avconv.c

            buf->refcount++;
            av_buffersrc_buffer(ost->input_video_filter, fb);
        } else
            av_vsrc_buffer_add_frame(ost->input_video_filter, decoded_frame,
                                     ist->pts, decoded_frame->sample_aspect_ratio);

        if (!ist->filtered_frame && !(ist->filtered_frame = avcodec_alloc_frame())) {
            av_free(buffer_to_free);
            return AVERROR(ENOMEM);
        } else
            avcodec_get_frame_defaults(ist->filtered_frame);
        filtered_frame = ist->filtered_frame;

        frame_available = avfilter_poll_frame(ost->output_video_filter->inputs[0]);
        while (frame_available) {
            AVRational ist_pts_tb;
            if (ost->output_video_filter)
                get_filtered_video_frame(ost->output_video_filter, filtered_frame, &ost->picref, &ist_pts_tb);
            if (ost->picref)
                ist->pts = av_rescale_q(ost->picref->pts, ist_pts_tb, AV_TIME_BASE_Q);
            if (ost->picref->video && !ost->frame_aspect_ratio)
                ost->st->codec->sample_aspect_ratio = ost->picref->video->pixel_aspect;
#else
            filtered_frame = decoded_frame;
#endif

            do_video_out(output_files[ost->file_index].ctx, ost, ist, filtered_frame, &frame_size,
                         same_quant ? quality : ost->st->codec->global_quality);
            if (vstats_filename && frame_size)
                do_video_stats(output_files[ost->file_index].ctx, ost, frame_size);
#if CONFIG_AVFILTER
            frame_available = ost->output_video_filter && avfilter_poll_frame(ost->output_video_filter->inputs[0]);
            if (ost->picref)
                avfilter_unref_buffer(ost->picref);
        }
#endif
    }

    av_free(buffer_to_free);
    return ret;
}

static int transcode_subtitles(InputStream *ist, AVPacket *pkt, int *got_output)
{
    AVSubtitle subtitle;
    int i, ret = avcodec_decode_subtitle2(ist->st->codec,
                                          &subtitle, got_output, pkt);
    if (ret < 0)
        return ret;
    if (!*got_output)
        return ret;

    rate_emu_sleep(ist);

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

        if (!check_output_constraints(ist, ost) || !ost->encoding_needed)
            continue;

        do_subtitle_out(output_files[ost->file_index].ctx, ost, ist, &subtitle, pkt->pts);
    }

    avsubtitle_free(&subtitle);
    return ret;
}

/* pkt = NULL means EOF (needed to flush decoder buffers) */
static int output_packet(InputStream *ist,
                         OutputStream *ost_table, int nb_ostreams,
                         const AVPacket *pkt)
{
    int i;
    int got_output;
    int64_t pkt_pts = AV_NOPTS_VALUE;
    AVPacket avpkt;

    if (ist->next_pts == AV_NOPTS_VALUE)
        ist->next_pts = ist->pts;

    if (pkt == NULL) {
        /* EOF handling */
        av_init_packet(&avpkt);
        avpkt.data = NULL;
        avpkt.size = 0;
        goto handle_eof;
    } else {
        avpkt = *pkt;
    }

    if (pkt->dts != AV_NOPTS_VALUE)
        ist->next_pts = ist->pts = av_rescale_q(pkt->dts, ist->st->time_base, AV_TIME_BASE_Q);
    if (pkt->pts != AV_NOPTS_VALUE)
        pkt_pts = av_rescale_q(pkt->pts, ist->st->time_base, AV_TIME_BASE_Q);

    // while we have more to decode or while the decoder did output something on EOF
    while (ist->decoding_needed && (avpkt.size > 0 || (!pkt && got_output))) {
        int ret = 0;
    handle_eof:

        ist->pts = ist->next_pts;

        if (avpkt.size && avpkt.size != pkt->size) {
            av_log(NULL, ist->showed_multi_packet_warning ? AV_LOG_VERBOSE : AV_LOG_WARNING,
                   "Multiple frames in a packet from stream %d\n", pkt->stream_index);
            ist->showed_multi_packet_warning = 1;
        }

        switch (ist->st->codec->codec_type) {
        case AVMEDIA_TYPE_AUDIO:
            ret = transcode_audio    (ist, &avpkt, &got_output);
            break;
        case AVMEDIA_TYPE_VIDEO:
            ret = transcode_video    (ist, &avpkt, &got_output, &pkt_pts);
            break;
        case AVMEDIA_TYPE_SUBTITLE:
            ret = transcode_subtitles(ist, &avpkt, &got_output);
            break;
        default:
            return -1;
        }

        if (ret < 0)
            return ret;
        // touch data and size only if not EOF
        if (pkt) {
            avpkt.data += ret;
            avpkt.size -= ret;
        }
        if (!got_output) {
            continue;
        }
    }

