ffmpeg.c

                codec->channel_layout = icodec->channel_layout;
                codec->sample_rate = icodec->sample_rate;
                codec->channels = icodec->channels;
                codec->frame_size = icodec->frame_size;
                codec->audio_service_type = icodec->audio_service_type;
                codec->block_align= icodec->block_align;
                if(codec->block_align == 1 && codec->codec_id == CODEC_ID_MP3)
                    codec->block_align= 0;
                if(codec->codec_id == CODEC_ID_AC3)
                    codec->block_align= 0;
                break;
            case AVMEDIA_TYPE_VIDEO:
                codec->pix_fmt = icodec->pix_fmt;
                codec->width = icodec->width;
                codec->height = icodec->height;
                codec->has_b_frames = icodec->has_b_frames;
                if (!codec->sample_aspect_ratio.num) {
                    codec->sample_aspect_ratio =
                    ost->st->sample_aspect_ratio =
                        ist->st->sample_aspect_ratio.num ? ist->st->sample_aspect_ratio :
                        ist->st->codec->sample_aspect_ratio.num ?
                        ist->st->codec->sample_aspect_ratio : (AVRational){0, 1};
                }
                break;
            case AVMEDIA_TYPE_SUBTITLE:
                codec->width = icodec->width;
                codec->height = icodec->height;
                break;
            case AVMEDIA_TYPE_DATA:
                break;
            default:
                abort();
            }
        } else {
            if (!ost->enc)
                ost->enc = avcodec_find_encoder(ost->st->codec->codec_id);
            switch(codec->codec_type) {
            case AVMEDIA_TYPE_AUDIO:
                ost->fifo= av_fifo_alloc(1024);
                if (!ost->fifo) {
                    return AVERROR(ENOMEM);
                }
                ost->reformat_pair = MAKE_SFMT_PAIR(AV_SAMPLE_FMT_NONE,AV_SAMPLE_FMT_NONE);
                if (!codec->sample_rate) {
                    codec->sample_rate = icodec->sample_rate;
                }
                choose_sample_rate(ost->st, ost->enc);
                codec->time_base = (AVRational){1, codec->sample_rate};
                if (codec->sample_fmt == AV_SAMPLE_FMT_NONE)
                    codec->sample_fmt = icodec->sample_fmt;
                choose_sample_fmt(ost->st, ost->enc);
                if (!codec->channels) {
                    codec->channels = icodec->channels;
                    codec->channel_layout = icodec->channel_layout;
                }
                if (av_get_channel_layout_nb_channels(codec->channel_layout) != codec->channels)
                    codec->channel_layout = 0;
                ost->audio_resample = codec->sample_rate != icodec->sample_rate || audio_sync_method > 1;
                icodec->request_channels = codec->channels;
                ist->decoding_needed = 1;
                ost->encoding_needed = 1;
                ost->resample_sample_fmt  = icodec->sample_fmt;
                ost->resample_sample_rate = icodec->sample_rate;
                ost->resample_channels    = icodec->channels;
                break;
            case AVMEDIA_TYPE_VIDEO:
                if (codec->pix_fmt == PIX_FMT_NONE)
                    codec->pix_fmt = icodec->pix_fmt;
                choose_pixel_fmt(ost->st, ost->enc);

                if (ost->st->codec->pix_fmt == PIX_FMT_NONE) {
                    fprintf(stderr, "Video pixel format is unknown, stream cannot be encoded\n");
                    exit_program(1);
                }

                if (!codec->width || !codec->height) {
                    codec->width  = icodec->width;
                    codec->height = icodec->height;
                }

                ost->video_resample = codec->width   != icodec->width  ||
                                      codec->height  != icodec->height ||
                                      codec->pix_fmt != icodec->pix_fmt;
                if (ost->video_resample) {
                    codec->bits_per_raw_sample= frame_bits_per_raw_sample;
                }

                ost->resample_height = icodec->height;
                ost->resample_width  = icodec->width;
                ost->resample_pix_fmt= icodec->pix_fmt;
                ost->encoding_needed = 1;
                ist->decoding_needed = 1;

                if (!ost->frame_rate.num)
                    ost->frame_rate = ist->st->r_frame_rate.num ? ist->st->r_frame_rate : (AVRational){25,1};
                if (ost->enc && ost->enc->supported_framerates && !force_fps) {
                    int idx = av_find_nearest_q_idx(ost->frame_rate, ost->enc->supported_framerates);
                    ost->frame_rate = ost->enc->supported_framerates[idx];
                }
                codec->time_base = (AVRational){ost->frame_rate.den, ost->frame_rate.num};
                if(   av_q2d(codec->time_base) < 0.001 && video_sync_method
                   && (video_sync_method==1 || (video_sync_method<0 && !(os->oformat->flags & AVFMT_VARIABLE_FPS)))){
                    av_log(os, AV_LOG_WARNING, "Frame rate very high for a muxer not effciciently supporting it.\n"
                                               "Please consider specifiying a lower framerate, a different muxer or -vsync 2\n");
                }

