[FFmpeg-devel] [PATCH 2/3] avformat/webpenc: Don't treat zero-sized packets as invalid

[Andreas Rheinhardt]

Before f9043de99a23e35a34c79bfbc9ef17b27f7236d1, sending zero-sized
packets to the WebP muxer led to memleaks (unless the muxer was already
in animation mode). Therefore said commit simply returned immediately
if such a packet were sent to the muxer.

But now it turns out that such packets are not that irregular; in
particular, one needs to account for them in the frame count.
This patch achieves this by treating such packets the same way that
they were treated before f9043de99a23e35a34c79bfbc9ef17b27f7236d1
with the only difference that they are not cached (and can therefore
not leak).

Fixes ticket #9179.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at outlook.com>
---
There is btw a big leak left in the encoder; I wonder whether we are
properly closing the library.

 libavformat/webpenc.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/libavformat/webpenc.c b/libavformat/webpenc.c
index ed8325c02d..3962986c32 100644
--- a/libavformat/webpenc.c
+++ b/libavformat/webpenc.c
@@ -56,6 +56,8 @@ static int is_animated_webp_packet(AVPacket *pkt)
     int skip = 0;
     unsigned flags = 0;
 
+    if (!pkt->size)
+        return 0;
     if (pkt->size < 4)
         return AVERROR_INVALIDDATA;
     if (AV_RL32(pkt->data) == AV_RL32("RIFF"))
@@ -145,8 +147,6 @@ static int webp_write_packet(AVFormatContext *s, AVPacket *pkt)
     WebpContext *w = s->priv_data;
     int ret;
 
-    if (!pkt->size)
-        return 0;
     ret = is_animated_webp_packet(pkt);
     if (ret < 0)
         return ret;
@@ -159,7 +159,8 @@ static int webp_write_packet(AVFormatContext *s, AVPacket *pkt)
         int ret;
         if ((ret = flush(s, 0, pkt->pts)) < 0)
             return ret;
-        av_packet_ref(&w->last_pkt, pkt);
+        if (pkt->size > 0)
+            av_packet_ref(&w->last_pkt, pkt);
     }
     ++w->frame_count;
 
-- 
2.27.0