From 07da07ddb0fb7ee6a4ddd26fc5676e4939dd7441 Mon Sep 17 00:00:00 2001
From: Anton Khirnov <anton@khirnov.net>
Date: Mon, 21 Mar 2022 17:29:21 +0100
Subject: [PATCH] fftools/ffmpeg: report new streams from the input thread

This avoids a potential race with the demuxer adding new streams. It is
also more efficient, since we no longer do inter-thread transfers of
packets that will be just discarded.
---
 fftools/ffmpeg.c       | 22 ----------------------
 fftools/ffmpeg_demux.c | 23 +++++++++++++++++++++++
 2 files changed, 23 insertions(+), 22 deletions(-)

diff --git a/fftools/ffmpeg.c b/fftools/ffmpeg.c
index 9757883961..b9cafb3c36 100644
--- a/fftools/ffmpeg.c
+++ b/fftools/ffmpeg.c
@@ -3277,21 +3277,6 @@ static int init_output_stream(OutputStream *ost, AVFrame *frame,
     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;
@@ -3831,13 +3816,6 @@ static int process_input(int file_index)
 
     reset_eagain();
 
-    /* the following test is needed in case new streams appear
-       dynamically in stream : we ignore them */
-    if (pkt->stream_index >= ifile->nb_streams) {
-        report_new_stream(file_index, pkt);
-        goto discard_packet;
-    }
-
     ist = input_streams[ifile->ist_index + pkt->stream_index];
 
     ist->data_size += pkt->size;
diff --git a/fftools/ffmpeg_demux.c b/fftools/ffmpeg_demux.c
index f9bd6d47fe..2d49a3c48c 100644
--- a/fftools/ffmpeg_demux.c
+++ b/fftools/ffmpeg_demux.c
@@ -20,6 +20,7 @@
 
 #include "libavutil/error.h"
 #include "libavutil/time.h"
+#include "libavutil/timestamp.h"
 #include "libavutil/thread.h"
 #include "libavutil/threadmessage.h"
 
@@ -27,6 +28,20 @@
 
 #include "libavformat/avformat.h"
 
+static void report_new_stream(InputFile *file, const AVPacket *pkt)
+{
+    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),
+           file->index, pkt->stream_index,
+           pkt->pos, av_ts2timestr(pkt->dts, &st->time_base));
+    file->nb_streams_warn = pkt->stream_index + 1;
+}
+
 static void *input_thread(void *arg)
 {
     InputFile *f = arg;
@@ -51,6 +66,14 @@ static void *input_thread(void *arg)
                              f->ctx->streams[pkt->stream_index]);
         }
 
+        /* the following test is needed in case new streams appear
+           dynamically in stream : we ignore them */
+        if (pkt->stream_index >= f->nb_streams) {
+            report_new_stream(f, pkt);
+            av_packet_unref(pkt);
+            continue;
+        }
+
         queue_pkt = av_packet_alloc();
         if (!queue_pkt) {
             av_packet_unref(pkt);