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libavcodec/parser.c

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00001 /*
00002  * Audio and Video frame extraction
00003  * Copyright (c) 2003 Fabrice Bellard
00004  * Copyright (c) 2003 Michael Niedermayer
00005  *
00006  * This file is part of FFmpeg.
00007  *
00008  * FFmpeg is free software; you can redistribute it and/or
00009  * modify it under the terms of the GNU Lesser General Public
00010  * License as published by the Free Software Foundation; either
00011  * version 2.1 of the License, or (at your option) any later version.
00012  *
00013  * FFmpeg is distributed in the hope that it will be useful,
00014  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00015  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00016  * Lesser General Public License for more details.
00017  *
00018  * You should have received a copy of the GNU Lesser General Public
00019  * License along with FFmpeg; if not, write to the Free Software
00020  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00021  */
00022 
00023 #include "parser.h"
00024 
00025 static AVCodecParser *av_first_parser = NULL;
00026 
00027 AVCodecParser* av_parser_next(AVCodecParser *p){
00028     if(p) return p->next;
00029     else  return av_first_parser;
00030 }
00031 
00032 void av_register_codec_parser(AVCodecParser *parser)
00033 {
00034     parser->next = av_first_parser;
00035     av_first_parser = parser;
00036 }
00037 
00038 AVCodecParserContext *av_parser_init(int codec_id)
00039 {
00040     AVCodecParserContext *s;
00041     AVCodecParser *parser;
00042     int ret;
00043 
00044     if(codec_id == CODEC_ID_NONE)
00045         return NULL;
00046 
00047     for(parser = av_first_parser; parser != NULL; parser = parser->next) {
00048         if (parser->codec_ids[0] == codec_id ||
00049             parser->codec_ids[1] == codec_id ||
00050             parser->codec_ids[2] == codec_id ||
00051             parser->codec_ids[3] == codec_id ||
00052             parser->codec_ids[4] == codec_id)
00053             goto found;
00054     }
00055     return NULL;
00056  found:
00057     s = av_mallocz(sizeof(AVCodecParserContext));
00058     if (!s)
00059         return NULL;
00060     s->parser = parser;
00061     s->priv_data = av_mallocz(parser->priv_data_size);
00062     if (!s->priv_data) {
00063         av_free(s);
00064         return NULL;
00065     }
00066     if (parser->parser_init) {
00067         ret = parser->parser_init(s);
00068         if (ret != 0) {
00069             av_free(s->priv_data);
00070             av_free(s);
00071             return NULL;
00072         }
00073     }
00074     s->fetch_timestamp=1;
00075     s->pict_type = FF_I_TYPE;
00076     s->key_frame = -1;
00077     s->convergence_duration = AV_NOPTS_VALUE;
00078     s->dts_sync_point       = INT_MIN;
00079     s->dts_ref_dts_delta    = INT_MIN;
00080     s->pts_dts_delta        = INT_MIN;
00081     return s;
00082 }
00083 
00084 void ff_fetch_timestamp(AVCodecParserContext *s, int off, int remove){
00085     int i;
00086 
00087     s->dts= s->pts= AV_NOPTS_VALUE;
00088     s->offset= 0;
00089     for(i = 0; i < AV_PARSER_PTS_NB; i++) {
00090         if (   s->next_frame_offset + off >= s->cur_frame_offset[i]
00091             &&(s->     frame_offset       <  s->cur_frame_offset[i] || !s->frame_offset)
00092             //check is disabled  becausue mpeg-ts doesnt send complete PES packets
00093             && /*s->next_frame_offset + off <*/  s->cur_frame_end[i]){
00094             s->dts= s->cur_frame_dts[i];
00095             s->pts= s->cur_frame_pts[i];
