ffmpeg.c

        av_opt_eval_flags(ost->enc_ctx, o, e->value, &codec_flags);
    }

    encoder_string_len = sizeof(LIBAVCODEC_IDENT) + strlen(ost->enc->name) + 2;
    encoder_string     = av_mallocz(encoder_string_len);
    if (!encoder_string)
        exit_program(1);

    if (!(format_flags & AVFMT_FLAG_BITEXACT) && !(codec_flags & AV_CODEC_FLAG_BITEXACT))
        av_strlcpy(encoder_string, LIBAVCODEC_IDENT " ", encoder_string_len);
    else
        av_strlcpy(encoder_string, "Lavc ", encoder_string_len);
    av_strlcat(encoder_string, ost->enc->name, encoder_string_len);
    av_dict_set(&ost->st->metadata, "encoder",  encoder_string,
                AV_DICT_DONT_STRDUP_VAL | AV_DICT_DONT_OVERWRITE);
}

static void parse_forced_key_frames(char *kf, OutputStream *ost,
                                    AVCodecContext *avctx)
{
    char *p;
    int n = 1, i, size, index = 0;
    int64_t t, *pts;

    for (p = kf; *p; p++)
        if (*p == ',')
            n++;
    size = n;
    pts = av_malloc_array(size, sizeof(*pts));
    if (!pts) {
        av_log(NULL, AV_LOG_FATAL, "Could not allocate forced key frames array.\n");
        exit_program(1);
    }

    p = kf;
    for (i = 0; i < n; i++) {
        char *next = strchr(p, ',');

        if (next)
            *next++ = 0;

        if (!memcmp(p, "chapters", 8)) {

            AVFormatContext *avf = output_files[ost->file_index]->ctx;
            int j;

            if (avf->nb_chapters > INT_MAX - size ||
                !(pts = av_realloc_f(pts, size += avf->nb_chapters - 1,
                                     sizeof(*pts)))) {
                av_log(NULL, AV_LOG_FATAL,
                       "Could not allocate forced key frames array.\n");
                exit_program(1);
            }
            t = p[8] ? parse_time_or_die("force_key_frames", p + 8, 1) : 0;
            t = av_rescale_q(t, AV_TIME_BASE_Q, avctx->time_base);

            for (j = 0; j < avf->nb_chapters; j++) {
                AVChapter *c = avf->chapters[j];
                av_assert1(index < size);
                pts[index++] = av_rescale_q(c->start, c->time_base,
                                            avctx->time_base) + t;
            }

        } else {

            t = parse_time_or_die("force_key_frames", p, 1);
            av_assert1(index < size);
            pts[index++] = av_rescale_q(t, AV_TIME_BASE_Q, avctx->time_base);

        }

        p = next;
    }

    av_assert0(index == size);
    qsort(pts, size, sizeof(*pts), compare_int64);
    ost->forced_kf_count = size;
    ost->forced_kf_pts   = pts;
}

static int init_output_stream_encode(OutputStream *ost)
{
    InputStream *ist = get_input_stream(ost);
    AVCodecContext *enc_ctx = ost->enc_ctx;
    AVCodecContext *dec_ctx = NULL;
    AVFormatContext *oc = output_files[ost->file_index]->ctx;
    int j, ret;

    set_encoder_id(output_files[ost->file_index], ost);

    if (ist) {
        ost->st->disposition          = ist->st->disposition;

        dec_ctx = ist->dec_ctx;

        enc_ctx->chroma_sample_location = dec_ctx->chroma_sample_location;
    } else {
        for (j = 0; j < oc->nb_streams; j++) {
            AVStream *st = oc->streams[j];
            if (st != ost->st && st->codecpar->codec_type == ost->st->codecpar->codec_type)
                break;
        }
        if (j == oc->nb_streams)
            if (ost->st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO ||
                ost->st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO)
                ost->st->disposition = AV_DISPOSITION_DEFAULT;
    }

    if ((enc_ctx->codec_type == AVMEDIA_TYPE_VIDEO ||
         enc_ctx->codec_type == AVMEDIA_TYPE_AUDIO) &&
         filtergraph_is_simple(ost->filter->graph)) {
            FilterGraph *fg = ost->filter->graph;

