Merge remote-tracking branch 'qatar/master'
[ffmpeg.git] / libavcodec / h264_parser.c
1 /*
2  * H.26L/H.264/AVC/JVT/14496-10/... parser
3  * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21
22 /**
23  * @file
24  * H.264 / AVC / MPEG4 part10 parser.
25  * @author Michael Niedermayer <michaelni@gmx.at>
26  */
27
28 #define UNCHECKED_BITSTREAM_READER 1
29
30 #include "parser.h"
31 #include "h264data.h"
32 #include "golomb.h"
33
34 #include <assert.h>
35
36
37 static int ff_h264_find_frame_end(H264Context *h, const uint8_t *buf, int buf_size)
38 {
39     int i, j;
40     uint32_t state;
41     ParseContext *pc = &(h->s.parse_context);
42     int next_avc= h->is_avc ? 0 : buf_size;
43
44 //printf("first %02X%02X%02X%02X\n", buf[0], buf[1],buf[2],buf[3]);
45 //    mb_addr= pc->mb_addr - 1;
46     state= pc->state;
47     if(state>13)
48         state= 7;
49
50     if(h->is_avc && !h->nal_length_size)
51         av_log(h->s.avctx, AV_LOG_ERROR, "AVC-parser: nal length size invalid\n");
52
53     for(i=0; i<buf_size; i++){
54         if(i >= next_avc) {
55             int nalsize = 0;
56             i = next_avc;
57             for(j = 0; j < h->nal_length_size; j++)
58                 nalsize = (nalsize << 8) | buf[i++];
59             if(nalsize <= 0 || nalsize > buf_size - i){
60                 av_log(h->s.avctx, AV_LOG_ERROR, "AVC-parser: nal size %d remaining %d\n", nalsize, buf_size - i);
61                 return buf_size;
62             }
63             next_avc= i + nalsize;
64             state= 5;
65         }
66
67         if(state==7){
68 #if HAVE_FAST_UNALIGNED
69         /* we check i<buf_size instead of i+3/7 because its simpler
70          * and there should be FF_INPUT_BUFFER_PADDING_SIZE bytes at the end
71          */
72 #    if HAVE_FAST_64BIT
73             while(i<next_avc && !((~*(const uint64_t*)(buf+i) & (*(const uint64_t*)(buf+i) - 0x0101010101010101ULL)) & 0x8080808080808080ULL))
74                 i+=8;
75 #    else
76             while(i<next_avc && !((~*(const uint32_t*)(buf+i) & (*(const uint32_t*)(buf+i) - 0x01010101U)) & 0x80808080U))
77                 i+=4;
78 #    endif
79 #endif
80             for(; i<next_avc; i++){
81                 if(!buf[i]){
82                     state=2;
83                     break;
84                 }
85             }
86         }else if(state<=2){
87             if(buf[i]==1)   state^= 5; //2->7, 1->4, 0->5
88             else if(buf[i]) state = 7;
89             else            state>>=1; //2->1, 1->0, 0->0
90         }else if(state<=5){
91             int v= buf[i] & 0x1F;
92             if(v==6 || v==7 || v==8 || v==9){
93                 if(pc->frame_start_found){
94                     i++;
95                     goto found;
96                 }
97             }else if(v==1 || v==2 || v==5){
98                 state+=8;
99                 continue;
100             }
101             state= 7;
102         }else{
103             h->parse_history[h->parse_history_count++]= buf[i];
104             if(h->parse_history_count>3){
105                 unsigned int mb, last_mb= h->parse_last_mb;
106                 GetBitContext gb;
107
108                 init_get_bits(&gb, h->parse_history, 8*h->parse_history_count);
109                 h->parse_history_count=0;
110                 mb= get_ue_golomb_long(&gb);
111                 last_mb= h->parse_last_mb;
112                 h->parse_last_mb= mb;
113                 if(pc->frame_start_found){
114                     if(mb <= last_mb)
115                         goto found;
116                 }else
117                     pc->frame_start_found = 1;
118                 state= 7;
119             }
120         }
121     }
122     pc->state= state;
123     if(h->is_avc)
124         return next_avc;
125     return END_NOT_FOUND;
126
127 found:
128     pc->state=7;
129     pc->frame_start_found= 0;
130     if(h->is_avc)
131         return next_avc;
132     return i-(state&5) - 3*(state>7);
133 }
134
135 /**
136  * Parse NAL units of found picture and decode some basic information.
137  *
138  * @param s parser context.
139  * @param avctx codec context.
140  * @param buf buffer with field/frame data.
141  * @param buf_size size of the buffer.