#if CONFIG_AVFILTER
                if (configure_video_filters(ist, ost)) {
                    fprintf(stderr, "Error opening filters!\n");
                    exit(1);
                }
#endif
                break;
            case AVMEDIA_TYPE_SUBTITLE:
                ost->encoding_needed = 1;
                ist->decoding_needed = 1;
                break;
            default:
                abort();
                break;
            }
            /* two pass mode */
            if (ost->encoding_needed && codec->codec_id != CODEC_ID_H264 &&
                (codec->flags & (CODEC_FLAG_PASS1 | CODEC_FLAG_PASS2))) {
                char logfilename[1024];
                FILE *f;

                snprintf(logfilename, sizeof(logfilename), "%s-%d.log",
                         pass_logfilename_prefix ? pass_logfilename_prefix : DEFAULT_PASS_LOGFILENAME_PREFIX,
                         i);
                if (codec->flags & CODEC_FLAG_PASS1) {
                    f = fopen(logfilename, "wb");
                    if (!f) {
                        fprintf(stderr, "Cannot write log file '%s' for pass-1 encoding: %s\n", logfilename, strerror(errno));
                        exit_program(1);
                    }
                    ost->logfile = f;
                } else {
                    char  *logbuffer;
                    size_t logbuffer_size;
                    if (read_file(logfilename, &logbuffer, &logbuffer_size) < 0) {
                        fprintf(stderr, "Error reading log file '%s' for pass-2 encoding\n", logfilename);
                        exit_program(1);
                    }
                    codec->stats_in = logbuffer;
                }
            }
        }
        if(codec->codec_type == AVMEDIA_TYPE_VIDEO){
            /* maximum video buffer size is 6-bytes per pixel, plus DPX header size */
            int size= codec->width * codec->height;
            bit_buffer_size= FFMAX(bit_buffer_size, 6*size + 1664);
        }
    }

    if (!bit_buffer)
        bit_buffer = av_malloc(bit_buffer_size);
    if (!bit_buffer) {
        fprintf(stderr, "Cannot allocate %d bytes output buffer\n",
                bit_buffer_size);
        return AVERROR(ENOMEM);
    }

    /* open each encoder */
    for (i = 0; i < nb_output_streams; i++) {
        ost = &output_streams[i];
        if (ost->encoding_needed) {
            AVCodec *codec = ost->enc;
            AVCodecContext *dec = input_streams[ost->source_index].st->codec;
            if (!codec) {
                snprintf(error, sizeof(error), "Encoder (codec %s) not found for output stream #%d.%d",
                         avcodec_get_name(ost->st->codec->codec_id), ost->file_index, ost->index);
                ret = AVERROR(EINVAL);
                goto dump_format;
            }
            if (dec->subtitle_header) {
                ost->st->codec->subtitle_header = av_malloc(dec->subtitle_header_size);
                if (!ost->st->codec->subtitle_header) {
                    ret = AVERROR(ENOMEM);
                    goto dump_format;
                }
                memcpy(ost->st->codec->subtitle_header, dec->subtitle_header, dec->subtitle_header_size);
                ost->st->codec->subtitle_header_size = dec->subtitle_header_size;
            }
            if (avcodec_open2(ost->st->codec, codec, &ost->opts) < 0) {
                snprintf(error, sizeof(error), "Error while opening encoder for output stream #%d.%d - maybe incorrect parameters such as bit_rate, rate, width or height",
                        ost->file_index, ost->index);
                ret = AVERROR(EINVAL);
                goto dump_format;
            }
            assert_codec_experimental(ost->st->codec, 1);
            assert_avoptions(ost->opts);
            if (ost->st->codec->bit_rate && ost->st->codec->bit_rate < 1000)
                av_log(NULL, AV_LOG_WARNING, "The bitrate parameter is set too low."
                                             "It takes bits/s as argument, not kbits/s\n");
            extra_size += ost->st->codec->extradata_size;
        }
    }