    /* handle stream copy */
    if (!ist->decoding_needed) {
        rate_emu_sleep(ist);
        ist->pts = ist->next_pts;
        switch (ist->st->codec->codec_type) {
        case AVMEDIA_TYPE_AUDIO:
            ist->next_pts += ((int64_t)AV_TIME_BASE * ist->st->codec->frame_size) /
                             ist->st->codec->sample_rate;
            break;
        case AVMEDIA_TYPE_VIDEO:
            if (ist->st->codec->time_base.num != 0) {
                int ticks = ist->st->parser ? ist->st->parser->repeat_pict + 1 : ist->st->codec->ticks_per_frame;
                ist->next_pts += ((int64_t)AV_TIME_BASE *
                                  ist->st->codec->time_base.num * ticks) /
                                  ist->st->codec->time_base.den;
            }
            break;
        }
    }
    for (i = 0; pkt && i < nb_ostreams; i++) {
        OutputStream *ost = &ost_table[i];

        if (!check_output_constraints(ist, ost) || ost->encoding_needed)
            continue;

        do_streamcopy(ist, ost, pkt);
    }

    return 0;
}

static void print_sdp(OutputFile *output_files, int n)
{
    char sdp[2048];
    int i;
    AVFormatContext **avc = av_malloc(sizeof(*avc) * n);

    if (!avc)
        exit_program(1);
    for (i = 0; i < n; i++)
        avc[i] = output_files[i].ctx;

    av_sdp_create(avc, n, sdp, sizeof(sdp));
    printf("SDP:\n%s\n", sdp);
    fflush(stdout);
    av_freep(&avc);
}

static int init_input_stream(int ist_index, OutputStream *output_streams, int nb_output_streams,
                             char *error, int error_len)
{
    int i;
    InputStream *ist = &input_streams[ist_index];
    if (ist->decoding_needed) {
        AVCodec *codec = ist->dec;
        if (!codec) {
            snprintf(error, error_len, "Decoder (codec id %d) not found for input stream #%d:%d",
                    ist->st->codec->codec_id, ist->file_index, ist->st->index);
            return AVERROR(EINVAL);
        }

        /* update requested sample format for the decoder based on the
           corresponding encoder sample format */
        for (i = 0; i < nb_output_streams; i++) {
            OutputStream *ost = &output_streams[i];
            if (ost->source_index == ist_index) {
                update_sample_fmt(ist->st->codec, codec, ost->st->codec);
                break;
            }
        }

        if (codec->type == AVMEDIA_TYPE_VIDEO && codec->capabilities & CODEC_CAP_DR1) {
            ist->st->codec->get_buffer     = codec_get_buffer;
            ist->st->codec->release_buffer = codec_release_buffer;
            ist->st->codec->opaque         = ist;
        }

        if (!av_dict_get(ist->opts, "threads", NULL, 0))
            av_dict_set(&ist->opts, "threads", "auto", 0);
        if (avcodec_open2(ist->st->codec, codec, &ist->opts) < 0) {
            snprintf(error, error_len, "Error while opening decoder for input stream #%d:%d",
                    ist->file_index, ist->st->index);
            return AVERROR(EINVAL);
        }
        assert_codec_experimental(ist->st->codec, 0);
        assert_avoptions(ist->opts);
    }

    ist->pts = ist->st->avg_frame_rate.num ? - ist->st->codec->has_b_frames * AV_TIME_BASE / av_q2d(ist->st->avg_frame_rate) : 0;
    ist->next_pts = AV_NOPTS_VALUE;
    init_pts_correction(&ist->pts_ctx);
    ist->is_start = 1;

    return 0;
}

static int transcode_init(OutputFile *output_files,
                          int nb_output_files,
                          InputFile *input_files,
                          int nb_input_files)
{
    int ret = 0, i, j, k;
    AVFormatContext *oc;
    AVCodecContext *codec, *icodec;
    OutputStream *ost;
    InputStream *ist;
    char error[1024];
    int want_sdp = 1;

    /* 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();
    }

    /* output stream init */
    for (i = 0; i < nb_output_files; i++) {
        oc = output_files[i].ctx;
        if (!oc->nb_streams && !(oc->oformat->flags & AVFMT_NOSTREAMS)) {
            av_dump_format(oc, i, oc->filename, 1);
            av_log(NULL, AV_LOG_ERROR, "Output file #%d does not contain any stream\n", i);
            return AVERROR(EINVAL);
        }
    }

    /* for each output stream, we compute the right encoding parameters */
    for (i = 0; i < nb_output_streams; i++) {
        ost = &output_streams[i];
        oc  = output_files[ost->file_index].ctx;
        ist = &input_streams[ost->source_index];

        if (ost->attachment_filename)
            continue;

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

        ost->st->disposition          = ist->st->disposition;
        codec->bits_per_raw_sample    = icodec->bits_per_raw_sample;
        codec->chroma_sample_location = icodec->chroma_sample_location;

        if (ost->stream_copy) {
            uint64_t extra_size = (uint64_t)icodec->extradata_size + FF_INPUT_BUFFER_PADDING_SIZE;

            if (extra_size > INT_MAX) {
                return AVERROR(EINVAL);
            }

