Using ProRes4444 when I don’t need an alpha channel

[Walter Soyka]

[Seth Marshall] “I do not know how ProRes compresses, but if my alpha channel doesn’t change would the file size be as if it was only saving RGB data and not alpha channel? Or would my files be bloated with data from an unchanging alpha channel?”

I have read elsewhere that the ProRes 4444 alpha channel uses lossless compression. A movie with full alpha shouldn’t be wasting much space on the fourth channel.

Walter Soyka
Principal & Designer at Keen Live
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
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[Seth Marshall]

Thanks Walter! I guess if there’s any compression, even if lossless, hopefully the algorithm would take into account situations where the alpha isn’t needed and compress that channel entirely (like a losslessly compressed audio file for an empty sound track).

Otherwise if it’s tied into the RGB channels it may eat up bandwidth. But I’m not an engineer, just overly concerned about file size.

[Seth Marshall]

Thanks Dave. I do like the 4:4:4 option but don’t need an alpha. As long as the compression does the alpha independently then using 4444 won’t be so bad.

[Seth Marshall]

Hi Dave, copy that for video from DSLR. But actually my files are raw stills (time lapse image sequences). I was the guy you helped yesterday with my mask issue. Thanks though 🙂

I just wanted to know the best codec for archiving the raw file image sequence before processing and after (so I can have an original and delivery both at highest fidelity).

I figure 4444 gains me 4:4:4 but depending on how the compression algorithm I’ll either waste bandwidth on an unnecessary Alpha channel or ideally the Alpha channel will recognize there is no transparency information and dedicate bandwidth for RGB or give me a smaller file.