00096             s->offset = s->next_frame_offset - s->cur_frame_offset[i];
00097             if(remove)
00098                 s->cur_frame_offset[i]= INT64_MAX;
00099         }
00100     }
00101 }
00102 
00127 int av_parser_parse(AVCodecParserContext *s,
00128                     AVCodecContext *avctx,
00129                     uint8_t **poutbuf, int *poutbuf_size,
00130                     const uint8_t *buf, int buf_size,
00131                     int64_t pts, int64_t dts)
00132 {
00133     int index, i;
00134     uint8_t dummy_buf[FF_INPUT_BUFFER_PADDING_SIZE];
00135 
00136     if (buf_size == 0) {
00137         /* padding is always necessary even if EOF, so we add it here */
00138         memset(dummy_buf, 0, sizeof(dummy_buf));
00139         buf = dummy_buf;
00140     } else {
00141         /* add a new packet descriptor */
00142         if(pts != AV_NOPTS_VALUE || dts != AV_NOPTS_VALUE){
00143             i = (s->cur_frame_start_index + 1) & (AV_PARSER_PTS_NB - 1);
00144             s->cur_frame_start_index = i;
00145             s->cur_frame_offset[i] = s->cur_offset;
00146             s->cur_frame_end[i] = s->cur_offset + buf_size;
00147             s->cur_frame_pts[i] = pts;
00148             s->cur_frame_dts[i] = dts;
00149         }
00150     }
00151 
00152     if (s->fetch_timestamp){
00153         s->fetch_timestamp=0;
00154         s->last_pts = s->pts;
00155         s->last_dts = s->dts;
00156         ff_fetch_timestamp(s, 0, 0);
00157     }
00158 
00159     /* WARNING: the returned index can be negative */
00160     index = s->parser->parser_parse(s, avctx, (const uint8_t **)poutbuf, poutbuf_size, buf, buf_size);
00161 //av_log(NULL, AV_LOG_DEBUG, "parser: in:%"PRId64", %"PRId64", out:%"PRId64", %"PRId64", in:%d out:%d id:%d\n", pts, dts, s->last_pts, s->last_dts, buf_size, *poutbuf_size, avctx->codec_id);
00162     /* update the file pointer */
00163     if (*poutbuf_size) {
00164         /* fill the data for the current frame */
00165         s->frame_offset = s->next_frame_offset;
00166 
00167         /* offset of the next frame */
00168         s->next_frame_offset = s->cur_offset + index;
00169         s->fetch_timestamp=1;
00170     }
00171     if (index < 0)
00172         index = 0;
00173     s->cur_offset += index;
00174     return index;
00175 }
00176 
00182 int av_parser_change(AVCodecParserContext *s,
00183                      AVCodecContext *avctx,
00184                      uint8_t **poutbuf, int *poutbuf_size,
00185                      const uint8_t *buf, int buf_size, int keyframe){
00186 
00187     if(s && s->parser->split){
00188         if((avctx->flags & CODEC_FLAG_GLOBAL_HEADER) || (avctx->flags2 & CODEC_FLAG2_LOCAL_HEADER)){
00189             int i= s->parser->split(avctx, buf, buf_size);
00190             buf += i;
00191             buf_size -= i;
00192         }
00193     }
00194 
00195     /* cast to avoid warning about discarding qualifiers */
00196     *poutbuf= (uint8_t *) buf;
00197     *poutbuf_size= buf_size;
00198     if(avctx->extradata){
00199         if(  (keyframe && (avctx->flags2 & CODEC_FLAG2_LOCAL_HEADER))
00200             /*||(s->pict_type != FF_I_TYPE && (s->flags & PARSER_FLAG_DUMP_EXTRADATA_AT_NOKEY))*/
00201             /*||(? && (s->flags & PARSER_FLAG_DUMP_EXTRADATA_AT_BEGIN)*/){
00202             int size= buf_size + avctx->extradata_size;
00203             *poutbuf_size= size;
00204             *poutbuf= av_malloc(size + FF_INPUT_BUFFER_PADDING_SIZE);
00205 
00206             memcpy(*poutbuf, avctx->extradata, avctx->extradata_size);
00207             memcpy((*poutbuf) + avctx->extradata_size, buf, buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
