Ask: Android phone can not pass in a way transmission of voice files

Android audio communication mobile development

I do android time not too long, recently had an idea: to dial a contact's phone, then hold a Button interface (called "hold down the talk"), after finished his speech, the speech by playing this telephone manner (rather than network) send to each other, somewhat similar to the micro-channel in voice chat feature.
I consider for a moment, Android was seemingly not provide such API directly, only AudioRecord and AudioTrack classes for recording and playback of voice and speech coding with speex, but it will eventually be transmitted through the network. If you implement these ideas, you may need to do a lot of the underlying work, the difficulty a little big, but I do not know how to engage in concrete.
Please pass prawn help analyze the idea is feasible? To achieve this, the entire process of how architecture? What are the underlying work to be done?
Thank you!
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Reply:
Impracticable, GSM protocol does not support this feature ah.
Reply:
Can be, but you do re-implement a set of almost acceptable "android system", from bottom to top, but this would have to walk a very low cost network, so you can engage in costly, there can be implemented
Reply:
Ah, if you want to engage in such a case, the application layer from the bottom to the workload is getting bigger. Even get, not much practical significance. Thank you!