->chroma_intra_matrix;
1479         component = n - 3;
1480     }
1481     diff = decode_dc(s, component);
1482     if (diff >= 0xffff)
1483         return -1;
1484     dc = s->last_dc[component];
1485     dc += diff;
1486     s->last_dc[component] = dc;
1487     block[0] = dc << (3 - s->intra_dc_precision);
1488     dprintf("dc=%d\n", block[0]);
1489     mismatch = block[0] ^ 1;
1490     i = 0;
1491     if (s->intra_vlc_format)
1492         rl = &rl_mpeg2;
1493     else
1494         rl = &rl_mpeg1;
1495
1496     {
1497         OPEN_READER(re, &s->gb);    
1498         /* now quantify & encode AC coefs */
1499         for(;;) {
1500             UPDATE_CACHE(re, &s->gb);
1501             GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2);
1502             
1503             if(level == 127){
1504                 break;
1505             } else if(level != 0) {
1506                 i += run;
1507                 j = scantable[i];
1508                 level= (level*qscale*quant_matrix[j])>>4;
1509                 level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
1510                 LAST_SKIP_BITS(re, &s->gb, 1);
1511             } else {
1512                 /* escape */
1513                 run = SHOW_UBITS(re, &s->gb, 6)+1; LAST_SKIP_BITS(re, &s->gb, 6);
1514                 UPDATE_CACHE(re, &s->gb);
1515                 level = SHOW_SBITS(re, &s->gb, 12); SKIP_BITS(re, &s->gb, 12);
1516                 i += run;
1517                 j = scantable[i];
1518                 if(level<0){
1519                     level= (-level*qscale*quant_matrix[j])>>4;
1520                     level= -level;
1521                 }else{
1522                     level= (level*qscale*quant_matrix[j])>>4;
1523                 }
1524             }
1525             if (i > 63){
1526                 fprintf(stderr, "ac-tex damaged at %d %d\n", s->mb_x, s->mb_y);
1527                 return -1;
1528             }
1529             
1530             mismatch^= level;
1531             block[j] = level;
1532         }
1533         CLOSE_READER(re, &s->gb);
1534     }
1535     block[63]^= mismatch&1;
1536     
1537     s->block_last_index[n] = i;
1538     return 0;
1539 }
1540
1541 typedef struct Mpeg1Context {
1542     MpegEncContext mpeg_enc_ctx;
1543     int mpeg_enc_ctx_allocated; /* true if decoding context allocated */
1544     int repeat_field; /* true if we must repeat the field */
1545 } Mpeg1Context;
1546
1547 static int mpeg_decode_init(AVCodecContext *avctx)
1548 {
1549     Mpeg1Context *s = avctx->priv_data;
1550     
1551     s->mpeg_enc_ctx.flags= avctx->flags;
1552     common_init(&s->mpeg_enc_ctx);
1553     init_vlcs(&s->mpeg_enc_ctx);
1554
1555     s->mpeg_enc_ctx_allocated = 0;
1556     s->mpeg_enc_ctx.picture_number = 0;
1557     s->repeat_field = 0;
1558     s->mpeg_enc_ctx.codec_id= avctx->codec->id;
1559     return 0;
1560 }
1561
1562 /* return the 8 bit start code value and update the search
1563    state. Return -1 if no start code found */
1564 static int find_start_code(uint8_t **pbuf_ptr, uint8_t *buf_end)
1565 {
1566     uint8_t *buf_ptr;
1567     unsigned int state=0xFFFFFFFF, v;
1568     int val;
1569
1570     buf_ptr = *pbuf_ptr;
1571     while (buf_ptr < buf_end) {
1572         v = *buf_ptr++;
1573         if (state == 0x000001) {
1574             state = ((state << 8) | v) & 0xffffff;
1575             val = state;
1576             goto found;
1577         }
1578         state = ((state << 8) | v) & 0xffffff;
1579     }
1580     val = -1;
1581  found:
1582     *pbuf_ptr = buf_ptr;
1583     return val;
1584 }
1585
1586 static int mpeg1_decode_picture(AVCodecContext *avctx, 
1587                                 uint8_t *buf, int buf_size)
1588 {
1589     Mpeg1Context *s1 = avctx->priv_data;
