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 <string.h>
00024 
00025 #include "parser.h"
00026 #include "libavutil/mem.h"
00027 
00028 static AVCodecParser *av_first_parser = NULL;
00029 
00030 AVCodecParser* av_parser_next(AVCodecParser *p){
00031     if(p) return p->next;
00032     else  return av_first_parser;
00033 }
00034 
00035 void av_register_codec_parser(AVCodecParser *parser)
00036 {
00037     parser->next = av_first_parser;
00038     av_first_parser = parser;
00039 }
00040 
00041 AVCodecParserContext *av_parser_init(int codec_id)
00042 {
00043     AVCodecParserContext *s;
00044     AVCodecParser *parser;
00045     int ret;
00046 
00047     if(codec_id == AV_CODEC_ID_NONE)
00048         return NULL;
00049 
00050     for(parser = av_first_parser; parser != NULL; parser = parser->next) {
00051         if (parser->codec_ids[0] == codec_id ||
00052             parser->codec_ids[1] == codec_id ||
00053             parser->codec_ids[2] == codec_id ||
00054             parser->codec_ids[3] == codec_id ||
00055             parser->codec_ids[4] == codec_id)
00056             goto found;
00057     }
00058     return NULL;
00059  found:
00060     s = av_mallocz(sizeof(AVCodecParserContext));
00061     if (!s)
00062         return NULL;
00063     s->parser = parser;
00064     s->priv_data = av_mallocz(parser->priv_data_size);
00065     if (!s->priv_data) {
00066         av_free(s);
00067         return NULL;
00068     }
00069     s->fetch_timestamp=1;
00070     s->pict_type = AV_PICTURE_TYPE_I;
00071     if (parser->parser_init) {
00072         ret = parser->parser_init(s);
00073         if (ret != 0) {
00074             av_free(s->priv_data);
00075             av_free(s);
00076             return NULL;
00077         }
00078     }
00079     s->key_frame = -1;
00080     s->convergence_duration = 0;
00081     s->dts_sync_point       = INT_MIN;
00082     s->dts_ref_dts_delta    = INT_MIN;
00083     s->pts_dts_delta        = INT_MIN;
00084     return s;
00085 }
00086 
00087 void ff_fetch_timestamp(AVCodecParserContext *s, int off, int remove){
00088     int i;
00089 
00090     s->dts= s->pts= AV_NOPTS_VALUE;
00091     s->pos= -1;
00092     s->offset= 0;
00093     for(i = 0; i < AV_PARSER_PTS_NB; i++) {
00094         if (   s->cur_offset + off >= s->cur_frame_offset[i]
00095             && (s->frame_offset < s->cur_frame_offset[i] ||
00096               (!s->frame_offset && !s->next_frame_offset)) // first field/frame
00097             //check is disabled because mpeg-ts doesn't send complete PES packets
00098             && /*s->next_frame_offset + off <*/  s->cur_frame_end[i]){
00099             s->dts= s->cur_frame_dts[i];
00100             s->pts= s->cur_frame_pts[i];
00101             s->pos= s->cur_frame_pos[i];
00102             s->offset = s->next_frame_offset - s->cur_frame_offset[i];
00103             if(remove)
00104                 s->cur_frame_offset[i]= INT64_MAX;
00105             if(s->cur_offset + off < s->cur_frame_end[i])
00106                 break;
00107         }
00108     }
00109 }
00110 
00111 int av_parser_parse2(AVCodecParserContext *s,
00112                      AVCodecContext *avctx,
00113                      uint8_t **poutbuf, int *poutbuf_size,
00114                      const uint8_t *buf, int buf_size,
00115                      int64_t pts, int64_t dts,
00116                      int64_t pos)
00117 {
00118     int index, i;
00119     uint8_t dummy_buf[FF_INPUT_BUFFER_PADDING_SIZE];
00120 
00121     if(!(s->flags & PARSER_FLAG_FETCHED_OFFSET)) {
00122         s->next_frame_offset =
00123         s->cur_offset        = pos;
00124         s->flags |= PARSER_FLAG_FETCHED_OFFSET;
00125     }
00126 
00127     if (buf_size == 0) {
00128         /* padding is always necessary even if EOF, so we add it here */
00129         memset(dummy_buf, 0, sizeof(dummy_buf));
00130         buf = dummy_buf;
00131     } else if (s->cur_offset + buf_size !=
00132                s->cur_frame_end[s->cur_frame_start_index]) { /* skip remainder packets */
00133         /* add a new packet descriptor */
00134             i = (s->cur_frame_start_index + 1) & (AV_PARSER_PTS_NB - 1);
00135             s->cur_frame_start_index = i;
00136             s->cur_frame_offset[i] = s->cur_offset;
00137             s->cur_frame_end[i] = s->cur_offset + buf_size;
00138             s->cur_frame_pts[i] = pts;
00139             s->cur_frame_dts[i] = dts;
00140             s->cur_frame_pos[i] = pos;
00141     }
00142 
00143     if (s->fetch_timestamp){
00144         s->fetch_timestamp=0;
00145         s->last_pts = s->pts;
00146         s->last_dts = s->dts;
00147         s->last_pos = s->pos;
00148         ff_fetch_timestamp(s, 0, 0);
00149     }
00150 
00151     /* WARNING: the returned index can be negative */
00152     index = s->parser->parser_parse(s, avctx, (const uint8_t **)poutbuf, poutbuf_size, buf, buf_size);
00153 //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);
00154     /* update the file pointer */
00155     if (*poutbuf_size) {
00156         /* fill the data for the current frame */
00157         s->frame_offset = s->next_frame_offset;
