Efficient Codec/Format with RGB + Alpha for Windows within After Effects

[izytang]

Hi all,

I'm looking for a solution to a data bottleneck in my VFX/compositing/animating workflow with Adobe After Effects. Often, there's a need to export content with alpha channels (transparency) to various editing platforms for other (human) editors for projects. However, file sizes are ridiculously large (1 GB for 20 seconds at 1080p) , and I'm looking to trim that by using a more efficient format within After Effects.

Does anyone know of a plugin for After Effects for a codec/format that has a RGB+A with similar efficiency as H.264? Often, 10 Mbps is sufficient for most YUV420 8-bit material with H.264, so I'm looking for something similar with an alpha channel. Ideally, I'd like like a format that's "high quality" (minimal blocking, banding, noise) at 20 - 25 Mbps with RGB+A at 10-bit 4222 (or even 4444) at 1080p, but with options for interframe/intraframe, CBR/VBR, progressive/interlaced, various aspect ratios, 4K+ resolutions, etc. This would be an intermediate format (not delivery), so widespread support on devices is not needed. Also, it'd be great if this plugin worked specifically with Adobe Premiere to render and encode directly, rather than to transcode and convert after After Effects. Even better if it works across all of Adobe software (Media Encoder, Premiere) and beyond (Cinema 4D, DaVinci Resolve, etc).

I've tried common formats that support alpha channels, such as Microsoft's AVI, QuickTime Animation, and GoPro CineForm, but they're all terribly inefficient (ie. super high bit rates of 250 Mbps+). Apple's ProRes4444 supports alpha channels, but unfortunately it is not supported for Windows - at least for encoding. And even so, I imagine the bit rates are still too high.

I appreciate any help or recommendations on greatly helping with this workflow!

[raffriff42]

UT Video.

8-bit RGBA test video (no actual alpha data, just opaque), 640x480, 10 sec: 56MB. That's about 5:1 compression, lossless of course.

Mac or Windows. Very fast. Free. (possibly a small donation required for the 10-bit version, I can't recall)

Compatible with After Effects
https://forums.adobe.com/thread/1171806
https://video.stackexchange.com/questions/5564/recommendable-production-codecs-for-ado...ucts/5572#5572

[izytang]

Thanks for the recommendation. I downloaded and installed that pack to test it out. I rendered out a 1920x1080 8-bit RGBA 4444 video of 10 seconds for a file output of 400 MB (350 Mbps). This bit rate is still much too high, but not a bad option for a loseless format with alpha.

I should probably have mentioned that in looking for an efficient format that it would by extension be lossy; in order to place it in the 20 - 25 Mbps range. Having the option of going loseless within the same format would be great, but not crucial.

[poisondeathray]

There aren't any in that range . 1920x1080 20-25Mbps means temporal compression. It's impossible to use intra only on typical content unless you're dealing with very simple content like 1 or 2 color graphics or simple toons

But Long GOP / high compression is for end delivery, not intermediate post production. All intermediate formats are intra only, thus the large filesizes many times larger than what you are looking for. Even the lossy codecs like prores, cineform, grass valley hqx, etc...

VP9 native supports YUVA420P8 , but it's very poor support for ingest and editing. (Again, it's for end delivery, for web)

Not very many RGB temporal compression formats available. x264 supports it as AVC, but no professional editing application supports that RGB version. FFV1 does, but again limited support for editing, and it's lossless (although it offers lossless temporal modes). So you're left YUV444 or YUV422. Not very many editing platforms support YUV444P8 or P10

How about a separate alpha channel? You can use h264 temporal compression YUV422 + h264 YUV420 temporal compression alpha. Adobe should support 10bit variety XAVC

[pandy]

If quality is not your goal then perhaps: https://github.com/vidvox/hap-qt-codec/releases/

[izytang]

Thanks for the feedback. Sorry again for not specifying enough information. I'm looking for an efficient format, and therefore would be lossy and interframe (temporal) compression. Some quality loss is acceptable, as I imagine it would be the only way to get bit rates around 20 - 25 Mbps with the alpha channel embedded. Yes, a "delivery" type format is what I'm looking for (though, technically it's "intermediate" in the sense of not yet going to web, but doesn't need widespread device support).

Maybe it would help to outline the base problem, and work a solution from there. I need a way to send pre-comped and animated content to remote collaborators that can drag and drop footage into an editing platform that will overlay on other content. The content to send has transparency for things like lower thirds, animated logos, transitions, and even entire green screened segments. Much of the content needs to be sent within the day or hour, and the existing workflow of rendering out intraframe 500 Mbps formats is causing a huge bottleneck. My thought was that if I could compress footage much like h264, but with an alpha channel, I could get it down to less than 30 Mbps, which would make the workflow much more fluid.

Unfortunately, other workarounds can't be used (ie. exporting separate YUV422 and YUV420 alpha files), because the files need to be drag and drop for the other editors. Think how you can drag a PNG file and the alpha channel works right away. Same thing with transcoding or luma/chroma keying on remote end - the solution has to be drag and drop, with bit rates that work on an hourly workflow.

Hopefully that outlines some of the constraints, and thus need for a specific efficient RGBA video format. Thanks again for the input - it's valued!

[pandy]

In theory you can compose RGBA in single grayscale frame and later decompose it back to RGBA (simple avisynth script should do job) - with such grayscale video any regular codec can be used... IMHO your requirement are contradictory at least from industry standard perspective.

[smrpix]

You're not going to find what you are looking for. Another possible approach: send them your AE project and any standalone graphics and let them render it out at high quality themselves.