Function process_input

ffmpeg-single-cmd/src/main/cpp/ffmpeg_mod.c:4185–4427

* 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 */

 * - AVERROR_EOF -- this function should not be called again
 */
static int process_input(int file_index)
{
    InputFile *ifile = input_files[file_index];
    AVFormatContext *is;
    InputStream *ist;
    AVPacket pkt;
    int ret, i, j;
    int64_t duration;
    int64_t pkt_dts;

    is  = ifile->ctx;
    ret = get_input_packet(ifile, &pkt);

    if (ret == AVERROR(EAGAIN)) {
        ifile->eagain = 1;
        return ret;
    }
    if (ret < 0 && ifile->loop) {
        if ((ret = seek_to_start(ifile, is)) < 0)
            return ret;
        ret = get_input_packet(ifile, &pkt);
        if (ret == AVERROR(EAGAIN)) {
            ifile->eagain = 1;
            return ret;
        }
    }
    if (ret < 0) {
        if (ret != AVERROR_EOF) {
            print_error(is->filename, ret);
            if (exit_on_error)
                exit_program(1);
        }

        for (i = 0; i < ifile->nb_streams; i++) {
            ist = input_streams[ifile->ist_index + i];
            if (ist->decoding_needed) {
                ret = process_input_packet(ist, NULL, 0);
                if (ret>0)
                    return 0;
            }

            /* mark all outputs that don't go through lavfi as finished */
            for (j = 0; j < nb_output_streams; j++) {
                OutputStream *ost = output_streams[j];

                if (ost->source_index == ifile->ist_index + i &&
                    (ost->stream_copy || ost->enc->type == AVMEDIA_TYPE_SUBTITLE))
                    finish_output_stream(ost);
            }
        }

        ifile->eof_reached = 1;
        return AVERROR(EAGAIN);
    }

    reset_eagain();

    if (do_pkt_dump) {