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

    /* for each output stream, we compute the right encoding parameters */
    for(i=0;i<nb_ostreams;i++) {
        ost = ost_table[i];
        ist = ist_table[ost->source_index];

        codec = &ost->st->codec;
        icodec = &ist->st->codec;

        if (ost->st->stream_copy) {
            /* if stream_copy is selected, no need to decode or encode */
            codec->codec_id = icodec->codec_id;
            codec->codec_type = icodec->codec_type;
            codec->codec_tag = icodec->codec_tag;
            codec->bit_rate = icodec->bit_rate;
            switch(codec->codec_type) {
            case CODEC_TYPE_AUDIO:
                codec->sample_rate = icodec->sample_rate;
                codec->channels = icodec->channels;
                codec->frame_size = icodec->frame_size;
                break;
            case CODEC_TYPE_VIDEO:
                codec->frame_rate = icodec->frame_rate;
                codec->frame_rate_base = icodec->frame_rate_base;
                codec->width = icodec->width;
                codec->height = icodec->height;
                break;
            default:
                av_abort();
            }
        } else {
            switch(codec->codec_type) {
            case CODEC_TYPE_AUDIO:
                if (fifo_init(&ost->fifo, 2 * MAX_AUDIO_PACKET_SIZE))
                    goto fail;
                
                if (codec->channels == icodec->channels &&
                    codec->sample_rate == icodec->sample_rate) {
                    ost->audio_resample = 0;
                } else {
                    if (codec->channels != icodec->channels &&
                        icodec->codec_id == CODEC_ID_AC3) {
                        /* Special case for 5:1 AC3 input */
                        /* and mono or stereo output      */
                        /* Request specific number of channels */
                        icodec->channels = codec->channels;
                        if (codec->sample_rate == icodec->sample_rate)
                            ost->audio_resample = 0;
                        else {
                            ost->audio_resample = 1;
                        }
                    } else {
                        ost->audio_resample = 1; 
                    }
                }
                if(audio_sync_method>1)
                    ost->audio_resample = 1;

                if(ost->audio_resample){
                    ost->resample = audio_resample_init(codec->channels, icodec->channels,
                                                    codec->sample_rate, icodec->sample_rate);
                    if(!ost->resample){
                        printf("Can't resample.  Aborting.\n");
                        av_abort();
                    }
                }
                ist->decoding_needed = 1;
                ost->encoding_needed = 1;
                break;
            case CODEC_TYPE_VIDEO:
                if (codec->width == icodec->width &&
                    codec->height == icodec->height &&
                    frame_topBand == 0 &&
                    frame_bottomBand == 0 &&
                    frame_leftBand == 0 &&
                    frame_rightBand == 0 && 
                    frame_padtop == 0 &&
                    frame_padbottom == 0 &&
                    frame_padleft == 0 &&
                    frame_padright == 0)
                {
                    ost->video_resample = 0;
                    ost->video_crop = 0;
                    ost->video_pad = 0;
                } else if ((codec->width == icodec->width -
                                (frame_leftBand + frame_rightBand)) &&
                        (codec->height == icodec->height -
                                (frame_topBand  + frame_bottomBand)))
                {
                    ost->video_resample = 0;
                    ost->video_crop = 1;
                    ost->topBand = frame_topBand;
                    ost->leftBand = frame_leftBand;
                } else if ((codec->width == icodec->width + 
                                (frame_padleft + frame_padright)) &&
                        (codec->height == icodec->height +
                                (frame_padtop + frame_padbottom))) {
                    ost->video_resample = 0;
                    ost->video_crop = 0;
                    ost->video_pad = 1;
                    ost->padtop = frame_padtop;
                    ost->padleft = frame_padleft;
                    ost->padbottom = frame_padbottom;
                    ost->padright = frame_padright;
                    avcodec_get_frame_defaults(&ost->pict_tmp);
                    if( avpicture_alloc( (AVPicture*)&ost->pict_tmp, PIX_FMT_YUV420P,
                                codec->width, codec->height ) )
                        goto fail;
                } else {
                    ost->video_resample = 1;
                    ost->video_crop = 0; // cropping is handled as part of resample
                    avcodec_get_frame_defaults(&ost->pict_tmp);
                    if( avpicture_alloc( (AVPicture*)&ost->pict_tmp, PIX_FMT_YUV420P,
                                         codec->width, codec->height ) )
                        goto fail;

                    ost->img_resample_ctx = img_resample_full_init( 
                                      ost->st->codec.width, ost->st->codec.height,
                                      ist->st->codec.width, ist->st->codec.height,
                                      frame_topBand, frame_bottomBand,
                            frame_leftBand, frame_rightBand, 
                            frame_padtop, frame_padbottom, 
                            frame_padleft, frame_padright);
                    
                    ost->padtop = frame_padtop;
                    ost->padleft = frame_padleft;
                    ost->padbottom = frame_padbottom;
                    ost->padright = frame_padright;
                   
