70d08f42540f038675f46e0cb04b18de72f83939
[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 #include "parser.h"
29 #include "h264_parser.h"
30 #include "h264data.h"
31 #include "golomb.h"
32
33 #include <assert.h>
34
35
36 int ff_h264_find_frame_end(H264Context *h, const uint8_t *buf, int buf_size)
37 {
38     int i;
39     uint32_t state;
40     ParseContext *pc = &(h->s.parse_context);
41 //printf("first %02X%02X%02X%02X\n", buf[0], buf[1],buf[2],buf[3]);
42 //    mb_addr= pc->mb_addr - 1;
43     state= pc->state;
44     if(state>13)
45         state= 7;
46
47     for(i=0; i<buf_size; i++){
48         if(state==7){
49 #if HAVE_FAST_UNALIGNED
50         /* we check i<buf_size instead of i+3/7 because its simpler
51          * and there should be FF_INPUT_BUFFER_PADDING_SIZE bytes at the end
52          */
53 #    if HAVE_FAST_64BIT
54             while(i<buf_size && !((~*(const uint64_t*)(buf+i) & (*(const uint64_t*)(buf+i) - 0x0101010101010101ULL)) & 0x8080808080808080ULL))
55                 i+=8;
56 #    else
57             while(i<buf_size && !((~*(const uint32_t*)(buf+i) & (*(const uint32_t*)(buf+i) - 0x01010101U)) & 0x80808080U))
58                 i+=4;
59 #    endif
60 #endif
61             for(; i<buf_size; i++){
62                 if(!buf[i]){
63                     state=2;
64                     break;
65                 }
66             }
67         }else if(state<=2){
68             if(buf[i]==1)   state^= 5; //2->7, 1->4, 0->5
69             else if(buf[i]) state = 7;
70             else            state>>=1; //2->1, 1->0, 0->0
71         }else if(state<=5){
72             int v= buf[i] & 0x1F;
73             if(v==6 || v==7 || v==8 || v==9){
74                 if(pc->frame_start_found){
75                     i++;
76                     goto found;
77                 }
78             }else if(v==1 || v==2 || v==5){
79                 if(pc->frame_start_found){
80                     state+=8;
81                     continue;
82                 }else
83                     pc->frame_start_found = 1;
84             }
85             state= 7;
86         }else{
87             if(buf[i] & 0x80)
88                 goto found;
89             state= 7;
90         }
91     }
92     pc->state= state;
93     return END_NOT_FOUND;
94
95 found:
96     pc->state=7;
97     pc->frame_start_found= 0;
98     return i-(state&5);
99 }
100
101 /*!
102  * Parse NAL units of found picture and decode some basic information.
103  *
104  * @param s parser context.
105  * @param avctx codec context.
106  * @param buf buffer with field/frame data.
107  * @param buf_size size of the buffer.