            /* if stream_copy is selected, no need to decode or encode */
            codec->codec_id   = icodec->codec_id;
            codec->codec_type = icodec->codec_type;

            if (!codec->codec_tag) {
                if (!oc->oformat->codec_tag ||
                     av_codec_get_id (oc->oformat->codec_tag, icodec->codec_tag) == codec->codec_id ||
                     av_codec_get_tag(oc->oformat->codec_tag, icodec->codec_id) <= 0)
                    codec->codec_tag = icodec->codec_tag;
            }

            codec->bit_rate       = icodec->bit_rate;
            codec->rc_max_rate    = icodec->rc_max_rate;
            codec->rc_buffer_size = icodec->rc_buffer_size;
            codec->field_order    = icodec->field_order;
            codec->extradata      = av_mallocz(extra_size);
            if (!codec->extradata) {
                return AVERROR(ENOMEM);
            }
            memcpy(codec->extradata, icodec->extradata, icodec->extradata_size);
            codec->extradata_size = icodec->extradata_size;
            if (!copy_tb) {
                codec->time_base      = icodec->time_base;
                codec->time_base.num *= icodec->ticks_per_frame;
                av_reduce(&codec->time_base.num, &codec->time_base.den,
                          codec->time_base.num, codec->time_base.den, INT_MAX);
            } else
                codec->time_base = ist->st->time_base;

            switch (codec->codec_type) {
            case AVMEDIA_TYPE_AUDIO:
                if (audio_volume != 256) {
                    av_log(NULL, AV_LOG_FATAL, "-acodec copy and -vol are incompatible (frames are not decoded)\n");
                    exit_program(1);
                }
                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;
                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:
            case AVMEDIA_TYPE_ATTACHMENT:
                break;
            default:
                abort();
            }
        } else {
            if (!ost->enc)
                ost->enc = avcodec_find_encoder(ost->st->codec->codec_id);

            ist->decoding_needed = 1;
            ost->encoding_needed = 1;

            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;
                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) {
                    av_log(NULL, AV_LOG_FATAL, "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) {
#if !CONFIG_AVFILTER
                    avcodec_get_frame_defaults(&ost->pict_tmp);
                    if (avpicture_alloc((AVPicture*)&ost->pict_tmp, codec->pix_fmt,
                                       codec->width, codec->height)) {
                        av_log(NULL, AV_LOG_FATAL, "Cannot allocate temp picture, check pix fmt\n");
                        exit_program(1);
                    }
                    ost->img_resample_ctx = sws_getContext(
                        icodec->width,
                        icodec->height,
                        icodec->pix_fmt,
                        codec->width,
                        codec->height,
                        codec->pix_fmt,
                        ost->sws_flags, NULL, NULL, NULL);
                    if (ost->img_resample_ctx == NULL) {
                        av_log(NULL, AV_LOG_FATAL, "Cannot get resampling context\n");
                        exit_program(1);
                    }
#endif
                    codec->bits_per_raw_sample = 0;
                }

                ost->resample_height  = icodec->height;
                ost->resample_width   = icodec->width;
                ost->resample_pix_fmt = icodec->pix_fmt;

                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 && !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];
                }
                codec->time_base = (AVRational){ost->frame_rate.den, ost->frame_rate.num};

#if CONFIG_AVFILTER
                if (configure_video_filters(ist, ost)) {
                    av_log(NULL, AV_LOG_FATAL, "Error opening filters!\n");
                    exit(1);
                }
#endif
                break;
            case AVMEDIA_TYPE_SUBTITLE:
                break;
            default:
                abort();
                break;
            }
            /* two pass mode */
            if ((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) {
                        av_log(NULL, AV_LOG_FATAL, "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 (cmdutils_read_file(logfilename, &logbuffer, &logbuffer_size) < 0) {
                        av_log(NULL, AV_LOG_FATAL, "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) {
            int        size = codec->width * codec->height;
            bit_buffer_size = FFMAX(bit_buffer_size, 6 * size + 200);
        }
    }

    if (!bit_buffer)
        bit_buffer = av_malloc(bit_buffer_size);
    if (!bit_buffer) {
        av_log(NULL, AV_LOG_ERROR, "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 id %d) not found for output stream #%d:%d",
                         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 (!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, output_streams, nb_output_streams, 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 (avformat_write_header(oc, &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(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_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;
        }
        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(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;

    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;

    av_log(NULL, AV_LOG_INFO, "Press ctrl-c to stop encoding\n");
    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;

        /* 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 >= 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;
            }
        }
        /* 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 (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 ((FFABS(delta) > 1LL * dts_delta_threshold * AV_TIME_BASE || pkt_dts + 1 < ist->pts) && !copy_ts) {
                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);
            }
        }

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

            av_log(NULL, AV_LOG_ERROR, "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, 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->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->pict_tmp.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 double parse_frame_aspect_ratio(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) {
        av_log(NULL, AV_LOG_FATAL, "Incorrect aspect ratio specification.\n");
        exit_program(1);
    }
    return ar;
}

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

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

static int opt_subtitle_codec(OptionsContext *o, const char *opt, const char *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;
    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);
        }
    }


    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;
}

/**
 * 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) {