Virtual Audio Driver for Windows

[MACAWI]

Is that there is an open source software (or other) to present a virtual sound card on windows? If not, is it feasible using Win DDK? I want to communicate two applications under Windows via a stream audio in and out. So each application communicates with its virtual map without realizing the other.

Thank you for your comments and suggestions.

[Raine]

It is possible and I even believe there is a commercial product for that. N TONYX or something like that Open Source I do not know. Otherwise with the SDK, there is no reason not to do it.

[MACAWI]

in fact, I want to interface with Skype. So I present my virtual sound card that uses the Skype in / out audio. the application to serve the audio is actually a specific USB driver and which do not have the USB Audio class.If ever, my device has the USB AUDIO, I would not need to see everything. but cannot I tried not to intervene in embedded on the device and try to act on driver windows.

[Sam.D]

One approach would be to use somebody else's virtual audio driver, such as Soundflower This works as a passthrough, so you can have one application send audio into it and another application which uses it as an input will read the first application's audio. You can then apply whatever effects you wish and send the audio out a real device. Using this you "only" have to do a bunch of CoreAudio stuff.

[Sam.D]

How To Use Soundflower

Soundflower presents itself as one of two audio devices (2ch / 16ch). The 2-channel device is sufficient for most situations.To send the output of one application to another, select Soundflower as the output device in the first application and Soundflower as the input device within the second application.If an application does not allow you to specify audio devices, you can make Soundflower the default input or output device inside the Sound panel in the System Preferences, or with the Audio MIDI Setup utility application.The 16-channel device is provided for more complex routing situations, and can be used with more than two applications simultaneously if the applications support audio routing to any channel, as Max/MSP does.

Note that Soundflower's audio channels represent a global audio space. If more than one application is sending its output to the same channel, the audio will be mixed. If you want an application to send and receive audio through Soundflower, (for instance using Max/MSP to manipulate and return another application's audio) you must send and receive the audio on different audio channels or a feedback loop will be created.If you are hearing clicks or breakups, try increasing the buffer size of both applications (set within each application).

[chroma]

You can Also Use Virtual Audio Cable

Virtual Audio Cable is a Windows WDM multimedia driver allowing you to transfer audio (wave) streams from one application to another. It creates a set of "Virtual Cables" each of them consists of a pair of the waveform input/output devices. Any application can send audio stream to an output side of a cable, and any other application can receive this stream from an input side. All transfers are made digitally, providing NO sound quality loss. VAC is a "wave-version" of the "MIDI loopback cable" like MultiMid or Hubi's Loopback drivers.

If more than one applications are sending audio to VAC, it will mix all streams together. If more than one applications are receiving audio from VAC, it will share the same audio data between all targets.

VAC is useful to record application's audio output in real time (for example - Generator, Reality or other software synth), or transfer a sound stream to another application processing it. You can, for example, use two or more software audio generators/synthesizers/sequencers to produce audio streams sending them to VAC Out, and record the mixed stream from VAC In using any recording software - Windows Sound Recorder, Sound Forge, WaveLab, Cool Edit, Gold Wave, Cakewalk, Cubase etc.

With an ASIO wrapper like ASIO4ALL from Michael Tippach, you can use VAC in ASIO supporting applications.If you use an audio encoder application that encodes a stream coming from a sound card, you can use VAC to supply such encoder with a stream produced by other application.You can use VAC to "thief" an output sound stream from the application that doesn't allow to write it into WAV file directly. Unlike Total Recorder allowing you to simply save audio stream, VAC allows to route it in real time.If you are using some Voice Over IP (VoIP) and/or Internet Telephony applications like Skype, you can use VAC to record your calls and conversations.VAC needs no audio card; it is a "virtual audio card" itself.

features

1. Up 256 Virtual Cables (Windows limits number of MME devices to 32. Number of DirectSound devices is not limited).
2. 1..20 milliseconds per interrupt.
3. 1..100 pin instances.
4. Almost any of fixed point PCM audio formats (200..1000000 samples per second, 8..32 bits per sample, 1..8 channels). Floating point formats are not supported.
5. Unlimited number of clients connected to each port.
6. Signal mixing (with saturation) between output port clients.
7. PCM format conversion.
8. Volume control features.
9. WDM/KS Audio technology.
10. Control Panel application to dynamically configure cables.
11. Audio Repeater application that transfers from any Wave In to any Wave Out port.