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

Michael Niedermayer michaelni at gmx.at
Tue Feb 10 11:34:52 CET 2015

On Tue, Feb 10, 2015 at 09:17:34AM +0000, Kevin Wheatley wrote:
> Hi,
> Just looking through the FATE tests and the changes I wanted to make
> on reading ACLR atoms and I came across an issue. I wondered what the
> expected encoding range is for Y'CbCr during the FATE test runs as
> well as more generally.
> It would appear that the assumption that the range should be
> AVCOL_RANGE_MPEG [16-235] during test runs. Unfortunately the DNxHD
> code assumes the opposite unless you specify (libavformat/movenc.c
> near line 1038).

> I would consider this logic to favor full range in the Avid tags
> incorrect and believe it should be reversed to assume [16-235] unless
> told full range. FWIW, the default within an Avid is 16-235 for
> optimal use of DNxHD.
> Thoughts?

if theres no way to store unknown range then your suggestion sounds
reasonable, can you send a patch?
is there some advantage in doing that default handling specific to
the codec_id ?


Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

I am the wisest man alive, for I know one thing, and that is that I know
nothing. -- Socrates
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