1590     MpegEncContext *s = &s1->mpeg_enc_ctx;
1591     int ref, f_code;
1592
1593     init_get_bits(&s->gb, buf, buf_size*8);
1594
1595     ref = get_bits(&s->gb, 10); /* temporal ref */
1596     s->pict_type = get_bits(&s->gb, 3);
1597     dprintf("pict_type=%d number=%d\n", s->pict_type, s->picture_number);
1598
1599     skip_bits(&s->gb, 16);
1600     if (s->pict_type == P_TYPE || s->pict_type == B_TYPE) {
1601         s->full_pel[0] = get_bits1(&s->gb);
1602         f_code = get_bits(&s->gb, 3);
1603         if (f_code == 0)
1604             return -1;
1605         s->mpeg_f_code[0][0] = f_code;
1606         s->mpeg_f_code[0][1] = f_code;
1607     }
1608     if (s->pict_type == B_TYPE) {
1609         s->full_pel[1] = get_bits1(&s->gb);
1610         f_code = get_bits(&s->gb, 3);
1611         if (f_code == 0)
1612             return -1;
1613         s->mpeg_f_code[1][0] = f_code;
1614         s->mpeg_f_code[1][1] = f_code;
1615     }
1616     s->current_picture.pict_type= s->pict_type;
1617     s->current_picture.key_frame= s->pict_type == I_TYPE;
1618     
1619     s->y_dc_scale = 8;
1620     s->c_dc_scale = 8;
1621     s->first_slice = 1;
1622     return 0;
1623 }
1624
1625 static void mpeg_decode_sequence_extension(MpegEncContext *s)
1626 {
1627     int horiz_size_ext, vert_size_ext;
1628     int bit_rate_ext, vbv_buf_ext;
1629     int frame_rate_ext_n, frame_rate_ext_d;
1630     float aspect;
1631
1632     skip_bits(&s->gb, 8); /* profil and level */
1633     s->progressive_sequence = get_bits1(&s->gb); /* progressive_sequence */
1634     skip_bits(&s->gb, 2); /* chroma_format */
1635     horiz_size_ext = get_bits(&s->gb, 2);
1636     vert_size_ext = get_bits(&s->gb, 2);
1637     s->width |= (horiz_size_ext << 12);
1638     s->height |= (vert_size_ext << 12);
1639     bit_rate_ext = get_bits(&s->gb, 12);  /* XXX: handle it */
1640     s->bit_rate = ((s->bit_rate / 400) | (bit_rate_ext << 12)) * 400;
1641     skip_bits1(&s->gb); /* marker */
1642     vbv_buf_ext = get_bits(&s->gb, 8);
1643     s->low_delay = get_bits1(&s->gb);
1644     frame_rate_ext_n = get_bits(&s->gb, 2);
1645     frame_rate_ext_d = get_bits(&s->gb, 5);
1646     av_reduce(
1647         &s->avctx->frame_rate, 
1648         &s->avctx->frame_rate_base, 
1649         frame_rate_tab[s->frame_rate_index] * (frame_rate_ext_n+1),
1650         MPEG1_FRAME_RATE_BASE * (frame_rate_ext_d+1),
1651         1<<30);
1652
1653     dprintf("sequence extension\n");
1654     s->mpeg2 = 1;
1655     s->avctx->sub_id = 2; /* indicates mpeg2 found */
1656
1657     aspect= mpeg2_aspect[s->aspect_ratio_info];
1658     if(aspect>0.0)      s->avctx->aspect_ratio= s->width/(aspect*s->height);
1659     else if(aspect<0.0) s->avctx->aspect_ratio= -1.0/aspect;
1660 }
1661
1662 static void mpeg_decode_quant_matrix_extension(MpegEncContext *s)
1663 {
1664     int i, v, j;
1665
1666     dprintf("matrix extension\n");
1667
1668     if (get_bits1(&s->gb)) {
1669         for(i=0;i<64;i++) {
1670             v = get_bits(&s->gb, 8);
1671             j= s->dsp.idct_permutation[ ff_zigzag_direct[i] ];
1672             s->intra_matrix[j] = v;
1673             s->chroma_intra_matrix[j] = v;
1674         }
1675     }
1676     if (get_bits1(&s->gb)) {
1677         for(i=0;i<64;i++) {
1678             v = get_bits(&s->gb, 8);
1679             j= s->dsp.idct_permutation[ ff_zigzag_direct[i] ];
1680             s->inter_matrix[j] = v;
1681             s->chroma_inter_matrix[j] = v;
1682         }
1683     }
1684     if (get_bits1(&s->gb)) {
1685         for(i=0;i<64;i++) {
1686             v = get_bits(&s->gb, 8);
1687             j= s->dsp.idct_permutation[ ff_zigzag_direct[i] ];
1688             s->chroma_intra_matrix[j] = v;
1689         }
1690     }
1691     if (get_bits1(&s->gb)) {
