2 * H.26L/H.264/AVC/JVT/14496-10/... parser
3 * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
5 * This file is part of FFmpeg.
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.
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.
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
24 * H.264 / AVC / MPEG4 part10 parser.
25 * @author Michael Niedermayer <michaelni@gmx.at>
28 #define UNCHECKED_BITSTREAM_READER 1
35 static int ff_h264_find_frame_end(H264Context *h, const uint8_t *buf, int buf_size)
39 ParseContext *pc = &(h->s.parse_context);
40 int next_avc= h->is_avc ? 0 : buf_size;
42 //printf("first %02X%02X%02X%02X\n", buf[0], buf[1],buf[2],buf[3]);
43 // mb_addr= pc->mb_addr - 1;
48 if(h->is_avc && !h->nal_length_size)
49 av_log(h->s.avctx, AV_LOG_ERROR, "AVC-parser: nal length size invalid\n");
51 for(i=0; i<buf_size; i++){
55 for(j = 0; j < h->nal_length_size; j++)
56 nalsize = (nalsize << 8) | buf[i++];
57 if(nalsize <= 0 || nalsize > buf_size - i){
58 av_log(h->s.avctx, AV_LOG_ERROR, "AVC-parser: nal size %d remaining %d\n", nalsize, buf_size - i);
61 next_avc= i + nalsize;
66 #if HAVE_FAST_UNALIGNED
67 /* we check i<buf_size instead of i+3/7 because its simpler
68 * and there should be FF_INPUT_BUFFER_PADDING_SIZE bytes at the end
71 while(i<next_avc && !((~*(const uint64_t*)(buf+i) & (*(const uint64_t*)(buf+i) - 0x0101010101010101ULL)) & 0x8080808080808080ULL))
74 while(i<next_avc && !((~*(const uint32_t*)(buf+i) & (*(const uint32_t*)(buf+i) - 0x01010101U)) & 0x80808080U))
78 for(; i<next_avc; i++){
85 if(buf[i]==1) state^= 5; //2->7, 1->4, 0->5
86 else if(buf[i]) state = 7;
87 else state>>=1; //2->1, 1->0, 0->0
90 if(v==6 || v==7 || v==8 || v==9){
91 if(pc->frame_start_found){
95 }else if(v==1 || v==2 || v==5){
101 h->parse_history[h->parse_history_count++]= buf[i];
102 if(h->parse_history_count>3){
103 unsigned int mb, last_mb= h->parse_last_mb;
106 init_get_bits(&gb, h->parse_history, 8*h->parse_history_count);
107 h->parse_history_count=0;
108 mb= get_ue_golomb_long(&gb);
109 last_mb= h->parse_last_mb;
110 h->parse_last_mb= mb;
111 if(pc->frame_start_found){
115 pc->frame_start_found = 1;
123 return END_NOT_FOUND;
127 pc->frame_start_found= 0;
130 return i-(state&5) - 3*(state>7);
134 * Parse NAL units of found picture and decode some basic information.
136 * @param s parser context.
137 * @param avctx codec context.
138 * @param buf buffer with field/frame data.
139 * @param buf_size size of the buffer.
141 static inline int parse_nal_units(AVCodecParserContext *s,
142 AVCodecContext *avctx,
143 const uint8_t *buf, int buf_size)
145 H264Context *h = s->priv_data;
146 const uint8_t *buf_end = buf + buf_size;
148 unsigned int slice_type;
151 int q264 = buf_size >=4 && !memcmp("Q264", buf, 4);
153 /* set some sane default values */
154 s->pict_type = AV_PICTURE_TYPE_I;
158 h->sei_recovery_frame_cnt = -1;
159 h->sei_dpb_output_delay = 0;
160 h->sei_cpb_removal_delay = -1;
161 h->sei_buffering_period_present = 0;
167 int src_length, dst_length, consumed, nalsize = 0;
170 if (h->nal_length_size >= buf_end - buf) break;
172 for (i = 0; i < h->nal_length_size; i++)
173 nalsize = (nalsize << 8) | *buf++;
174 if (nalsize <= 0 || nalsize > buf_end - buf) {
175 av_log(h->s.avctx, AV_LOG_ERROR, "AVC: nal size %d\n", nalsize);
178 src_length = nalsize;
180 buf = avpriv_mpv_find_start_code(buf, buf_end, &state);
184 src_length = buf_end - buf;
186 switch (state & 0x1f) {
189 // Do not walk the whole buffer just to decode slice header
194 ptr= ff_h264_decode_nal(h, buf, &dst_length, &consumed, src_length);
195 if (ptr==NULL || dst_length < 0)
198 init_get_bits(&h->s.gb, ptr, 8*dst_length);
199 switch(h->nal_unit_type) {
201 ff_h264_decode_seq_parameter_set(h);
204 ff_h264_decode_picture_parameter_set(h, h->s.gb.size_in_bits);
207 ff_h264_decode_sei(h);
213 get_ue_golomb_long(&h->s.gb); // skip first_mb_in_slice
214 slice_type = get_ue_golomb_31(&h->s.gb);
215 s->pict_type = golomb_to_pict_type[slice_type % 5];
216 if (h->sei_recovery_frame_cnt >= 0) {
