Question / Help Base Canvas Resolution - settings affect CPU usage?

[RaizT1]

Main monitor: 1440p
Gaming at: 1080p
Streaming at: 900p

1. My question is, if I have my base canvas at 1440p, and OBS has to downscale to 900p, does that take MORE processing power than setting the Base Canvas to 1080p and downscaling to 900p?

2. Would it create any color banding issues since my monitor is 1440p if I set Base Canvas to 1080p?

Since my final output is at 900p, I'm just trying to get the best possible settings to decrease processor load and increase final output quality.

 

[carlmmii]

The only time you have to worry about processor load is when you use the "Rescale output" option in the output settings. The only time this should only be necessary is if you're streaming at one resolution, and recording at another.

For any other situation (like just streaming), you should be setting the "Output (scaled)" resolution in your Video settings to whatever your final resolution is. This leverages the GPU, where all the compositing is already taking place, and has very little impact. You're not going to see any performance difference from the rescaling operation there between a 1440p canvas or a 1080p canvas.

Where you possibly could see any sort of impact is in the resources needed for the overall scene compositing, since there's just more memory and pixels to work with for a 1440p canvas. That said, all of this is still done on the GPU, and the most impact is actually just going to be on how high of a resolution the source elements are to work with.

For banding issues, you're not likely to see any real artifacting unless you use a lower-quality sampling algorithm like bilinear or trilinear. The only time you're ever really going to notice banding issues is if you have a very regular pattern at 1440p that lines up with the actual pixel resolution. Unless you're working with a very fine grid pattern, you're not going to run into this, and the encoding process is going to introduce its own artifacts that would hide any type of moire pattern anyway.

Also, since you're gaming at 1080p anyway, most of this is a moot point. You should just use 1080p for your canvas resolution, capture your game using game capture if possible (for a 1080p source), set your Output (scaled) resolution to 900p, and call it a day.

 

[RaizT1]

Thank you so much for the detailed answer! Setting the Base (canvas) to 1080p, Output (scaled) to 1600x900, downscale to bicubic, and fps to 60. Really appreciate your help!