1692         for(i=0;i<64;i++) {
1693             v = get_bits(&s->gb, 8);
1694             j= s->dsp.idct_permutation[ ff_zigzag_direct[i] ];
1695             s->chroma_inter_matrix[j] = v;
1696         }
1697     }
1698 }
1699
1700 static void mpeg_decode_picture_coding_extension(MpegEncContext *s)
1701 {
1702     s->full_pel[0] = s->full_pel[1] = 0;
1703     s->mpeg_f_code[0][0] = get_bits(&s->gb, 4);
1704     s->mpeg_f_code[0][1] = get_bits(&s->gb, 4);
1705     s->mpeg_f_code[1][0] = get_bits(&s->gb, 4);
1706     s->mpeg_f_code[1][1] = get_bits(&s->gb, 4);
1707     s->intra_dc_precision = get_bits(&s->gb, 2);
1708     s->picture_structure = get_bits(&s->gb, 2);
1709     s->top_field_first = get_bits1(&s->gb);
1710     s->frame_pred_frame_dct = get_bits1(&s->gb);
1711     s->concealment_motion_vectors = get_bits1(&s->gb);
1712     s->q_scale_type = get_bits1(&s->gb);
1713     s->intra_vlc_format = get_bits1(&s->gb);
1714     s->alternate_scan = get_bits1(&s->gb);
1715     s->repeat_first_field = get_bits1(&s->gb);
1716     s->chroma_420_type = get_bits1(&s->gb);
1717     s->progressive_frame = get_bits1(&s->gb);
1718     
1719     if(s->picture_structure == PICT_FRAME)
1720         s->first_field=0;
1721     else{
1722         s->first_field ^= 1;
1723         memset(s->mbskip_table, 0, s->mb_stride*s->mb_height);
1724     }
1725     
1726     if(s->alternate_scan){
1727         ff_init_scantable(s, &s->inter_scantable  , ff_alternate_vertical_scan);
1728         ff_init_scantable(s, &s->intra_scantable  , ff_alternate_vertical_scan);
1729         ff_init_scantable(s, &s->intra_h_scantable, ff_alternate_vertical_scan);
1730         ff_init_scantable(s, &s->intra_v_scantable, ff_alternate_vertical_scan);
1731     }else{
1732         ff_init_scantable(s, &s->inter_scantable  , ff_zigzag_direct);
1733         ff_init_scantable(s, &s->intra_scantable  , ff_zigzag_direct);
1734         ff_init_scantable(s, &s->intra_h_scantable, ff_alternate_horizontal_scan);
1735         ff_init_scantable(s, &s->intra_v_scantable, ff_alternate_vertical_scan);
1736     }
1737     
1738     /* composite display not parsed */
1739     dprintf("intra_dc_precision=%d\n", s->intra_dc_precision);
1740     dprintf("picture_structure=%d\n", s->picture_structure);
1741     dprintf("top field first=%d\n", s->top_field_first);
1742     dprintf("repeat first field=%d\n", s->repeat_first_field);
1743     dprintf("conceal=%d\n", s->concealment_motion_vectors);
1744     dprintf("intra_vlc_format=%d\n", s->intra_vlc_format);
1745     dprintf("alternate_scan=%d\n", s->alternate_scan);
1746     dprintf("frame_pred_frame_dct=%d\n", s->frame_pred_frame_dct);
1747     dprintf("progressive_frame=%d\n", s->progressive_frame);
1748 }
1749
1750 static void mpeg_decode_extension(AVCodecContext *avctx, 
1751                                   uint8_t *buf, int buf_size)
1752 {
1753     Mpeg1Context *s1 = avctx->priv_data;
1754     MpegEncContext *s = &s1->mpeg_enc_ctx;
1755     int ext_type;
1756
1757     init_get_bits(&s->gb, buf, buf_size*8);
1758     
1759     ext_type = get_bits(&s->gb, 4);
1760     switch(ext_type) {
1761     case 0x1:
1762         /* sequence ext */
1763         mpeg_decode_sequence_extension(s);
1764         break;
1765     case 0x3:
1766         /* quant matrix extension */
1767         mpeg_decode_quant_matrix_extension(s);
1768         break;
1769     case 0x8:
1770         /* picture extension */
1771         mpeg_decode_picture_coding_extension(s);
1772         break;
1773     }
1774 }
1775
1776 #define DECODE_SLICE_MB_ADDR_ERROR -3 //we faild decoding the mb_x/y info
1777 #define DECODE_SLICE_FATAL_ERROR -2
1778 #define DECODE_SLICE_ERROR -1
1779 #define DECODE_SLICE_OK 0
1780 #define DECODE_SLICE_EOP 1
1781
1782 /**
1783  * decodes a slice.