217 /* key frame, since recovery_frame_cnt is set */
220 pps_id= get_ue_golomb(&h->s.gb);
221 if(pps_id>=MAX_PPS_COUNT) {
222 av_log(h->s.avctx, AV_LOG_ERROR, "pps_id out of range\n");
225 if(!h->pps_buffers[pps_id]) {
226 av_log(h->s.avctx, AV_LOG_ERROR, "non-existing PPS referenced\n");
229 h->pps= *h->pps_buffers[pps_id];
230 if(!h->sps_buffers[h->pps.sps_id]) {
231 av_log(h->s.avctx, AV_LOG_ERROR, "non-existing SPS referenced\n");
234 h->sps = *h->sps_buffers[h->pps.sps_id];
235 h->frame_num = get_bits(&h->s.gb, h->sps.log2_max_frame_num);
237 avctx->profile = ff_h264_get_profile(&h->sps);
238 avctx->level = h->sps.level_idc;
240 if(h->sps.frame_mbs_only_flag){
241 h->s.picture_structure= PICT_FRAME;
243 if(get_bits1(&h->s.gb)) { //field_pic_flag
244 h->s.picture_structure= PICT_TOP_FIELD + get_bits1(&h->s.gb); //bottom_field_flag
246 h->s.picture_structure= PICT_FRAME;
250 if(h->sps.pic_struct_present_flag) {
251 switch (h->sei_pic_struct) {
252 case SEI_PIC_STRUCT_TOP_FIELD:
253 case SEI_PIC_STRUCT_BOTTOM_FIELD:
256 case SEI_PIC_STRUCT_FRAME:
257 case SEI_PIC_STRUCT_TOP_BOTTOM:
258 case SEI_PIC_STRUCT_BOTTOM_TOP:
261 case SEI_PIC_STRUCT_TOP_BOTTOM_TOP:
262 case SEI_PIC_STRUCT_BOTTOM_TOP_BOTTOM:
265 case SEI_PIC_STRUCT_FRAME_DOUBLING:
268 case SEI_PIC_STRUCT_FRAME_TRIPLING:
272 s->repeat_pict = h->s.picture_structure == PICT_FRAME ? 1 : 0;
276 s->repeat_pict = h->s.picture_structure == PICT_FRAME ? 1 : 0;
279 return 0; /* no need to evaluate the rest */
281 buf += h->is_avc ? nalsize : consumed;
285 /* didn't find a picture! */
286 av_log(h->s.avctx, AV_LOG_ERROR, "missing picture in access unit with size %d\n", buf_size);
290 static int h264_parse(AVCodecParserContext *s,
291 AVCodecContext *avctx,
292 const uint8_t **poutbuf, int *poutbuf_size,
293 const uint8_t *buf, int buf_size)
295 H264Context *h = s->priv_data;
296 ParseContext *pc = &h->s.parse_context;
301 if (avctx->extradata_size) {
303 // must be done like in decoder, otherwise opening the parser,
304 // letting it create extradata and then closing and opening again
305 // will cause has_b_frames to be always set.
306 // Note that estimate_timings_from_pts does exactly this.
307 if (!avctx->has_b_frames)
309 ff_h264_decode_extradata(h, avctx->extradata, avctx->extradata_size);
313 if(s->flags & PARSER_FLAG_COMPLETE_FRAMES){
316 next= ff_h264_find_frame_end(h, buf, buf_size);
318 if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
324 if(next<0 && next != END_NOT_FOUND){
325 av_assert1(pc->last_index + next >= 0 );
326 ff_h264_find_frame_end(h, &pc->buffer[pc->last_index + next], -next); //update state
330 parse_nal_units(s, avctx, buf, buf_size);
332 if (h->sei_cpb_removal_delay >= 0) {
333 s->dts_sync_point = h->sei_buffering_period_present;
334 s->dts_ref_dts_delta = h->sei_cpb_removal_delay;
335 s->pts_dts_delta = h->sei_dpb_output_delay;
337 s->dts_sync_point = INT_MIN;
338 s->dts_ref_dts_delta = INT_MIN;
339 s->pts_dts_delta = INT_MIN;
342 if (s->flags & PARSER_FLAG_ONCE) {
343 s->flags &= PARSER_FLAG_COMPLETE_FRAMES;
347 *poutbuf_size = buf_size;
351 static int h264_split(AVCodecContext *avctx,
352 const uint8_t *buf, int buf_size)
358 for(i=0; i<=buf_size; i++){
359 if((state&0xFFFFFF1F) == 0x107)
361 /* if((state&0xFFFFFF1F) == 0x101 || (state&0xFFFFFF1F) == 0x102 || (state&0xFFFFFF1F) == 0x105){
363 if((state&0xFFFFFF00) == 0x100 && (state&0xFFFFFF1F) != 0x107 && (state&0xFFFFFF1F) != 0x108 && (state&0xFFFFFF1F) != 0x109){
365 while(i>4 && buf[i-5]==0) i--;
370 state= (state<<8) | buf[i];
375 static void close(AVCodecParserContext *s)
377 H264Context *h = s->priv_data;
378 ParseContext *pc = &h->s.parse_context;
381 ff_h264_free_context(h);
384 static int init(AVCodecParserContext *s)
386 H264Context *h = s->priv_data;
387 h->thread_context[0] = h;
388 h->s.slice_context_count = 1;
392 AVCodecParser ff_h264_parser = {
393 .codec_ids = { CODEC_ID_H264 },
394 .priv_data_size = sizeof(H264Context),
396 .parser_parse = h264_parse,
397 .parser_close = close,