FFmpeg: libavcodec/parser.c Source File

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     s->fetch_timestamp=1;
00067     s->pict_type = AV_PICTURE_TYPE_I;
00068     if (parser->parser_init) {
00069         ret = parser->parser_init(s);
00070         if (ret != 0) {
00071             av_free(s->priv_data);
00072             av_free(s);
00073             return NULL;
00074         }
00075     }
00076     s->key_frame = -1;
00077     s->convergence_duration = 0;
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->pos= -1;
00089     s->offset= 0;
00090     for(i = 0; i < AV_PARSER_PTS_NB; i++) {
00091         if (   s->cur_offset + off >= s->cur_frame_offset[i]
00092             && (s->frame_offset < s->cur_frame_offset[i] ||
00093               (!s->frame_offset && !s->next_frame_offset)) // first field/frame
00094             //check is disabled  because mpeg-ts doesnt send complete PES packets
00095             && /*s->next_frame_offset + off <*/  s->cur_frame_end[i]){
00096             s->dts= s->cur_frame_dts[i];
00097             s->pts= s->cur_frame_pts[i];
00098             s->pos= s->cur_frame_pos[i];
00099             s->offset = s->next_frame_offset - s->cur_frame_offset[i];
00100             if(remove)
00101                 s->cur_frame_offset[i]= INT64_MAX;
00102             if(s->cur_offset + off < s->cur_frame_end[i])
00103                 break;
00104         }
00105     }
00106 }
00107 
00108 int av_parser_parse2(AVCodecParserContext *s,
00109                      AVCodecContext *avctx,
00110                      uint8_t **poutbuf, int *poutbuf_size,
00111                      const uint8_t *buf, int buf_size,
00112                      int64_t pts, int64_t dts,
00113                      int64_t pos)
00114 {
00115     int index, i;
00116     uint8_t dummy_buf[FF_INPUT_BUFFER_PADDING_SIZE];
00117 
00118     if(!(s->flags & PARSER_FLAG_FETCHED_OFFSET)) {
00119         s->next_frame_offset =
00120         s->cur_offset        = pos;
00121         s->flags |= PARSER_FLAG_FETCHED_OFFSET;
00122     }
00123 
00124     if (buf_size == 0) {
00125         /* padding is always necessary even if EOF, so we add it here */
00126         memset(dummy_buf, 0, sizeof(dummy_buf));
00127         buf = dummy_buf;
00128     } else if (s->cur_offset + buf_size !=
00129                s->cur_frame_end[s->cur_frame_start_index]) { /* skip remainder packets */
00130         /* add a new packet descriptor */
00131             i = (s->cur_frame_start_index + 1) & (AV_PARSER_PTS_NB - 1);
00132             s->cur_frame_start_index = i;
00133             s->cur_frame_offset[i] = s->cur_offset;
00134             s->cur_frame_end[i] = s->cur_offset + buf_size;
00135             s->cur_frame_pts[i] = pts;
00136             s->cur_frame_dts[i] = dts;
00137             s->cur_frame_pos[i] = pos;
00138     }
00139 
00140     if (s->fetch_timestamp){
00141         s->fetch_timestamp=0;
00142         s->last_pts = s->pts;
00143         s->last_dts = s->dts;
00144         s->last_pos = s->pos;
00145         ff_fetch_timestamp(s, 0, 0);
00146     }
00147 
00148     /* WARNING: the returned index can be negative */
00149     index = s->parser->parser_parse(s, avctx, (const uint8_t **)poutbuf, poutbuf_size, buf, buf_size);
00150 //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);
00151     /* update the file pointer */
00152     if (*poutbuf_size) {
00153         /* fill the data for the current frame */
00154         s->frame_offset = s->next_frame_offset;
00155 
00156         /* offset of the next frame */
00157         s->next_frame_offset = s->cur_offset + index;
00158         s->fetch_timestamp=1;
00159     }
00160     if (index < 0)
00161         index = 0;
00162     s->cur_offset += index;
00163     return index;
00164 }
00165 
00171 int av_parser_change(AVCodecParserContext *s,
00172                      AVCodecContext *avctx,
00173                      uint8_t **poutbuf, int *poutbuf_size,
00174                      const uint8_t *buf, int buf_size, int keyframe){
00175 
00176     if(s && s->parser->split){
00177         if((avctx->flags & CODEC_FLAG_GLOBAL_HEADER) || (avctx->flags2 & CODEC_FLAG2_LOCAL_HEADER)){
00178             int i= s->parser->split(avctx, buf, buf_size);
00179             buf += i;
00180             buf_size -= i;
