ffmpeg.c

F:图像处理资料264264书籍ffmpeg-0.4.9-pre1VideoStream.rar 一个视频解压缩源代码

                ret = avcodec_decode_audio(&ist->st->codec, samples, &data_size,
                                           ptr, len);
                if (ret < 0)
                    goto fail_decode;
                ptr += ret;
                len -= ret;
                /* Some bug in mpeg audio decoder gives */
                /* data_size < 0, it seems they are overflows */
                if (data_size <= 0) {
                    /* no audio frame */
                    continue;
                }
                data_buf = (uint8_t *)samples;
                ist->next_pts += ((int64_t)AV_TIME_BASE/2 * data_size) / 
                    (ist->st->codec.sample_rate * ist->st->codec.channels);
                break;
            case CODEC_TYPE_VIDEO:
                    data_size = (ist->st->codec.width * ist->st->codec.height * 3) / 2;
                    /* XXX: allocate picture correctly */
                    avcodec_get_frame_defaults(&picture);

                    ret = avcodec_decode_video(&ist->st->codec, 
                                               &picture, &got_picture, ptr, len);
                    ist->st->quality= picture.quality;
                    if (ret < 0) 
                        goto fail_decode;
                    if (!got_picture) {
                        /* no picture yet */
                        goto discard_packet;
                    }
                    if (ist->st->codec.frame_rate_base != 0) {
                        ist->next_pts += ((int64_t)AV_TIME_BASE * 
                                          ist->st->codec.frame_rate_base) /
                            ist->st->codec.frame_rate;
                    }
                    len = 0;
                    break;
                default:
                    goto fail_decode;
                }
            } else {
                data_buf = ptr;
                data_size = len;
                ret = len;
                len = 0;
            }

            buffer_to_free = NULL;
            if (ist->st->codec.codec_type == CODEC_TYPE_VIDEO) {
                pre_process_video_frame(ist, (AVPicture *)&picture, 
                                        &buffer_to_free);
            }

            /* frame rate emulation */
            if (ist->st->codec.rate_emu) {
                int64_t pts = av_rescale((int64_t) ist->frame * ist->st->codec.frame_rate_base, 1000000, ist->st->codec.frame_rate);
                int64_t now = av_gettime() - ist->start;
                if (pts > now)
                    usleep(pts - now);

                ist->frame++;
            }

#if 0
            /* mpeg PTS deordering : if it is a P or I frame, the PTS
               is the one of the next displayed one */
            /* XXX: add mpeg4 too ? */
            if (ist->st->codec.codec_id == CODEC_ID_MPEG1VIDEO) {
                if (ist->st->codec.pict_type != B_TYPE) {
                    int64_t tmp;
                    tmp = ist->last_ip_pts;
                    ist->last_ip_pts  = ist->frac_pts.val;
                    ist->frac_pts.val = tmp;
                }
            }
#endif
            /* if output time reached then transcode raw format, 
	       encode packets and output them */
            if (start_time == 0 || ist->pts >= start_time)
                for(i=0;i<nb_ostreams;i++) {
                    int frame_size;

                    ost = ost_table[i];
                    if (ost->source_index == ist_index) {
                        os = output_files[ost->file_index];

#if 0
                        printf("%d: got pts=%0.3f %0.3f\n", i, 
                               (double)pkt->pts / AV_TIME_BASE, 
                               ((double)ist->pts / AV_TIME_BASE) - 
                               ((double)ost->st->pts.val * ost->st->time_base.num / ost->st->time_base.den));
#endif
                        /* set the input output pts pairs */
                        ost->sync_ipts = (double)(ist->pts + input_files_ts_offset[ist->file_index])/ AV_TIME_BASE;

                        if (ost->encoding_needed) {
                            switch(ost->st->codec.codec_type) {
                            case CODEC_TYPE_AUDIO:
                                do_audio_out(os, ost, ist, data_buf, data_size);
                                break;
                            case CODEC_TYPE_VIDEO:
                                /* find an audio stream for synchro */
                                {
                                    int i;
                                    AVOutputStream *audio_sync, *ost1;
                                    audio_sync = NULL;
                                    for(i=0;i<nb_ostreams;i++) {
                                        ost1 = ost_table[i];
                                        if (ost1->file_index == ost->file_index &&
                                            ost1->st->codec.codec_type == CODEC_TYPE_AUDIO) {
                                            audio_sync = ost1;
                                            break;
                                        }
                                    }

