[FFmpeg-devel] [PATCH]lavc/pgssubdec: Fix palette colourspace

Carl Eugen Hoyos cehoyos at ag.or.at
Sun Apr 17 20:38:12 CEST 2016

Reimar Döffinger <Reimar.Doeffinger <at> gmx.de> writes:

> On Sun, Apr 17, 2016 at 05:54:00PM +0000, Carl Eugen Hoyos wrote:
> > wm4 <nfxjfg <at> googlemail.com> writes:
> > > What proves that the sample you have renders correctly now?
> > 
> > Nothing.
> > 
> > You think that it is more likely that the sample was 
> > intentionally made to fool the vlc developers than to 
> > help them?
> I don't like this "passive-aggressive" arguing style
> you are using on each other...

Me neither;-)

But refusing this patch is imo equivalent to assuming a 
malicious sample which I think is unlikely given the 
effort made (but definitely possible).

> FWIW, I agree with Carl that lacking a sample it makes 
> worse while having a simple it improves, applying this
> seems to be reasonable.

> But I agree with wm4 that it would be good to have
> a better explanation/reasoning than just a single sample.

I don't have one, sorry.

> In particular, I have an uncomfortable suspicion that
> PGS might be designed to match the movie's colour space,
> in which case neither variant would give correct results
> but instead it would have to depend on what format the
> corresponding video track uses (and it probably would
> be more than just the 255/224 factor that would differ).

While this is certainly true, I assumed that pgs only 
happens on HDMV content which uses some defined 
colour space.
Or to say it differently: Even if another colour space 
is allowed, I assume that this sample was made 
specifically to fix the common case.

Carl Eugen

More information about the ffmpeg-devel mailing list