[FFmpeg-devel] [PATCH] lavfi: protection against premultiplied alpha (was: The patch series about premultiplied alpha)

Nicolas George george at nsup.org
Tue Aug 5 12:05:54 EEST 2025


Niklas Haas (HE12025-08-05):
> I will repeat myself briefly here that such a flag should be an opt-out, not
> an opt-in. Supporting premultiplied alpha should be the default assumption
> unless provable otherwise.

Absolutely not.

Do you dereference a pointer when you can prove it cannot be NULL or
when you cannot prove it can be NULL? It is the same: if you cannot
prove a filter produces a valid result, then we protect by default. It
is already too much that it is not blocking when it is unspecified. On
this I will stand firm.

> On a side note, I don't think it's necessary to add a new "default" struct
> just for one particular combination of flags;

Of course it is not necessary, it just makes a dozen other patches much
much shorter.

>						especially not if your intention
> is (as you state) to have such flags for every other AVFrame property.

It does not make it either harder nor easier.

-- 
  Nicolas George


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