[FFmpeg-devel] [PATCH] pngdec: set correct range

[wm4]

On Fri, 8 May 2015 11:29:18 +0000 (UTC)
Carl Eugen Hoyos <cehoyos at ag.or.at> wrote:

> wm4 <nfxjfg <at> googlemail.com> writes:
> 
> > > As said, I had no objections against your patch (on 
> > > the contrary) but I wonder why you want to set a field 
> > > that is mostly useful when using libswscale if you 
> > > don't use libswscale.
> > 
> > Uh, what?
> > 
> > Do you think libswscale is the only thing that 
> > processes video?
> 
> No, but it seemed to me that this is what your commit 
> message implied.
> 
> > > > What is your opinion about this?
> > > 
> > > I committed part of the change making gray full range...
> > > 
> > > Whoever wants to use frame->data[0] should use it
> > 
> > What do you even mean?
> 
> I thought your question was "Do you agree that gray 
> should be full-range?" Some people need the yuv -> 

In what context? Yes, png outputs full range gray, but that doesn't
mean other codecs outputting gray do this.

> gray conversion not to change the values, and I 
> always wonder why they call libswscale in the 
> beginning, instead of simply using the Y plane.

What does this have to do with anything? This sounds like a libswscale
or ffmpeg.c problem at best.

> > So what is the API user supposed to do? Special-case 
> > by codec? Just what is it?
> 
> How is this codec-related / when is gray not full-scale 
> (and FFmpeg can know it)?

I just want to know how to get non-broken data from lavc?