[FFmpeg-devel] [PATCH 4/4] avformat/mov: Stash mfra size if we're reading it anyway

[James Almer]

On 9/1/2020 1:06 PM, Derek Buitenhuis wrote:
> On 01/09/2020 17:02, James Almer wrote:
>> How else would you read 32bit signed integers using AVIOContext function
>> helpers if not with avio_rb32()?
> 
> The mfra size is not signed. It is an unsigned 32-bit integer.
> 
> Spec (mfro is the last part of the mfra):
> 
>     aligned(8) class MovieFragmentRandomAccessOffsetBox
>       extends FullBox(‘mfro’, version, 0) {
>         unsigned   int(32)   size;
>     }
> 
> - Derek

Oh, you mean how it worked with mfra_size being declared as an int32_t.
I was just mentioning why there was a <= 0 check for it. And I guess
because no mfra box parsed by lavf was ever bigger than ~2gb, so it
never failed.
But yes, it was a bug that you're fixing in this set.

(For that matter, size could in theory also be a 64bit integer according
to the spec).