SubmitInput() failed with error 29. Sunshine seems picky about resolutions.

[lil-greasy]

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Does anyone know what this error means? I’m on an unusual setup so there are a lot of things I suspect it could be related to.

I just set Sunshine up on a Windows VM with a passed-through R9-290 and Virtual Display Driver (and Looking Glass for local access). Because the purpose of the VM is to run a piece of software that doesn’t handle desktop scaling well, my goal is to stream to a Surface Pro at a resolution of 2304×1536, which is the Surface Pro’s native resolution divided by 125%.

At that resolution, and most others I’ve tried, the video stream never comes up, although I can briefly control the mouse cursor on the VM while it’s trying.

To be clear, I’m talking about the resolution that I enter for the connection in Moonlight. The resolution of the display on the VM doesn’t appear to be a factor in the success or failure of the connection, as far as I can tell so far.

The stream works just fine at a selection of more typical resolutions, notably lower ones. I’ve been having an LLM coach me through the process of getting this VM dialed in, and it assures me that bandwidth is not the problem, but I’m not totally convinced.

Here’s an example of what the Sunshine log says during an unsuccessful attempt:

[2026-07-13 18:47:36.094]: Info: Desktop resolution [2304x1536]
[2026-07-13 18:47:36.094]: Info: Desktop format [DXGI_FORMAT_B8G8R8A8_UNORM]
[2026-07-13 18:47:36.095]: Info: Display refresh rate [60Hz]
[2026-07-13 18:47:36.095]: Info: Requested frame rate [60fps]
[2026-07-13 18:47:36.109]: Info: Creating encoder [h264_amf]
[2026-07-13 18:47:36.109]: Info: Color coding: SDR (Rec. 601)
[2026-07-13 18:47:36.109]: Info: Color depth: 8-bit
[2026-07-13 18:47:36.109]: Info: Color range: MPEG
[2026-07-13 18:47:36.133]: Info: Capture format [DXGI_FORMAT_B8G8R8A8_UNORM]
[2026-07-13 18:47:36.315]: Info: Streaming bitrate is 29388000
[2026-07-13 18:47:36.341]: Info: [D3D11VA @ 000001d78a728180] AMF via D3D11.
[2026-07-13 18:47:36.503]: Info: Minimum FPS target set to ~30fps (33.3333ms)
[2026-07-13 18:47:36.517]: Error: [h264_amf @ 000001d7853256c0] SubmitInput() failed with error 29
[2026-07-13 18:47:36.517]: Error: Could not send a frame for encoding: Unknown error occurred
[2026-07-13 18:47:36.517]: Error: Could not encode video packet
[2026-07-13 18:47:46.746]: Info: CLIENT DISCONNECTED

Thanks in advance for any insights!