Is it ACTUALLY better to use my desktop resolution as a base canvas size?

[PikaChokeMe]

I mean this as more of like a technical question...
not just like a... once upon a time in a YouTube video some guy said said always use my desktop resolution so that's the end solution.

I have a 3440x1440 ultrawide monitor, but I basically never stream at the 3440x1440 native resolution. I usually stream at a 1720x720 video output resolution because that's 50% of my regular resolution and some form of a "720p", I guess. I do play games at a 3440x1440 resolution, but I also have a vtuber application running.

Currently I'm running my games at 3440x1440 desktop resolution and capture that window.
Then I run a vtuber application at 1600x900 and capture that window as well.
I then also have some graphics and overlays which I have laid out on my canvas, and my guess is somehow this all goes through some nebulous process of being smashed together, and then gets downscaled using a bicubic filter.


I'm thinking alternatively what I can do is:
Set base canvas resolution to 1720x720.
Capture and resize one game window by 50% in the scene editor (I'm not sure how this actually gets rescaled or how expensive this is comparatively)
Capture and run one vtuber application at 960x540 and output this at it's "base resolution".
Capture a bunch of smaller graphics and overlays at their "base resolution".
Save computation costs on downscaling or upscaling filters since base canvas and output resolution is the same?

I'm thinking in the case where I'm using 720p as my base and output resolution, not only are a lot of my assets smaller, but I'm also not rescaling as much stuff as a whole, and in some cases I'm not making bigger graphics or capturing other windows at a higher resolution just to scale them back down to a smaller resolution. To my human brain that knows almost nothing about how the inner workings of OBS rescales stuff, this seems like it should be more efficient and technically the less computationally expensive option, but everywhere I've looked everything just says, "Set your base canvas to your desktop resolution."

Can someone give me more insight on to the technical details of how this works or if my logic makes sense. Is my method or idea more efficient? Or is it actually still better to just use my desktop as my base canvas size and downscale?

 

[koala]

Start your evaluation with the output resolution.
I recommend you use an output resolution with an aspect ratio of 16:9, because 16:9 is the aspect ratio of about 90% of your viewers. At least that's what you get if you look at the primary monitor resolution in the current steam hardware survey.
So the aspect ratio of 16:9 will get you to either 1280x720 or 1920x1080 as output resolution.
This will get you aspect ratio of 16:9 for your canvas as well, so you can choose one of these as canvas resolution, or the next higher one of 2560x1440.

Streaming with the native aspect ratio of your 3440x1440 monitor, which is 21.5x9, as you do currently, will produce black bars to the top and bottom of your stream if viewed by 90% of your viewers. Don't waste the black bars. Use this space and include it in your stream. It might look strange on your widescreen monitor, but imagine how it will look on the monitor of your viewers, which will mainly be 1920x1080 (66% of all) or 2560x1440 (9%) or 1366x768 (8%). Widescreen usage is exceptionally rare.

Your idea to choose a canvas resolution in a way that you don't need to upscale any of your sources is good. However, if this includes static content like images, consider creating these images with a higher resolution in the first place.
Rescaling doesn't need much resources, since this is a very efficient operation for GPUs. Bad for quality is upscaling, then again downscaling. But your main focus should be to create a good source composition. Don't let the mantra "no rescaling" dictate and cripple your composition. The function of rescaling exists to make good compositions. It's not there to avoid it.

 

[utc221]

somehow on me, there are blackbars and i don't know how to fix them. what's the resulotion for it? i really need help.