[FFmpeg-devel] [PATCH v2 1/2] lavc: consider an error during decoder draining as EOF

wm4 nfxjfg at googlemail.com
Thu Mar 2 11:45:23 EET 2017


There is no reason that draining couldn't return an error or two. But
some decoders don't handle this very well, and might always return an
error. This can lead to API users getting into an infinite loop and
burning CPU, because no progress is made and EOF is never returned.

In fact, ffmpeg.c contains a hack against such a case. It is removed
with this patch. This particular error case seems to have been fixed
since the hack was added, though.

This might lose frames if decoding returns errors during draining.
---
Minor lavc bump missing.
---
 libavcodec/utils.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/libavcodec/utils.c b/libavcodec/utils.c
index 1156e43079..db3adb18d4 100644
--- a/libavcodec/utils.c
+++ b/libavcodec/utils.c
@@ -2807,12 +2807,12 @@ static int do_decode(AVCodecContext *avctx, AVPacket *pkt)
     if (ret == AVERROR(EAGAIN))
         ret = pkt->size;
 
-    if (ret < 0)
-        return ret;
-
     if (avctx->internal->draining && !got_frame)
         avctx->internal->draining_done = 1;
 
+    if (ret < 0)
+        return ret;
+
     if (ret >= pkt->size) {
         av_packet_unref(avctx->internal->buffer_pkt);
     } else {
-- 
2.11.0



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