            if (configure_filtergraph(fg)) {
                av_log(NULL, AV_LOG_FATAL, "Error opening filters!\n");
                exit_program(1);
            }
    }

    if (enc_ctx->codec_type == AVMEDIA_TYPE_VIDEO) {
        if (!ost->frame_rate.num)
            ost->frame_rate = av_buffersink_get_frame_rate(ost->filter->filter);
        if (ist && !ost->frame_rate.num)
            ost->frame_rate = ist->framerate;
        if (ist && !ost->frame_rate.num)
            ost->frame_rate = ist->st->r_frame_rate;
        if (ist && !ost->frame_rate.num) {
            ost->frame_rate = (AVRational){25, 1};
            av_log(NULL, AV_LOG_WARNING,
                   "No information "
                   "about the input framerate is available. Falling "
                   "back to a default value of 25fps for output stream #%d:%d. Use the -r option "
                   "if you want a different framerate.\n",
                   ost->file_index, ost->index);
        }
//      ost->frame_rate = ist->st->avg_frame_rate.num ? ist->st->avg_frame_rate : (AVRational){25, 1};
        if (ost->enc && ost->enc->supported_framerates && !ost->force_fps) {
            int idx = av_find_nearest_q_idx(ost->frame_rate, ost->enc->supported_framerates);
            ost->frame_rate = ost->enc->supported_framerates[idx];
        }
        // reduce frame rate for mpeg4 to be within the spec limits
        if (enc_ctx->codec_id == AV_CODEC_ID_MPEG4) {
            av_reduce(&ost->frame_rate.num, &ost->frame_rate.den,
                      ost->frame_rate.num, ost->frame_rate.den, 65535);
        }
    }

    switch (enc_ctx->codec_type) {
    case AVMEDIA_TYPE_AUDIO:
        enc_ctx->sample_fmt     = ost->filter->filter->inputs[0]->format;
        if (dec_ctx)
            enc_ctx->bits_per_raw_sample = FFMIN(dec_ctx->bits_per_raw_sample,
                                                 av_get_bytes_per_sample(enc_ctx->sample_fmt) << 3);
        enc_ctx->sample_rate    = ost->filter->filter->inputs[0]->sample_rate;
        enc_ctx->channel_layout = ost->filter->filter->inputs[0]->channel_layout;
        enc_ctx->channels       = avfilter_link_get_channels(ost->filter->filter->inputs[0]);
        enc_ctx->time_base      = (AVRational){ 1, enc_ctx->sample_rate };
        break;
    case AVMEDIA_TYPE_VIDEO:
        enc_ctx->time_base = av_inv_q(ost->frame_rate);
        if (!(enc_ctx->time_base.num && enc_ctx->time_base.den))
            enc_ctx->time_base = ost->filter->filter->inputs[0]->time_base;
        if (   av_q2d(enc_ctx->time_base) < 0.001 && video_sync_method != VSYNC_PASSTHROUGH
           && (video_sync_method == VSYNC_CFR || video_sync_method == VSYNC_VSCFR || (video_sync_method == VSYNC_AUTO && !(oc->oformat->flags & AVFMT_VARIABLE_FPS)))){
            av_log(oc, AV_LOG_WARNING, "Frame rate very high for a muxer not efficiently supporting it.\n"
                                       "Please consider specifying a lower framerate, a different muxer or -vsync 2\n");
        }
        for (j = 0; j < ost->forced_kf_count; j++)
            ost->forced_kf_pts[j] = av_rescale_q(ost->forced_kf_pts[j],
                                                 AV_TIME_BASE_Q,
                                                 enc_ctx->time_base);

