Re: [PATCH v5 0/2] MR7833: mf: Update state and start clock for both paused and stopped.

[Nikolay Sivov (＠nsivov)]

> It was calling `OnClockStart`, but it turns out that was because I had hard-coded the value in my `MESourceStarted` and `MEStreamStarted` events. After changing these events to instead use `pvarStartPosition` passed in `IMFMediaSource::Start`, I get:
> 1330.024952|10088|source_mock_Start: format: {00000000-0000-0000-0000-000000000000} (GUID_NULL) position: <EMPTY>
> 1330.025598|10088|clock_sink_OnClockRestart: system time 13300255028
>
> So sending those events with a hard-coded `VT_I8` value of zero caused `OnClockStart` to be called, but now those events have a value of `VT_EMPTY` and `OnClockRestart` is called.

I see, this is something we do differently. We are using original session Start() timestamp when restarting the clock, and Windows apparently is using whatever source reports. I think there is a value in doing the same - the idea here I'm guessing is to adjust to the source time, which could deviate both ways from the time client asked for. What we'll need to figure out is which stamp we should actually be using for the new clock position. You can have multiple sources with multiple streams, so number of events with timestamps is potentially number of streams across all sources + number of sources.