NAudio: Recording Audio-Card's Actual Output

0
votes

I successfully use WasapiLoopbackCapture() for recording audio played on system, but I'm looking for a way to record what the user would actually hear through the speakers. I'll explain: If a certain application plays music, WASAPI Loopback shall intercept music samples, even if Windows main volume-control is set to 0, meaning: even if no sound is actually heard through audio-card's output-jack (speakers/headphone/etc). I'd like to intercept the audio actually "reaching" the output-jack (after ALL mixers on the audio-path have "done their job").

Is this possible using NAudio (or other infrastructure)? A code-sample or a link to a such could come in handy.

Thanks much.

1
naudio

1 Answers

1
votes

No, this is not directly possible. The loopback capture provided by WASAPI is the stream of data being sent to the audio hardware. It is the hardware that controls the actual output sound, and this is where the volume level is applied to change the output signal strength. Apart from some hardware- and driver-specific options - or some interesting hardware solutions like loopback cables or external ADC - there is no direct method to get the true output data.

One option is to get the volume level from the mixer and apply it as a scaling factor on any data you receive from the loopback stream. This is not a perfect solution, but possibly the best you can do without specific hardware support.