        enc_ctx->width  = ost->filter->filter->inputs[0]->w;
        enc_ctx->height = ost->filter->filter->inputs[0]->h;
        enc_ctx->sample_aspect_ratio = ost->st->sample_aspect_ratio =
            ost->frame_aspect_ratio.num ? // overridden by the -aspect cli option
            av_mul_q(ost->frame_aspect_ratio, (AVRational){ enc_ctx->height, enc_ctx->width }) :
            ost->filter->filter->inputs[0]->sample_aspect_ratio;
        if (!strncmp(ost->enc->name, "libx264", 7) &&
            enc_ctx->pix_fmt == AV_PIX_FMT_NONE &&
            ost->filter->filter->inputs[0]->format != AV_PIX_FMT_YUV420P)
            av_log(NULL, AV_LOG_WARNING,
                   "No pixel format specified, %s for H.264 encoding chosen.\n"
                   "Use -pix_fmt yuv420p for compatibility with outdated media players.\n",
                   av_get_pix_fmt_name(ost->filter->filter->inputs[0]->format));
        if (!strncmp(ost->enc->name, "mpeg2video", 10) &&
            enc_ctx->pix_fmt == AV_PIX_FMT_NONE &&
            ost->filter->filter->inputs[0]->format != AV_PIX_FMT_YUV420P)
            av_log(NULL, AV_LOG_WARNING,
                   "No pixel format specified, %s for MPEG-2 encoding chosen.\n"
                   "Use -pix_fmt yuv420p for compatibility with outdated media players.\n",
                   av_get_pix_fmt_name(ost->filter->filter->inputs[0]->format));
        enc_ctx->pix_fmt = ost->filter->filter->inputs[0]->format;
        if (dec_ctx)
            enc_ctx->bits_per_raw_sample = FFMIN(dec_ctx->bits_per_raw_sample,
                                                 av_pix_fmt_desc_get(enc_ctx->pix_fmt)->comp[0].depth);

        ost->st->avg_frame_rate = ost->frame_rate;

        if (!dec_ctx ||
            enc_ctx->width   != dec_ctx->width  ||
            enc_ctx->height  != dec_ctx->height ||
            enc_ctx->pix_fmt != dec_ctx->pix_fmt) {
            enc_ctx->bits_per_raw_sample = frame_bits_per_raw_sample;
        }

        if (ost->forced_keyframes) {
            if (!strncmp(ost->forced_keyframes, "expr:", 5)) {
                ret = av_expr_parse(&ost->forced_keyframes_pexpr, ost->forced_keyframes+5,
                                    forced_keyframes_const_names, NULL, NULL, NULL, NULL, 0, NULL);
                if (ret < 0) {
                    av_log(NULL, AV_LOG_ERROR,
                           "Invalid force_key_frames expression '%s'\n", ost->forced_keyframes+5);
                    return ret;
                }
                ost->forced_keyframes_expr_const_values[FKF_N] = 0;
                ost->forced_keyframes_expr_const_values[FKF_N_FORCED] = 0;
                ost->forced_keyframes_expr_const_values[FKF_PREV_FORCED_N] = NAN;
                ost->forced_keyframes_expr_const_values[FKF_PREV_FORCED_T] = NAN;

            // Don't parse the 'forced_keyframes' in case of 'keep-source-keyframes',
            // parse it only for static kf timings
            } else if(strncmp(ost->forced_keyframes, "source", 6)) {
                parse_forced_key_frames(ost->forced_keyframes, ost, ost->enc_ctx);
            }
        }
        break;
    case AVMEDIA_TYPE_SUBTITLE:
        enc_ctx->time_base = (AVRational){1, 1000};
        if (!enc_ctx->width) {
            enc_ctx->width     = input_streams[ost->source_index]->st->codecpar->width;
            enc_ctx->height    = input_streams[ost->source_index]->st->codecpar->height;
        }
        break;
    case AVMEDIA_TYPE_DATA:
        break;
    default:
        abort();
        break;
    }

    return 0;
}

static int init_output_stream(OutputStream *ost, char *error, int error_len)
{
    int ret = 0;

    if (ost->encoding_needed) {
        AVCodec      *codec = ost->enc;
        AVCodecContext *dec = NULL;
        InputStream *ist;

        ret = init_output_stream_encode(ost);
        if (ret < 0)
            return ret;

        if ((ist = get_input_stream(ost)))
            dec = ist->dec_ctx;
        if (dec && dec->subtitle_header) {
            /* ASS code assumes this buffer is null terminated so add extra byte. */
            ost->enc_ctx->subtitle_header = av_mallocz(dec->subtitle_header_size + 1);
            if (!ost->enc_ctx->subtitle_header)
                return AVERROR(ENOMEM);
            memcpy(ost->enc_ctx->subtitle_header, dec->subtitle_header, dec->subtitle_header_size);
            ost->enc_ctx->subtitle_header_size = dec->subtitle_header_size;
        }
        if (!av_dict_get(ost->encoder_opts, "threads", NULL, 0))
            av_dict_set(&ost->encoder_opts, "threads", "auto", 0);
        if (ost->enc->type == AVMEDIA_TYPE_AUDIO &&
            !codec->defaults &&
            !av_dict_get(ost->encoder_opts, "b", NULL, 0) &&
            !av_dict_get(ost->encoder_opts, "ab", NULL, 0))
            av_dict_set(&ost->encoder_opts, "b", "128000", 0);

