I want to get low-latency access to the raw PCM audio stream from a call-in-progress (downlink). I am only targeting S^1 (S60/5th) and later platforms.
As I need continuous streaming access I figure I need to use the CMdaAudioInputStream class. I have been browsing the forums as well as the examples etc. for a while but a couple of questions are still not clear to me:
- How do I select the audio data to come from the call-in-progress (downlink) voice? It appears that CAudioInput using the EVoiceCall option could do the job, but this feature has been deprecated? Has anybody got experience making it work? On which platforms/phones?
- What is the approximate latency of the audio samples? I can use small buffers, e.g. 64 samples @ 8 KHz => 8 ms, but there is probably additional latency in the system itself?