1784  * @return DECODE_SLICE_FATAL_ERROR if a non recoverable error occured<br>
1785  *         DECODE_SLICE_ERROR if the slice is damaged<br>
1786  *         DECODE_SLICE_OK if this slice is ok<br>
1787  *         DECODE_SLICE_EOP if the end of the picture is reached
1788  */
1789 static int mpeg_decode_slice(AVCodecContext *avctx, 
1790                               AVFrame *pict,
1791                               int start_code,
1792                               uint8_t **buf, int buf_size)
1793 {
1794     Mpeg1Context *s1 = avctx->priv_data;
1795     MpegEncContext *s = &s1->mpeg_enc_ctx;
1796     int ret;
1797     const int field_pic= s->picture_structure != PICT_FRAME;
1798
1799     start_code = (start_code - 1) & 0xff;
1800     if (start_code >= s->mb_height){
1801         fprintf(stderr, "slice below image (%d >= %d)\n", start_code, s->mb_height);
1802         return DECODE_SLICE_MB_ADDR_ERROR;
1803     }
1804     
1805     ff_mpeg1_clean_buffers(s);
1806     s->interlaced_dct = 0;
1807         
1808     /* start frame decoding */
1809     if (s->first_slice) {
1810       if(s->first_field || s->picture_structure==PICT_FRAME){
1811         if(MPV_frame_start(s, avctx) < 0)
1812             return DECODE_SLICE_FATAL_ERROR;
1813
1814         ff_er_frame_start(s);
1815
1816         /* first check if we must repeat the frame */
1817         s->current_picture.repeat_pict = 0;
1818
1819         if (s->repeat_first_field) {
1820             if (s->progressive_sequence) {
1821                 if (s->top_field_first)
1822                     s->current_picture.repeat_pict = 4;
1823                 else
1824                     s->current_picture.repeat_pict = 2;
1825             } else if (s->progressive_frame) {
1826                 s->current_picture.repeat_pict = 1;
1827             }
1828         }         
1829 //        printf("%d \n", s->current_picture.repeat_pict);
1830
1831         if(s->avctx->debug&FF_DEBUG_PICT_INFO){
1832              printf("qp:%d fc:%2d%2d%2d%2d %s %s %s %s dc:%d pstruct:%d fdct:%d cmv:%d qtype:%d ivlc:%d rff:%d %s\n", 
1833                  s->qscale, s->mpeg_f_code[0][0],s->mpeg_f_code[0][1],s->mpeg_f_code[1][0],s->mpeg_f_code[1][1],
1834                  s->pict_type == I_TYPE ? "I" : (s->pict_type == P_TYPE ? "P" : (s->pict_type == B_TYPE ? "B" : "S")), 
1835                  s->progressive_sequence ? "pro" :"", s->alternate_scan ? "alt" :"", s->top_field_first ? "top" :"", 
1836                  s->intra_dc_precision, s->picture_structure, s->frame_pred_frame_dct, s->concealment_motion_vectors,
1837                  s->q_scale_type, s->intra_vlc_format, s->repeat_first_field, s->chroma_420_type ? "420" :"");
1838         }
1839       }else{ //second field
1840             int i;
1841             
1842             if(!s->current_picture_ptr){
1843                 fprintf(stderr, "first field missing\n");
1844                 return -1;
1845             }
1846             
1847             for(i=0; i<4; i++){
1848                 s->current_picture.data[i] = s->current_picture_ptr->data[i];
1849                 if(s->picture_structure == PICT_BOTTOM_FIELD){
1850                     s->current_picture.data[i] += s->current_picture_ptr->linesize[i];
1851                 } 
1852             }
1853       }
1854     }
1855     s->first_slice = 0;
1856
1857     init_get_bits(&s->gb, *buf, buf_size*8);
1858
1859     s->qscale = get_qscale(s);
1860     if(s->qscale == 0){
1861         fprintf(stderr, "qscale == 0\n");
1862         return DECODE_SLICE_MB_ADDR_ERROR;
1863     }
1864     
1865     /* extra slice info */
1866     while (get_bits1(&s->gb) != 0) {
1867         skip_bits(&s->gb, 8);
1868     }
1869     
1870     s->mb_x=0;
1871
1872     for(;;) {
1873         int code = get_vlc2(&s->gb, mbincr_vlc.table, MBINCR_VLC_BITS, 2);
1874         if (code < 0){
1875             fprintf(stderr, "first mb_incr damaged\n");
1876             return DECODE_SLICE_MB_ADDR_ERROR;
1877         }
1878         if (code >= 33) {
1879             if (code == 33) {
1880                 s->mb_x += 33;
1881             }
