[FFmpeg-devel] [PATCH v2] avcodec/h2645_parse: Don't treat 0x000002 as a start code and truncate

[Anton Khirnov]

Quoting Mattias Wadman (2024-02-13 11:17:46)
> According to ITU-T H.265 7.4.2.1 this byte sequence should not appear in a
> NAL unit but in practice in rare cases it seems it does, possibly due to buggy
> encoders. Other players like VLC and Quicktime seem to be fine with it.
> 
> Currently when this sequence is found it is treated as if the next start code
> has been found and the NAL unit gets truncated.
> 
> This change limits the code to only look for first start code 0x0000001 or
> first escape 0x000003.
> 
> Sadly i can't share the original source file with the issue but the first
> 80 bytes of the NAL unit looks like this:
> 
>        │00 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f│0123456789abcdef│
> 0x00000│00 00 00 01 02 01 d0 bc 57 a1 b8 44 70 01 00 0b│........W..Dp...│
> 0x00010│80 2e 00 c2 6c ec 3e b9 e3 03 fb 91 2e d2 43 cb│....l.>.......C.│
> 0x00020│1d 2c 00 00 02 00 02 00 5c 93 72 6f 31 76 18 00│.,......\.ro1v..│
> 0x00030│08 38 aa b1 4c 33 3f fd 08 cb 77 9b d4 3c db 02│.8..L3?...w..<..│
> 0x00040│a2 04 73 15 75 de 3b c4 67 c0 8f ca ad 31 f1 99│..s.u.;.g....1..│
> ---
>  libavcodec/h2645_parse.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)

Will push if nobody sees a problem with it.

-- 
Anton Khirnov