avconv: split the code for processing input packets out of transcode()

avconv.c

@@ -2106,13 +2106,137 @@ static void reset_eagain(void)
         input_files[i]->eagain = 0;
 }
 
+/**
+ * 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_program(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->is_past_recording_time = 1;
+            }
+        }
+
+        if (opt_shortest)
+            return AVERROR_EOF;
+        else
+            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_program(1);
+    }
+
+discard_packet:
+    av_free_packet(&pkt);
+
+    return 0;
+}
+
 /*
  * The following code is the main loop of the file converter
  */
 static int transcode(void)
 {
-    int ret, i;
-    AVFormatContext *is, *os;
+    int ret, i, need_input = 1;
+    AVFormatContext *os;
     OutputStream *ost;
     InputStream *ist;
     int64_t timer_start;
@@ -2132,107 +2256,28 @@ static int transcode(void)
 #endif
 
     while (!received_sigterm) {
-        InputFile *ifile;
-        AVPacket pkt;
-
         /* 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 */
-        ifile = select_input_file();
-        /* if none, if is finished */
-        if (!ifile) {
-            if (got_eagain()) {
-                reset_eagain();
-                av_usleep(10000);
-                continue;
-            }
-            av_log(NULL, AV_LOG_VERBOSE, "No more inputs to read from, finishing.\n");
-            break;
+        /* read and process one input packet if needed */
+        if (need_input) {
+            ret = process_input();
+            if (ret == AVERROR_EOF)
+                need_input = 0;
         }
 
-        is  = ifile->ctx;
-        ret = get_input_packet(ifile, &pkt);
-
-        if (ret == AVERROR(EAGAIN)) {
-            ifile->eagain = 1;
-            continue;
-        }
+        ret = poll_filters();
         if (ret < 0) {
-            if (ret != AVERROR_EOF) {
-                print_error(is->filename, ret);
-                if (exit_on_error)
-                    exit_program(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);
-            }
-
-            if (opt_shortest)
-                break;
-            else
+            if (ret == AVERROR_EOF || ret == AVERROR(EAGAIN))
                 continue;
-        }
-
-        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);
-            }
-        }
 
-        if (output_packet(ist, &pkt) < 0 || poll_filters() < 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;
+            av_log(NULL, AV_LOG_ERROR, "Error while filtering.\n");
+            break;
         }
 
-    discard_packet:
-        av_free_packet(&pkt);
-
         /* dump report by using the output first video and audio streams */
         print_report(0, timer_start);
     }