1882             /* otherwise, stuffing, nothing to do */
1883         } else {
1884             s->mb_x += code;
1885             break;
1886         }
1887     }
1888     
1889     s->resync_mb_x= s->mb_x;
1890     s->resync_mb_y= s->mb_y = start_code;
1891     s->mb_skip_run= 0;
1892
1893     for(;;) {
1894         s->dsp.clear_blocks(s->block[0]);
1895
1896         ret = mpeg_decode_mb(s, s->block);
1897
1898         dprintf("ret=%d\n", ret);
1899         if (ret < 0)
1900             return -1;
1901             
1902         if(s->motion_val && s->pict_type != B_TYPE){ //note motion_val is normally NULL unless we want to extract the MVs
1903             const int wrap = s->block_wrap[0];
1904             const int xy = s->mb_x*2 + 1 + (s->mb_y*2 +1)*wrap;
1905             int motion_x, motion_y;
1906
1907             if (s->mb_intra || s->mv_type == MV_TYPE_16X16) {
1908                 motion_x = s->mv[0][0][0];
1909                 motion_y = s->mv[0][0][1];
1910             } else /*if (s->mv_type == MV_TYPE_FIELD)*/ {
1911                 motion_x = s->mv[0][0][0] + s->mv[0][1][0];
1912                 motion_y = s->mv[0][0][1] + s->mv[0][1][1];
1913                 motion_x = (motion_x>>1) | (motion_x&1);
1914             }
1915             s->motion_val[xy][0] = motion_x;
1916             s->motion_val[xy][1] = motion_y;
1917             s->motion_val[xy + 1][0] = motion_x;
1918             s->motion_val[xy + 1][1] = motion_y;
1919             s->motion_val[xy + wrap][0] = motion_x;
1920             s->motion_val[xy + wrap][1] = motion_y;
1921             s->motion_val[xy + 1 + wrap][0] = motion_x;
1922             s->motion_val[xy + 1 + wrap][1] = motion_y;
1923         }
1924         
1925         MPV_decode_mb(s, s->block);
1926
1927         if (++s->mb_x >= s->mb_width) {
1928             if(s->picture_structure==PICT_FRAME){
1929                 ff_draw_horiz_band(s, 16*s->mb_y, 16);
1930             }else{
1931                 if(!s->first_field){
1932                     ff_draw_horiz_band(s, 32*s->mb_y, 32);
1933                 }
1934             }
1935
1936             s->mb_x = 0;
1937             s->mb_y++;
1938         }
1939
1940         /* skip mb handling */
1941         if (s->mb_skip_run == -1) {
1942             /* read again increment */
1943             s->mb_skip_run = 0;
1944             for(;;) {
1945                 int code = get_vlc2(&s->gb, mbincr_vlc.table, MBINCR_VLC_BITS, 2);
1946                 if (code < 0){
1947                     fprintf(stderr, "mb incr damaged\n");
1948                     return -1;
1949                 }
1950                 if (code >= 33) {
1951                     if (code == 33) {
1952                         s->mb_skip_run += 33;
1953                     }else if(code == 35){
1954                         if(s->mb_skip_run != 0 || show_bits(&s->gb, 15) != 0){
1955                             fprintf(stderr, "slice missmatch\n");
1956                             return -1;
1957                         }
1958                         goto eos; /* end of slice */
1959                     }
1960                     /* otherwise, stuffing, nothing to do */
1961                 } else {
1962                     s->mb_skip_run += code;
1963                     break;
1964                 }
1965             }
1966         }
1967         if(s->mb_y<<field_pic >= s->mb_height){
1968             fprintf(stderr, "slice too long\n");
1969             return DECODE_SLICE_ERROR;
1970         }
1971     }
1972 eos: //end of slice
1973 //printf("y %d %d %d %d\n", s->resync_mb_x, s->resync_mb_y, s->mb_x, s->mb_y);
1974     ff_er_add_slice(s, s->resync_mb_x, s->resync_mb_y, s->mb_x-1, s->mb_y, AC_END|DC_END|MV_END);
1975
1976     emms_c();
1977     
1978     *buf += get_bits_count(&s->gb)/8 - 1;
1979     
1980 //intf("%d %d %d %d\n", s->mb_y, s->mb_height, s->pict_type, s->picture_number);
1981     /* end of slice reached */
1982     if (s->mb_y<<field_pic == s->mb_height && !s->first_field) {
1983         /* end of image */
1984
1985         if(s->mpeg2){
