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 = NULL;
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         goto err_out;
00063     s->parser = parser;
00064     s->priv_data = av_mallocz(parser->priv_data_size);
00065     if (!s->priv_data)
00066         goto err_out;
00067     s->fetch_timestamp=1;
00068     s->pict_type = AV_PICTURE_TYPE_I;
00069     if (parser->parser_init) {
00070         ret = parser->parser_init(s);
00071         if (ret != 0)
00072             goto err_out;
00073     }
00074     s->key_frame = -1;
00075     s->convergence_duration = 0;
00076     s->dts_sync_point       = INT_MIN;
00077     s->dts_ref_dts_delta    = INT_MIN;
00078     s->pts_dts_delta        = INT_MIN;
00079     return s;
00080 
00081 err_out:
00082     if (s)
00083         av_freep(&s->priv_data);
00084     av_free(s);
00085     return NULL;
00086 }
00087 
00088 void ff_fetch_timestamp(AVCodecParserContext *s, int off, int remove){
00089     int i;
00090 
00091     s->dts= s->pts= AV_NOPTS_VALUE;
00092     s->pos= -1;
00093     s->offset= 0;
00094     for(i = 0; i < AV_PARSER_PTS_NB; i++) {
00095         if (   s->cur_offset + off >= s->cur_frame_offset[i]
00096             && (s->frame_offset < s->cur_frame_offset[i] ||
00097               (!s->frame_offset && !s->next_frame_offset)) // first field/frame
00098             //check is disabled because mpeg-ts doesn't send complete PES packets
00099             && /*s->next_frame_offset + off <*/  s->cur_frame_end[i]){
00100             s->dts= s->cur_frame_dts[i];
00101             s->pts= s->cur_frame_pts[i];
00102             s->pos= s->cur_frame_pos[i];
00103             s->offset = s->next_frame_offset - s->cur_frame_offset[i];
00104             if(remove)
00105                 s->cur_frame_offset[i]= INT64_MAX;
00106             if(s->cur_offset + off < s->cur_frame_end[i])
00107                 break;
00108         }
00109     }
00110 }
00111 
00112 int av_parser_parse2(AVCodecParserContext *s,
00113                      AVCodecContext *avctx,
00114                      uint8_t **poutbuf, int *poutbuf_size,
00115                      const uint8_t *buf, int buf_size,
00116                      int64_t pts, int64_t dts,
00117                      int64_t pos)
00118 {
00119     int index, i;
00120     uint8_t dummy_buf[FF_INPUT_BUFFER_PADDING_SIZE];
00121 
00122     if(!(s->flags & PARSER_FLAG_FETCHED_OFFSET)) {
00123         s->next_frame_offset =
00124         s->cur_offset        = pos;
00125         s->flags |= PARSER_FLAG_FETCHED_OFFSET;
00126     }
00127 
00128     if (buf_size == 0) {
00129         /* padding is always necessary even if EOF, so we add it here */
00130         memset(dummy_buf, 0, sizeof(dummy_buf));
00131         buf = dummy_buf;
00132     } else if (s->cur_offset + buf_size !=
00133                s->cur_frame_end[s->cur_frame_start_index]) { /* skip remainder packets */
00134         /* add a new packet descriptor */
00135             i = (s->cur_frame_start_index + 1) & (AV_PARSER_PTS_NB - 1);
00136             s->cur_frame_start_index = i;
00137             s->cur_frame_offset[i] = s->cur_offset;
00138             s->cur_frame_end[i] = s->cur_offset + buf_size;
00139             s->cur_frame_pts[i] = pts;
00140             s->cur_frame_dts[i] = dts;
00141             s->cur_frame_pos[i] = pos;
00142     }
00143 
00144     if (s->fetch_timestamp){
00145         s->fetch_timestamp=0;
00146         s->last_pts = s->pts;
00147         s->last_dts = s->dts;
00148         s->last_pos = s->pos;
00149         ff_fetch_timestamp(s, 0, 0);
00150     }
00151 
00152     /* WARNING: the returned index can be negative */
00153     index = s->parser->parser_parse(s, avctx, (const uint8_t **)poutbuf, poutbuf_size, buf, buf_size);
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 
00169 int av_parser_change(AVCodecParserContext *s,
00170                      AVCodecContext *avctx,
00171                      uint8_t **poutbuf, int *poutbuf_size,
00172                      const uint8_t *buf, int buf_size, int keyframe){
00173 
00174     if(s && s->parser->split){
00175         if((avctx->flags & CODEC_FLAG_GLOBAL_HEADER) || (avctx->flags2 & CODEC_FLAG2_LOCAL_HEADER)){
00176             int i= s->parser->split(avctx, buf, buf_size);
00177             buf += i;
00178             buf_size -= i;
00179         }
