ffmpeg.c

                        }
                        ost->logfile = f;
                    }
                }
            }
        }
    }

    /* 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 = NULL;

            if ((ist = get_input_stream(ost)))
                dec = ist->st->codec;
            if (dec && 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 (!av_dict_get(ost->opts, "threads", NULL, 0))
                av_dict_set(&ost->opts, "threads", "auto", 0);
            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;

            if (ost->st->codec->me_threshold)
                input_streams[ost->source_index]->st->codec->debug |= FF_DEBUG_MV;
        }
    }

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

    /* discard unused programs */
    for (i = 0; i < nb_input_files; i++) {
        InputFile *ifile = input_files[i];
        for (j = 0; j < ifile->ctx->nb_programs; j++) {
            AVProgram *p = ifile->ctx->programs[j];
            int discard  = AVDISCARD_ALL;

            for (k = 0; k < p->nb_stream_indexes; k++)
                if (!input_streams[ifile->ist_index + p->stream_index[k]]->discard) {
                    discard = AVDISCARD_DEFAULT;
                    break;
                }
            p->discard = discard;
        }
    }

    /* open files and write file headers */
    for (i = 0; i < nb_output_files; i++) {
        oc = output_files[i]->ctx;
        oc->interrupt_callback = int_cb;
        if ((ret = avformat_write_header(oc, &output_files[i]->opts)) < 0) {
            char errbuf[128];
            const char *errbuf_ptr = errbuf;
            if (av_strerror(ret, errbuf, sizeof(errbuf)) < 0)
                errbuf_ptr = strerror(AVUNERROR(ret));
            snprintf(error, sizeof(error), "Could not write header for output file #%d (incorrect codec parameters ?): %s", i, errbuf_ptr);
            ret = AVERROR(EINVAL);
            goto dump_format;
        }
//         assert_avoptions(output_files[i]->opts);
        if (strcmp(oc->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 */
    av_log(NULL, AV_LOG_INFO, "Stream mapping:\n");
    for (i = 0; i < nb_input_streams; i++) {
        ist = input_streams[i];

        for (j = 0; j < ist->nb_filters; j++) {
            if (ist->filters[j]->graph->graph_desc) {
                av_log(NULL, AV_LOG_INFO, "  Stream #%d:%d (%s) -> %s",
                       ist->file_index, ist->st->index, ist->dec ? ist->dec->name : "?",
                       ist->filters[j]->name);
                if (nb_filtergraphs > 1)
                    av_log(NULL, AV_LOG_INFO, " (graph %d)", ist->filters[j]->graph->index);
                av_log(NULL, AV_LOG_INFO, "\n");
            }
        }
    }

    for (i = 0; i < nb_output_streams; i++) {
        ost = output_streams[i];

        if (ost->attachment_filename) {
            /* an attached file */
            av_log(NULL, AV_LOG_INFO, "  File %s -> Stream #%d:%d\n",
                   ost->attachment_filename, ost->file_index, ost->index);
            continue;
        }

        if (ost->filter && ost->filter->graph->graph_desc) {
            /* output from a complex graph */
            av_log(NULL, AV_LOG_INFO, "  %s", ost->filter->name);
            if (nb_filtergraphs > 1)
                av_log(NULL, AV_LOG_INFO, " (graph %d)", ost->filter->graph->index);

            av_log(NULL, AV_LOG_INFO, " -> Stream #%d:%d (%s)\n", ost->file_index,
                   ost->index, ost->enc ? ost->enc->name : "?");
            continue;
        }

        av_log(NULL, AV_LOG_INFO, "  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])
            av_log(NULL, AV_LOG_INFO, " [sync #%d:%d]",
                   ost->sync_ist->file_index,
                   ost->sync_ist->st->index);
        if (ost->stream_copy)
            av_log(NULL, AV_LOG_INFO, " (copy)");
        else
            av_log(NULL, AV_LOG_INFO, " (%s -> %s)", input_streams[ost->source_index]->dec ?
                   input_streams[ost->source_index]->dec->name : "?",
                   ost->enc ? ost->enc->name : "?");
        av_log(NULL, AV_LOG_INFO, "\n");
    }

    if (ret) {
        av_log(NULL, AV_LOG_ERROR, "%s\n", error);
        return ret;
    }

    if (want_sdp) {
        print_sdp();
    }

    return 0;
}

/**
 * @return 1 if there are still streams where more output is wanted,
 *         0 otherwise
 */
static int need_output(void)
{
    int i;