1986             s->current_picture_ptr->qscale_type= FF_QSCALE_TYPE_MPEG2;
1987         }else
1988             s->current_picture_ptr->qscale_type= FF_QSCALE_TYPE_MPEG1;
1989
1990         ff_er_frame_end(s);
1991
1992         MPV_frame_end(s);
1993
1994         if (s->pict_type == B_TYPE || s->low_delay) {
1995             *pict= *(AVFrame*)&s->current_picture;
1996             ff_print_debug_info(s, s->current_picture_ptr);
1997         } else {
1998             s->picture_number++;
1999             /* latency of 1 frame for I and P frames */
2000             /* XXX: use another variable than picture_number */
2001             if (s->last_picture_ptr != NULL) {
2002                 *pict= *(AVFrame*)&s->last_picture;
2003                  ff_print_debug_info(s, s->last_picture_ptr);
2004             }
2005         }
2006         return DECODE_SLICE_EOP;
2007     } else {
2008         return DECODE_SLICE_OK;
2009     }
2010 }
2011
2012 static int mpeg1_decode_sequence(AVCodecContext *avctx, 
2013                                  uint8_t *buf, int buf_size)
2014 {
2015     Mpeg1Context *s1 = avctx->priv_data;
2016     MpegEncContext *s = &s1->mpeg_enc_ctx;
2017     int width, height, i, v, j;
2018     float aspect;
2019
2020     init_get_bits(&s->gb, buf, buf_size*8);
2021
2022     width = get_bits(&s->gb, 12);
2023     height = get_bits(&s->gb, 12);
2024     s->aspect_ratio_info= get_bits(&s->gb, 4);
2025     if(!s->mpeg2){
2026         aspect= mpeg1_aspect[s->aspect_ratio_info];
2027         if(aspect!=0.0) avctx->aspect_ratio= width/(aspect*height);
2028     }
2029
2030     s->frame_rate_index = get_bits(&s->gb, 4);
2031     if (s->frame_rate_index == 0)
2032         return -1;
2033     s->bit_rate = get_bits(&s->gb, 18) * 400;
2034     if (get_bits1(&s->gb) == 0) /* marker */
2035         return -1;
2036     if (width <= 0 || height <= 0 ||
2037         (width % 2) != 0 || (height % 2) != 0)
2038         return -1;
2039     if (width != s->width ||
2040         height != s->height) {
2041         /* start new mpeg1 context decoding */
2042         s->out_format = FMT_MPEG1;
2043         if (s1->mpeg_enc_ctx_allocated) {
2044             MPV_common_end(s);
2045         }
2046         s->width = width;
2047         s->height = height;
2048         avctx->has_b_frames= 1;
2049         s->avctx = avctx;
2050         avctx->width = width;
2051         avctx->height = height;
2052         av_reduce(
2053             &avctx->frame_rate, 
2054             &avctx->frame_rate_base,
2055             frame_rate_tab[s->frame_rate_index],
2056             MPEG1_FRAME_RATE_BASE, //FIXME store in allready reduced form 
2057             1<<30
2058             );
2059         avctx->bit_rate = s->bit_rate;
2060         
2061         if (MPV_common_init(s) < 0)
2062             return -1;
2063         s1->mpeg_enc_ctx_allocated = 1;
2064     }
2065
2066     skip_bits(&s->gb, 10); /* vbv_buffer_size */
2067     skip_bits(&s->gb, 1);
2068
2069     /* get matrix */
2070     if (get_bits1(&s->gb)) {
2071         for(i=0;i<64;i++) {
2072             v = get_bits(&s->gb, 8);
2073             j = s->intra_scantable.permutated[i];
2074             s->intra_matrix[j] = v;
2075             s->chroma_intra_matrix[j] = v;
2076         }
2077 #ifdef DEBUG
2078         dprintf("intra matrix present\n");
2079         for(i=0;i<64;i++)
2080             dprintf(" %d", s->intra_matrix[s->intra_scantable.permutated[i]]);
2081         printf("\n");
2082 #endif
2083     } else {
2084         for(i=0;i<64;i++) {
2085             int j= s->dsp.idct_permutation[i];
2086             v = ff_mpeg1_default_intra_matrix[i];
2087             s->intra_matrix[j] = v;
2088             s->chroma_intra_matrix[j] = v;
2089         }
2090     }
2091     if (get_bits1(&s->gb)) {
2092         for(i=0;i<64;i++) {
2093             v = get_bits(&s->gb, 8);
2094             j = s->intra_scantable.permutated[i];
2095             s->inter_matrix[j] = v;
2096             s->chroma_inter_matrix[j] = v;
2097         }
2098 #ifdef DEBUG
2099         dprintf("non intra matrix present\n");