        if (ost->filter && ost->filter->filter->inputs[0]->hw_frames_ctx) {
            ost->enc_ctx->hw_frames_ctx = av_buffer_ref(ost->filter->filter->inputs[0]->hw_frames_ctx);
            if (!ost->enc_ctx->hw_frames_ctx)
                return AVERROR(ENOMEM);
        }

        if ((ret = avcodec_open2(ost->enc_ctx, codec, &ost->encoder_opts)) < 0) {
            if (ret == AVERROR_EXPERIMENTAL)
                abort_codec_experimental(codec, 1);
            snprintf(error, error_len,
                     "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);
            return ret;
        }
        if (ost->enc->type == AVMEDIA_TYPE_AUDIO &&
            !(ost->enc->capabilities & AV_CODEC_CAP_VARIABLE_FRAME_SIZE))
            av_buffersink_set_frame_size(ost->filter->filter,
                                            ost->enc_ctx->frame_size);
        assert_avoptions(ost->encoder_opts);
        if (ost->enc_ctx->bit_rate && ost->enc_ctx->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");

        ret = avcodec_parameters_from_context(ost->st->codecpar, ost->enc_ctx);
        if (ret < 0) {
            av_log(NULL, AV_LOG_FATAL,
                   "Error initializing the output stream codec context.\n");
            exit_program(1);
        }
        /*
         * FIXME: ost->st->codec should't be needed here anymore.
         */
        ret = avcodec_copy_context(ost->st->codec, ost->enc_ctx);
        if (ret < 0)
            return ret;

        if (ost->enc_ctx->nb_coded_side_data) {
            int i;

            ost->st->side_data = av_realloc_array(NULL, ost->enc_ctx->nb_coded_side_data,
                                                  sizeof(*ost->st->side_data));
            if (!ost->st->side_data)
                return AVERROR(ENOMEM);

            for (i = 0; i < ost->enc_ctx->nb_coded_side_data; i++) {
                const AVPacketSideData *sd_src = &ost->enc_ctx->coded_side_data[i];
                AVPacketSideData *sd_dst = &ost->st->side_data[i];

                sd_dst->data = av_malloc(sd_src->size);
                if (!sd_dst->data)
                    return AVERROR(ENOMEM);
                memcpy(sd_dst->data, sd_src->data, sd_src->size);
                sd_dst->size = sd_src->size;
                sd_dst->type = sd_src->type;
                ost->st->nb_side_data++;
            }
        }

        // copy timebase while removing common factors
        ost->st->time_base = av_add_q(ost->enc_ctx->time_base, (AVRational){0, 1});
        ost->st->codec->codec= ost->enc_ctx->codec;
    } else if (ost->stream_copy) {
        ret = init_output_stream_streamcopy(ost);
        if (ret < 0)
            return ret;

        /*
         * FIXME: will the codec context used by the parser during streamcopy
         * This should go away with the new parser API.
         */
        ret = avcodec_parameters_to_context(ost->parser_avctx, ost->st->codecpar);
        if (ret < 0)
            return ret;
    }

