I can’t say I’m a fan of the new V3 interface as a lot of the older options now seem to be missing for lower quality video. Also I’d much prefer the constant quality variable bitrate to reappear as it’s much more efficient than setting one bitrate for all. Please remove looping the video playback, it’s much easier at a glance when doing other things if the video stops once it’s done and it also doesn’t use resources. While having multiple previews available now it’s not really easy to compare different ones unless they are side by side as in the previous version.
I’ve seen a massive performance increase swapping my old GTX1080 for an RTX3070 as rendering times have dropped by around 60% but today I wanted a relatively small upscale of a VR video from 34001700 up to 40962048 (120%). OK it’s 59.94 fps and 46 minutes long but I was still shocked by the estimated 4+ DAYS to render (0.2fps) … so that’s not happening. I went back to my old fallback of using Xmedia Recode which upscaled in less than 1 hour (50+fps). To justify running that long it would have to give more than a marginal difference to the output.
Do you mean CBR vs VBR?
CFR is for constant rate factor. It’s for encoding H.264 and H.265. It’s not possible with hardware encoding… and that’s all that’s available in TVAI 3.
I find it odd that they are not sticking to widely accepted and fully compatible formats that are used in professional production.
Kind of 
. CRF which was in V2 Constant Rate Factor as far as I am aware is like setting a Constant Quality Factor. It will create an output with VBR allowing to use higher bitrates to maintain picture quality during fast action sequence and reduce it during slower scenes. Setting CBR or Auto as is now available is more likely to give varying results dependent upon content. CBR if set too high will just create larger files or too low produce more artifacts/moire/blocking etc.