2100         for(i=0;i<64;i++)
2101             dprintf(" %d", s->inter_matrix[s->intra_scantable.permutated[i]]);
2102         printf("\n");
2103 #endif
2104     } else {
2105         for(i=0;i<64;i++) {
2106             int j= s->dsp.idct_permutation[i];
2107             v = ff_mpeg1_default_non_intra_matrix[i];
2108             s->inter_matrix[j] = v;
2109             s->chroma_inter_matrix[j] = v;
2110         }
2111     }
2112
2113     /* we set mpeg2 parameters so that it emulates mpeg1 */
2114     s->progressive_sequence = 1;
2115     s->progressive_frame = 1;
2116     s->picture_structure = PICT_FRAME;
2117     s->frame_pred_frame_dct = 1;
2118     s->mpeg2 = 0;
2119     avctx->sub_id = 1; /* indicates mpeg1 */
2120     return 0;
2121 }
2122
2123 static void mpeg_decode_user_data(AVCodecContext *avctx, 
2124                                   const uint8_t *buf, int buf_size)
2125 {
2126     const uint8_t *p;
2127     int len, flags;
2128     p = buf;
2129     len = buf_size;
2130
2131     /* we parse the DTG active format information */
2132     if (len >= 5 &&
2133         p[0] == 'D' && p[1] == 'T' && p[2] == 'G' && p[3] == '1') {
2134         flags = p[4];
2135         p += 5;
2136         len -= 5;
2137         if (flags & 0x80) {
2138             /* skip event id */
2139             if (len < 2)
2140                 return;
2141             p += 2;
2142             len -= 2;
2143         }
2144         if (flags & 0x40) {
2145             if (len < 1)
2146                 return;
2147             avctx->dtg_active_format = p[0] & 0x0f;
2148         }
2149     }
2150 }
2151
2152 /**
2153  * finds the end of the current frame in the bitstream.
2154  * @return the position of the first byte of the next frame, or -1
2155  */
2156 static int mpeg1_find_frame_end(MpegEncContext *s, uint8_t *buf, int buf_size){
2157     ParseContext *pc= &s->parse_context;
2158     int i;
2159     uint32_t state;
2160     
2161     state= pc->state;
2162     
2163     i=0;
2164     if(!pc->frame_start_found){
2165         for(i=0; i<buf_size; i++){
2166             state= (state<<8) | buf[i];
2167             if(state >= SLICE_MIN_START_CODE && state <= SLICE_MAX_START_CODE){
2168                 i++;
2169                 pc->frame_start_found=1;
2170                 break;
2171             }
2172         }
2173     }
2174     
2175     if(pc->frame_start_found){
2176         for(; i<buf_size; i++){
2177             state= (state<<8) | buf[i];
2178             if((state&0xFFFFFF00) == 0x100){
2179                 if(state < SLICE_MIN_START_CODE || state > SLICE_MAX_START_CODE){
2180                     pc->frame_start_found=0;
2181                     pc->state=-1; 
2182                     return i-3;
2183                 }
2184             }
2185         }
2186     }        
2187     pc->state= state;
2188     return END_NOT_FOUND;
2189 }
2190
2191 /* handle buffering and image synchronisation */
2192 static int mpeg_decode_frame(AVCodecContext *avctx, 
2193                              void *data, int *data_size,
2194                              uint8_t *buf, int buf_size)
2195 {
2196     Mpeg1Context *s = avctx->priv_data;
2197     uint8_t *buf_end, *buf_ptr;
2198     int ret, start_code, input_size;
2199     AVFrame *picture = data;
2200     MpegEncContext *s2 = &s->mpeg_enc_ctx;
2201     dprintf("fill_buffer\n");
2202
2203     *data_size = 0;
2204
2205     /* special case for last picture */
2206     if (buf_size == 0) {
2207         if (s2->picture_number > 0) {
2208             *picture= *(AVFrame*)&s2->next_picture;
2209
2210             *data_size = sizeof(AVFrame);
2211         }
2212         return 0;
2213     }
2214
2215     if(s2->flags&CODEC_FLAG_TRUNCATED){
2216         int next= mpeg1_find_frame_end(s2, buf, buf_size);
2217         
2218         if( ff_combine_frame(s2, next, &buf, &buf_size) < 0 )
2219             return buf_size;
2220     }    
2221     
2222     buf_ptr = buf;
2223     buf_end = buf + buf_size;
2224
2225 #if 0    
2226     if (s->repeat_field % 2 == 1) { 
2227         s->repeat_field++;