108  */
109 static inline int parse_nal_units(AVCodecParserContext *s,
110                                   AVCodecContext *avctx,
111                                   const uint8_t *buf, int buf_size)
112 {
113     H264Context *h = s->priv_data;
114     const uint8_t *buf_end = buf + buf_size;
115     unsigned int pps_id;
116     unsigned int slice_type;
117     int state = -1;
118     const uint8_t *ptr;
119
120     /* set some sane default values */
121     s->pict_type = FF_I_TYPE;
122     s->key_frame = 0;
123
124     h->s.avctx= avctx;
125     h->sei_recovery_frame_cnt = -1;
126     h->sei_dpb_output_delay         =  0;
127     h->sei_cpb_removal_delay        = -1;
128     h->sei_buffering_period_present =  0;
129
130     if (!buf_size)
131         return 0;
132
133     for(;;) {
134         int src_length, dst_length, consumed;
135         buf = ff_find_start_code(buf, buf_end, &state);
136         if(buf >= buf_end)
137             break;
138         --buf;
139         src_length = buf_end - buf;
140         switch (state & 0x1f) {
141         case NAL_SLICE:
142         case NAL_IDR_SLICE:
143             // Do not walk the whole buffer just to decode slice header
144             if (src_length > 20)
145                 src_length = 20;
146             break;
147         }
148         ptr= ff_h264_decode_nal(h, buf, &dst_length, &consumed, src_length);
149         if (ptr==NULL || dst_length < 0)
150             break;
151
152         init_get_bits(&h->s.gb, ptr, 8*dst_length);
153         switch(h->nal_unit_type) {
154         case NAL_SPS:
155             ff_h264_decode_seq_parameter_set(h);
156             break;
157         case NAL_PPS:
158             ff_h264_decode_picture_parameter_set(h, h->s.gb.size_in_bits);
159             break;
160         case NAL_SEI:
161             ff_h264_decode_sei(h);
162             break;
163         case NAL_IDR_SLICE:
164             s->key_frame = 1;
165             /* fall through */
166         case NAL_SLICE:
167             get_ue_golomb(&h->s.gb);  // skip first_mb_in_slice
168             slice_type = get_ue_golomb_31(&h->s.gb);
169             s->pict_type = golomb_to_pict_type[slice_type % 5];
170             if (h->sei_recovery_frame_cnt >= 0) {
171                 /* key frame, since recovery_frame_cnt is set */
172                 s->key_frame = 1;
173             }
174             pps_id= get_ue_golomb(&h->s.gb);
175             if(pps_id>=MAX_PPS_COUNT) {
176                 av_log(h->s.avctx, AV_LOG_ERROR, "pps_id out of range\n");
177                 return -1;
178             }
179             if(!h->pps_buffers[pps_id]) {
180                 av_log(h->s.avctx, AV_LOG_ERROR, "non-existing PPS referenced\n");
181                 return -1;
182             }
183             h->pps= *h->pps_buffers[pps_id];
184             if(!h->sps_buffers[h->pps.sps_id]) {
185                 av_log(h->s.avctx, AV_LOG_ERROR, "non-existing SPS referenced\n");
186                 return -1;
187             }
188             h->sps = *h->sps_buffers[h->pps.sps_id];
189             h->frame_num = get_bits(&h->s.gb, h->sps.log2_max_frame_num);
190
191             avctx->profile = h->sps.profile_idc;
192             avctx->level   = h->sps.level_idc;
193
194             if(h->sps.frame_mbs_only_flag){
195                 h->s.picture_structure= PICT_FRAME;
196             }else{
197                 if(get_bits1(&h->s.gb)) { //field_pic_flag
198                     h->s.picture_structure= PICT_TOP_FIELD + get_bits1(&h->s.gb); //bottom_field_flag
199                 } else {
200                     h->s.picture_structure= PICT_FRAME;
201                 }
202             }
203
204             if(h->sps.pic_struct_present_flag) {
205                 switch (h->sei_pic_struct) {
206                     case SEI_PIC_STRUCT_TOP_FIELD:
207                     case SEI_PIC_STRUCT_BOTTOM_FIELD:
208                         s->repeat_pict = 0;
209                         break;
210                     case SEI_PIC_STRUCT_FRAME:
211                     case SEI_PIC_STRUCT_TOP_BOTTOM:
212                     case SEI_PIC_STRUCT_BOTTOM_TOP:
213                         s->repeat_pict = 1;
214                         break;
