On 30/01/2024 12:31, Nuo Mi wrote:
On Tue, Jan 30, 2024 at 5:41 PM<p...@frankplowman.com> wrote:
From: Frank Plowman<p...@frankplowman.com>
Check that vps_each_layer_is_an_ols_flag, which indicates that "at
least one OLS specified by the VPS contains more than one layer," is
set if num_multi_layer_olss is non-zero.
Fixes:
65160/clusterfuzz-testcase-minimized-ffmpeg_BSF_VVC_METADATA_fuzzer-4665241535119360
Found-by: continuous fuzzing process
https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by
<https://github.com/google/oss-fuzz/tree/master/projects/ffmpegSigned-off-by>:
Frank Plowman<p...@frankplowman.com>
---
libavcodec/cbs_h266_syntax_template.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/libavcodec/cbs_h266_syntax_template.c
b/libavcodec/cbs_h266_syntax_template.c
index 2f3478e5e1..37dc3acba0 100644
--- a/libavcodec/cbs_h266_syntax_template.c
+++ b/libavcodec/cbs_h266_syntax_template.c
@@ -911,6 +911,8 @@ static int FUNC(vps) (CodedBitstreamContext *ctx,
RWContext *rw,
num_multi_layer_olss++;
}
}
+ if (!current->vps_each_layer_is_an_ols_flag &&
num_multi_layer_olss == 0)
+ return AVERROR_INVALIDDATA;
}
The specification does not provide information on how to obtain
TotalNumOlss (total_num_olss) when ols_mode_idc is set to 3.
Therefore, the earlier line "u(8, vps_num_ptls_minus1, 0, total_num_olss -
1)" is undefined.
We'd better return a patch welcome error instead of printing a warning
before vps_num_ptls_minus1 line
This is the same behaviour James suggested in an earlier patch. The spec
says "decoders conforming to this version of this Specification shall
ignore the OLSs with vps_ols_mode_idc equal to 3." I don't think this
should be an error as the spec is unambiguous here. Perhaps we can
instead skip the remainder of the VPS if vps_ols_mode_idc is 3? Or is
there some better way to ignore these OLSs?
_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
To unsubscribe, visit link above, or email
ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
