@FerretBomb - could I get you to elaborate, or point me to reference material where I can learn more about this.
I don't use Studio Mode. And for my streaming, I am resizing (and/or cropping) lots of pre-recorded videos from different sources. I don't care that much if the Preview window isn't as attractive as it could be as long stream/recording is. But If using default resizing is negatively impacting stream quality, I wish to learn more to make sure I'm not shooting myself in the foot (so to speak).
Thanks in advance
This has nothing to do with Studio Mode.
When resizing a source in the Preview window (as opposed to changing its native resolution to suit), by default a very low-quality fast rescale is used. This generally results in jaggies and low visual quality, getting worse as the resize becomes more extreme. You can see this by creating a text source, choosing a font with high detail (such as a CRT/scanline-emulation), using around 200pt, then resizing the text down. The edges will get jaggies, the details will be blurred and/or uneven (some scanlines missing, in the stated example). If you switch the source's Scale Filtering to Bicubic, that detail will clear up and get nice and sharp again.
It's subtle and you've gotta look for it, but once you see it, the difference becomes HUGE.
Scale filtering defaulted to 'disable':
Scale filtering on the source set to 'bicubic':
The same thing happens on the edges of sources, notably those with transparency. Webcams with a greenscreen are especially visible, and make them look subconsciously crappy.