    for (i = 0; i < nb_output_streams; i++) {
        OutputStream *ost    = output_streams[i];
        OutputFile *of       = output_files[ost->file_index];
        AVFormatContext *os  = output_files[ost->file_index]->ctx;

        if (ost->is_past_recording_time ||
            (os->pb && avio_tell(os->pb) >= of->limit_filesize))
            continue;
        if (ost->frame_number >= ost->max_frames) {
            int j;
            for (j = 0; j < of->ctx->nb_streams; j++)
                output_streams[of->ost_index + j]->is_past_recording_time = 1;
            continue;
        }

        return 1;
    }

    return 0;
}

static int select_input_file(uint8_t *no_packet)
{
    int64_t ipts_min = INT64_MAX;
    int i, file_index = -1;

    for (i = 0; i < nb_input_streams; i++) {
        InputStream *ist = input_streams[i];
        int64_t ipts     = ist->pts;

        if (ist->discard || no_packet[ist->file_index])
            continue;
        if (!input_files[ist->file_index]->eof_reached) {
            if (ipts < ipts_min) {
                ipts_min = ipts;
                file_index = ist->file_index;
            }
        }
    }

    return file_index;
}

static int check_keyboard_interaction(int64_t cur_time)
{
    int i, ret, key;
    static int64_t last_time;
    if (received_nb_signals)
        return AVERROR_EXIT;
    /* read_key() returns 0 on EOF */
    if(cur_time - last_time >= 100000 && !run_as_daemon){
        key =  read_key();
        last_time = cur_time;
    }else
        key = -1;
    if (key == 'q')
        return AVERROR_EXIT;
    if (key == '+') av_log_set_level(av_log_get_level()+10);
    if (key == '-') av_log_set_level(av_log_get_level()-10);
    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 buf[4096], target[64], command[256], arg[256] = {0};
        double time;
        int k, n = 0;
        fprintf(stderr, "\nEnter command: <target> <time> <command>[ <argument>]\n");
        i = 0;
        while ((k = read_key()) != '\n' && k != '\r' && i < sizeof(buf)-1)
            if (k > 0)
                buf[i++] = k;
        buf[i] = 0;
        if (k > 0 &&
            (n = sscanf(buf, "%63[^ ] %lf %255[^ ] %255[^\n]", target, &time, command, arg)) >= 3) {
            av_log(NULL, AV_LOG_DEBUG, "Processing command target:%s time:%f command:%s arg:%s",
                   target, time, command, arg);
            for (i = 0; i < nb_filtergraphs; i++) {
                FilterGraph *fg = filtergraphs[i];
                if (fg->graph) {
                    if (time < 0) {
                        ret = avfilter_graph_send_command(fg->graph, target, command, arg, buf, sizeof(buf),
                                                          key == 'c' ? AVFILTER_CMD_FLAG_ONE : 0);
                        fprintf(stderr, "Command reply for stream %d: ret:%d res:%s\n", i, ret, buf);
                    } else {
                        ret = avfilter_graph_queue_command(fg->graph, target, command, arg, 0, time);
                    }
                }
            }
        } else {
            av_log(NULL, AV_LOG_ERROR,
                   "Parse error, at least 3 arguments were expected, "
                   "only %d given in string '%s'\n", n, buf);
        }
    }
    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
            if(scanf("%d", &debug)!=1)
                fprintf(stderr,"error parsing debug value\n");
        for(i=0;i<nb_input_streams;i++) {
            input_streams[i]->st->codec->debug = debug;
        }
        for(i=0;i<nb_output_streams;i++) {
            OutputStream *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"
        );
    }
    return 0;
}

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

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

    ret = transcode_init();
    if (ret < 0)
        goto fail;

    if (!using_stdin) {
        av_log(NULL, AV_LOG_INFO, "Press [q] to stop, [?] for help\n");
    }

    timer_start = av_gettime();

    for (; received_sigterm == 0;) {
        int file_index, ist_index;
        AVPacket pkt;
        int64_t cur_time= av_gettime();

        /* if 'q' pressed, exits */
        if (!using_stdin)
            if (check_keyboard_interaction(cur_time) < 0)
                break;

        /* check if there's any stream where output is still needed */
        if (!need_output()) {
            av_log(NULL, AV_LOG_VERBOSE, "No more output streams to write to, finishing.\n");
            break;
        }