    // parse user provided disposition, and update stream values
    if (ost->disposition) {
        static const AVOption opts[] = {
            { "disposition"         , NULL, 0, AV_OPT_TYPE_FLAGS, { .i64 = 0 }, INT64_MIN, INT64_MAX, .unit = "flags" },
            { "default"             , NULL, 0, AV_OPT_TYPE_CONST, { .i64 = AV_DISPOSITION_DEFAULT           },    .unit = "flags" },
            { "dub"                 , NULL, 0, AV_OPT_TYPE_CONST, { .i64 = AV_DISPOSITION_DUB               },    .unit = "flags" },
            { "original"            , NULL, 0, AV_OPT_TYPE_CONST, { .i64 = AV_DISPOSITION_ORIGINAL          },    .unit = "flags" },
            { "comment"             , NULL, 0, AV_OPT_TYPE_CONST, { .i64 = AV_DISPOSITION_COMMENT           },    .unit = "flags" },
            { "lyrics"              , NULL, 0, AV_OPT_TYPE_CONST, { .i64 = AV_DISPOSITION_LYRICS            },    .unit = "flags" },
            { "karaoke"             , NULL, 0, AV_OPT_TYPE_CONST, { .i64 = AV_DISPOSITION_KARAOKE           },    .unit = "flags" },
            { "forced"              , NULL, 0, AV_OPT_TYPE_CONST, { .i64 = AV_DISPOSITION_FORCED            },    .unit = "flags" },
            { "hearing_impaired"    , NULL, 0, AV_OPT_TYPE_CONST, { .i64 = AV_DISPOSITION_HEARING_IMPAIRED  },    .unit = "flags" },
            { "visual_impaired"     , NULL, 0, AV_OPT_TYPE_CONST, { .i64 = AV_DISPOSITION_VISUAL_IMPAIRED   },    .unit = "flags" },
            { "clean_effects"       , NULL, 0, AV_OPT_TYPE_CONST, { .i64 = AV_DISPOSITION_CLEAN_EFFECTS     },    .unit = "flags" },
            { "captions"            , NULL, 0, AV_OPT_TYPE_CONST, { .i64 = AV_DISPOSITION_CAPTIONS          },    .unit = "flags" },
            { "descriptions"        , NULL, 0, AV_OPT_TYPE_CONST, { .i64 = AV_DISPOSITION_DESCRIPTIONS      },    .unit = "flags" },
            { "metadata"            , NULL, 0, AV_OPT_TYPE_CONST, { .i64 = AV_DISPOSITION_METADATA          },    .unit = "flags" },
            { NULL },
        };
        static const AVClass class = {
            .class_name = "",
            .item_name  = av_default_item_name,
            .option     = opts,
            .version    = LIBAVUTIL_VERSION_INT,
        };
        const AVClass *pclass = &class;

        ret = av_opt_eval_flags(&pclass, &opts[0], ost->disposition, &ost->st->disposition);
        if (ret < 0)
            return ret;
    }

    /* initialize bitstream filters for the output stream
     * needs to be done here, because the codec id for streamcopy is not
     * known until now */
    ret = init_output_bsfs(ost);
    if (ret < 0)
        return ret;

    ost->initialized = 1;

    ret = check_init_output_file(output_files[ost->file_index], ost->file_index);
    if (ret < 0)
        return ret;

    return ret;
}

static void report_new_stream(int input_index, AVPacket *pkt)
{
    InputFile *file = input_files[input_index];
    AVStream *st = file->ctx->streams[pkt->stream_index];

    if (pkt->stream_index < file->nb_streams_warn)
        return;
    av_log(file->ctx, AV_LOG_WARNING,
           "New %s stream %d:%d at pos:%"PRId64" and DTS:%ss\n",
           av_get_media_type_string(st->codecpar->codec_type),
           input_index, pkt->stream_index,
           pkt->pos, av_ts2timestr(pkt->dts, &st->time_base));
    file->nb_streams_warn = pkt->stream_index + 1;
}

static int transcode_init(void)
{
    int ret = 0, i, j, k;
    AVFormatContext *oc;
    OutputStream *ost;
    InputStream *ist;
    char error[1024] = {0};

    for (i = 0; i < nb_filtergraphs; i++) {
        FilterGraph *fg = filtergraphs[i];
        for (j = 0; j < fg->nb_outputs; j++) {
            OutputFilter *ofilter = fg->outputs[j];
            if (!ofilter->ost || ofilter->ost->source_index >= 0)
                continue;
            if (fg->nb_inputs != 1)
                continue;
            for (k = nb_input_streams-1; k >= 0 ; k--)
                if (fg->inputs[0]->ist == input_streams[k])
                    break;
            ofilter->ost->source_index = k;
        }
    }

    /* init framerate emulation */
    for (i = 0; i < nb_input_files; i++) {
        InputFile *ifile = input_files[i];
        if (ifile->rate_emu)
            for (j = 0; j < ifile->nb_streams; j++)
                input_streams[j + ifile->ist_index]->start = av_gettime_relative();
    }