215                     case SEI_PIC_STRUCT_TOP_BOTTOM_TOP:
216                     case SEI_PIC_STRUCT_BOTTOM_TOP_BOTTOM:
217                         s->repeat_pict = 2;
218                         break;
219                     case SEI_PIC_STRUCT_FRAME_DOUBLING:
220                         s->repeat_pict = 3;
221                         break;
222                     case SEI_PIC_STRUCT_FRAME_TRIPLING:
223                         s->repeat_pict = 5;
224                         break;
225                     default:
226                         s->repeat_pict = h->s.picture_structure == PICT_FRAME ? 1 : 0;
227                         break;
228                 }
229             } else {
230                 s->repeat_pict = h->s.picture_structure == PICT_FRAME ? 1 : 0;
231             }
232
233             return 0; /* no need to evaluate the rest */
234         }
235         buf += consumed;
236     }
237     /* didn't find a picture! */
238     av_log(h->s.avctx, AV_LOG_ERROR, "missing picture in access unit\n");
239     return -1;
240 }
241
242 static int h264_parse(AVCodecParserContext *s,
243                       AVCodecContext *avctx,
244                       const uint8_t **poutbuf, int *poutbuf_size,
245                       const uint8_t *buf, int buf_size)
246 {
247     H264Context *h = s->priv_data;
248     ParseContext *pc = &h->s.parse_context;
249     int next;
250
251     if (!h->got_first) {
252         h->got_first = 1;
253         if (avctx->extradata_size) {
254             h->s.avctx = avctx;
255             ff_h264_decode_extradata(h);
256         }
257     }
258
259     if(s->flags & PARSER_FLAG_COMPLETE_FRAMES){
260         next= buf_size;
261     }else{
262         next= ff_h264_find_frame_end(h, buf, buf_size);
263
264         if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
265             *poutbuf = NULL;
266             *poutbuf_size = 0;
267             return buf_size;
268         }
269
270         if(next<0 && next != END_NOT_FOUND){
271             assert(pc->last_index + next >= 0 );
272             ff_h264_find_frame_end(h, &pc->buffer[pc->last_index + next], -next); //update state
273         }
274
275         parse_nal_units(s, avctx, buf, buf_size);
276
277         if (h->sei_cpb_removal_delay >= 0) {
278             s->dts_sync_point    = h->sei_buffering_period_present;
279             s->dts_ref_dts_delta = h->sei_cpb_removal_delay;
280             s->pts_dts_delta     = h->sei_dpb_output_delay;
281         } else {
282             s->dts_sync_point    = INT_MIN;
283             s->dts_ref_dts_delta = INT_MIN;
284             s->pts_dts_delta     = INT_MIN;
285         }
286         if (s->flags & PARSER_FLAG_ONCE) {
287             s->flags &= PARSER_FLAG_COMPLETE_FRAMES;
288         }
289     }
290
291     *poutbuf = buf;
292     *poutbuf_size = buf_size;
293     return next;
294 }
295
296 static int h264_split(AVCodecContext *avctx,
297                       const uint8_t *buf, int buf_size)
298 {
299     int i;
300     uint32_t state = -1;
301     int has_sps= 0;
302
303     for(i=0; i<=buf_size; i++){
304         if((state&0xFFFFFF1F) == 0x107)
305             has_sps=1;
306 /*        if((state&0xFFFFFF1F) == 0x101 || (state&0xFFFFFF1F) == 0x102 || (state&0xFFFFFF1F) == 0x105){
307         }*/
308         if((state&0xFFFFFF00) == 0x100 && (state&0xFFFFFF1F) != 0x107 && (state&0xFFFFFF1F) != 0x108 && (state&0xFFFFFF1F) != 0x109){
309             if(has_sps){
310                 while(i>4 && buf[i-5]==0) i--;
311                 return i-4;
312             }
313         }
314         if (i<buf_size)
315             state= (state<<8) | buf[i];
316     }
317     return 0;
318 }
319
320 static void close(AVCodecParserContext *s)
321 {
322     H264Context *h = s->priv_data;
323     ParseContext *pc = &h->s.parse_context;
324
325     av_free(pc->buffer);
326     ff_h264_free_context(h);
327 }
328
329 static int init(AVCodecParserContext *s)
330 {
331     H264Context *h = s->priv_data;
332     h->thread_context[0] = h;
333     return 0;
334 }
335
336 AVCodecParser h264_parser = {
337     { CODEC_ID_H264 },
338     sizeof(H264Context),
339     init,
340     h264_parse,
341     close,
342     h264_split,
343 };