        /* select the stream that we must read now */
        file_index = select_input_file(no_packet);
        /* 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;

            for (i = 0; i < input_files[file_index]->nb_streams; i++) {
                ist = input_streams[input_files[file_index]->ist_index + i];
                if (ist->decoding_needed)
                    output_packet(ist, NULL);
            }

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

        if (debug_ts) {
            av_log(NULL, AV_LOG_INFO, "demuxer -> ist_index:%d type:%s "
                    "next_dts:%s next_dts_time:%s next_pts:%s next_pts_time:%s  pkt_pts:%s pkt_pts_time:%s pkt_dts:%s pkt_dts_time:%s off:%"PRId64"\n",
                    ist_index, av_get_media_type_string(ist->st->codec->codec_type),
                    av_ts2str(ist->next_dts), av_ts2timestr(ist->next_dts, &ist->st->time_base),
                    av_ts2str(ist->next_pts), av_ts2timestr(ist->next_pts, &ist->st->time_base),
                    av_ts2str(pkt.pts), av_ts2timestr(pkt.pts, &ist->st->time_base),
                    av_ts2str(pkt.dts), av_ts2timestr(pkt.dts, &ist->st->time_base),
                    input_files[ist->file_index]->ts_offset);
        }

        if (pkt.dts != AV_NOPTS_VALUE && ist->next_dts != AV_NOPTS_VALUE && !copy_ts) {
            int64_t pkt_dts = av_rescale_q(pkt.dts, ist->st->time_base, AV_TIME_BASE_Q);
            int64_t delta   = pkt_dts - ist->next_dts;
            if (is->iformat->flags & AVFMT_TS_DISCONT) {
            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){
                input_files[ist->file_index]->ts_offset -= delta;
                av_log(NULL, AV_LOG_DEBUG,
                       "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);
            }
            } else {
                if ( delta < -1LL*dts_error_threshold*AV_TIME_BASE ||
                    (delta > 1LL*dts_error_threshold*AV_TIME_BASE && ist->st->codec->codec_type != AVMEDIA_TYPE_SUBTITLE) ||
                     pkt_dts+1<ist->pts){
                    av_log(NULL, AV_LOG_WARNING, "DTS %"PRId64", next:%"PRId64" st:%d invalid dropping\n", pkt.dts, ist->next_dts, pkt.stream_index);
                    pkt.dts = AV_NOPTS_VALUE;
                }
                if (pkt.pts != AV_NOPTS_VALUE){
                    int64_t pkt_pts = av_rescale_q(pkt.pts, ist->st->time_base, AV_TIME_BASE_Q);
                    delta   = pkt_pts - ist->next_dts;
                    if ( delta < -1LL*dts_error_threshold*AV_TIME_BASE ||
                        (delta > 1LL*dts_error_threshold*AV_TIME_BASE && ist->st->codec->codec_type != AVMEDIA_TYPE_SUBTITLE) ||
                        pkt_pts+1<ist->pts) {
                        av_log(NULL, AV_LOG_WARNING, "PTS %"PRId64", next:%"PRId64" invalid dropping st:%d\n", pkt.pts, ist->next_dts, pkt.stream_index);
                        pkt.pts = AV_NOPTS_VALUE;
                    }
                }
            }
        }

        // fprintf(stderr,"read #%d.%d size=%d\n", ist->file_index, ist->st->index, pkt.size);
        if ((ret = output_packet(ist, &pkt)) < 0 ||
            ((ret = poll_filters()) < 0 && ret != AVERROR_EOF)) {
            char buf[128];
            av_strerror(ret, buf, sizeof(buf));
            av_log(NULL, AV_LOG_ERROR, "Error while decoding stream #%d:%d: %s\n",
                   ist->file_index, ist->st->index, buf);
            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(0, timer_start, cur_time);
    }

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

    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(1, timer_start, av_gettime());

    /* 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);
        }
    }

    /* 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(&no_packet);

    if (output_streams) {
        for (i = 0; i < nb_output_streams; i++) {
            ost = output_streams[i];
            if (ost) {
                if (ost->stream_copy)
                    av_freep(&ost->st->codec->extradata);
                if (ost->logfile) {
                    fclose(ost->logfile);
                    ost->logfile = NULL;
                }
                av_freep(&ost->st->codec->subtitle_header);
                av_free(ost->forced_kf_pts);
                av_dict_free(&ost->opts);
            }
        }
    }
    return ret;
}