    /* hwaccel transcoding */
    for (i = 0; i < nb_output_streams; i++) {
        ost = output_streams[i];

        if (!ost->stream_copy) {
#if CONFIG_LIBMFX
            if (qsv_transcode_init(ost))
                exit_program(1);
#endif

#if CONFIG_CUVID
            if (cuvid_transcode_init(ost))
                exit_program(1);
#endif
        }
    }

    /* init input streams */
    for (i = 0; i < nb_input_streams; i++)
        if ((ret = init_input_stream(i, error, sizeof(error))) < 0) {
            for (i = 0; i < nb_output_streams; i++) {
                ost = output_streams[i];
                avcodec_close(ost->enc_ctx);
            }
            goto dump_format;
        }

    /* open each encoder */
    for (i = 0; i < nb_output_streams; i++) {
        ret = init_output_stream(output_streams[i], error, sizeof(error));
        if (ret < 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;
        }
    }

    /* write headers for files with no streams */
    for (i = 0; i < nb_output_files; i++) {
        oc = output_files[i]->ctx;
        if (oc->oformat->flags & AVFMT_NOSTREAMS && oc->nb_streams == 0) {
            ret = check_init_output_file(output_files[i], i);
            if (ret < 0)
                goto dump_format;
        }
    }

 dump_format:
    /* 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 (!filtergraph_is_simple(ist->filters[j]->graph)) {
                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 && !filtergraph_is_simple(ost->filter->graph)) {
            /* 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 {
            const AVCodec *in_codec    = input_streams[ost->source_index]->dec;
            const AVCodec *out_codec   = ost->enc;
            const char *decoder_name   = "?";
            const char *in_codec_name  = "?";
            const char *encoder_name   = "?";
            const char *out_codec_name = "?";
            const AVCodecDescriptor *desc;

            if (in_codec) {
                decoder_name  = in_codec->name;
                desc = avcodec_descriptor_get(in_codec->id);
                if (desc)
                    in_codec_name = desc->name;
                if (!strcmp(decoder_name, in_codec_name))
                    decoder_name = "native";
            }

            if (out_codec) {
                encoder_name   = out_codec->name;
                desc = avcodec_descriptor_get(out_codec->id);
                if (desc)
                    out_codec_name = desc->name;
                if (!strcmp(encoder_name, out_codec_name))
                    encoder_name = "native";
            }

            av_log(NULL, AV_LOG_INFO, " (%s (%s) -> %s (%s))",
                   in_codec_name, decoder_name,
                   out_codec_name, encoder_name);
        }
        av_log(NULL, AV_LOG_INFO, "\n");
    }

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

    transcode_init_done = 1;

    return 0;
}

/* Return 1 if there remain 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->finished ||
            (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++)
                close_output_stream(output_streams[of->ost_index + j]);
            continue;
        }

        return 1;
    }

    return 0;
}

/**
 * Select the output stream to process.
 *
 * @return  selected output stream, or NULL if none available
 */
static OutputStream *choose_output(void)
{
    int i;
    int64_t opts_min = INT64_MAX;
    OutputStream *ost_min = NULL;

    for (i = 0; i < nb_output_streams; i++) {
        OutputStream *ost = output_streams[i];
        int64_t opts = ost->st->cur_dts == AV_NOPTS_VALUE ? INT64_MIN :
                       av_rescale_q(ost->st->cur_dts, ost->st->time_base,
                                    AV_TIME_BASE_Q);
        if (ost->st->cur_dts == AV_NOPTS_VALUE)
            av_log(NULL, AV_LOG_DEBUG, "cur_dts is invalid (this is harmless if it occurs once at the start per stream)\n");

        if (!ost->finished && opts < opts_min) {
            opts_min = opts;
            ost_min  = ost->unavailable ? NULL : ost;
        }
    }
    return ost_min;
}

static void set_tty_echo(int on)
{
#if HAVE_TERMIOS_H
    struct termios tty;
    if (tcgetattr(0, &tty) == 0) {
        if (on) tty.c_lflag |= ECHO;
        else    tty.c_lflag &= ~ECHO;
        tcsetattr(0, TCSANOW, &tty);
    }
#endif
}