2228         //fprintf(stderr,"\nRepeating last frame: %d -> %d! pict: %d %d", avctx->frame_number-1, avctx->frame_number,
2229         //        s2->picture_number, s->repeat_field);
2230         if (avctx->flags & CODEC_FLAG_REPEAT_FIELD) {
2231             *data_size = sizeof(AVPicture);
2232             goto the_end;
2233         }
2234     }
2235 #endif
2236     for(;;) {
2237         /* find start next code */
2238         start_code = find_start_code(&buf_ptr, buf_end);
2239         if (start_code < 0){
2240 //            printf("missing end of picture\n");
2241             return FFMAX(0, buf_ptr - buf - s2->parse_context.last_index);
2242         }
2243
2244                 /* prepare data for next start code */
2245                 input_size = buf_end - buf_ptr;
2246                 switch(start_code) {
2247                 case SEQ_START_CODE:
2248                     mpeg1_decode_sequence(avctx, buf_ptr, 
2249                                           input_size);
2250                     break;
2251                             
2252                 case PICTURE_START_CODE:
2253                     /* we have a complete image : we try to decompress it */
2254                     mpeg1_decode_picture(avctx, 
2255                                          buf_ptr, input_size);
2256                     break;
2257                 case EXT_START_CODE:
2258                     mpeg_decode_extension(avctx,
2259                                           buf_ptr, input_size);
2260                     break;
2261                 case USER_START_CODE:
2262                     mpeg_decode_user_data(avctx, 
2263                                           buf_ptr, input_size);
2264                     break;
2265                 default:
2266                     if (start_code >= SLICE_MIN_START_CODE &&
2267                         start_code <= SLICE_MAX_START_CODE) {
2268                         
2269                         /* skip b frames if we dont have reference frames */
2270                         if(s2->last_picture_ptr==NULL && s2->pict_type==B_TYPE) break;
2271                         /* skip b frames if we are in a hurry */
2272                         if(avctx->hurry_up && s2->pict_type==B_TYPE) break;
2273                         /* skip everything if we are in a hurry>=5 */
2274                         if(avctx->hurry_up>=5) break;
2275                         
2276                         if (!s->mpeg_enc_ctx_allocated) break;
2277
2278                         ret = mpeg_decode_slice(avctx, picture,
2279                                                 start_code, &buf_ptr, input_size);
2280
2281                         if (ret == DECODE_SLICE_EOP) {
2282                             if(s2->last_picture_ptr) //FIXME merge with the stuff in mpeg_decode_slice
2283                                 *data_size = sizeof(AVPicture);
2284                             return FFMAX(0, buf_ptr - buf - s2->parse_context.last_index);
2285                         }else if(ret < 0){
2286                             if(ret == DECODE_SLICE_ERROR)
2287                                 ff_er_add_slice(s2, s2->resync_mb_x, s2->resync_mb_y, s2->mb_x, s2->mb_y, AC_ERROR|DC_ERROR|MV_ERROR);
2288                                 
2289                             fprintf(stderr,"Error while decoding slice\n");
2290                             if(ret==DECODE_SLICE_FATAL_ERROR) return -1;
2291                         }
2292                     }
2293                     break;
2294                 }
2295     }
2296 }
2297
2298 static int mpeg_decode_end(AVCodecContext *avctx)
2299 {
2300     Mpeg1Context *s = avctx->priv_data;
2301
2302     if (s->mpeg_enc_ctx_allocated)
2303         MPV_common_end(&s->mpeg_enc_ctx);
2304     return 0;
2305 }
2306
2307 AVCodec mpeg_decoder = {
2308     "mpegvideo",
2309     CODEC_TYPE_VIDEO,
2310     CODEC_ID_MPEG1VIDEO,
2311     sizeof(Mpeg1Context),
2312     mpeg_decode_init,
2313     NULL,
2314     mpeg_decode_end,
2315     mpeg_decode_frame,
2316     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1 | CODEC_CAP_TRUNCATED,
2317 };