                }
                ost->encoding_needed = 1;
                ist->decoding_needed = 1;
                break;
            default:
                av_abort();
            }
            /* two pass mode */
            if (ost->encoding_needed && 
                (codec->flags & (CODEC_FLAG_PASS1 | CODEC_FLAG_PASS2))) {
                char logfilename[1024];
                FILE *f;
                int size;
                char *logbuffer;
                
                snprintf(logfilename, sizeof(logfilename), "%s-%d.log", 
                         pass_logfilename ? 
                         pass_logfilename : DEFAULT_PASS_LOGFILENAME, i);
                if (codec->flags & CODEC_FLAG_PASS1) {
                    f = fopen(logfilename, "w");
                    if (!f) {
                        perror(logfilename);
                        exit(1);
                    }
                    ost->logfile = f;
                } else {
                    /* read the log file */
                    f = fopen(logfilename, "r");
                    if (!f) {
                        perror(logfilename);
                        exit(1);
                    }
                    fseek(f, 0, SEEK_END);
                    size = ftell(f);
                    fseek(f, 0, SEEK_SET);
                    logbuffer = av_malloc(size + 1);
                    if (!logbuffer) {
                        fprintf(stderr, "Could not allocate log buffer\n");
                        exit(1);
                    }
                    size = fread(logbuffer, 1, size, f);
                    fclose(f);
                    logbuffer[size] = '\0';
                    codec->stats_in = logbuffer;
                }
            }
        }
    }

    /* dump the file output parameters - cannot be done before in case
       of stream copy */
    for(i=0;i<nb_output_files;i++) {
        dump_format(output_files[i], i, output_files[i]->filename, 1);
    }

    /* dump the stream mapping */
    if (verbose >= 0) {
        fprintf(stderr, "Stream mapping:\n");
        for(i=0;i<nb_ostreams;i++) {
            ost = ost_table[i];
            fprintf(stderr, "  Stream #%d.%d -> #%d.%d\n",
                    ist_table[ost->source_index]->file_index,
                    ist_table[ost->source_index]->index,
                    ost->file_index, 
                    ost->index);
        }
    }

    /* open each encoder */
    for(i=0;i<nb_ostreams;i++) {
        ost = ost_table[i];
        if (ost->encoding_needed) {
            AVCodec *codec;
            codec = avcodec_find_encoder(ost->st->codec.codec_id);
            if (!codec) {
                fprintf(stderr, "Unsupported codec for output stream #%d.%d\n", 
                        ost->file_index, ost->index);
                exit(1);
            }
            if (avcodec_open(&ost->st->codec, codec) < 0) {
                fprintf(stderr, "Error while opening codec for stream #%d.%d - maybe incorrect parameters such as bit_rate, rate, width or height\n", 
                        ost->file_index, ost->index);
                exit(1);
            }
            extra_size += ost->st->codec.extradata_size;
        }
    }

    /* open each decoder */
    for(i=0;i<nb_istreams;i++) {
        ist = ist_table[i];
        if (ist->decoding_needed) {
            AVCodec *codec;
            codec = avcodec_find_decoder(ist->st->codec.codec_id);
            if (!codec) {
                fprintf(stderr, "Unsupported codec (id=%d) for input stream #%d.%d\n", 
                        ist->st->codec.codec_id, ist->file_index, ist->index);
                exit(1);
            }
            if (avcodec_open(&ist->st->codec, codec) < 0) {
                fprintf(stderr, "Error while opening codec for input stream #%d.%d\n", 
                        ist->file_index, ist->index);
                exit(1);
            }
            //if (ist->st->codec.codec_type == CODEC_TYPE_VIDEO)
            //    ist->st->codec.flags |= CODEC_FLAG_REPEAT_FIELD;
        }
    }

