[FFmpeg-devel] [PATCH] pthread_frame: don't return stale error codes after flush

[wm4]

Consider the following sequence of events:

- open a codec without AV_CODEC_CAP_DELAY
- decode call fails with an error
- ff_thread_flush() is called
- drain packet is sent

Then the last step would make ff_thread_decode_frame() return an error,
because p->result can still be set to an error value. This is because
submit_packet returns immediately if AV_CODEC_CAP_DELAY is not set, and
no worker thread gets the chance to reset p->result, yet its value is
trusted by ff_thread_decode_frame().

Fix this by clearing the error fields on flush.
---
 libavcodec/pthread_frame.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/libavcodec/pthread_frame.c b/libavcodec/pthread_frame.c
index 9a6b83ac45..7586f00bec 100644
--- a/libavcodec/pthread_frame.c
+++ b/libavcodec/pthread_frame.c
@@ -859,6 +859,7 @@ void ff_thread_flush(AVCodecContext *avctx)
         // Make sure decode flush calls with size=0 won't return old frames
         p->got_frame = 0;
         av_frame_unref(p->frame);
+        p->result = 0;
 
         release_delayed_buffers(p);
 
-- 
2.11.0