You need to arrange for the clock in your hardware to drive the audio. The
sample can’t do this because there is no hardware.
From: wdmaudiodev-bounce@xxxxxxxxxxxxx <wdmaudiodev-bounce@xxxxxxxxxxxxx> On
Behalf Of K. Weller
Sent: Friday, March 24, 2023 5:14 AM
To: wdmaudiodev@xxxxxxxxxxxxx
Subject: [EXTERNAL] [wdmaudiodev] SetWritePacket in a MiniportWaveRTStream
DATA_OVERRUN handling
Hi all,
I have implemented the Microsoft SimpleAudioSample from Github.
I have added an SPDIF Pin for rendering and I have connected everything to my
hardware and all is fine and works like expected.
But if I start a 5.1 Dolby Digital Video for example with the Microsoft Media
Player or the "TV & Video" App which is default on Win 11 for example it
starts to get distorted.
Right now I still run the MiniportWaveRTSteam with the notification timer like
it is in the example to focus on this issue and do not add new possible bugs.
If the stream starts in event driven mode like this:
m_ulDmaBufferSize 38400
m_ulDmaMovementRate 192000
ulBufferDurationMs 200
m_ulNotificationIntervalMs 100
NotificationCount_ 2
I get the first call into
CMiniportWaveRTStream::SetWritePacket
PacketNumber = 1
Flags = 0
Eos = 19200
KSSTATE is still KSSTATE_PAUSE
next call will be the same like above but in KSSTATE_RUN.
Now I save the first half of the buffer to the hardware and after the
m_ulNotificationIntervalMs period I trigger the event which is actually the
first call to KSetEvent in the timer callback.
I get another call into:
CMiniportWaveRTStream::SetWritePacket
PacketNumber = 3
Flags = 0
Eos = 19200
A the same time I only have triggered one (1) event in my timer.
In the timer the:
m_llPacketCounter is incremented and should match the PacketNumber from the
SetWritePacket like this:
(m_llPacketCounter + 1) == PacketNumber
Because there is one package missing in between, I'll run into a data overrun
and the current sample implementation returns a STATUS_DATA_OVERRUN.
Also my stream is distorted.
Well for me there are several questions:
1. Why is this PackageNumber not continuously?
2. Where is it counted and is the information retrieved somewhere out of my
driver?
3. How do I handle something like this correctly to get an proper stream after
the next event?
It seems this only happens if I have a bigger buffer and longer duration like:
ulBufferDurationMs 200
m_ulNotificationIntervalMs 100
A stereo stream for example with
ulBufferDurationMs 20
m_ulNotificationIntervalMs 10
works perfect.
Also:
If I use VLCPlayer for example which will not use event driven mode the movie
will playback as expected. So I can be sure the issue is not on the hardware
side of the implementation etc.
Thanks for any help and feedback,
Regards
K. Weller
