Simple Protocol Server
This is a server that sends all the available sound card audio from a Windows PC to the network. This is meant to be the Windows counterpart to the simple protocol module in PulseAudio. The simple protocol streams uncompressed 16 bit 2 channel PCM data.
The server is meant to be used with the Simple Protocol Player client on Android. The play store link is here: https://play.google.com/store/apps/details?id=com.kaytat.simpleprotocolplayer .
The client source is here: https://github.com/kaytat/SimpleProtocolPlayer
WSAPI Loopback
The server uses the Windows Audio Session API to capture the audio. And for each audio frame, it sends that data to the connected client.
The code is a simple modification to an existing MSDN example: http://blogs.msdn.com/b/matthew_van_eerde/archive/2014/11/05/draining-the-wasapi-capture-buffer-fully.aspx . Instead of writing the data to a MMIO file, the data is send over a socket.
Limitations
One client only
Although PulseAudio's module will allow multiple connections, this server does not.
No XP support
I've only tested this with one Win7 machine. And it doesn't seem to work with XP.
The Win7 machine was recently upgraded to Win10 and that seems to work.
Sampling rate / format
The Android app supports 4 sampling frequencies - 48, 44.1, 24, and 22.05kHz and both stereo and mono. The app assumes 16-bit samples.
My sound card doesn't support the lower sampling rates and so the server has a command line option to use an integer divider to downsample.
The sampling rate may need to be manually adjusted by the user since the default format may not be a format supported by the Android app. To do this, the user will need to manually configure the properties in the "Advanced" tab of the playback device. Please also see this: http://kaytat.com/blog/?p=332
Usage
simpleserver.exe [--device "Device long name"] [--mono] [--div divisor]
-? prints this message.
--list-devices displays the long names of all active playback devices.
--device captures from the specified device (default if omitted)
--mono convert from stereo to mono
--div divisor reduce sample rate by a factor of divisor