[FFmpeg-devel] [PATCH] mov: Skip computing SAR from invalid display matrix elements

[Carl Eugen Hoyos]

Am Di., 30. März 2021 um 19:24 Uhr schrieb Vittorio Giovara
<vittorio.giovara at gmail.com>:
>
> Hello,
> I was debugging an issue with a video file containing an invalid
> display matrix, probably produced by a non conforming software.
>
> The content of the matrix is:
> 00000000:            0       65536           0
> 00000001:           -1           0           0
> 00000002:            0           0  1073741824
>
> The -1 (stored as 4294967295) was probably a 1 shifted 32 times instead
> of 16. The problem is that this value is bypassing the validation check
> in the code below, and the resulting computed SAR value becomes 1:65536.
>
> This change interprets extremely low entries as invalid and makes sure
> to skip them in the SAR computation. This passes fate, but I haven't been
> able to test this extensively.
> Please see the attached patch, any feedback or better solution is welcome.

Is this related to ticket #7277?

Carl Eugen