Games

Titles we have taken on, and what was measured on each. Every row comes from an installed copy rather than from memory; where a claim comes from a static scan rather than from playing the game, it says so.

Tested on an M4 Max, macOS 27, CrossOver 26.2 patched with winevideo, GPTK 4.0b2.

Fixed

Mortal Shell 2 — Unreal Engine 5.6.1

Cutscenes	61 × VP9 in .mp4, inside pakchunk0-Windows.pak and loose
Played by	Electra, decoding VP9 with its own libvpx
Symptom	EXCEPTION_ACCESS_VIOLATION reading 0x0 in FElectraMediaDecoderOutputBufferPoolBlock_DX12::AllocateBuffer
Fix	Runtime patch — 4 patch sites, all four confirmed at runtime

Both modes work. The runtime patch leaves the original VP9 files untouched; re-encoding is the fallback.

Diagnosed, not yet fixed

DYNASTY WARRIORS: ORIGINS — Koei Tecmo, in-house engine

Cutscenes	355 .webm, VP9 Profile 0. 42 of them 2560x1440 and up to four minutes; the rest 960x540 interface clips
Played by	IMFSourceReader, on a separate D3D11 device created only for video
Symptom	Cutscene plays with sound, picture stays black. No crash

Where it stands. The player now runs: it opens the file, builds a reader, negotiates NV12 at 2560x1440, reads samples, seeks, and the audio plays. What it never does is put a frame on screen.

The chain, in the order it was found. Each of these was a real blocker; none of them was the last one.

1. ID3D11VideoDevice and ID3D11VideoContext return E_NOINTERFACE. The player queries the D3D11 device for both and gives up if either fails. With CX_GRAPHICS_BACKEND=d3dmetal, CrossOver puts Apple's GPTK ahead of Wine, and GPTK's 136 KB d3d11.dll is a shim over D3DMetal carrying neither. Wine's own 425 KB d3d11.dll implements ID3D11VideoDevice1 with 24 real methods, but the game never sees it.

2. MF_SOURCE_READER_D3D_MANAGER. The game asks the source reader to decode into D3D video textures, which nothing under D3DMetal can produce. Dropping that attribute makes it decode in software, and winegstreamer's VP9 support handles it without complaint.

3. The video processor. Converting the decoded NV12 into the BGRA texture the game draws is ID3D11VideoProcessor's job. The player walks the rate conversion caps looking for one specific bit — ProcessorCaps bit 1, DEINTERLACE_BOB — and returns E_FAIL when no entry has it.

4. And then the tension that has no easy way out. The executable references IMFDXGIBuffer, ID3D11Texture2D and IDXGIResource, but neither IMF2DBuffer nor IMFMediaBuffer. It only knows how to consume samples backed by D3D textures: query the buffer for IMFDXGIBuffer, take the texture, wrap it in a VideoProcessorInputView, blit.

   So the attribute dropped in step 2 to make decoding work is exactly the one its presentation path depends on. Give it back and decoding fails; leave it off and there is no texture to present.

What a fix would take. Software decoding that still hands back D3D-backed samples: intercept ReadSample, upload each frame into a texture, and present it through an IMFDXGIBuffer the game can consume. That is what Windows does when the decoder is software and a device manager is set, and it is what neither D3DMetal nor Wine's source reader does here.

The alternative is upstream: D3DMetal implementing ID3D11VideoDevice, at which point steps 1 through 4 all disappear at once.

How it was found. Worth recording, because most of it was wrong turns. Eight hypotheses were tested and discarded before the disassembler was used properly: a missing codec registration, the absent audio track, the container duration, a missing pixel aspect ratio and interlace mode (setting those actively broke the negotiation), NV12 texture creation, and the shared texture. What worked was reading the code — find-callsites.py locating the player statically, then following the branches — and answering interface queries with logging stubs so the game itself said what it wanted next.

Adding a row

This page covers titles we have deliberately taken on, not everything that happens to be installed on someone's machine. A game gets a row when there is a reason to work on it.

To add one: run the survey on that game's folder, and if it misbehaves, the probe. Both are in diagnostics/, and both are described in Diagnosing a new game. Paste what they print — measurements are the point of this page, and a row without one is worse than no row.