00158 
00159         /* offset of the next frame */
00160         s->next_frame_offset = s->cur_offset + index;
00161         s->fetch_timestamp=1;
00162     }
00163     if (index < 0)
00164         index = 0;
00165     s->cur_offset += index;
00166     return index;
00167 }
00168 
00174 int av_parser_change(AVCodecParserContext *s,
00175                      AVCodecContext *avctx,
00176                      uint8_t **poutbuf, int *poutbuf_size,
00177                      const uint8_t *buf, int buf_size, int keyframe){
00178 
00179     if(s && s->parser->split){
00180         if((avctx->flags & CODEC_FLAG_GLOBAL_HEADER) || (avctx->flags2 & CODEC_FLAG2_LOCAL_HEADER)){
00181             int i= s->parser->split(avctx, buf, buf_size);
00182             buf += i;
00183             buf_size -= i;
00184         }
00185     }
00186 
00187     /* cast to avoid warning about discarding qualifiers */
00188     *poutbuf= (uint8_t *) buf;
00189     *poutbuf_size= buf_size;
00190     if(avctx->extradata){
00191         if(  (keyframe && (avctx->flags2 & CODEC_FLAG2_LOCAL_HEADER))
00192             /*||(s->pict_type != AV_PICTURE_TYPE_I && (s->flags & PARSER_FLAG_DUMP_EXTRADATA_AT_NOKEY))*/
00193             /*||(? && (s->flags & PARSER_FLAG_DUMP_EXTRADATA_AT_BEGIN)*/){
00194             int size= buf_size + avctx->extradata_size;
00195             *poutbuf_size= size;
00196             *poutbuf= av_malloc(size + FF_INPUT_BUFFER_PADDING_SIZE);
00197 
00198             memcpy(*poutbuf, avctx->extradata, avctx->extradata_size);
00199             memcpy((*poutbuf) + avctx->extradata_size, buf, buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
00200             return 1;
00201         }
00202     }
00203 
00204     return 0;
00205 }
00206 
00207 void av_parser_close(AVCodecParserContext *s)
00208 {
00209     if(s){
00210         if (s->parser->parser_close)
00211             s->parser->parser_close(s);
00212         av_free(s->priv_data);
00213         av_free(s);
00214     }
00215 }
00216 
00217 /*****************************************************/
00218 
00223 int ff_combine_frame(ParseContext *pc, int next, const uint8_t **buf, int *buf_size)
00224 {
00225     if(pc->overread){
00226         av_dlog(NULL, "overread %d, state:%X next:%d index:%d o_index:%d\n",
00227                 pc->overread, pc->state, next, pc->index, pc->overread_index);
00228         av_dlog(NULL, "%X %X %X %X\n", (*buf)[0], (*buf)[1], (*buf)[2], (*buf)[3]);
00229     }
00230 
00231     /* Copy overread bytes from last frame into buffer. */
00232     for(; pc->overread>0; pc->overread--){
00233         pc->buffer[pc->index++]= pc->buffer[pc->overread_index++];
00234     }
00235 
00236     /* flush remaining if EOF */
00237     if(!*buf_size && next == END_NOT_FOUND){
00238         next= 0;
00239     }
00240 
00241     pc->last_index= pc->index;
00242 
00243     /* copy into buffer end return */
00244     if(next == END_NOT_FOUND){
00245         void* new_buffer = av_fast_realloc(pc->buffer, &pc->buffer_size, (*buf_size) + pc->index + FF_INPUT_BUFFER_PADDING_SIZE);
00246 
00247         if(!new_buffer)
00248             return AVERROR(ENOMEM);
00249         pc->buffer = new_buffer;
00250         memcpy(&pc->buffer[pc->index], *buf, *buf_size);
00251         pc->index += *buf_size;
00252         return -1;
00253     }
00254 
00255     *buf_size=
00256     pc->overread_index= pc->index + next;
00257 
00258     /* append to buffer */
00259     if(pc->index){
00260         void* new_buffer = av_fast_realloc(pc->buffer, &pc->buffer_size, next + pc->index + FF_INPUT_BUFFER_PADDING_SIZE);
00261 
00262         if(!new_buffer)
00263             return AVERROR(ENOMEM);
00264         pc->buffer = new_buffer;
00265         memcpy(&pc->buffer[pc->index], *buf, next + FF_INPUT_BUFFER_PADDING_SIZE );
00266         pc->index = 0;
00267         *buf= pc->buffer;
00268     }
00269 
00270     /* store overread bytes */
00271     for(;next < 0; next++){
00272         pc->state = (pc->state<<8) | pc->buffer[pc->last_index + next];
00273         pc->state64 = (pc->state64<<8) | pc->buffer[pc->last_index + next];
00274         pc->overread++;
00275     }
00276 
00277     if(pc->overread){
00278         av_dlog(NULL, "overread %d, state:%X next:%d index:%d o_index:%d\n",
00279                 pc->overread, pc->state, next, pc->index, pc->overread_index);
00280         av_dlog(NULL, "%X %X %X %X\n", (*buf)[0], (*buf)[1],(*buf)[2],(*buf)[3]);
00281     }
00282 
00283     return 0;
00284 }
00285 
00286 void ff_parse_close(AVCodecParserContext *s)
00287 {
00288     ParseContext *pc = s->priv_data;
00289 
00290     av_freep(&pc->buffer);
00291 }
00292 
00293 /*************************/
00294 
00295 int ff_mpeg4video_split(AVCodecContext *avctx,
00296                            const uint8_t *buf, int buf_size)
00297 {
00298     int i;
00299     uint32_t state= -1;
00300 
00301     for(i=0; i<buf_size; i++){
00302         state= (state<<8) | buf[i];
00303         if(state == 0x1B3 || state == 0x1B6)
00304             return i-3;
00305     }
00306     return 0;
00307 }