[FFmpeg-devel] Default color range encoding in Avid ACLR tags embeedded in QuickTime .movs

[Michael Niedermayer]

On Tue, Feb 10, 2015 at 10:45:46AM +0000, Kevin Wheatley wrote:
> On Tue, Feb 10, 2015 at 10:34 AM, Michael Niedermayer <michaelni at gmx.at> wrote:
> > if theres no way to store unknown range then your suggestion sounds
> > reasonable, can you send a patch?
> 
> I'm not aware of a value to specify in the ACLR atom for unspecified -
> I could guess at a value of 0 but that is pure speculation, Avid
> directly (or via the official QuickTime codecs) only ever uses the
> values of 1 or 2 from what I can see.
> 
> Patch yes I can do that, should this be a simple if statement modification e.g.
> 

>     if (track->enc->color_range == AVCOL_RANGE_MPEG || /* Legal range
> (16-235) */
>         track->enc->color_range == AVCOL_RANGE_UNSPECIFIED) {
>         avio_wb32(pb, 1); /* Corresponds to 709 in official encoder */
>     } else { /* Full range (0-255) */
>         avio_wb32(pb, 2); /* Corresponds to RGB in official encoder */
>     }
> 
> or does ffmpeg favor a switch/multiple if to handle each of the cases?

pick what you prefer


> 
> > is there some advantage in doing that default handling specific to
> > the codec_id ?
> 
> I'm not sure what you mean, in this case the atom being written is
> specific to certain codecs (although currently ffmpeg only does this
> for DNxHD)

then i misunderstood your mention of dnxhd, i assumed this was
used for a codec id as welll for which a different default would make
sense

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

He who knows, does not speak. He who speaks, does not know. -- Lao Tsu
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