[FFmpeg-devel] libavcodec/hap : add HapAlphaOnly decoding/encoding

[Martin Vignali]

>
> > IMO, the ffmpeg support is mostly interesting to convert hap
> > file to something else or to check what we can encode with
> > the ffmpeg hap encoder.
>
> I don't disagree (on the contrary), I believe we should make it
> as easy as possible for users to work with it:
> Do you believe that it would be easier for users if HAP alpha only
> is represented as FFmpeg RGBA or gray?
>
> <http://ffmpeg.org/mailman/listinfo/ffmpeg-devel>
>

IMHO, from a compositing point of view, alpha only and gray is the same
thing.
It's common (in cgi compositing for example), to use alpha (or matte) as
separate gray only file.

But like the maintainer of the hapdec/enc in ffmpeg doesn't want this way
of interpreting
the HAP alpha only codec, (and like i doesn't want to fight on this point)
we can make some example in the doc, using filter, to help user to work
with that codec

Martin