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

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

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_audio_codec(OptionsContext *o, const char *opt, const char *arg)
{
    audio_codec_name = arg;
    return parse_option(o, "codec:a", arg, options);
}

static int opt_video_codec(OptionsContext *o, const char *opt, const char *arg)
{
    video_codec_name = arg;
    return parse_option(o, "codec:v", arg, options);
}

static int opt_subtitle_codec(OptionsContext *o, const char *opt, const char *arg)
{
    subtitle_codec_name = arg;
    return parse_option(o, "codec:s", arg, options);
}

static int opt_data_codec(OptionsContext *o, const char *opt, const char *arg)
{
    return parse_option(o, "codec:d", arg, options);
}

static int opt_map(OptionsContext *o, const char *opt, const char *arg)
{
    StreamMap *m = NULL;
    int i, negative = 0, file_idx;
    int sync_file_idx = -1, sync_stream_idx = 0;
    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_FATAL, "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_FATAL, "Sync stream specification in map %s does not "
                                       "match any streams.\n", arg);
            exit_program(1);
        }
    }


    if (map[0] == '[') {
        /* this mapping refers to lavfi output */
        const char *c = map + 1;
        o->stream_maps = grow_array(o->stream_maps, sizeof(*o->stream_maps),
                                    &o->nb_stream_maps, o->nb_stream_maps + 1);
        m = &o->stream_maps[o->nb_stream_maps - 1];
        m->linklabel = av_get_token(&c, "]");
        if (!m->linklabel) {
            av_log(NULL, AV_LOG_ERROR, "Invalid output link label: %s.\n", map);
            exit_program(1);
        }
    } else {
        file_idx = strtol(map, &p, 0);
        if (file_idx >= nb_input_files || file_idx < 0) {
            av_log(NULL, AV_LOG_FATAL, "Invalid input file index: %d.\n", file_idx);
            exit_program(1);
        }
        if (negative)
            /* disable some already defined maps */
            for (i = 0; i < o->nb_stream_maps; i++) {
                m = &o->stream_maps[i];
                if (file_idx == m->file_index &&
                    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;
                o->stream_maps = grow_array(o->stream_maps, sizeof(*o->stream_maps),
                                            &o->nb_stream_maps, o->nb_stream_maps + 1);
                m = &o->stream_maps[o->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_FATAL, "Stream map '%s' matches no streams.\n", arg);
        exit_program(1);
    }

    av_freep(&map);
    return 0;
}

static int opt_attach(OptionsContext *o, const char *opt, const char *arg)
{
    o->attachments = grow_array(o->attachments, sizeof(*o->attachments),
                                &o->nb_attachments, o->nb_attachments + 1);
    o->attachments[o->nb_attachments - 1] = arg;
    return 0;
}

static int opt_map_channel(OptionsContext *o, const char *opt, const char *arg)
{
    int n;
    AVStream *st;
    AudioChannelMap *m;

    o->audio_channel_maps =
        grow_array(o->audio_channel_maps, sizeof(*o->audio_channel_maps),
                   &o->nb_audio_channel_maps, o->nb_audio_channel_maps + 1);
    m = &o->audio_channel_maps[o->nb_audio_channel_maps - 1];

    /* muted channel syntax */
    n = sscanf(arg, "%d:%d.%d", &m->channel_idx, &m->ofile_idx, &m->ostream_idx);
    if ((n == 1 || n == 3) && m->channel_idx == -1) {
        m->file_idx = m->stream_idx = -1;
        if (n == 1)
            m->ofile_idx = m->ostream_idx = -1;
        return 0;
    }

    /* normal syntax */
    n = sscanf(arg, "%d.%d.%d:%d.%d",
               &m->file_idx,  &m->stream_idx, &m->channel_idx,
               &m->ofile_idx, &m->ostream_idx);

    if (n != 3 && n != 5) {
        av_log(NULL, AV_LOG_FATAL, "Syntax error, mapchan usage: "
               "[file.stream.channel|-1][:syncfile:syncstream]\n");
        exit_program(1);
    }

    if (n != 5) // only file.stream.channel specified
        m->ofile_idx = m->ostream_idx = -1;

