[FFmpeg-devel] [PATCH] avcodec: only warn about hwaccel with frame threads

[Andreas Cadhalpun]

On 23.01.2016 12:27, Hendrik Leppkes wrote:
> On Sat, Jan 23, 2016 at 12:22 PM, Andreas Cadhalpun
> <andreas.cadhalpun at googlemail.com> wrote:
>> Not fixing serious regressions is not acceptable.
> 
> Then do so without introducing new ones.

This change can't introduce new regressions as it simply reverts the
behavior to what it was before your commit.

> As far as I can see on the ML, you are the only one considering this a
> "serious regression".

Not everything happens on this ML.

On 23.01.2016 12:29, wm4 wrote:
> So far you've expressed a strong opinion that it works with vdpau or
> vaapi. I don't remember which. (Also keep in mind that API wrapper
> drivers for each other can change behavior. And that you didn't
> necessarily confirm this for sure - I mean, if we e.g. removed all
> malloc checks from the codebase, it would apparently still work.)
> 
> This doesn't change that VP9 will be broken, and that VLC will have to
> fix this fundamental issue anyway.

The vp9 hwaccel is brand new, so if it fails, it's no regression.
If it really can't work with threading, you can make it error out.

But breaking all other hwaccels, which can work fine with threading,
is not OK.

> Also, if I understand this right,
> DXVA is normally broken, unless you apply heavy workarounds like VLC
> did.
> 
> If you really care (and care much more about this than the VLC dev,
> which is strange),

As you explained "the VLC dev" successfully prevented this change in
Libav.

> then maybe you could investigate the wrapper decoder
> idea or other ideas?

Unfortunately I don't have time for this.

> Also, this is not a regression. It's a change in behavior. Maybe we
> forgot to bump the version number, but that's trivial to fix.

Before this change VLC's hwaccels worked fine, after it they don't work
at all. If that's not a regression, I don't know what is one.

Best regards,
Andreas