[FFmpeg-devel] [PATCH] avcodec/hevc_sei: fix amount of bits skipped when reading picture timing SEI message

Michael Niedermayer michael at niedermayer.cc
Wed May 10 14:06:09 EEST 2017

On Tue, May 09, 2017 at 12:29:55PM -0300, James Almer wrote:
> The code was skipping the entire reported SEI message size regardless of 
> the amount of bits read.
> While in theory safe for NALU where the picture timing SEI message is alone
> or at the end as we're using the checked bitstream reader, it isn't in any
> other situation, where every SEI message in the NALU after the picture
> timing one would potentially fail to parse.
> Change the function name to one more in line with the rest of file, and
> remove the bogus "Skipped SEI" debug message while at it.
> Signed-off-by: James Almer <jamrial at gmail.com>
> ---
> No test case, all the files i checked plus those in the FATE suite seem to
> have one SEI message per NALU, or the Picture Timing SEI as the last one.
>  libavcodec/hevc_sei.c | 15 +++++++--------
>  1 file changed, 7 insertions(+), 8 deletions(-)

I think the "skip to match the size" should be done in a single place
for all SEI units and parsing should probably continue even if a SEI
unit has a failure of some kind.

the patch is fine too ...

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

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