Downscaling my BD movies to SD resolutions

[Nossty]

I'm trying to encode a small portion of my BD collection to SD resolutions, so I've got something to watch while away.
What I'm doing is pretty basic stuff: Rip my bluray with MakeMKV, then use Handbrake's x264 High@L4.1, with RF values that usually return a 600-900MB .mp4 file (I don't mind the sub-par bitrates), and also butcher the sound to something like, HE-AAC @ 64kbps, since I don't really mind.

I'd like to ask though, what kind of SD resolution should I go for, and based on what criteria should I choose? So far I've downscaled 3-4 films in 864xYYY (480p), and they look alright on the 11.6'' Dell. Is my only other option to set width to 960? What happens if I settle for non-standard intermediate, like 896xYYY or 928xYYY, any disadvantage to that, or simply dumb and illogical?
Another thing is, if I decide to bother with megui/avisynth, is there a resize filter that is exactly suitable for this job and would give much better results than Handbrake's Lanczos filter? (spline / blackman etc)?

[Bernix]

Ad resolution, nothing happens when watching on PC. I am using instead of 864 848 x 480 you can also use 852 or 854 which is closes to 16/9 modern codecs handles Mod2. When you resize to higher resolution, your CRF will generate more bitrate -> bigger file size (bit slower encoding). But you lost less information of original file (you have to test it for your eyes) but you stated you dont care.. On 11,6'' monitor I dont think it is worth of it. Half resolution of original file advantage is you dont needed deinterlace the video, when is interlaced.

Bernix

[Cornucopia]

It would be best to think of this deterministically.
How/where are you going to view this?
If you are using a PC showing on a 1080p large monitor or TV, you gain nothing by reducing the resolution except a smaller size, but you'd certainly be reducing the quality, both by the re-encoding and by the subsquent necessary upsizing on playback.
But if your playback device is a phone with a smaller screen and rez (say 4" and 480x854), it makes great sense to reduce it to EXACTLY 854x480 at like 1/10th to 1/25th, and there will be very little perceivable loss (even though there is actual loss), and no need to resize at all.

Summary: Match your resizing to your playback devices.

Also, Spline36 is a preferred resize method.

Scott