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>|all <time>|-1 <command>[ <argument>]\n");
        i = 0;
        set_tty_echo(1);
        while ((k = read_key()) != '\n' && k != '\r' && i < sizeof(buf)-1)
            if (k > 0)
                buf[i++] = k;
        buf[i] = 0;
        set_tty_echo(0);
        fprintf(stderr, "\n");
        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:\n%s", i, ret, buf);
                    } else if (key == 'c') {
                        fprintf(stderr, "Queuing commands only on filters supporting the specific command is unsupported\n");
                        ret = AVERROR_PATCHWELCOME;
                    } else {
                        ret = avfilter_graph_queue_command(fg->graph, target, command, arg, 0, time);
                        if (ret < 0)
                            fprintf(stderr, "Queuing command failed with error %s\n", av_err2str(ret));
                    }
                }
            }
        } 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{
            char buf[32];
            int k = 0;
            i = 0;
            set_tty_echo(1);
            while ((k = read_key()) != '\n' && k != '\r' && i < sizeof(buf)-1)
                if (k > 0)
                    buf[i++] = k;
            buf[i] = 0;
            set_tty_echo(0);
            fprintf(stderr, "\n");
            if (k <= 0 || sscanf(buf, "%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->enc_ctx->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 first matching filter supporting it\n"
                        "C      Send/Queue command to all matching filters\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;
}

#if HAVE_PTHREADS
static void *input_thread(void *arg)
{
    InputFile *f = arg;
    unsigned flags = f->non_blocking ? AV_THREAD_MESSAGE_NONBLOCK : 0;
    int ret = 0;

    while (1) {
        AVPacket pkt;
        ret = av_read_frame(f->ctx, &pkt);

        if (ret == AVERROR(EAGAIN)) {
            av_usleep(10000);
            continue;
        }
        if (ret < 0) {
            av_thread_message_queue_set_err_recv(f->in_thread_queue, ret);
            break;
        }
        ret = av_thread_message_queue_send(f->in_thread_queue, &pkt, flags);
        if (flags && ret == AVERROR(EAGAIN)) {
            flags = 0;
            ret = av_thread_message_queue_send(f->in_thread_queue, &pkt, flags);
            av_log(f->ctx, AV_LOG_WARNING,
                   "Thread message queue blocking; consider raising the "
                   "thread_queue_size option (current value: %d)\n",
                   f->thread_queue_size);
        }
        if (ret < 0) {
            if (ret != AVERROR_EOF)
                av_log(f->ctx, AV_LOG_ERROR,
                       "Unable to send packet to main thread: %s\n",
                       av_err2str(ret));
            av_packet_unref(&pkt);
            av_thread_message_queue_set_err_recv(f->in_thread_queue, ret);
            break;
        }
    }

    return NULL;
}

static void free_input_threads(void)
{
    int i;

    for (i = 0; i < nb_input_files; i++) {
        InputFile *f = input_files[i];
        AVPacket pkt;

        if (!f || !f->in_thread_queue)
            continue;
        av_thread_message_queue_set_err_send(f->in_thread_queue, AVERROR_EOF);
        while (av_thread_message_queue_recv(f->in_thread_queue, &pkt, 0) >= 0)
            av_packet_unref(&pkt);

        pthread_join(f->thread, NULL);
        f->joined = 1;
        av_thread_message_queue_free(&f->in_thread_queue);
    }
}

static int init_input_threads(void)
{
    int i, ret;

    if (nb_input_files == 1)
        return 0;

    for (i = 0; i < nb_input_files; i++) {
        InputFile *f = input_files[i];

        if (f->ctx->pb ? !f->ctx->pb->seekable :
            strcmp(f->ctx->iformat->name, "lavfi"))
            f->non_blocking = 1;
        ret = av_thread_message_queue_alloc(&f->in_thread_queue,
                                            f->thread_queue_size, sizeof(AVPacket));
        if (ret < 0)
            return ret;

        if ((ret = pthread_create(&f->thread, NULL, input_thread, f))) {
            av_log(NULL, AV_LOG_ERROR, "pthread_create failed: %s. Try to increase `ulimit -v` or decrease `ulimit -s`.\n", strerror(ret));
            av_thread_message_queue_free(&f->in_thread_queue);
            return AVERROR(ret);
        }
    }
    return 0;
}

