Unimplemented
Opposite to what the feature may imply, video playback/codecs itself should be fine, it's the audio that's the issue (for video-only files, yes)
Affected titles use 64-bit winmm.dll and audio graph a lot, resulting in once again filters crashes (which aren't even in use)
Patches to fix those winmm.dll crashes include disabling one callback (with fail branch of "Could not create source filter to graph! hr=0x%x"), which seems to result in no video stream being outputted, may be some flag, may be whole graph? being uninitialized, hard to tell without extensive winmm internals knowledge
Could not create source filter to graph! hr=0x80040218
winegstreamer: failed to create glupload, are 32-bit GStreamer "base" plugins installed? even though 32bit plugin is present may imply issues on proton-ge side, possibly need to test with variousn proton version, if no change move to dependency tree - something (from d3d9 family) may need native implementation