I usual send a test pattern and check whether the pattern gets altered!
In my Signal Analyzer & Wave Generator I have built in a custom step pattern …
On the receiver part just analyze the pattern whether data is missing or
Required is a 100% bit perfect interface as WASAPI Exclusive or ASIO where no
mixer is involved :D
Download evaluation version at http://www.hpw-works.com
[mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx] On Behalf Of Matthieu Collette
Sent: Mittwoch, 11. Mai 2016 16:14
Subject: [wdmaudiodev] Crackles when playing audio
I am developing a virtual audio driver based on the MSVAD project which I have
modified to send audio data from kernel to user space using a connection
oriented socket. The audio data is then sent over a network to a remote
This works almost as expected but I am noticing some crackles when playing
audio on the remote playback device.
I have implemented a wav file recorder in order to know where the problem is
located in my kernel driver, user space application or on the remote playback
device. This recorder actually runs in user space and records everything sent
from my kernel driver.
Here is what I do:
I am playing audio from an online source
I send the audio data format from kernel to user space using a connection
I send the audio data as provided from IDMAChannel::CopyTo using the previous
In user space, I append in a buffer all audio data packets as received from the
I periodically save to file a wav file based and the audio format and data
I can ear crackles when I play the recorded wav file, meaning the problem is
located in my kernel driver.
Could those crackles come from an alignment issue ?
Could it be due to a bad estimation of the DMA position ?
Any kind of help is welcome ;)
Thanks in advance !