    /* check input */
    if (m->file_idx < 0 || m->file_idx >= nb_input_files) {
        av_log(NULL, AV_LOG_FATAL, "mapchan: invalid input file index: %d\n",
               m->file_idx);
        exit_program(1);
    }
    if (m->stream_idx < 0 ||
        m->stream_idx >= input_files[m->file_idx]->nb_streams) {
        av_log(NULL, AV_LOG_FATAL, "mapchan: invalid input file stream index #%d.%d\n",
               m->file_idx, m->stream_idx);
        exit_program(1);
    }
    st = input_files[m->file_idx]->ctx->streams[m->stream_idx];
    if (st->codec->codec_type != AVMEDIA_TYPE_AUDIO) {
        av_log(NULL, AV_LOG_FATAL, "mapchan: stream #%d.%d is not an audio stream.\n",
               m->file_idx, m->stream_idx);
        exit_program(1);
    }
    if (m->channel_idx < 0 || m->channel_idx >= st->codec->channels) {
        av_log(NULL, AV_LOG_FATAL, "mapchan: invalid audio channel #%d.%d.%d\n",
               m->file_idx, m->stream_idx, m->channel_idx);
        exit_program(1);
    }
    return 0;
}

/**
 * Parse a metadata specifier in arg.
 * @param type metadata type is written here -- g(lobal)/s(tream)/c(hapter)/p(rogram)
 * @param index for type c/p, chapter/program index is written here
 * @param stream_spec for type s, the stream specifier is written here
 */
static void parse_meta_type(char *arg, char *type, int *index, const char **stream_spec)
{
    if (*arg) {
        *type = *arg;
        switch (*arg) {
        case 'g':
            break;
        case 's':
            if (*(++arg) && *arg != ':') {
                av_log(NULL, AV_LOG_FATAL, "Invalid metadata specifier %s.\n", arg);
                exit_program(1);
            }
            *stream_spec = *arg == ':' ? arg + 1 : "";
            break;
        case 'c':
        case 'p':
            if (*(++arg) == ':')
                *index = strtol(++arg, NULL, 0);
            break;
        default:
            av_log(NULL, AV_LOG_FATAL, "Invalid metadata type %c.\n", *arg);
            exit_program(1);
        }
    } else
        *type = 'g';
}

static int copy_metadata(char *outspec, char *inspec, AVFormatContext *oc, AVFormatContext *ic, OptionsContext *o)
{
    AVDictionary **meta_in = NULL;
    AVDictionary **meta_out = NULL;
    int i, ret = 0;
    char type_in, type_out;
    const char *istream_spec = NULL, *ostream_spec = NULL;
    int idx_in = 0, idx_out = 0;

    parse_meta_type(inspec,  &type_in,  &idx_in,  &istream_spec);
    parse_meta_type(outspec, &type_out, &idx_out, &ostream_spec);

    if (!ic) {
        if (type_out == 'g' || !*outspec)
            o->metadata_global_manual = 1;
        if (type_out == 's' || !*outspec)
            o->metadata_streams_manual = 1;
        if (type_out == 'c' || !*outspec)
            o->metadata_chapters_manual = 1;
        return 0;
    }

    if (type_in == 'g' || type_out == 'g')
        o->metadata_global_manual = 1;
    if (type_in == 's' || type_out == 's')
        o->metadata_streams_manual = 1;
    if (type_in == 'c' || type_out == 'c')
        o->metadata_chapters_manual = 1;

#define METADATA_CHECK_INDEX(index, nb_elems, desc)\
    if ((index) < 0 || (index) >= (nb_elems)) {\
        av_log(NULL, AV_LOG_FATAL, "Invalid %s index %d while processing metadata maps.\n",\
                (desc), (index));\
        exit_program(1);\
    }

#define SET_DICT(type, meta, context, index)\
        switch (type) {\
        case 'g':\
            meta = &context->metadata;\
            break;\
        case 'c':\
            METADATA_CHECK_INDEX(index, context->nb_chapters, "chapter")\
            meta = &context->chapters[index]->metadata;\
            break;\
        case 'p':\
            METADATA_CHECK_INDEX(index, context->nb_programs, "program")\
            meta = &context->programs[index]->metadata;\
            break;\
        }\

    SET_DICT(type_in, meta_in, ic, idx_in);
    SET_DICT(type_out, meta_out, oc, idx_out);

