826c17a0f1e415d23add71bfa17b8e2ce69d1521
[libav.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 Libav.
6 *
7 * Libav 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 * Libav 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 Libav; 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 "h264data.h"
30 #include "golomb.h"
31
32 #include <assert.h>
33
34
35 static int ff_h264_find_frame_end(H264Context *h, const uint8_t *buf, int buf_size)
36 {
37 int i;
38 uint32_t state;
39 ParseContext *pc = &(h->s.parse_context);
40 //printf("first %02X%02X%02X%02X\n", buf[0], buf[1],buf[2],buf[3]);
41 // mb_addr= pc->mb_addr - 1;
42 state= pc->state;
43 if(state>13)
44 state= 7;
45
46 for(i=0; i<buf_size; i++){
47 if(state==7){
48 #if HAVE_FAST_UNALIGNED
49 /* we check i<buf_size instead of i+3/7 because its simpler
50 * and there should be FF_INPUT_BUFFER_PADDING_SIZE bytes at the end
51 */
52 # if HAVE_FAST_64BIT
53 while(i<buf_size && !((~*(const uint64_t*)(buf+i) & (*(const uint64_t*)(buf+i) - 0x0101010101010101ULL)) & 0x8080808080808080ULL))
54 i+=8;
55 # else
56 while(i<buf_size && !((~*(const uint32_t*)(buf+i) & (*(const uint32_t*)(buf+i) - 0x01010101U)) & 0x80808080U))
57 i+=4;
58 # endif
59 #endif
60 for(; i<buf_size; i++){
61 if(!buf[i]){
62 state=2;
63 break;
64 }
65 }
66 }else if(state<=2){
67 if(buf[i]==1) state^= 5; //2->7, 1->4, 0->5
68 else if(buf[i]) state = 7;
69 else state>>=1; //2->1, 1->0, 0->0
70 }else if(state<=5){
71 int v= buf[i] & 0x1F;
72 if(v==6 || v==7 || v==8 || v==9){
73 if(pc->frame_start_found){
74 i++;
75 goto found;
76 }
77 }else if(v==1 || v==2 || v==5){
78 if(pc->frame_start_found){
79 state+=8;
80 continue;
81 }else
82 pc->frame_start_found = 1;
83 }
84 state= 7;
85 }else{
86 if(buf[i] & 0x80)
87 goto found;
88 state= 7;
89 }
90 }
91 pc->state= state;
92 return END_NOT_FOUND;
93
94 found:
95 pc->state=7;
96 pc->frame_start_found= 0;
97 return i-(state&5);
98 }
99
100 /**
101 * Parse NAL units of found picture and decode some basic information.
102 *
103 * @param s parser context.
104 * @param avctx codec context.
105 * @param buf buffer with field/frame data.
106 * @param buf_size size of the buffer.
107 */
108 static inline int parse_nal_units(AVCodecParserContext *s,
109 AVCodecContext *avctx,
110 const uint8_t *buf, int buf_size)
111 {
112 H264Context *h = s->priv_data;
113 const uint8_t *buf_end = buf + buf_size;
114 unsigned int pps_id;
115 unsigned int slice_type;
116 int state = -1;
117 const uint8_t *ptr;
118
119 /* set some sane default values */
120 s->pict_type = AV_PICTURE_TYPE_I;
121 s->key_frame = 0;
122
123 h->s.avctx= avctx;
124 h->sei_recovery_frame_cnt = -1;
125 h->sei_dpb_output_delay = 0;
126 h->sei_cpb_removal_delay = -1;
127 h->sei_buffering_period_present = 0;
128
129 if (!buf_size)
130 return 0;
131
132 for(;;) {
133 int src_length, dst_length, consumed;
134 buf = avpriv_mpv_find_start_code(buf, buf_end, &state);
135 if(buf >= buf_end)
136 break;
137 --buf;
138 src_length = buf_end - buf;
139 switch (state & 0x1f) {
140 case NAL_SLICE:
141 case NAL_IDR_SLICE:
142 // Do not walk the whole buffer just to decode slice header
143 if (src_length > 20)
144 src_length = 20;
145 break;
146 }
147 ptr= ff_h264_decode_nal(h, buf, &dst_length, &consumed, src_length);
148 if (ptr==NULL || dst_length < 0)
149 break;
150
151 init_get_bits(&h->s.gb, ptr, 8*dst_length);
152 switch(h->nal_unit_type) {
153 case NAL_SPS:
154 ff_h264_decode_seq_parameter_set(h);
155 break;
156 case NAL_PPS:
157 ff_h264_decode_picture_parameter_set(h, h->s.gb.size_in_bits);
158 break;
159 case NAL_SEI:
160 ff_h264_decode_sei(h);
161 break;
162 case NAL_IDR_SLICE:
163 s->key_frame = 1;
164 /* fall through */
165 case NAL_SLICE:
166 get_ue_golomb(&h->s.gb); // skip first_mb_in_slice
167 slice_type = get_ue_golomb_31(&h->s.gb);
168 s->pict_type = golomb_to_pict_type[slice_type % 5];
169 if (h->sei_recovery_frame_cnt >= 0) {
170 /* key frame, since recovery_frame_cnt is set */
171 s->key_frame = 1;
172 }
173 pps_id= get_ue_golomb(&h->s.gb);
174 if(pps_id>=MAX_PPS_COUNT) {
175 av_log(h->s.avctx, AV_LOG_ERROR, "pps_id out of range\n");
176 return -1;
177 }
178 if(!h->pps_buffers[pps_id]) {
179 av_log(h->s.avctx, AV_LOG_ERROR, "non-existing PPS referenced\n");
180 return -1;
181 }
182 h->pps= *h->pps_buffers[pps_id];
183 if(!h->sps_buffers[h->pps.sps_id]) {
184 av_log(h->s.avctx, AV_LOG_ERROR, "non-existing SPS referenced\n");
185 return -1;
186 }
187 h->sps = *h->sps_buffers[h->pps.sps_id];
188 h->frame_num = get_bits(&h->s.gb, h->sps.log2_max_frame_num);
189
190 avctx->profile = ff_h264_get_profile(&h->sps);
191 avctx->level = h->sps.level_idc;
192
193 if(h->sps.frame_mbs_only_flag){
194 h->s.picture_structure= PICT_FRAME;
195 }else{
196 if(get_bits1(&h->s.gb)) { //field_pic_flag
197 h->s.picture_structure= PICT_TOP_FIELD + get_bits1(&h->s.gb); //bottom_field_flag
198 } else {
199 h->s.picture_structure= PICT_FRAME;
200 }
201 }
202
203 if(h->sps.pic_struct_present_flag) {
204 switch (h->sei_pic_struct) {
205 case SEI_PIC_STRUCT_TOP_FIELD:
206 case SEI_PIC_STRUCT_BOTTOM_FIELD:
207 s->repeat_pict = 0;
208 break;
209 case SEI_PIC_STRUCT_FRAME:
210 case SEI_PIC_STRUCT_TOP_BOTTOM:
211 case SEI_PIC_STRUCT_BOTTOM_TOP:
212 s->repeat_pict = 1;
213 break;
214 case SEI_PIC_STRUCT_TOP_BOTTOM_TOP:
215 case SEI_PIC_STRUCT_BOTTOM_TOP_BOTTOM:
216 s->repeat_pict = 2;
217 break;
218 case SEI_PIC_STRUCT_FRAME_DOUBLING:
219 s->repeat_pict = 3;
220 break;
221 case SEI_PIC_STRUCT_FRAME_TRIPLING:
222 s->repeat_pict = 5;
223 break;
224 default:
225 s->repeat_pict = h->s.picture_structure == PICT_FRAME ? 1 : 0;
226 break;
227 }
228 } else {
229 s->repeat_pict = h->s.picture_structure == PICT_FRAME ? 1 : 0;
230 }
231
232 return 0; /* no need to evaluate the rest */
233 }
234 buf += consumed;
235 }
236 /* didn't find a picture! */
237 av_log(h->s.avctx, AV_LOG_ERROR, "missing picture in access unit\n");
238 return -1;
239 }
240
241 static int h264_parse(AVCodecParserContext *s,
242 AVCodecContext *avctx,
243 const uint8_t **poutbuf, int *poutbuf_size,
244 const uint8_t *buf, int buf_size)
245 {
246 H264Context *h = s->priv_data;
247 ParseContext *pc = &h->s.parse_context;
248 int next;
249
250 if (!h->got_first) {
251 h->got_first = 1;
252 if (avctx->extradata_size) {
253 h->s.avctx = avctx;
254 ff_h264_decode_extradata(h);
255 }
256 }
257
258 if(s->flags & PARSER_FLAG_COMPLETE_FRAMES){
259 next= buf_size;
260 }else{
261 next= ff_h264_find_frame_end(h, buf, buf_size);
262
263 if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
264 *poutbuf = NULL;
265 *poutbuf_size = 0;
266 return buf_size;
267 }
268
269 if(next<0 && next != END_NOT_FOUND){
270 assert(pc->last_index + next >= 0 );
271 ff_h264_find_frame_end(h, &pc->buffer[pc->last_index + next], -next); //update state
272 }
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
287 if (s->flags & PARSER_FLAG_ONCE) {
288 s->flags &= PARSER_FLAG_COMPLETE_FRAMES;
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 ff_h264_parser = {
337 .codec_ids = { CODEC_ID_H264 },
338 .priv_data_size = sizeof(H264Context),
339 .parser_init = init,
340 .parser_parse = h264_parse,
341 .parser_close = close,
342 .split = h264_split,
343 };