Ability to set default video format

[Planks]

In our stream PC we have an SC542-N4 HDMI capture card that supports multiple video formats. The default selected in Studio is RGB that in our experience, while not causing exceptional CPU load, OBS is unable to support capturing even one 1080p60 source without what one might call micro-stutter down to about 50fps. I'd file a proper report to investigate if this is a bug or just a lack of raw CPU, but don't currently have access to the PC in question, so can't provide diagnostic logs or demonstration videos.

However. If we set the video format to YV12 this micro-stutter goes away and we can in fact capture four simultaneous 1080p60 sources via the card onto one 1920x1080 canvas at 60fps. So a workaround, without being able to reproduce the "bug", would be allowing us to set a global preferred video format that doesn't reset every time the driver is removed and re-added to OBS.

 

[oasiz]

Seconding this,
Possibly caused by some extra RGB <-> YUV conversion that is happening.
Similar issues happened with my datapath e2s, where it defaulted to XRGB always on capture, setting this to YUV would get rid of it. One annoying part is that it requires always checking "custom format", which means manually inputting whatever resolution and frame rate the capture is to happen at.

Without setting the color space, performance can alternate between 30~50fps on what gets shown on capture.
This is even with just a single source and no actual encoding going on.

I recall trying with 4 inputs on the said 4-way SC542 card (I was also present during the above mentioned test) and even with 4 inputs enabled, the performance doesn't change between 1-4 inputs at the same time (30~50fps) until color space gets changed manually.