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Participant
December 10, 2024
Answered

Video not exporting with Luma Key

  • December 10, 2024
  • 2 replies
  • 353 views

Hi! I have a video that needs to use luma key to turn off dark pixels so they can be overlaid as a frame for a live broadcast. I have my Luma Key set up, everything looks good in the workspace preview, but every time I export, the Luma Key is left out. 

 

I am required to export this is H.264, so no Pro Res or Quicktime option will work. 

 

The comp is only one layer, a single After Effects comp, with the Luma Key. That's all the needs to render. 

 

I'm proably missing something in my export settings, but I've tried everything I know to. Any help is much appreciated!

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Correct answer PaulMurphy

The H.264 codec does not support alpha channels. This means any transparency (such as a luma key or chroma key effect) will not be preserved when exporting in this format.


If you need to retain transparency, consider using a codec that supports alpha channels, such as:

  • Apple ProRes 4444
  • GoPro CineForm
  • DNxHR with Alpha


For more details, you can refer to this helpful resource: List of Video Formats Supporting Alpha Channels.

2 replies

PaulMurphyCommunity ExpertCorrect answer
Community Expert
December 11, 2024

The H.264 codec does not support alpha channels. This means any transparency (such as a luma key or chroma key effect) will not be preserved when exporting in this format.


If you need to retain transparency, consider using a codec that supports alpha channels, such as:

  • Apple ProRes 4444
  • GoPro CineForm
  • DNxHR with Alpha


For more details, you can refer to this helpful resource: List of Video Formats Supporting Alpha Channels.

Participant
December 10, 2024

For reference, I'm using Version 24.3.0 on an iMac