support for alpha/transparency per apple interoperability proposal

[Matteo Fogli]

Hi all,

I don’t know if this is the right place to discuss this, but searching did not provide any result, so I am taking a chance. In May 2019 Apple released and implemented a proposal for alpha channel support (so called transparent videos/movies) encoded in HEVC. Currently, it seems only Apple tools (avconvert and Compressor) support this format. ffmpeg with the current libx265 fails while encoding as it does not support a pixel format with alpha support (ffmpeg relevant ticket https://trac.ffmpeg.org/ticket/7965 ).

Is it planned or has it been evaluated providing support for videos with alpha? Or is it something that can already be accomplished with command line flags?

TIA

[Alexander]

It would be great to see alpha transparency supported in the libx265 encoder that comes with FFMpeg. It might look like a minor issue but it’s really not. In WebGL toolkits like Verge3D, transparent textures are used to create various cool effects. In Chrome/Firefox/Edge we have WebM, but for Safari (for both desktop and mobile), HEVC is the only option. Right now we recommend our users to use FFMpeg with VideoToolbox encoder, but it is limited to Macs only.

[Jozef Chúťka]

Adding my vote. Would be really great to have transparency support.