    /* init input streams */
    for (i = 0; i < nb_input_streams; i++)
        if ((ret = init_input_stream(i, output_streams, nb_output_streams, error, sizeof(error)) < 0))
            goto dump_format;

    /* open files and write file headers */
    for (i = 0; i < nb_output_files; i++) {
        os = output_files[i].ctx;
        if (avformat_write_header(os, &output_files[i].opts) < 0) {
            snprintf(error, sizeof(error), "Could not write header for output file #%d (incorrect codec parameters ?)", i);
            ret = AVERROR(EINVAL);
            goto dump_format;
        }
//        assert_avoptions(output_files[i].opts);
        if (strcmp(os->oformat->name, "rtp")) {
            want_sdp = 0;
        }
    }

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

    /* dump the stream mapping */
    if (verbose >= 0) {
        fprintf(stderr, "Stream mapping:\n");
        for (i = 0; i < nb_output_streams;i ++) {
            ost = &output_streams[i];
            fprintf(stderr, "  Stream #%d.%d -> #%d.%d",
                    input_streams[ost->source_index].file_index,
                    input_streams[ost->source_index].st->index,
                    ost->file_index,
                    ost->index);
            if (ost->sync_ist != &input_streams[ost->source_index])
                fprintf(stderr, " [sync #%d.%d]",
                        ost->sync_ist->file_index,
                        ost->sync_ist->st->index);
            if (ost->st->stream_copy)
                fprintf(stderr, " (copy)");
            else
                fprintf(stderr, " (%s -> %s)", input_streams[ost->source_index].dec ?
                        input_streams[ost->source_index].dec->name : "?",
                        ost->enc ? ost->enc->name : "?");
            fprintf(stderr, "\n");
        }
    }

    if (ret) {
        fprintf(stderr, "%s\n", error);
        return ret;
    }

    if (want_sdp) {
        print_sdp(output_files, nb_output_files);
    }

    return 0;
}

/*
 * The following code is the main loop of the file converter
 */
static int transcode(OutputFile *output_files,
                     int nb_output_files,
                     InputFile *input_files,
                     int nb_input_files)
{
    int ret, i;
    AVFormatContext *is, *os;
    OutputStream *ost;
    InputStream *ist;
    uint8_t *no_packet;
    int no_packet_count=0;
    int64_t timer_start;
    int key;

    if (!(no_packet = av_mallocz(nb_input_files)))
        exit_program(1);

    ret = transcode_init(output_files, nb_output_files, input_files, nb_input_files);
    if (ret < 0)
        goto fail;

    if (!using_stdin) {
        if(verbose >= 0)
            fprintf(stderr, "Press [q] to stop, [?] for help\n");
        avio_set_interrupt_cb(decode_interrupt_cb);
    }
    term_init();

    timer_start = av_gettime();

    for(; received_sigterm == 0;) {
        int file_index, ist_index;
        AVPacket pkt;
        int64_t ipts_min;
        double opts_min;

