Thanks for your interest everyone. We've chosen a candidate and notified the others.
We're looking for a C coder to create one or two modules for a specific SIP stack. The modules should enable changing gain and volume per call through the command line interface. SIP-related skills are not required.
There are two existing modules to help you understand what needs to be done: One which allows changing gain, but on the audio input and not per call. Another which mixes calls into a conference, as such works on per call audio but without volume control.
Since we need the conference module anyway, it would be best if volume control would be added directly. Input gain should probably go into a separate module. For stereo signals, levels must be controllable per channel.
The work must be licensed under BSD 3-Clause to be added to the main project. As such, the author may retain copyright.
We do not have any in-house C skills, but are happy to provide assistance with audio processing in general.
Depending on your experience, I'm guessing this will take a couple days. We're looking for offers in the USD $500 ballpark.
Thanks!
Thomas
Edit: Added stereo requirement.