+/*
+ * Read one packet from an input file and send it for
+ * - decoding -> lavfi (audio/video)
+ * - decoding -> encoding -> muxing (subtitles)
+ * - muxing (streamcopy)
+ *
+ * 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
+ */
+static int process_input(void)
+{
+ InputFile *ifile;
+ AVFormatContext *is;
+ InputStream *ist;
+ AVPacket pkt;
+ int ret, i, j;
+
+ /* select the stream that we must read now */
+ ifile = select_input_file();
+ /* if none, if is finished */
+ if (!ifile) {
+ if (got_eagain()) {
+ reset_eagain();
+ av_usleep(10000);
+ return AVERROR(EAGAIN);
+ }
+ av_log(NULL, AV_LOG_VERBOSE, "No more inputs to read from.\n");
+ return AVERROR_EOF;
+ }
+
+ is = ifile->ctx;
+ 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(1);
+ }
+ ifile->eof_reached = 1;
+
+ for (i = 0; i < ifile->nb_streams; i++) {
+ ist = input_streams[ifile->ist_index + i];
+ if (ist->decoding_needed)
+ output_packet(ist, NULL);
+
+ /* 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))
+ ost->finished= 1;
+ }
+ }
+
+ return AVERROR(EAGAIN);
+ }
+
+ reset_eagain();
+
+ 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 >= ifile->nb_streams)
+ goto discard_packet;
+
+ ist = input_streams[ifile->ist_index + pkt.stream_index];
+ if (ist->discard)
+ goto discard_packet;
+
+ if (pkt.dts != AV_NOPTS_VALUE)
+ pkt.dts += av_rescale_q(ifile->ts_offset, AV_TIME_BASE_Q, ist->st->time_base);
+ if (pkt.pts != AV_NOPTS_VALUE)
+ pkt.pts += av_rescale_q(ifile->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 (pkt.dts != AV_NOPTS_VALUE && ist->next_dts != 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_dts;
+
+ if ((FFABS(delta) > 1LL * dts_delta_threshold * AV_TIME_BASE || pkt_dts + 1 < ist->last_dts) && !copy_ts) {
+ ifile->ts_offset -= delta;
+ av_log(NULL, AV_LOG_DEBUG,
+ "timestamp discontinuity %"PRId64", new offset= %"PRId64"\n",
+ delta, ifile->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);
+ }
+ }
+
+ ret = output_packet(ist, &pkt);
+ if (ret < 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(1);
+ }
+
+discard_packet:
+ av_free_packet(&pkt);
+
+ return 0;
+}
+