        ipts_min= INT64_MAX;
        opts_min= 1e100;
        /* if 'q' pressed, exits */
        if (!using_stdin) {
            if (q_pressed)
                break;
            /* read_key() returns 0 on EOF */
            key = read_key();
            if (key == 'q')
                break;
            if (key == '+') verbose++;
            if (key == '-') verbose--;
            if (key == 's') qp_hist     ^= 1;
            if (key == 'h'){
                if (do_hex_dump){
                    do_hex_dump = do_pkt_dump = 0;
                } else if(do_pkt_dump){
                    do_hex_dump = 1;
                } else
                    do_pkt_dump = 1;
                av_log_set_level(AV_LOG_DEBUG);
            }
            if (key == 'c' || key == 'C'){
                char ret[4096], target[64], cmd[256], arg[256]={0};
                double ts;
                int k;
                fprintf(stderr, "\nEnter command: <target> <time> <command>[ <argument>]\n");
                i=0;
                while((k=read_key()) !='\n' && k!='\r' && i<sizeof(ret)-1)
                    if(k>0) ret[i++]= k;
                ret[i]= 0;
                if(k>0 && sscanf(ret, "%63[^ ] %lf %255[^ ] %255[^\n]", target, &ts, cmd, arg) >= 3){
                    for(i=0;i<nb_output_streams;i++) {
                        int r;
                        ost = &output_streams[i];
                        if(ost->graph){
                            if(ts<0){
                                r= avfilter_graph_send_command(ost->graph, target, cmd, arg, ret, sizeof(ret), key == 'c' ? AVFILTER_CMD_FLAG_ONE : 0);
                                fprintf(stderr, "Command reply for %d: %d, %s\n", i, r, ret);
                            }else{
                                r= avfilter_graph_queue_command(ost->graph, target, cmd, arg, 0, ts);
                            }
                        }
                    }
                }else{
                    fprintf(stderr, "Parse error\n");
                }
            }
            if (key == 'd' || key == 'D'){
                int debug=0;
                if(key == 'D') {
                    debug = input_streams[0].st->codec->debug<<1;
                    if(!debug) debug = 1;
                    while(debug & (FF_DEBUG_DCT_COEFF|FF_DEBUG_VIS_QP|FF_DEBUG_VIS_MB_TYPE)) //unsupported, would just crash
                        debug += debug;
                }else
                    scanf("%d", &debug);
                for(i=0;i<nb_input_streams;i++) {
                    input_streams[i].st->codec->debug = debug;
                }
                for(i=0;i<nb_output_streams;i++) {
                    ost = &output_streams[i];
                    ost->st->codec->debug = debug;
                }
                if(debug) av_log_set_level(AV_LOG_DEBUG);
                fprintf(stderr,"debug=%d\n", debug);
            }
            if (key == '?'){
                fprintf(stderr, "key    function\n"
                                "?      show this help\n"
                                "+      increase verbosity\n"
                                "-      decrease verbosity\n"
                                "c      Send command to filtergraph\n"
                                "D      cycle through available debug modes\n"
                                "h      dump packets/hex press to cycle through the 3 states\n"
                                "q      quit\n"
                                "s      Show QP histogram\n"
                );
            }
        }

        /* select the stream that we must read now by looking at the
           smallest output pts */
        file_index = -1;
        for (i = 0; i < nb_output_streams; i++) {
            OutputFile *of;
            int64_t ipts;
            double  opts;
            ost = &output_streams[i];
            of = &output_files[ost->file_index];
            os = output_files[ost->file_index].ctx;
            ist = &input_streams[ost->source_index];
            if (ost->is_past_recording_time || no_packet[ist->file_index] ||
                (os->pb && avio_tell(os->pb) >= of->limit_filesize))
                continue;
            opts = ost->st->pts.val * av_q2d(ost->st->time_base);
            ipts = ist->pts;
            if (!input_files[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(ost->frame_number >= max_frames[ost->st->codec->codec_type]){
                file_index= -1;
                break;
            }
        }
        /* if none, if is finished */
        if (file_index < 0) {
            if(no_packet_count){
                no_packet_count=0;
                memset(no_packet, 0, nb_input_files);
                usleep(10000);
                continue;
            }
            break;
        }

        /* read a frame from it and output it in the fifo */
        is = input_files[file_index].ctx;
        ret= av_read_frame(is, &pkt);
        if(ret == AVERROR(EAGAIN)){
            no_packet[file_index]=1;
            no_packet_count++;
            continue;
        }
        if (ret < 0) {
            input_files[file_index].eof_reached = 1;
            if (opt_shortest)
                break;
            else
                continue;
        }

        no_packet_count=0;
        memset(no_packet, 0, nb_input_files);

        if (do_pkt_dump) {
            av_pkt_dump_log2(NULL, AV_LOG_DEBUG, &pkt, do_hex_dump,
                             is->streams[pkt.stream_index]);
        }
        /* the following test is needed in case new streams appear
           dynamically in stream : we ignore them */
        if (pkt.stream_index >= input_files[file_index].nb_streams)
            goto discard_packet;
        ist_index = input_files[file_index].ist_index + pkt.stream_index;
        ist = &input_streams[ist_index];
        if (ist->discard)
            goto discard_packet;

        if (pkt.dts != AV_NOPTS_VALUE)
            pkt.dts += av_rescale_q(input_files[ist->file_index].ts_offset, AV_TIME_BASE_Q, ist->st->time_base);
        if (pkt.pts != AV_NOPTS_VALUE)
            pkt.pts += av_rescale_q(input_files[ist->file_index].ts_offset, AV_TIME_BASE_Q, ist->st->time_base);

        if (ist->ts_scale) {
            if(pkt.pts != AV_NOPTS_VALUE)
                pkt.pts *= ist->ts_scale;
            if(pkt.dts != AV_NOPTS_VALUE)
                pkt.dts *= ist->ts_scale;
        }

