[FFmpeg-devel] [PATCH 1/4] avformat/demux: don't propagate unsupported skip samples packet side data values

[James Almer]

Should fix ticket #9622

Signed-off-by: James Almer <jamrial at gmail.com>
---
I'm not sure if this is ok or not. The AV_PKT_DATA_SKIP_SAMPLES doxy states
the skip samples value is a little endian uint32 value, so even if the mov
demuxer wrote a truncated int64_t value in sti->skip_samples (which, being an
int, can be negative), it would still be "valid" when written into the packet
as side data.

Chromium's fix is https://chromium-review.googlesource.com/c/chromium/src/+/3424556
where you can see they have been reading the skip samples value from
AV_PKT_DATA_SKIP_SAMPLES as an int.

 libavformat/demux.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/libavformat/demux.c b/libavformat/demux.c
index f895f0ba85..09d539af68 100644
--- a/libavformat/demux.c
+++ b/libavformat/demux.c
@@ -1354,6 +1354,7 @@ static int read_frame_internal(AVFormatContext *s, AVPacket *pkt)
         }
         if (sti->start_skip_samples && (pkt->pts == 0 || pkt->pts == RELATIVE_TS_BASE))
             sti->skip_samples = sti->start_skip_samples;
+        sti->skip_samples = FFMAX(0, sti->skip_samples);
         if (sti->skip_samples || discard_padding) {
             uint8_t *p = av_packet_new_side_data(pkt, AV_PKT_DATA_SKIP_SAMPLES, 10);
             if (p) {
-- 
2.34.1