How to Record a Video with an Alpha Channel in OBS Studio

[Elusien]

In Feb 2022 I created the following thread:

How to Export with Alpha Channel in OBS Studio

I have been using OBS for some time now to complement Shotcut. I do quite a few animations using HTML/CSS/Javascript and up until now I have either used an old version of Shotcut (20.07.11) to record them, or OBS. If the animation contained transparency (an alpha channel) then v20.07.11 was the best option (though not always possible), exporting the file using “Quicktime Animation”, which preserves the alpha channel. It was possible to export a “green-screen” version using OBS but if elements a…

Unfortunately those instructions do not work for OBS Studio version 28.1.0 onwards. However all is not lost: I have found another way to do it. Please be aware that the videos produced by this new method are uncompresed and as such are considerbly larger than those produced by the old method. For this reason you may want to keep a portable copy of version 28.0.3 and use the old method instead.

In OBS Studio click on Settings then do the following (images shown below):

1. Click on Output
2. Set Output Mode to Advanced
3. Click on the Recording tab
4. Set Type to Custom Output (FFmpeg)
5. Set Container Format to matroska
6. Set Video Encoder to ayuv

Then:

1. Click on Advanced
2. Set Colour Format to BGRA (8-bit)
3. Set Colour Space to Rec. 709
4. Set Colour Range to Full

Do not forget to reset these to the defaults for your normal use of OBS.

[jonray]

Thanks @elusien. VERY useful information.

[Elusien]

Unfortunately the new method produces VERY large uncompressed files, so I’m keeping an older version available and using the previous method.

[Josh_Forbes]

Just wanted to add here that you might have to check the box “Show all codecs” for the ayuv encoder to show up.