Forums

Re: how to input sound directly from a audio player(like windows media player) into

Started by Jeff Brower January 30, 2011
Nangergong-

> I want to do an experiment
>
> reference .wav file(signed 16bit, 8000Hz) ----> audio_player
> --------> VOIP program on computer A -----------> network
> ----------------> VOIP program on computer A
> ------------->audio recorder
>
> when I use 'mixer' mode of recording device on Windows system
> for transferring sound stream, the sound stream will be
> processed by system hardware/drivers, which degrade PESQ a
> lot,(frequency conversion, A/D, D/A conversion, background
> noise, etc).
>
> I have found a piece of software named TotalRecorder for
> recording, which can capture sound stream directly from VOIP
> program without passing through system hardware/driver. However,
> I havn't found any program/software which could input sound
> stream directly from audio player to VOIP program.

What is the point of the experiment? The data flow you describe above is a digital
loopback -- by definition it's perfect, unless a) the "network" has packet loss
(jitter), or b) you're using G729 or other codec over the network. If b), then
suggest to download ITU G729 software (or other codec software) and use file
operations.

Another way to do this is use a VoIP program that can play recorded announcements.
Then the program will either encode the .wav file as it reads it, or the program may
required the file be preprocessed and stored in encoded format.

-Jeff