//        fprintf(stderr, "next:%"PRId64" dts:%"PRId64" off:%"PRId64" %d\n", ist->next_pts, pkt.dts, input_files[ist->file_index].ts_offset, ist->st->codec->codec_type);
        if (pkt.dts != AV_NOPTS_VALUE && ist->next_pts != AV_NOPTS_VALUE
            && (is->iformat->flags & AVFMT_TS_DISCONT)) {
            int64_t pkt_dts= av_rescale_q(pkt.dts, ist->st->time_base, AV_TIME_BASE_Q);
            int64_t delta= pkt_dts - ist->next_pts;
            if((delta < -1LL*dts_delta_threshold*AV_TIME_BASE ||
                (delta > 1LL*dts_delta_threshold*AV_TIME_BASE &&
                 ist->st->codec->codec_type != AVMEDIA_TYPE_SUBTITLE) ||
                pkt_dts+1<ist->pts)&& !copy_ts){
                input_files[ist->file_index].ts_offset -= delta;
                if (verbose > 2)
                    fprintf(stderr, "timestamp discontinuity %"PRId64", new offset= %"PRId64"\n",
                            delta, input_files[ist->file_index].ts_offset);
                pkt.dts-= av_rescale_q(delta, AV_TIME_BASE_Q, ist->st->time_base);
                if(pkt.pts != AV_NOPTS_VALUE)
                    pkt.pts-= av_rescale_q(delta, AV_TIME_BASE_Q, ist->st->time_base);
            }
        }

        //fprintf(stderr,"read #%d.%d size=%d\n", ist->file_index, ist->st->index, pkt.size);
        if (output_packet(ist, ist_index, output_streams, nb_output_streams, &pkt) < 0) {

            if (verbose >= 0)
                fprintf(stderr, "Error while decoding stream #%d.%d\n",
                        ist->file_index, ist->st->index);
            if (exit_on_error)
                exit_program(1);
            av_free_packet(&pkt);
            continue;
        }

    discard_packet:
        av_free_packet(&pkt);

        /* dump report by using the output first video and audio streams */
        print_report(output_files, output_streams, nb_output_streams, 0, timer_start);
    }

    /* at the end of stream, we must flush the decoder buffers */
    for (i = 0; i < nb_input_streams; i++) {
        ist = &input_streams[i];
        if (ist->decoding_needed) {
            output_packet(ist, i, output_streams, nb_output_streams, NULL);
        }
    }
    flush_encoders(output_streams, nb_output_streams);

    term_exit();

    /* write the trailer if needed and close file */
    for(i=0;i<nb_output_files;i++) {
        os = output_files[i].ctx;
        av_write_trailer(os);
    }

    /* dump report by using the first video and audio streams */
    print_report(output_files, output_streams, nb_output_streams, 1, timer_start);

    /* close each encoder */
    for (i = 0; i < nb_output_streams; i++) {
        ost = &output_streams[i];
        if (ost->encoding_needed) {
            av_freep(&ost->st->codec->stats_in);
            avcodec_close(ost->st->codec);
        }
#if CONFIG_AVFILTER
        avfilter_graph_free(&ost->graph);
#endif
    }

    /* close each decoder */
    for (i = 0; i < nb_input_streams; i++) {
        ist = &input_streams[i];
        if (ist->decoding_needed) {
            avcodec_close(ist->st->codec);
        }
    }

    /* finished ! */
    ret = 0;

 fail:
    av_freep(&bit_buffer);
    av_freep(&no_packet);

    if (output_streams) {
        for (i = 0; i < nb_output_streams; i++) {
            ost = &output_streams[i];
            if (ost) {
                if (ost->st->stream_copy)
                    av_freep(&ost->st->codec->extradata);
                if (ost->logfile) {
                    fclose(ost->logfile);
                    ost->logfile = NULL;
                }
                av_fifo_free(ost->fifo); /* works even if fifo is not
                                             initialized but set to zero */
                av_freep(&ost->st->codec->subtitle_header);
                av_free(ost->resample_frame.data[0]);
                av_free(ost->forced_kf_pts);
                if (ost->video_resample)
                    sws_freeContext(ost->img_resample_ctx);
                if (ost->resample)
                    audio_resample_close(ost->resample);
                if (ost->reformat_ctx)
                    av_audio_convert_free(ost->reformat_ctx);
                av_dict_free(&ost->opts);
            }
        }
    }
    return ret;
}