142  */
143 static inline int parse_nal_units(AVCodecParserContext *s,
144                                   AVCodecContext *avctx,
145                                   const uint8_t *buf, int buf_size)
146 {
147     H264Context *h = s->priv_data;
148     const uint8_t *buf_end = buf + buf_size;
149     unsigned int pps_id;
150     unsigned int slice_type;
151     int state = -1;
152     const uint8_t *ptr;
153     int q264 = buf_size >=4 && !memcmp("Q264", buf, 4);
154
155     /* set some sane default values */
156     s->pict_type = AV_PICTURE_TYPE_I;
157     s->key_frame = 0;
158
159     h->s.avctx= avctx;
160     h->sei_recovery_frame_cnt = -1;
161     h->sei_dpb_output_delay         =  0;
162     h->sei_cpb_removal_delay        = -1;
163     h->sei_buffering_period_present =  0;
164
165     if (!buf_size)
166         return 0;
167
168     for(;;) {
169         int src_length, dst_length, consumed;
170         buf = avpriv_mpv_find_start_code(buf, buf_end, &state);
171         if(buf >= buf_end)
172             break;
173         --buf;
174         src_length = buf_end - buf;
175         switch (state & 0x1f) {
176         case NAL_SLICE:
177         case NAL_IDR_SLICE:
178             // Do not walk the whole buffer just to decode slice header
179             if (src_length > 20)
180                 src_length = 20;
181             break;
182         }
183         ptr= ff_h264_decode_nal(h, buf, &dst_length, &consumed, src_length);
184         if (ptr==NULL || dst_length < 0)
185             break;
186
187         init_get_bits(&h->s.gb, ptr, 8*dst_length);
188         switch(h->nal_unit_type) {
189         case NAL_SPS:
190             ff_h264_decode_seq_parameter_set(h);
191             break;
192         case NAL_PPS:
193             ff_h264_decode_picture_parameter_set(h, h->s.gb.size_in_bits);
194             break;
195         case NAL_SEI:
196             ff_h264_decode_sei(h);
197             break;
198         case NAL_IDR_SLICE:
199             s->key_frame = 1;
200             /* fall through */
201         case NAL_SLICE:
202             get_ue_golomb_long(&h->s.gb);  // skip first_mb_in_slice
203             slice_type = get_ue_golomb_31(&h->s.gb);
204             s->pict_type = golomb_to_pict_type[slice_type % 5];
205             if (h->sei_recovery_frame_cnt >= 0) {
206                 /* key frame, since recovery_frame_cnt is set */
207                 s->key_frame = 1;
208             }
209             pps_id= get_ue_golomb(&h->s.gb);
210             if(pps_id>=MAX_PPS_COUNT) {
211                 av_log(h->s.avctx, AV_LOG_ERROR, "pps_id out of range\n");
212                 return -1;
213             }
214             if(!h->pps_buffers[pps_id]) {
215                 av_log(h->s.avctx, AV_LOG_ERROR, "non-existing PPS referenced\n");
216                 return -1;
217             }
218             h->pps= *h->pps_buffers[pps_id];
219             if(!h->sps_buffers[h->pps.sps_id]) {
220                 av_log(h->s.avctx, AV_LOG_ERROR, "non-existing SPS referenced\n");
221                 return -1;
222             }
223             h->sps = *h->sps_buffers[h->pps.sps_id];
224             h->frame_num = get_bits(&h->s.gb, h->sps.log2_max_frame_num);
225
226             avctx->profile = ff_h264_get_profile(&h->sps);
227             avctx->level   = h->sps.level_idc;
228
229             if(h->sps.frame_mbs_only_flag){
230                 h->s.picture_structure= PICT_FRAME;
231             }else{
232                 if(get_bits1(&h->s.gb)) { //field_pic_flag
233                     h->s.picture_structure= PICT_TOP_FIELD + get_bits1(&h->s.gb); //bottom_field_flag
234                 } else {
235                     h->s.picture_structure= PICT_FRAME;
236                 }
237             }
238
239             if(h->sps.pic_struct_present_flag) {
240                 switch (h->sei_pic_struct) {
241                     case SEI_PIC_STRUCT_TOP_FIELD:
242                     case SEI_PIC_STRUCT_BOTTOM_FIELD:
243                         s->repeat_pict = 0;
244                         break;
245                     case SEI_PIC_STRUCT_FRAME:
246                     case SEI_PIC_STRUCT_TOP_BOTTOM:
247                     case SEI_PIC_STRUCT_BOTTOM_TOP:
248                         s->repeat_pict = 1;
249                         break;
250                     case SEI_PIC_STRUCT_TOP_BOTTOM_TOP:
251                     case SEI_PIC_STRUCT_BOTTOM_TOP_BOTTOM:
252                         s->repeat_pict = 2;
253                         break;
254                     case SEI_PIC_STRUCT_FRAME_DOUBLING:
255                         s->repeat_pict = 3;
256                         break;
257                     case SEI_PIC_STRUCT_FRAME_TRIPLING:
258                         s->repeat_pict = 5;
259                         break;
260                     default:
261                         s->repeat_pict = h->s.picture_structure == PICT_FRAME ? 1 : 0;
262                         break;
263                 }
264             } else {
265                 s->repeat_pict = h->s.picture_structure == PICT_FRAME ? 1 : 0;
266             }
267
268             return 0; /* no need to evaluate the rest */
269         }
270         buf += consumed;
271     }
272     if (q264)
273         return 0;
274     /* didn't find a picture! */
275     av_log(h->s.avctx, AV_LOG_ERROR, "missing picture in access unit with size %d\n", buf_size);
276     return -1;
277 }
278
279 static int h264_parse(AVCodecParserContext *s,
280                       AVCodecContext *avctx,
281                       const uint8_t **poutbuf, int *poutbuf_size,
282                       const uint8_t *buf, int buf_size)
283 {
284     H264Context *h = s->priv_data;
285     ParseContext *pc = &h->s.parse_context;
286     int next;
287
288     if (!h->got_first) {
289         h->got_first = 1;
290         if (avctx->extradata_size) {
291             h->s.avctx = avctx;
292             // must be done like in decoder, otherwise opening the parser,
293             // letting it create extradata and then closing and opening again
294             // will cause has_b_frames to be always set.
