Commit a7b0af0071 for ffmpeg

commit a7b0af0071c0d95f657719372a84bea7c6fd84f3
Author: James Almer <jamrial@gmail.com>
Date:   Wed Sep 30 13:47:06 2026 -0300

    avformat/movenc: reject MPEG-H 3D Audio streams with no extradata

    It's not clear if mpegh3daConfigLength is allowed to be 0, so reject it outright.

    Signed-off-by: James Almer <jamrial@gmail.com>

diff --git a/libavformat/movenc.c b/libavformat/movenc.c
index 6c2a009ac3..6492f4ffb3 100644
--- a/libavformat/movenc.c
+++ b/libavformat/movenc.c
@@ -975,7 +975,8 @@ static int mov_write_mhac_tag(AVFormatContext *s, AVIOContext *pb, MOVTrack *tra
     int64_t pos = avio_tell(pb);
     int layout = 0;

-    if (track->extradata_size[track->last_stsd_index] > UINT16_MAX) {
+    if (!track->extradata_size[track->last_stsd_index] ||
+         track->extradata_size[track->last_stsd_index] > UINT16_MAX) {
         av_log(s, AV_LOG_ERROR,
                "Invalid extradata size %d for MPEGH-H stream.\n",
                track->extradata_size[track->last_stsd_index]);