static int opt_format(const char *opt, const char *arg)
{
    last_asked_format = arg;
    return 0;
}

static int opt_video_rc_override_string(const char *opt, const char *arg)
{
    video_rc_override_string = arg;
    return 0;
}

static int opt_me_threshold(const char *opt, const char *arg)
{
    me_threshold = parse_number_or_die(opt, arg, OPT_INT64, INT_MIN, INT_MAX);
    return 0;
}

static int opt_verbose(const char *opt, const char *arg)
{
    verbose = parse_number_or_die(opt, arg, OPT_INT64, -10, 10);
    return 0;
}

static int opt_frame_rate(const char *opt, const char *arg)
{
    if (av_parse_video_rate(&frame_rate, arg) < 0) {
        fprintf(stderr, "Incorrect value for %s: %s\n", opt, arg);
        exit_program(1);
    }
    return 0;
}

static int opt_frame_crop(const char *opt, const char *arg)
{
    fprintf(stderr, "Option '%s' has been removed, use the crop filter instead\n", opt);
    return AVERROR(EINVAL);
}

static int opt_frame_size(const char *opt, const char *arg)
{
    if (av_parse_video_size(&frame_width, &frame_height, arg) < 0) {
        fprintf(stderr, "Incorrect frame size\n");
        return AVERROR(EINVAL);
    }
    return 0;
}

static int opt_pad(const char *opt, const char *arg) {
    fprintf(stderr, "Option '%s' has been removed, use the pad filter instead\n", opt);
    return -1;
}

static int opt_frame_pix_fmt(const char *opt, const char *arg)
{
    if (strcmp(arg, "list")) {
        frame_pix_fmt = av_get_pix_fmt(arg);
        if (frame_pix_fmt == PIX_FMT_NONE) {
            fprintf(stderr, "Unknown pixel format requested: %s\n", arg);
            return AVERROR(EINVAL);
        }
    } else {
        opt_pix_fmts(NULL, NULL);
        exit_program(0);
    }
    return 0;
}

static int opt_frame_aspect_ratio(const char *opt, const char *arg)
{
    int x = 0, y = 0;
    double ar = 0;
    const char *p;
    char *end;

    p = strchr(arg, ':');
    if (p) {
        x = strtol(arg, &end, 10);
        if (end == p)
            y = strtol(end+1, &end, 10);
        if (x > 0 && y > 0)
            ar = (double)x / (double)y;
    } else
        ar = strtod(arg, NULL);

    if (!ar) {
        fprintf(stderr, "Incorrect aspect ratio specification.\n");
        return AVERROR(EINVAL);
    }
    frame_aspect_ratio = ar;
    return 0;
}

static int opt_metadata(const char *opt, const char *arg)
{
    char *mid= strchr(arg, '=');

    if(!mid){
        fprintf(stderr, "Missing =\n");
        exit_program(1);
    }
    *mid++= 0;

    av_dict_set(&metadata, arg, mid, 0);

    return 0;
}

static int opt_qscale(const char *opt, const char *arg)
{
    video_qscale = parse_number_or_die(opt, arg, OPT_FLOAT, 0, 255);
    if (video_qscale <= 0 || video_qscale > 255) {
        fprintf(stderr, "qscale must be > 0.0 and <= 255\n");
        return AVERROR(EINVAL);
    }
    return 0;
}

static int opt_top_field_first(const char *opt, const char *arg)
{
    top_field_first = parse_number_or_die(opt, arg, OPT_INT, 0, 1);
    return opt_default(opt, arg);
}

static int opt_thread_count(const char *opt, const char *arg)
{
    thread_count= parse_number_or_die(opt, arg, OPT_INT64, 0, INT_MAX);
#if !HAVE_THREADS
    if (verbose >= 0)
        fprintf(stderr, "Warning: not compiled with thread support, using thread emulation\n");
#endif
    return 0;
}

static int opt_audio_sample_fmt(const char *opt, const char *arg)
{
    if (strcmp(arg, "list")) {
        audio_sample_fmt = av_get_sample_fmt(arg);
        if (audio_sample_fmt == AV_SAMPLE_FMT_NONE) {
            av_log(NULL, AV_LOG_ERROR, "Invalid sample format '%s'\n", arg);
            return AVERROR(EINVAL);
        }
    } else {
        int i;
        char fmt_str[128];
        for (i = -1; i < AV_SAMPLE_FMT_NB; i++)
            printf("%s\n", av_get_sample_fmt_string(fmt_str, sizeof(fmt_str), i));
        exit_program(0);
    }
    return 0;
}

