[FFmpeg-devel] [PATCH]lavd/decklink_dec: Do not claim to output transparency information

Maksym Veremeyenko verem at m1stereo.tv
Sat Oct 7 11:22:26 EEST 2017

06.10.2017 22:10, Marton Balint пише:
> On Thu, 5 Oct 2017, Maksym Veremeyenko wrote:
>> 29.09.2017 0:20, Carl Eugen Hoyos пише:
>>> Hi!
>>> I don't have decklink hardware but I assume it never outputs actual
>>> transparency.
>>> Or does it?
>> it outputs or use internal keyer to put it over passthrow SDI signal.
>> in external keyer mode it accept BGRA frame and output two SDI 
>> signals: one for *fill* another one for *key*
> That is true, but that is the feature of the decklink output device.
> Is the decklink *input* device capable of capturing in RGBA with useful 
> alpha? I'd say, probably not.

i would say that it is probably *yes* because of that feature (capturing 
fill&key signal) mentioned in press release:

> https://www.blackmagicdesign.com/media/release/20150413-16
> [...]
> .... get simultaneous fill and key capture and playback ... 

on other hand, if capturing RGB from HDMI returns transparent picture - 
then yes - this patch should be applied.

Maksym Veremeyenko

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