static int get_input_packet_mt(InputFile *f, AVPacket *pkt)
{
    return av_thread_message_queue_recv(f->in_thread_queue, pkt,
                                        f->non_blocking ?
                                        AV_THREAD_MESSAGE_NONBLOCK : 0);
}
#endif

static int get_input_packet(InputFile *f, AVPacket *pkt)
{
    if (f->rate_emu) {
        int i;
        for (i = 0; i < f->nb_streams; i++) {
            InputStream *ist = input_streams[f->ist_index + i];
            int64_t pts = av_rescale(ist->dts, 1000000, AV_TIME_BASE);
            int64_t now = av_gettime_relative() - ist->start;
            if (pts > now)
                return AVERROR(EAGAIN);
        }
    }

#if HAVE_PTHREADS
    if (nb_input_files > 1)
        return get_input_packet_mt(f, pkt);
#endif
    return av_read_frame(f->ctx, pkt);
}

static int got_eagain(void)
{
    int i;
    for (i = 0; i < nb_output_streams; i++)
        if (output_streams[i]->unavailable)
            return 1;
    return 0;
}

static void reset_eagain(void)
{
    int i;
    for (i = 0; i < nb_input_files; i++)
        input_files[i]->eagain = 0;
    for (i = 0; i < nb_output_streams; i++)
        output_streams[i]->unavailable = 0;
}

// set duration to max(tmp, duration) in a proper time base and return duration's time_base
static AVRational duration_max(int64_t tmp, int64_t *duration, AVRational tmp_time_base,
                                AVRational time_base)
{
    int ret;

    if (!*duration) {
        *duration = tmp;
        return tmp_time_base;
    }

    ret = av_compare_ts(*duration, time_base, tmp, tmp_time_base);
    if (ret < 0) {
        *duration = tmp;
        return tmp_time_base;
    }

    return time_base;
}

static int seek_to_start(InputFile *ifile, AVFormatContext *is)
{
    InputStream *ist;
    AVCodecContext *avctx;
    int i, ret, has_audio = 0;
    int64_t duration = 0;

    ret = av_seek_frame(is, -1, is->start_time, 0);
    if (ret < 0)
        return ret;

    for (i = 0; i < ifile->nb_streams; i++) {
        ist   = input_streams[ifile->ist_index + i];
        avctx = ist->dec_ctx;

        // flush decoders
        if (ist->decoding_needed) {
            process_input_packet(ist, NULL, 1);
            avcodec_flush_buffers(avctx);
        }

        /* duration is the length of the last frame in a stream
         * when audio stream is present we don't care about
         * last video frame length because it's not defined exactly */
        if (avctx->codec_type == AVMEDIA_TYPE_AUDIO && ist->nb_samples)
            has_audio = 1;
    }

    for (i = 0; i < ifile->nb_streams; i++) {
        ist   = input_streams[ifile->ist_index + i];
        avctx = ist->dec_ctx;

        if (has_audio) {
            if (avctx->codec_type == AVMEDIA_TYPE_AUDIO && ist->nb_samples) {
                AVRational sample_rate = {1, avctx->sample_rate};

                duration = av_rescale_q(ist->nb_samples, sample_rate, ist->st->time_base);
            } else
                continue;
        } else {
            if (ist->framerate.num) {
                duration = av_rescale_q(1, ist->framerate, ist->st->time_base);
            } else if (ist->st->avg_frame_rate.num) {
                duration = av_rescale_q(1, ist->st->avg_frame_rate, ist->st->time_base);
            } else duration = 1;
        }
        if (!ifile->duration)
            ifile->time_base = ist->st->time_base;
        /* the total duration of the stream, max_pts - min_pts is
         * the duration of the stream without the last frame */
        duration += ist->max_pts - ist->min_pts;
        ifile->time_base = duration_max(duration, &ifile->duration, ist->st->time_base,
                                        ifile->time_base);
    }

    if (ifile->loop > 0)
        ifile->loop--;

    return ret;
}

/*
 * Return
 * - 0 -- one packet was read and processed
 * - AVERROR(EAGAIN) -- no packets were available for selected file,
 *   this function should be called again
 * - AVERROR_EOF -- this function should not be called again
 */