00181         }
00182     }
00183 
00184     /* cast to avoid warning about discarding qualifiers */
00185     *poutbuf= (uint8_t *) buf;
00186     *poutbuf_size= buf_size;
00187     if(avctx->extradata){
00188         if(  (keyframe && (avctx->flags2 & CODEC_FLAG2_LOCAL_HEADER))
00189             /*||(s->pict_type != AV_PICTURE_TYPE_I && (s->flags & PARSER_FLAG_DUMP_EXTRADATA_AT_NOKEY))*/
00190             /*||(? && (s->flags & PARSER_FLAG_DUMP_EXTRADATA_AT_BEGIN)*/){
00191             int size= buf_size + avctx->extradata_size;
00192             *poutbuf_size= size;
00193             *poutbuf= av_malloc(size + FF_INPUT_BUFFER_PADDING_SIZE);
00194 
00195             memcpy(*poutbuf, avctx->extradata, avctx->extradata_size);
00196             memcpy((*poutbuf) + avctx->extradata_size, buf, buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
00197             return 1;
00198         }
00199     }
00200 
00201     return 0;
00202 }
00203 
00204 void av_parser_close(AVCodecParserContext *s)
00205 {
00206     if(s){
00207         if (s->parser->parser_close)
00208             s->parser->parser_close(s);
00209         av_free(s->priv_data);
00210         av_free(s);
00211     }
00212 }
00213 
00214 /*****************************************************/
00215 
00220 int ff_combine_frame(ParseContext *pc, int next, const uint8_t **buf, int *buf_size)
00221 {
00222     if(pc->overread){
00223         av_dlog(NULL, "overread %d, state:%X next:%d index:%d o_index:%d\n",
00224                 pc->overread, pc->state, next, pc->index, pc->overread_index);
00225         av_dlog(NULL, "%X %X %X %X\n", (*buf)[0], (*buf)[1], (*buf)[2], (*buf)[3]);
00226     }
00227 
00228     /* Copy overread bytes from last frame into buffer. */
00229     for(; pc->overread>0; pc->overread--){
00230         pc->buffer[pc->index++]= pc->buffer[pc->overread_index++];
00231     }
00232 
00233     /* flush remaining if EOF */
00234     if(!*buf_size && next == END_NOT_FOUND){
00235         next= 0;
00236     }
00237 
00238     pc->last_index= pc->index;
00239 
00240     /* copy into buffer end return */
00241     if(next == END_NOT_FOUND){
00242         void* new_buffer = av_fast_realloc(pc->buffer, &pc->buffer_size, (*buf_size) + pc->index + FF_INPUT_BUFFER_PADDING_SIZE);
00243 
00244         if(!new_buffer)
00245             return AVERROR(ENOMEM);
00246         pc->buffer = new_buffer;
00247         memcpy(&pc->buffer[pc->index], *buf, *buf_size);
00248         pc->index += *buf_size;
00249         return -1;
00250     }
00251 
00252     *buf_size=
00253     pc->overread_index= pc->index + next;
00254 
00255     /* append to buffer */
00256     if(pc->index){
00257         void* new_buffer = av_fast_realloc(pc->buffer, &pc->buffer_size, next + pc->index + FF_INPUT_BUFFER_PADDING_SIZE);
00258 
00259         if(!new_buffer)
00260             return AVERROR(ENOMEM);
00261         pc->buffer = new_buffer;
00262         memcpy(&pc->buffer[pc->index], *buf, next + FF_INPUT_BUFFER_PADDING_SIZE );
00263         pc->index = 0;
00264         *buf= pc->buffer;
00265     }
00266 
00267     /* store overread bytes */
00268     for(;next < 0; next++){
00269         pc->state = (pc->state<<8) | pc->buffer[pc->last_index + next];
00270         pc->state64 = (pc->state64<<8) | pc->buffer[pc->last_index + next];
00271         pc->overread++;
00272     }
00273 
00274     if(pc->overread){
00275         av_dlog(NULL, "overread %d, state:%X next:%d index:%d o_index:%d\n",
00276                 pc->overread, pc->state, next, pc->index, pc->overread_index);
00277         av_dlog(NULL, "%X %X %X %X\n", (*buf)[0], (*buf)[1],(*buf)[2],(*buf)[3]);
00278     }
00279 
00280     return 0;
00281 }
00282 
00283 void ff_parse_close(AVCodecParserContext *s)
00284 {
00285     ParseContext *pc = s->priv_data;
00286 
00287     av_freep(&pc->buffer);
00288 }
00289 
00290 /*************************/
00291 
00292 int ff_mpeg4video_split(AVCodecContext *avctx,
00293                            const uint8_t *buf, int buf_size)
00294 {
00295     int i;
00296     uint32_t state= -1;
00297 
00298     for(i=0; i<buf_size; i++){
00299         state= (state<<8) | buf[i];
00300         if(state == 0x1B3 || state == 0x1B6)
00301             return i-3;
00302     }
00303     return 0;
00304 }