On Thu, Aug 10, 2017 at 11:40:28AM -0400, Alberto Llamas wrote:
Once you have the recording you need a third-party tool to convert those files to a wav format for instance. It depends on the codec the call is being recorded the convert tool you have to use like ffmpeg.
Thank you for your feedback, Alberto.
Extracting the audio payload from RTP frames and mixing them together with 'sox' is not an incredibly difficult task. It works for 90% of simple calls. The problem with this approach to call recording is that certain calls have non-straightforward RTP timing scenarios which would lead to unintelligible garbage if simply interleaving the audio frames together. This is what sets the sophisticated call recording systems apart; they are RTP-aware, and emit playable recordings in an RTP-aware way that takes these nuances into account. RTP can get quite complex.
-- Alex