[Nintendo Maniac 64]

I may not know what clsid has in mind, but from my view I think the best method would be a sort of priority-based fallback system while the three codecs themselves (AV1 > VP9 > H264; VP8 is excluded because that exists for only a single resolution being 360p and is lower quality than the equivalent H264 encode) additionally operate with their own priority-based fallback system.

In other words, I figure the first thing to try falling-back would be the codec, then it would try the resolution, then it'd try the frame rate.



As an example, let's say you have MPC-HC set to 1080p 60fps AV1.

First it'll check for that exact configuration - AV1 @ 1080p60. If it does not exist, it will fall-back the codec to VP9 and try VP9 @ 1080p60. If that doesn't exist, it'll check H264 @ 1080p60.

If that still doesn't exist, then it will start over with AV1 but at 720p60. And once again if it doesn't exist, it will then try VP9 @ 720p60 and if that doesn't exist then H264 @ 720p60.

If none of that exists, then it will start over with AV1 and 1080p once again but this time at 30fps. From there it will then try AV1 @ 1080p30, VP9 @ 1080p30, H264 @ 1080p30, AV1 720p30, VP9 @ 720p30, H264 @ 720p30, AV1 @ 480p30, VP9 @ 480p30, H264 @ 480p30, etc.



Now much like the resolution setting that currently exists in MPC-HC v1.8.6, my idea is that the codec and frame rate settings are upper-limits, so it would specifically start at those given upper-limits and never try anything above them. This means that, if you set MPC-HC to VP9 720p 60fps, it would follow the same sort of fallback process as the above example but would completely exclude the 1080p+ resolutions as well as AV1.

So in this case it would try in order: VP9 @ 720p60, H264 @ 720p60, VP9 @ 720p30, H264 @ 720p30, VP9 @ 480p30, H264@480p30, etc

This also means that, if you set H264, you would then always get nothing but H264.



Therefore, in the two examples given in my previous post, setting 1440p H264 in MPC-HC would indeed play back H264 @ 1080p while setting AV1 1440p would play back VP9 @ 1440p.