                                    do_video_out(os, ost, ist, &picture, &frame_size);
                                    video_size += frame_size;
                                    if (do_vstats && frame_size)
                                        do_video_stats(os, ost, frame_size);
                                }
                                break;
                            default:
                                av_abort();
                            }
                        } else {
                            AVFrame avframe; //FIXME/XXX remove this
                            AVPacket opkt;
                            av_init_packet(&opkt);

                            /* no reencoding needed : output the packet directly */
                            /* force the input stream PTS */
                        
                            avcodec_get_frame_defaults(&avframe);
                            ost->st->codec.coded_frame= &avframe;
                            avframe.key_frame = pkt->flags & PKT_FLAG_KEY; 

                            if(ost->st->codec.codec_type == CODEC_TYPE_AUDIO)
                                audio_size += data_size;
                            else if (ost->st->codec.codec_type == CODEC_TYPE_VIDEO)
                                video_size += data_size;

                            opkt.stream_index= ost->index;
                            opkt.data= data_buf;
                            opkt.size= data_size;
                            opkt.pts= pkt->pts + input_files_ts_offset[ist->file_index];
                            opkt.dts= pkt->dts + input_files_ts_offset[ist->file_index];
                            opkt.flags= pkt->flags;
                            
                            av_interleaved_write_frame(os, &opkt);
                            ost->st->codec.frame_number++;
                            ost->frame_number++;
                        }
                    }
                }
            av_free(buffer_to_free);
        }
 discard_packet:
    if (pkt == NULL) {
        /* EOF handling */
  
        for(i=0;i<nb_ostreams;i++) {
            ost = ost_table[i];
            if (ost->source_index == ist_index) {
                AVCodecContext *enc= &ost->st->codec;
                os = output_files[ost->file_index];
                
                if(ost->st->codec.codec_type == CODEC_TYPE_AUDIO && enc->frame_size <=1)
                    continue;
                if(ost->st->codec.codec_type == CODEC_TYPE_VIDEO && (os->oformat->flags & AVFMT_RAWPICTURE))
                    continue;

                if (ost->encoding_needed) {
                    for(;;) {
                        AVPacket pkt;
                        av_init_packet(&pkt);
                        pkt.stream_index= ost->index;
 
                        switch(ost->st->codec.codec_type) {
                        case CODEC_TYPE_AUDIO:        
                            ret = avcodec_encode_audio(enc, bit_buffer, VIDEO_BUFFER_SIZE, NULL);
                            audio_size += ret;
                            pkt.flags |= PKT_FLAG_KEY;
                            break;
                        case CODEC_TYPE_VIDEO:
                            ret = avcodec_encode_video(enc, bit_buffer, VIDEO_BUFFER_SIZE, NULL);
                            video_size += ret;
                            if(enc->coded_frame && enc->coded_frame->key_frame)
                                pkt.flags |= PKT_FLAG_KEY;
                            if (ost->logfile && enc->stats_out) {
                                fprintf(ost->logfile, "%s", enc->stats_out);
                            }
                            break;
                        default:
                            ret=-1;
                        }
                            
                        if(ret<=0)
                            break;
                        pkt.data= bit_buffer;
                        pkt.size= ret;
                        if(enc->coded_frame)
                            pkt.pts= enc->coded_frame->pts;
                        av_interleaved_write_frame(os, &pkt);
                    }
                }
            }
        }
    }
 
    return 0;
 fail_decode:
    return -1;
}


/*
 * The following code is the main loop of the file converter
 */
static int av_encode(AVFormatContext **output_files,
                     int nb_output_files,
                     AVFormatContext **input_files,
                     int nb_input_files,
                     AVStreamMap *stream_maps, int nb_stream_maps)
{
    int ret, i, j, k, n, nb_istreams = 0, nb_ostreams = 0;
    AVFormatContext *is, *os;
    AVCodecContext *codec, *icodec;
    AVOutputStream *ost, **ost_table = NULL;
    AVInputStream *ist, **ist_table = NULL;
    AVInputFile *file_table;
    AVFormatContext *stream_no_data;
    int key;

    file_table= (AVInputFile*) av_mallocz(nb_input_files * sizeof(AVInputFile));
    if (!file_table)
        goto fail;

    if (!bit_buffer)
        bit_buffer = av_malloc(VIDEO_BUFFER_SIZE);
    if (!bit_buffer)
        goto fail;
        
