avcodec/prores_aw : add support for prores 444 with alpha
authorMartin Vignali <martin.vignali@gmail.com>
Thu, 8 Nov 2018 21:10:29 +0000 (22:10 +0100)
committerMartin Vignali <martin.vignali@gmail.com>
Thu, 8 Nov 2018 21:21:13 +0000 (22:21 +0100)
commitff3b4f91cd56896366a044f8e45a88956dd66d39
treef0b19c9fd1a20535c759b587c324d960acf2069a
parent4d32c2b4e0df79b38343600d658e4670f9e78c24
avcodec/prores_aw : add support for prores 444 with alpha

only 16b alpha is supported (not 8 bits)

following official encoder, alpha data doesn't impact
yuv plane quality.

So the alpha data encoding is done after the yuv part.
It's also avoid to loose quality in yuv part when
alpha is not uniform.

the alpha encoding funcs is mainly take from prores_ks
encoder, except for the alpha data reorganization
libavcodec/proresenc_anatoliy.c