More options beside "Force 4:2:2"

[sam_nazarko]

What options do Oppo make available?
IIRC, they have a feature called source direct which is popular.

[nabsltd]

@grahamh

I just had to ask Google and according to this the chroma is not an average of four pixels but (is treated as) a sample at a particular location in each 2x2 pixel block,

Since there isn’t anything there to actually sample…you have to use the values from the 4 pixels in some way. So, it’s not a straight average, but rather a weighted average, with the weighting coming from exactly where “in-between” the pixels the “sample” is taken. Just averaging the 4 pixels would mean the “sample” comes from exactly the center of all 4 pixels.

Since it devolves down to a single number, it still gives no help in figuring out the original pixels, even knowing exactly where the “sample” comes from. You can show this in a simpler way by using just two pixels, one black and one white. Moving the “sample” between them gives you all shades of grey. But, just knowing the grey value and where it came from can’t tell you what the two pixels were…there will always be at least 128 different value pairs for the pixels that could result in the sample value from any particular location (assuming 8-bit chroma).

[angry.sardine]

@grahamh

Unless we can achieve ‘passthrough’ of 420, I’m afraid the OP is stuck with AML’s method of upsampling.

True, but you can pass 420 for 4K/50 and 4K/60, and 422 for lower resolutions. Or rather you can’t - you can only do one of those two things at a time - but you could do both if you made the change I’m asking for.

@sam_nazarko

What options do Oppo make available?
IIRC, they have a feature called source direct which is popular.

Source Direct is indeed very useful, but that’s in a slightly different functional area from what we’re discussing here; that just means the output resolution should always match the resolution of the source video whenever possible (including 480i and 576i for DVDs).

The one I was thinking of is the “Auto/Safe” option on the Colour Space menu, which means “use the lowest-bandwidth option that is legal for any given resolution and bit-depth”, i.e. 420 for 4K/50 and 60, and 422 for other modes, thus ensuring maximum compatibility. (By contrast, IIRC “Auto” means 444 for lower resolutions and 422 for all 4K modes; and you can also lock it to 444 or 422 for all possible resolutions).

[sam_nazarko]

Usually you only offer a Chroma setting if you’re having problems implementing auto switching. Sorry NVIDIA…

I’m not sure we can rely on a user to do a better job.