static int opt_audio_rate(const char *opt, const char *arg)
{
    audio_sample_rate = parse_number_or_die(opt, arg, OPT_INT64, 0, INT_MAX);
    return 0;
}

static int opt_audio_channels(const char *opt, const char *arg)
{
    audio_channels = parse_number_or_die(opt, arg, OPT_INT64, 0, INT_MAX);
    return 0;
}

static int opt_video_channel(const char *opt, const char *arg)
{
    av_log(NULL, AV_LOG_WARNING, "This option is deprecated, use -channel.\n");
    return opt_default("channel", arg);
}

static int opt_video_standard(const char *opt, const char *arg)
{
    av_log(NULL, AV_LOG_WARNING, "This option is deprecated, use -standard.\n");
    return opt_default("standard", arg);
}

static int opt_codec(const char *opt, const char *arg)
{
    return av_dict_set(&codec_names, opt, arg, 0);
}

static int opt_audio_codec(const char *opt, const char *arg)
{
    return opt_codec("codec:a", arg);
}

static int opt_video_codec(const char *opt, const char *arg)
{
    return opt_codec("codec:v", arg);
}

static int opt_subtitle_codec(const char *opt, const char *arg)
{
    return opt_codec("codec:s", arg);
}

static int opt_data_codec(const char *opt, const char *arg)
{
    return opt_codec("codec:d", arg);
}

static int opt_codec_tag(const char *opt, const char *arg)
{
    char *tail;
    uint32_t *codec_tag;

    codec_tag = !strcmp(opt, "atag") ? &audio_codec_tag :
                !strcmp(opt, "vtag") ? &video_codec_tag :
                !strcmp(opt, "stag") ? &subtitle_codec_tag : NULL;
    if (!codec_tag)
        return -1;

    *codec_tag = strtol(arg, &tail, 0);
    if (!tail || *tail)
        *codec_tag = AV_RL32(arg);

    return 0;
}

static int opt_map(const char *opt, const char *arg)
{
    StreamMap *m = NULL;
    int i, negative = 0, file_idx;
    int sync_file_idx = -1, sync_stream_idx;
    char *p, *sync;
    char *map;

    if (*arg == '-') {
        negative = 1;
        arg++;
    }
    map = av_strdup(arg);

    /* parse sync stream first, just pick first matching stream */
    if (sync = strchr(map, ',')) {
        *sync = 0;
        sync_file_idx = strtol(sync + 1, &sync, 0);
        if (sync_file_idx >= nb_input_files || sync_file_idx < 0) {
            av_log(NULL, AV_LOG_ERROR, "Invalid sync file index: %d.\n", sync_file_idx);
            exit_program(1);
        }
        if (*sync)
            sync++;
        for (i = 0; i < input_files[sync_file_idx].nb_streams; i++)
            if (check_stream_specifier(input_files[sync_file_idx].ctx,
                                       input_files[sync_file_idx].ctx->streams[i], sync) == 1) {
                sync_stream_idx = i;
                break;
            }
        if (i == input_files[sync_file_idx].nb_streams) {
            av_log(NULL, AV_LOG_ERROR, "Sync stream specification in map %s does not "
                                       "match any streams.\n", arg);
            exit_program(1);
        }
    }


    file_idx = strtol(map, &p, 0);
    if (file_idx >= nb_input_files || file_idx < 0) {
        av_log(NULL, AV_LOG_ERROR, "Invalid input file index: %d.\n", file_idx);
        exit_program(1);
    }
    if (negative)
        /* disable some already defined maps */
        for (i = 0; i < nb_stream_maps; i++) {
            m = &stream_maps[i];
            if (check_stream_specifier(input_files[m->file_index].ctx,
                                       input_files[m->file_index].ctx->streams[m->stream_index],
                                       *p == ':' ? p + 1 : p) > 0)
                m->disabled = 1;
        }
    else
        for (i = 0; i < input_files[file_idx].nb_streams; i++) {
            if (check_stream_specifier(input_files[file_idx].ctx, input_files[file_idx].ctx->streams[i],
                        *p == ':' ? p + 1 : p) <= 0)
                continue;
            stream_maps = grow_array(stream_maps, sizeof(*stream_maps), &nb_stream_maps, nb_stream_maps + 1);
            m = &stream_maps[nb_stream_maps - 1];