    /* input stream init */
    j = 0;
    for(i=0;i<nb_input_files;i++) {
        is = input_files[i];
        file_table[i].ist_index = j;
        file_table[i].nb_streams = is->nb_streams;
        j += is->nb_streams;
    }
    nb_istreams = j;

    ist_table = av_mallocz(nb_istreams * sizeof(AVInputStream *));
    if (!ist_table)
        goto fail;
    
    for(i=0;i<nb_istreams;i++) {
        ist = av_mallocz(sizeof(AVInputStream));
        if (!ist)
            goto fail;
        ist_table[i] = ist;
    }
    j = 0;
    for(i=0;i<nb_input_files;i++) {
        is = input_files[i];
        for(k=0;k<is->nb_streams;k++) {
            ist = ist_table[j++];
            ist->st = is->streams[k];
            ist->file_index = i;
            ist->index = k;
            ist->discard = 1; /* the stream is discarded by default
                                 (changed later) */

            if (ist->st->codec.rate_emu) {
                ist->start = av_gettime();
                ist->frame = 0;
            }
        }
    }

    /* output stream init */
    nb_ostreams = 0;
    for(i=0;i<nb_output_files;i++) {
        os = output_files[i];
        nb_ostreams += os->nb_streams;
    }
    if (nb_stream_maps > 0 && nb_stream_maps != nb_ostreams) {
        fprintf(stderr, "Number of stream maps must match number of output streams\n");
        exit(1);
    }

    /* Sanity check the mapping args -- do the input files & streams exist? */
    for(i=0;i<nb_stream_maps;i++) {
        int fi = stream_maps[i].file_index;
        int si = stream_maps[i].stream_index;
        
        if (fi < 0 || fi > nb_input_files - 1 ||
            si < 0 || si > file_table[fi].nb_streams - 1) {
            fprintf(stderr,"Could not find input stream #%d.%d\n", fi, si);
            exit(1);
        }
    }
    
    ost_table = av_mallocz(sizeof(AVOutputStream *) * nb_ostreams);
    if (!ost_table)
        goto fail;
    for(i=0;i<nb_ostreams;i++) {
        ost = av_mallocz(sizeof(AVOutputStream));
        if (!ost)
            goto fail;
        ost_table[i] = ost;
    }
    
    n = 0;
    for(k=0;k<nb_output_files;k++) {
        os = output_files[k];
        for(i=0;i<os->nb_streams;i++) {
            int found;
            ost = ost_table[n++];
            ost->file_index = k;
            ost->index = i;
            ost->st = os->streams[i];
            if (nb_stream_maps > 0) {
                ost->source_index = file_table[stream_maps[n-1].file_index].ist_index + 
                    stream_maps[n-1].stream_index;
                    
                /* Sanity check that the stream types match */
                if (ist_table[ost->source_index]->st->codec.codec_type != ost->st->codec.codec_type) {
                    fprintf(stderr, "Codec type mismatch for mapping #%d.%d -> #%d.%d\n",
                        stream_maps[n-1].file_index, stream_maps[n-1].stream_index,
                        ost->file_index, ost->index);
                    exit(1);
                }
                
            } else {
                /* get corresponding input stream index : we select the first one with the right type */
                found = 0;
                for(j=0;j<nb_istreams;j++) {
                    ist = ist_table[j];
                    if (ist->discard && 
                        ist->st->codec.codec_type == ost->st->codec.codec_type) {
                        ost->source_index = j;
                        found = 1;
                    }
                }
                
                if (!found) {
                    /* try again and reuse existing stream */
                    for(j=0;j<nb_istreams;j++) {
                        ist = ist_table[j];
                        if (ist->st->codec.codec_type == ost->st->codec.codec_type) {
                            ost->source_index = j;
                            found = 1;
                        }
                    }
                    if (!found) {
                        fprintf(stderr, "Could not find input stream matching output stream #%d.%d\n",
                                ost->file_index, ost->index);
                        exit(1);
                    }
                }
            }
            ist = ist_table[ost->source_index];
            ist->discard = 0;
        }
    }