295             // Note that estimate_timings_from_pts does exactly this.
296             if (!avctx->has_b_frames)
297                 h->s.low_delay = 1;
298             ff_h264_decode_extradata(h, avctx->extradata, avctx->extradata_size);
299         }
300     }
301
302     if(s->flags & PARSER_FLAG_COMPLETE_FRAMES){
303         next= buf_size;
304     }else{
305         next= ff_h264_find_frame_end(h, buf, buf_size);
306
307         if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
308             *poutbuf = NULL;
309             *poutbuf_size = 0;
310             return buf_size;
311         }
312
313         if(next<0 && next != END_NOT_FOUND){
314             assert(pc->last_index + next >= 0 );
315             ff_h264_find_frame_end(h, &pc->buffer[pc->last_index + next], -next); //update state
316         }
317     }
318
319     if(!h->is_avc){
320     parse_nal_units(s, avctx, buf, buf_size);
321
322     if (h->sei_cpb_removal_delay >= 0) {
323         s->dts_sync_point    = h->sei_buffering_period_present;
324         s->dts_ref_dts_delta = h->sei_cpb_removal_delay;
325         s->pts_dts_delta     = h->sei_dpb_output_delay;
326     } else {
327         s->dts_sync_point    = INT_MIN;
328         s->dts_ref_dts_delta = INT_MIN;
329         s->pts_dts_delta     = INT_MIN;
330     }
331
332     if (s->flags & PARSER_FLAG_ONCE) {
333         s->flags &= PARSER_FLAG_COMPLETE_FRAMES;
334     }
335     }
336
337     *poutbuf = buf;
338     *poutbuf_size = buf_size;
339     return next;
340 }
341
342 static int h264_split(AVCodecContext *avctx,
343                       const uint8_t *buf, int buf_size)
344 {
345     int i;
346     uint32_t state = -1;
347     int has_sps= 0;
348
349     for(i=0; i<=buf_size; i++){
350         if((state&0xFFFFFF1F) == 0x107)
351             has_sps=1;
352 /*        if((state&0xFFFFFF1F) == 0x101 || (state&0xFFFFFF1F) == 0x102 || (state&0xFFFFFF1F) == 0x105){
353         }*/
354         if((state&0xFFFFFF00) == 0x100 && (state&0xFFFFFF1F) != 0x107 && (state&0xFFFFFF1F) != 0x108 && (state&0xFFFFFF1F) != 0x109){
355             if(has_sps){
356                 while(i>4 && buf[i-5]==0) i--;
357                 return i-4;
358             }
359         }
360         if (i<buf_size)
361             state= (state<<8) | buf[i];
362     }
363     return 0;
364 }
365
366 static void close(AVCodecParserContext *s)
367 {
368     H264Context *h = s->priv_data;
369     ParseContext *pc = &h->s.parse_context;
370
371     av_free(pc->buffer);
372     ff_h264_free_context(h);
373 }
374
375 static int init(AVCodecParserContext *s)
376 {
377     H264Context *h = s->priv_data;
378     h->thread_context[0] = h;
379     h->s.slice_context_count = 1;
380     return 0;
381 }
382
383 AVCodecParser ff_h264_parser = {
384     .codec_ids      = { CODEC_ID_H264 },
385     .priv_data_size = sizeof(H264Context),
386     .parser_init    = init,
387     .parser_parse   = h264_parse,
388     .parser_close   = close,
389     .split          = h264_split,
390 };