00180     }
00181 
00182     /* cast to avoid warning about discarding qualifiers */
00183     *poutbuf= (uint8_t *) buf;
00184     *poutbuf_size= buf_size;
00185     if(avctx->extradata){
00186         if(  (keyframe && (avctx->flags2 & CODEC_FLAG2_LOCAL_HEADER))
00187             /*||(s->pict_type != AV_PICTURE_TYPE_I && (s->flags & PARSER_FLAG_DUMP_EXTRADATA_AT_NOKEY))*/
00188             /*||(? && (s->flags & PARSER_FLAG_DUMP_EXTRADATA_AT_BEGIN)*/){
00189             int size= buf_size + avctx->extradata_size;
00190             *poutbuf_size= size;
00191             *poutbuf= av_malloc(size + FF_INPUT_BUFFER_PADDING_SIZE);
00192 
00193             memcpy(*poutbuf, avctx->extradata, avctx->extradata_size);
00194             memcpy((*poutbuf) + avctx->extradata_size, buf, buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
00195             return 1;
00196         }
00197     }
00198 
00199     return 0;
00200 }
00201 
00202 void av_parser_close(AVCodecParserContext *s)
00203 {
00204     if(s){
00205         if (s->parser->parser_close)
00206             s->parser->parser_close(s);
00207         av_free(s->priv_data);
00208         av_free(s);
00209     }
00210 }
00211 
00212 /*****************************************************/
00213 
00214 int ff_combine_frame(ParseContext *pc, int next, const uint8_t **buf, int *buf_size)
00215 {
00216     if(pc->overread){
00217         av_dlog(NULL, "overread %d, state:%X next:%d index:%d o_index:%d\n",
00218                 pc->overread, pc->state, next, pc->index, pc->overread_index);
00219         av_dlog(NULL, "%X %X %X %X\n", (*buf)[0], (*buf)[1], (*buf)[2], (*buf)[3]);
00220     }
00221 
00222     /* Copy overread bytes from last frame into buffer. */
00223     for(; pc->overread>0; pc->overread--){
00224         pc->buffer[pc->index++]= pc->buffer[pc->overread_index++];
00225     }
00226 
00227     /* flush remaining if EOF */
00228     if(!*buf_size && next == END_NOT_FOUND){
00229         next= 0;
00230     }
00231 
00232     pc->last_index= pc->index;
00233 
00234     /* copy into buffer end return */
00235     if(next == END_NOT_FOUND){
00236         void* new_buffer = av_fast_realloc(pc->buffer, &pc->buffer_size, (*buf_size) + pc->index + FF_INPUT_BUFFER_PADDING_SIZE);
00237 
00238         if(!new_buffer)
00239             return AVERROR(ENOMEM);
00240         pc->buffer = new_buffer;
00241         memcpy(&pc->buffer[pc->index], *buf, *buf_size);
00242         pc->index += *buf_size;
00243         return -1;
00244     }
00245 
00246     *buf_size=
00247     pc->overread_index= pc->index + next;
00248 
00249     /* append to buffer */
00250     if(pc->index){
00251         void* new_buffer = av_fast_realloc(pc->buffer, &pc->buffer_size, next + pc->index + FF_INPUT_BUFFER_PADDING_SIZE);
00252 
00253         if(!new_buffer)
00254             return AVERROR(ENOMEM);
00255         pc->buffer = new_buffer;
00256         if (next > -FF_INPUT_BUFFER_PADDING_SIZE)
00257             memcpy(&pc->buffer[pc->index], *buf,
00258                    next + FF_INPUT_BUFFER_PADDING_SIZE);
00259         pc->index = 0;
00260         *buf= pc->buffer;
00261     }
00262 
00263     /* store overread bytes */
00264     for(;next < 0; next++){
00265         pc->state = (pc->state<<8) | pc->buffer[pc->last_index + next];
00266         pc->state64 = (pc->state64<<8) | pc->buffer[pc->last_index + next];
00267         pc->overread++;
00268     }
00269 
00270     if(pc->overread){
00271         av_dlog(NULL, "overread %d, state:%X next:%d index:%d o_index:%d\n",
00272                 pc->overread, pc->state, next, pc->index, pc->overread_index);
00273         av_dlog(NULL, "%X %X %X %X\n", (*buf)[0], (*buf)[1],(*buf)[2],(*buf)[3]);
00274     }
00275 
00276     return 0;
00277 }
00278 
00279 void ff_parse_close(AVCodecParserContext *s)
00280 {
00281     ParseContext *pc = s->priv_data;
00282 
00283     av_freep(&pc->buffer);
00284 }
00285 
00286 /*************************/
00287 
00288 int ff_mpeg4video_split(AVCodecContext *avctx,
00289                            const uint8_t *buf, int buf_size)
00290 {
00291     int i;
00292     uint32_t state= -1;
00293 
00294     for(i=0; i<buf_size; i++){
00295         state= (state<<8) | buf[i];
00296         if(state == 0x1B3 || state == 0x1B6)
00297             return i-3;
00298     }
00299     return 0;
00300 }