PotPlayer - ZMBV poor/lossy color reproduction?

[largactyl]

VLC has been letting me down lately, so I'm giving PotPlayer a try -- it works nicely so far, except for one thing: I cannot watch ZMBV videos in their original quality.
(ZMBV is a lossless codec, used for instance by emulators such as DOSBox and Altirra.)

Here is a sample video, plus two zoomed-up still shots that clarify the problem:

VLC (top) shows the video as originally recorded.
PotPlayer (bottom) shows a blurry mess w/ poor colors.

I went through every video renderer in PotPlayer, and every colorspace setting; I took an hour or so to explore the menus(!). Nothing helped -- what I'm suspecting now is the decoder.
It almost looks like the chroma is being decoded at a lower resolution than the luma. But why would that happen? Doesn't PotPlayer use ffmpeg decoders, just like VLC does? Can anyone even guess what's happening here?

[jagabo]

Can you force the video decoder to output RGB? It's putting out YV12 on your computer. MPCHC plays it properly with the video decoder (LAV) set to RGB.

[largactyl]

Yeah, already tried forcing the output colorspace to RGB (various types thereof). This didn't help - I see now that certain renderers fall back to YUY12 when forced, while others (e.g. VMR 9 Renderless) claim to be showing RGB, but I still get the same visual result.

Well, thanks for testing. I might experiment with using LAV decoders in PotPlayer then...

[largactyl]

Okay, this is extremely strange: both MPCHC (w/LAV filters) and VLC can play these files fine.
So I tell PotPlayer to use the LAV Video Decoder, and adjust the output to RGB... nope: still the exact same issue as above. I check the playback info to make sure that the settings were successfully applied. They were, but there's no improvement.

Too bad - I *like* PotPlayer for being so flexible and configurable... but if all those options are not enough to properly decode my videos, I guess I'll have to go with something else. :(

[AllisOne]

It's just a guess, but PotPlayer uses internal intermediate video filter (the audio one as well) - 'Built-in Video Codec/Transform'. It might have unexpected effects - as far as I remember it can increase CPU use by the player for HEVC videos for example. Maybe you should go to Preferences - Filter Control - then to the right side and change 'Built-in Video processing filter settings' conditions , etc.

[largactyl]

@AllisOne: yes, that was it - excellent, thanks for the tip!

[jagabo]

I have the built-in video processor disabled. PotPlayer still has a problem with the video here.

[AllisOne]

@largactyl: actually I'm curious as well - what have you changed to make it work? After writing you about my suspicions I didn't have time to fiddle with the settings and I just tried to add ZMBV, ZIP and YV12 in FourCC for Conditions: Disable with the following conditions. But it doesn't seem to turn 'Built-in Video Codec/Transform' off in this case. What splitter, video decoder etc are you using for your video?

[largactyl]

I'm using the LAV audio decoder, splitter, splitter source, and video decoder (added all four under Filter Control > Filter Priority (Default), and set their Priority to "Prefer"). As for the built-in filters, I just disabled them all; haven't really tried setting FourCC-specific conditions yet.