I’ve been using bc7 since 2012, and even have a video codec using bc7 keyframes (we needed alpha videos, even have a patent for it). Our emphasis is not file size, but playback speed. Bc7 renders 20-40% faster than raw rgba32, and we overlay 5-7 videos on screen simultanously, so every boost helps.

We also have custom encoders for the custom video format.

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kookamamie 3 days ago | parent | next [-]

You have a patent for alpha in videos? Curious to hear more about this - the application you describe sounds eerily familiar to me.

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chmod775 3 days ago | parent | prev | next [-]

HAP is a family of codecs for GPU accelerated decoding. HAP R uses BC7 frames.

There's support for various HAP codecs in ffmpeg, VLC, etc, but I think support for HAP R is lacking. However HAP, HAP Alpha, HAP Q and HAP Q Alpha have wide support. They use DXT1/DXT3/DXT5/RGTC afaik.

Compared to your implementation, their addition of BC7 is quite recent, yet they did have support for alpha channels for probably a decade.

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_def 3 days ago | parent | prev [-]

Is there some open equivalent of alpha in videos?

	▲	the8472 3 days ago \| parent [-]
		vp9 and avif have alpha, whether it's patented I don't know. https://pomf2.lain.la/f/kg9r139e.webm needs non-black background, change the <html> element's background-color in developer tools if necessary