            m->file_index   = file_idx;
            m->stream_index = i;

            if (sync_file_idx >= 0) {
                m->sync_file_index   = sync_file_idx;
                m->sync_stream_index = sync_stream_idx;
            } else {
                m->sync_file_index   = file_idx;
                m->sync_stream_index = i;
            }
        }

    if (!m) {
        av_log(NULL, AV_LOG_ERROR, "Stream map '%s' matches no streams.\n", arg);
        exit_program(1);
    }

    av_freep(&map);
    return 0;
}

static void parse_meta_type(char *arg, char *type, int *index)
{
    if (*arg == ':') {
        *type = *(++arg);
        switch (*arg) {
        case 'g':
            break;
        case 's':
        case 'c':
        case 'p':
            if (*(++arg) == ':')
                *index = strtol(++arg, NULL, 0);
            break;
        default:
            fprintf(stderr, "Invalid metadata type %c.\n", *arg);
            exit_program(1);
        }
    } else
        *type = 'g';
}

static int opt_map_metadata(const char *opt, const char *arg)
{
    MetadataMap *m, *m1;
    char *p;

    meta_data_maps = grow_array(meta_data_maps, sizeof(*meta_data_maps),
                                &nb_meta_data_maps, nb_meta_data_maps + 1);

    m = &meta_data_maps[nb_meta_data_maps - 1][1];
    m->file = strtol(arg, &p, 0);
    parse_meta_type(p, &m->type, &m->index);

    m1 = &meta_data_maps[nb_meta_data_maps - 1][0];
    if (p = strchr(opt, ':'))
        parse_meta_type(p, &m1->type, &m1->index);
    else
        m1->type = 'g';

    if (m->type == 'g' || m1->type == 'g')
        metadata_global_autocopy = 0;
    if (m->type == 's' || m1->type == 's')
        metadata_streams_autocopy = 0;
    if (m->type == 'c' || m1->type == 'c')
        metadata_chapters_autocopy = 0;

    return 0;
}

static int opt_map_meta_data(const char *opt, const char *arg)
{
    fprintf(stderr, "-map_meta_data is deprecated and will be removed soon. "
                    "Use -map_metadata instead.\n");
    return opt_map_metadata(opt, arg);
}

static int opt_input_ts_scale(const char *opt, const char *arg)
{
    return av_dict_set(&ts_scale, opt, arg, 0);
}

static int opt_recording_time(const char *opt, const char *arg)
{
    recording_time = parse_time_or_die(opt, arg, 1);
    return 0;
}

static int opt_start_time(const char *opt, const char *arg)
{
    start_time = parse_time_or_die(opt, arg, 1);
    return 0;
}

static int opt_recording_timestamp(const char *opt, const char *arg)
{
    char buf[128];
    int64_t recording_timestamp = parse_time_or_die(opt, arg, 0) / 1E6;
    struct tm time = *gmtime((time_t*)&recording_timestamp);
    strftime(buf, sizeof(buf), "creation_time=%FT%T%z", &time);
    opt_metadata("metadata", buf);

    av_log(NULL, AV_LOG_WARNING, "%s is deprecated, set the 'creation_time' metadata "
                                 "tag instead.\n", opt);
    return 0;
}

static int opt_input_ts_offset(const char *opt, const char *arg)
{
    input_ts_offset = parse_time_or_die(opt, arg, 1);
    return 0;
}

static enum CodecID find_codec_or_die(const char *name, enum AVMediaType type, int encoder)
{
    const char *codec_string = encoder ? "encoder" : "decoder";
    AVCodec *codec;

    if(!name)
        return CODEC_ID_NONE;
    codec = encoder ?
        avcodec_find_encoder_by_name(name) :
        avcodec_find_decoder_by_name(name);
    if(!codec) {
        av_log(NULL, AV_LOG_ERROR, "Unknown %s '%s'\n", codec_string, name);
        exit_program(1);
    }
    if(codec->type != type) {
        av_log(NULL, AV_LOG_ERROR, "Invalid %s type '%s'\n", codec_string, name);
        exit_program(1);
    }
    return codec->id;
}

static AVCodec *choose_codec(AVFormatContext *s, AVStream *st, enum AVMediaType type, AVDictionary *codec_names)
{
    AVDictionaryEntry *e = NULL;
    char *codec_name = NULL;
    int ret;

    while (e = av_dict_get(codec_names, "", e, AV_DICT_IGNORE_SUFFIX)) {