Re: [PATCH v4 0/7] MR9979: mf/tests: Test SAR's IMFPresentationTimeSource interface.

[Brendan McGrath (＠redmcg)]

On Thu Jan 29 20:11:09 2026 +0000, Brendan McGrath wrote:
> Sorry, I still haven't looked in to this. One thing I did recall seeing
> is ([src](https://learn.microsoft.com/en-us/windows/win32/medfound/streaming-audio-ren...)):
> > If the playback rate is faster or slower than 1×, the SAR
> > automatically adjusts the pitch.
> > This makes it sound like SAR itself does pitch scaling and therefore
> > probably also defines those values. But I'll need to investigate further
> > to be sure.
> > I suspect this may be hard coded in SAR. I tried every media type (using `IMFMediaTypeHandler::SetCurrentMediaType`) on every device (using `MF_AUDIO_RENDERER_ATTRIBUTE_ENDPOINT_ID`) and it was always the same result:
slowest rate 0.125000
fastest rate 8.000000

I tested the following devices:
```
Speakers (3- High Definition Audio Device)
Headphones (3- High Definition Audio Device)
SMBX2450 (NVIDIA High Definition Audio)
Digital Audio (S/PDIF) (3- High Definition Audio Device)
```

And the following subtypes:
```
MFAudioFormat_Dolby_AC3_SPDIF
MFAudioFormat_DTS
MFAudioFormat_Float
MFAudioFormat_Float_SpatialObjects
```

The only sample rate I tested though was 48kHz. None of the devices on my PC offered a media type with a different value.

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/9979#note_128838