[FFmpeg-devel] [PATCH 01/26] avformat/matroskadec: Move AVBufferRef instead of copying, fix memleak

[Andreas Rheinhardt]

EBML binary elements are already made reference-counted when read;
so when populating the AVStream.attached_pic, one does not need to
allocate a new buffer for the data; instead the current code just
creates a new reference to the underlying AVBuffer. But this can be
improved even further: Just move the already existing reference.

This also fixes a memleak that happens upon error because
matroska_read_close has not been called in this scenario.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at gmail.com>
---
This fixes one of the memleaks that I found during the work on my patchset
[1] that intended to automatically call a demuxer's read_close function
if reading the header fails. Several other of the patches of this
patchset also fix such memleaks.

I intend to apply this patchset soon so that 4.3 can finally be
released.

[1]: https://ffmpeg.org/pipermail/ffmpeg-devel/2020-March/258831.html

 libavformat/matroskadec.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/libavformat/matroskadec.c b/libavformat/matroskadec.c
index bb3a126c29..b1da40983f 100644
--- a/libavformat/matroskadec.c
+++ b/libavformat/matroskadec.c
@@ -2938,9 +2938,8 @@ static int matroska_read_header(AVFormatContext *s)
                 st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
 
                 av_init_packet(pkt);
-                pkt->buf = av_buffer_ref(attachments[j].bin.buf);
-                if (!pkt->buf)
-                    return AVERROR(ENOMEM);
+                pkt->buf          = attachments[j].bin.buf;
+                attachments[j].bin.buf = NULL;
                 pkt->data         = attachments[j].bin.data;
                 pkt->size         = attachments[j].bin.size;
                 pkt->stream_index = st->index;
-- 
2.20.1