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

Martin Vignali martin.vignali at gmail.com
Fri Sep 29 12:03:21 EEST 2017

2017-09-28 23:24 GMT+02:00 Carl Eugen Hoyos <ceffmpeg at gmail.com>:

> 2017-09-28 21:50 GMT+02:00 Martin Vignali <martin.vignali at gmail.com>:
> > After comments about the previous patchs
> Please explain how this encoder and decoder can be used
> from the FFmpeg cli: What kind of input could be used, what
> could be done with the output?
> I believe you force every user to add an additional filter
> to do anything useful, please convince me that this is wrong.
> Hello,

I didn't design the HAP codec, so my answer mostly follow the comments
of Tom Butterworth. (in the previous discussion of decoding/encoding)

Like it seems that the Hap Alpha Only is only design to be use for alpha
channel encoding
(not to encode gray), it use in this new patch  : RGBA input/output (using
only the alpha channel)

In a more general way, HAP is only useful when use with GPU
decoding/compositing (specially in very big resolution, with lot of video
(not the case in the ffmpeg).

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.


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