Academic Question: Video Capture Device - Native Res vs. Resize

dontpanicflip

New Member
Assume for the sake of this discussion all of the following:
  1. My OBS canvas is 1920 x 1080
  2. My output resolution to Twitch is 1920 x 1080 (60fps) at 6000 bitrate
  3. I have NO hardware limitations (I have all the video/processor/USB/internets)
  4. I have 3 camera sources in my OBS scene that I need to display simultaneously in one scene
  5. Each camera can output at either 1920 x 1080, 1280 x 720, or 640 x 360 (for the sake of this discussion)
  6. My goal is to display each camera's output side-by-side at 640 x 360 so it takes up the entire width of the canvas.
My Question: For the best image quality which setup would produce a better overall image from OBS to Twitch:
  1. Natively set the output resolution from each camera to 1920 x 1080 and resize each source to 640 x 360 in OBS?
    1. This will result in a significant amount of downscaling
  2. Natively set the output resolution from each camera to 1280 x 720 and resize each source to 640 x 360 in OBS?
    1. This will result in a less significant amount of downscaling
  3. Natively set the output resolution from each camera to 640 x 360?
    1. This will result in NO downscaling
* I realize that the differences between the 3 above options will likely not be detectable by the human eye. I'd still like to know. I'd like to better understand how OBS downscales a source in a scene and how that downscaling compares to a typical camera's ability to output at a lower than RAW format.

* I realize that OBS allows 3 different types of downscale filters to be used to scale your canvas on output if not symmetric. As far as I can tell, this filter choice doesn't apply to in-scene source size adjustments. But that assumption may be incorrect and maybe OBS uses the filter selected here for both overall output and in-scene downscaling?

* I know I can potentially stack sources a little differently to get a better resolution from each source individually. That's not relevant to this discussion.

Follow Up Question: Does changing the cameras from 3 x C920s to 3 x Sony A6400s alter the above assumptions? Does Sony's native downscaling tech meet or beat what OBS uses to downscale an image in a scene? I AM aware that the A6400 can only output at 1080 (at the lowest). Assume it could downscale to 640 for the sake of this discussion.

Follow Up Question: Knowing that I have unlimited computing resources, is there a way to utilize better downscaling of a video capture device source in OBS within a scene? My computer I would imagine is much more capable than a mirrorless or DSLR camera and as such, should have access to a wider range of filters to perform "better" downscaling.

Thank you for your thoughts, comments, clarifications, etc... and realize that I'm a complete noob with regards to cameras (and many other unrelated topics).

George
 
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