    /* init pts */
    for(i=0;i<nb_istreams;i++) {
        ist = ist_table[i];
	is = input_files[ist->file_index];
        ist->pts = 0;
        ist->next_pts = 0;
        ist->is_start = 1;
    }
    
    /* compute buffer size max (should use a complete heuristic) */
    for(i=0;i<nb_input_files;i++) {
        file_table[i].buffer_size_max = 2048;
    }

    /* open files and write file headers */
    for(i=0;i<nb_output_files;i++) {
        os = output_files[i];
        if (av_write_header(os) < 0) {
            fprintf(stderr, "Could not write header for output file #%d (incorrect codec paramters ?)\n", i);
            ret = -EINVAL;
            goto fail;
        }
    }

#ifndef CONFIG_WIN32
    if ( !using_stdin && verbose >= 0) {
        fprintf(stderr, "Press [q] to stop encoding\n");
        url_set_interrupt_cb(decode_interrupt_cb);
    }
#endif
    term_init();

    stream_no_data = 0;
    key = -1;

    for(; received_sigterm == 0;) {
        int file_index, ist_index;
        AVPacket pkt;
        double ipts_min= 1e100;
        double opts_min= 1e100;

    redo:
        /* if 'q' pressed, exits */
        if (!using_stdin) {
            if (q_pressed)
                break;
            /* read_key() returns 0 on EOF */
            key = read_key();
            if (key == 'q')
                break;
        }

        /* select the stream that we must read now by looking at the
           smallest output pts */
        file_index = -1;
        for(i=0;i<nb_ostreams;i++) {
            double ipts, opts;
            ost = ost_table[i];
            os = output_files[ost->file_index];
            ist = ist_table[ost->source_index];
            if(ost->st->codec.codec_type == CODEC_TYPE_VIDEO)
                opts = (double)ost->sync_opts * ost->st->codec.frame_rate_base / ost->st->codec.frame_rate;
            else
                opts = (double)ost->st->pts.val * ost->st->time_base.num / ost->st->time_base.den;
            ipts = (double)ist->pts;
            if (!file_table[ist->file_index].eof_reached){
                if(ipts < ipts_min) {
                    ipts_min = ipts;
                    if(input_sync ) file_index = ist->file_index;
                }
                if(opts < opts_min) {
                    opts_min = opts;
                    if(!input_sync) file_index = ist->file_index;
                }
            }
        }
        /* if none, if is finished */
        if (file_index < 0) {
            break;
        }

        /* finish if recording time exhausted */
        if (recording_time > 0 && opts_min >= (recording_time / 1000000.0))
            break;

        /* read a frame from it and output it in the fifo */
        is = input_files[file_index];
        if (av_read_frame(is, &pkt) < 0) {
            file_table[file_index].eof_reached = 1;
            continue;
        }

        if (!pkt.size) {
            stream_no_data = is;
        } else {
            stream_no_data = 0;
        }
        if (do_pkt_dump) {
            av_pkt_dump(stdout, &pkt, do_hex_dump);
        }
        /* the following test is needed in case new streams appear
           dynamically in stream : we ignore them */
        if (pkt.stream_index >= file_table[file_index].nb_streams)
            goto discard_packet;
        ist_index = file_table[file_index].ist_index + pkt.stream_index;
        ist = ist_table[ist_index];
        if (ist->discard)
            goto discard_packet;

//        fprintf(stderr, "next:%lld dts:%lld off:%lld %d\n", ist->next_pts, pkt.dts, input_files_ts_offset[ist->file_index], ist->st->codec.codec_type);
        if (pkt.dts != AV_NOPTS_VALUE) {
            int64_t delta= pkt.dts - ist->next_pts;
            if(ABS(delta) > 10LL*AV_TIME_BASE && !copy_ts){
                input_files_ts_offset[ist->file_index]-= delta;
                if (verbose > 2)
                    fprintf(stderr, "timestamp discontinuity %lld, new offset= %lld\n", delta, input_files_ts_offset[ist->file_index]);
                for(i=0; i<file_table[file_index].nb_streams; i++){
                    int index= file_table[file_index].ist_index + i;
                    ist_table[index]->next_pts += delta;
                    ist_table[index]->is_start=1;
                }
            }
        }

        //fprintf(stderr,"read #%d.%d size=%d\n", ist->fi