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moonlight-stream / moonlight-qt

GameStream client for PCs (Windows, Mac, Linux, and Steam Link)
GNU General Public License v3.0
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Are there options to disable the default chroma subsampling and force full-resolution (4:4:4)? #1022

Closed Adnn closed 2 months ago

Adnn commented 1 year ago

Chromatic degradation in the default configuration are noticeable (washed out colors, notably visible in dark color theme with bureautic applications).

I suppose this might be due to a form of chroma subsampling in the video encoding (likely 4:2:0, or 4:2:2). Is there any way to enable full resolution for chroma information (4:4:4)? If not, any plan to allow that in the future?

I was not able to find any reference to this question in this issue tracker.

n00mkrad commented 12 months ago

Bump.

I don't see any reason why 4:4:4 shouldn't be supported.

In terms of encoders, NVENC supports it for H264, H265, and AV1. QSV and AMF might not, but a majority of users use NVENC I presume.

cgutman commented 12 months ago

The main issue is that 4:4:4 support is much less mature in drivers, software, and video APIs.

For example, there is no official D3D11VA profile that supports decoding HEVC 4:4:4. Intel has their own proprietary HEVC 4:4:4 D3D11VA profile while Nvidia requires the use of CUDA for that rather than standard D3D11VA. AMD AMF might support it similar to CUDA, but I have not checked.

There's also issues with AV1 4:4:4, namely that it is only supported in Profile 1 and 2. There are D3D11VA profiles defined for AV1 Profile 1 and 2, but I belive the current generations of hardware (Lovelace and RDNA3) only support hardware decoding of Profile 0 content, which can only be 4:2:0.

Vulkan might improve this, so it could be doable with the Vulkan renderer soon.

cgutman commented 2 months ago

This has been implemented.

Adnn commented 2 months ago

@cgutman That is excellent news, thank you! Is it already released? Do you have a link to a PR to track it and check how to enable it?

cgutman commented 2 months ago

The main work was done in #1282 with follow up work for a D3D11VA implementation completed after that. There's an option in the Moonlight settings page to enable YUV444. It requires both Moonlight and Sunshine nightly builds.