00208             return 1;
00209         }
00210     }
00211 
00212     return 0;
00213 }
00214 
00215 void av_parser_close(AVCodecParserContext *s)
00216 {
00217     if(s){
00218         if (s->parser->parser_close)
00219             s->parser->parser_close(s);
00220         av_free(s->priv_data);
00221         av_free(s);
00222     }
00223 }
00224 
00225 /*****************************************************/
00226 
00231 int ff_combine_frame(ParseContext *pc, int next, const uint8_t **buf, int *buf_size)
00232 {
00233 #if 0
00234     if(pc->overread){
00235         printf("overread %d, state:%X next:%d index:%d o_index:%d\n", pc->overread, pc->state, next, pc->index, pc->overread_index);
00236         printf("%X %X %X %X\n", (*buf)[0], (*buf)[1],(*buf)[2],(*buf)[3]);
00237     }
00238 #endif
00239 
00240     /* Copy overread bytes from last frame into buffer. */
00241     for(; pc->overread>0; pc->overread--){
00242         pc->buffer[pc->index++]= pc->buffer[pc->overread_index++];
00243     }
00244 
00245     /* flush remaining if EOF */
00246     if(!*buf_size && next == END_NOT_FOUND){
00247         next= 0;
00248     }
00249 
00250     pc->last_index= pc->index;
00251 
00252     /* copy into buffer end return */
00253     if(next == END_NOT_FOUND){
00254         void* new_buffer = av_fast_realloc(pc->buffer, &pc->buffer_size, (*buf_size) + pc->index + FF_INPUT_BUFFER_PADDING_SIZE);
00255 
00256         if(!new_buffer)
00257             return AVERROR(ENOMEM);
00258         pc->buffer = new_buffer;
00259         memcpy(&pc->buffer[pc->index], *buf, *buf_size);
00260         pc->index += *buf_size;
00261         return -1;
00262     }
00263 
00264     *buf_size=
00265     pc->overread_index= pc->index + next;
00266 
00267     /* append to buffer */
00268     if(pc->index){
00269         void* new_buffer = av_fast_realloc(pc->buffer, &pc->buffer_size, next + pc->index + FF_INPUT_BUFFER_PADDING_SIZE);
00270 
00271         if(!new_buffer)
00272             return AVERROR(ENOMEM);
00273         pc->buffer = new_buffer;
00274         memcpy(&pc->buffer[pc->index], *buf, next + FF_INPUT_BUFFER_PADDING_SIZE );
00275         pc->index = 0;
00276         *buf= pc->buffer;
00277     }
00278 
00279     /* store overread bytes */
00280     for(;next < 0; next++){
00281         pc->state = (pc->state<<8) | pc->buffer[pc->last_index + next];
00282         pc->state64 = (pc->state64<<8) | pc->buffer[pc->last_index + next];
00283         pc->overread++;
00284     }
00285 
00286 #if 0
00287     if(pc->overread){
00288         printf("overread %d, state:%X next:%d index:%d o_index:%d\n", pc->overread, pc->state, next, pc->index, pc->overread_index);
00289         printf("%X %X %X %X\n", (*buf)[0], (*buf)[1],(*buf)[2],(*buf)[3]);
00290     }
00291 #endif
00292 
00293     return 0;
00294 }
00295 
00296 void ff_parse_close(AVCodecParserContext *s)
00297 {
00298     ParseContext *pc = s->priv_data;
00299 
00300     av_freep(&pc->buffer);
00301 }
00302 
00303 void ff_parse1_close(AVCodecParserContext *s)
00304 {
00305     ParseContext1 *pc1 = s->priv_data;
00306 
00307     av_free(pc1->pc.buffer);
00308     av_free(pc1->enc);
00309 }
00310 
00311 /*************************/
00312 
00313 int ff_mpeg4video_split(AVCodecContext *avctx,
00314                            const uint8_t *buf, int buf_size)
00315 {
00316     int i;
00317     uint32_t state= -1;
00318 
00319     for(i=0; i<buf_size; i++){
00320         state= (state<<8) | buf[i];
00321         if(state == 0x1B3 || state == 0x1B6)
00322             return i-3;
00323     }
00324     return 0;
00325 }

Generated on Sat Feb 16 2013 09:23:13 for ffmpeg by  doxygen 1.7.1