mirror of https://github.com/mpv-player/mpv
a9f9601ca8
This adds vsync reporting to the D3D11 backend using the presentation feedback provided by DXGI, which is pretty similar to what's provided by GLX_OML_sync_control in the GLX backend. In DirectX, PresentCount is the SBC, PresentRefreshCount and SyncRefreshCount are kind of like the MSC and SyncQPCTime is the UST. Unlike GLX, the DXGI API makes it possible for PresentCount and SyncQPCTime to refer to different physical vsyncs, in which case PresentRefreshCount and SyncRefreshCount will be different. The code supports this possibility, even though it's not clear whether it can happen when using flip-model presentation. The docs say for flip-model apps, PresentRefreshCount is equal to SyncRefreshCount "when the app presents on every vsync," but on my hardware, they're always equal, even when mpv misses a vsync. They can definitely be different in exclusive fullscreen bitblt mode, though, which mpv doesn't support now, but might support in future. Another difference to GLX is that, at least on my hardware, PresentRefreshCount and SyncRefreshCount always refer to the last physical vsync on which mpv presented a frame, but glxGetSyncValues can apparently return a MSC and UST from the most recent physical vsync, even if mpv didn't present a new frame on it. This might result in different behaviour between the two backends after dropped frames or brief pauses. Also note, the docs for the DXGI presentation feedback APIs are pretty awful, even by Microsoft standards. In particular the docs for DXGI_FRAME_STATISTICS are misleading (PresentCount really is the number of times Present() has been called for that frame, not "the running total count of times that an image was presented to the monitor since the computer booted.") For good documentation, try these: https://docs.microsoft.com/en-us/windows/win32/direct3ddxgi/dxgi-flip-model https://docs.microsoft.com/en-us/windows/win32/direct3d9/d3dpresentstats https://docs.microsoft.com/en-us/windows-hardware/drivers/ddi/content/d3dkmthk/ns-d3dkmthk-_d3dkmt_present_stats (Yeah, the docs for the D3D9Ex and even the kernel-mode version of this structure are better than the DXGI ones. It seems possible that they're all rewordings of the same internal Microsoft docs, but whoever wrote the DXGI one didn't really understand it.) |
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| .. | ||
| context.c | ||
| hwdec_d3d11va.c | ||
| hwdec_dxva2dxgi.c | ||
| ra_d3d11.c | ||
| ra_d3d11.h | ||