# Scenes with Single Video Capture Device as the Source



## Ken Ishizu (May 15, 2019)

Hi! 

I was wondering if there was a way to avoid the rendering / scene compositing step of frames acquired from a capture card, if I setup a simple scene with the video capture device as the single source of that scene. Would that alleviate my GPU usage for other tasks?

I looked at the functions render_main_texture and render_output_texture, which are called after tick_sources. Can I simply 'copy' the frame acquired from the capture card and consider it as 'rendered'?

Thanks in advance and I apologize if those questions were too silly or naive. I still have much to learn about this type of development.


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## Jim (May 15, 2019)

OBS is fundamentally a video/audio compositor underneath.  It is not be possible to bypass it because that is what it is.  You'd likely be better just writing a custom program that exclusively captures the video device rather than using OBS in that particular case.


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## Ken Ishizu (May 15, 2019)

Understood, thanks for the response, Jim.

Is there a way to select another GPU to do the scene compositing instead?


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## Jim (May 17, 2019)

You can change the video adapter OBS uses to render, but it's purposely undocumented.  In global.ini, add or go to "[Video]" section, and add "AdapterIdx=1".  It's zero-based, so 0 is your default primary adapter, and 1 is your secondary (if it exists).  I don't recommend doing this as it can impact performance and prevent captures from working properly.


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## Ken Ishizu (May 17, 2019)

Jim said:


> You can change the video adapter OBS uses to render, but it's purposely undocumented.  In global.ini, add or go to "[Video]" section, and add "AdapterIdx=1".  It's zero-based, so 0 is your default primary adapter, and 1 is your secondary (if it exists).  I don't recommend doing this as it can impact performance and prevent captures from working properly.


Thanks for replying. I'll try changing that configuration later to do some testing, but I'll likely end up sticking with the default option, as my second adapter is Intel's iGPU.


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