    /* for input streams choose first matching stream */
    if (type_in == 's') {
        for (i = 0; i < ic->nb_streams; i++) {
            if ((ret = check_stream_specifier(ic, ic->streams[i], istream_spec)) > 0) {
                meta_in = &ic->streams[i]->metadata;
                break;
            } else if (ret < 0)
                exit_program(1);
        }
        if (!meta_in) {
            av_log(NULL, AV_LOG_FATAL, "Stream specifier %s does not match  any streams.\n", istream_spec);
            exit_program(1);
        }
    }

    if (type_out == 's') {
        for (i = 0; i < oc->nb_streams; i++) {
            if ((ret = check_stream_specifier(oc, oc->streams[i], ostream_spec)) > 0) {
                meta_out = &oc->streams[i]->metadata;
                av_dict_copy(meta_out, *meta_in, AV_DICT_DONT_OVERWRITE);
            } else if (ret < 0)
                exit_program(1);
        }
    } else
        av_dict_copy(meta_out, *meta_in, AV_DICT_DONT_OVERWRITE);

    return 0;
}

static int opt_recording_timestamp(OptionsContext *o, 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);
    parse_option(o, "metadata", buf, options);

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

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

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

static AVCodec *choose_decoder(OptionsContext *o, AVFormatContext *s, AVStream *st)
{
    char *codec_name = NULL;

    MATCH_PER_STREAM_OPT(codec_names, str, codec_name, s, st);
    if (codec_name) {
        AVCodec *codec = find_codec_or_die(codec_name, st->codec->codec_type, 0);
        st->codec->codec_id = codec->id;
        return codec;
    } else
        return avcodec_find_decoder(st->codec->codec_id);
}

/**
 * Add all the streams from the given input file to the global
 * list of input streams.
 */
static void add_input_streams(OptionsContext *o, AVFormatContext *ic)
{
    int i;
    char *next, *codec_tag = NULL;

    for (i = 0; i < ic->nb_streams; i++) {
        AVStream *st = ic->streams[i];
        AVCodecContext *dec = st->codec;
        InputStream *ist = av_mallocz(sizeof(*ist));
        char *framerate = NULL;

        if (!ist)
            exit_program(1);

        input_streams = grow_array(input_streams, sizeof(*input_streams), &nb_input_streams, nb_input_streams + 1);
        input_streams[nb_input_streams - 1] = ist;

        ist->st = st;
        ist->file_index = nb_input_files;
        ist->discard = 1;
        st->discard  = AVDISCARD_ALL;
        ist->opts = filter_codec_opts(codec_opts, choose_decoder(o, ic, st), ic, st);

        ist->ts_scale = 1.0;
        MATCH_PER_STREAM_OPT(ts_scale, dbl, ist->ts_scale, ic, st);

        MATCH_PER_STREAM_OPT(codec_tags, str, codec_tag, ic, st);
        if (codec_tag) {
            uint32_t tag = strtol(codec_tag, &next, 0);
            if (*next)
                tag = AV_RL32(codec_tag);
            st->codec->codec_tag = tag;
        }

        ist->dec = choose_decoder(o, ic, st);

        switch (dec->codec_type) {
        case AVMEDIA_TYPE_VIDEO:
            if(!ist->dec)
                ist->dec = avcodec_find_decoder(dec->codec_id);
            if (dec->lowres) {
                dec->flags |= CODEC_FLAG_EMU_EDGE;
            }

            ist->resample_height  = dec->height;
            ist->resample_width   = dec->width;
            ist->resample_pix_fmt = dec->pix_fmt;

            MATCH_PER_STREAM_OPT(frame_rates, str, framerate, ic, st);
            if (framerate && av_parse_video_rate(&ist->framerate,
                                                 framerate) < 0) {
                av_log(NULL, AV_LOG_ERROR, "Error parsing framerate %s.\n",
                       framerate);
                exit_program(1);
            }

            ist->top_field_first = -1;
            MATCH_PER_STREAM_OPT(top_field_first, i, ist->top_field_first, ic, st);

            break;
        case AVMEDIA_TYPE_AUDIO:
            guess_input_channel_layout(ist);

            ist->resample_sample_fmt     = dec->sample_fmt;
            ist->resample_sample_rate    = dec->sample_rate;
            ist->resample_channels       = dec->channels;
            ist->resample_channel_layout = dec->channel_layout;

            break;
        case AVMEDIA_TYPE_DATA:
        case AVMEDIA_TYPE_SUBTITLE:
            if(!ist->dec)
                ist->dec = avcodec_find_decoder(dec->codec_id);
            break;
        case AVMEDIA_TYPE_ATTACHMENT:
        case AVMEDIA_TYPE_UNKNOWN:
            break;
        default:
            abort();
        }
    }
}

static void assert_file_overwrite(const char *filename)
{