[FFmpeg-devel] [PATCH] ffmpeg_mux: terminate stream thread queue only on sq_send EOF

Gyan Doshi ffmpeg at gyani.pro
Sat Feb 4 12:01:21 EET 2023


Prior to 2d924b3a630, ffmpeg would exit if any packet write failed.
After the switch to threaded mode for muxing, ffmpeg only closes that
OutputStream instead of closng the file. This happens because EOF
returned by write_packet isn't distinguished from EOF returned by sq_send,
both relayed via sync_queue_process.

This breaks the abort behaviour when there are multiple streams in an output,
and can leave the ffmpeg process running beyond the intended point of abortion.

Fixed by marking the OutputStream as finished upon sq_send EOF and letting
write_packet EOF lead to muxer termination.
---
 fftools/ffmpeg_mux.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/fftools/ffmpeg_mux.c b/fftools/ffmpeg_mux.c
index 5d427b44ea..b40a2d01a7 100644
--- a/fftools/ffmpeg_mux.c
+++ b/fftools/ffmpeg_mux.c
@@ -160,8 +160,12 @@ static int sync_queue_process(Muxer *mux, OutputStream *ost, AVPacket *pkt)
 
     if (ost->sq_idx_mux >= 0) {
         int ret = sq_send(mux->sq_mux, ost->sq_idx_mux, SQPKT(pkt));
-        if (ret < 0)
+        if (ret < 0) {
+            if (ret == AVERROR_EOF)
+                ost->finished |= ENCODER_FINISHED;
             return ret;
+        }
+
 
         while (1) {
             ret = sq_receive(mux->sq_mux, -1, SQPKT(mux->sq_pkt));
@@ -215,7 +219,7 @@ static void *muxer_thread(void *arg)
         ost = of->streams[stream_idx];
         ret = sync_queue_process(mux, ost, ret < 0 ? NULL : pkt);
         av_packet_unref(pkt);
-        if (ret == AVERROR_EOF)
+        if (ret == AVERROR_EOF && ost->finished)
             tq_receive_finish(mux->tq, stream_idx);
         else if (ret < 0) {
             av_log(mux, AV_LOG_ERROR, "Error muxing a packet\n");
-- 
2.39.1



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