Android: Record an audio stream and retrieve the latency information

1. I want to write simple test program to record audio stream from input jack (microphone?).
2. I must calculate the audio latency information and show it.

I must use NDK or SDK? Does there exist a simple source code t开发者_如何学Gohat does this for me?

In the end, how I can start to write it?

This might help as a start

http://developer.android.com/guide/topics/media/index.html

for the latency problem you might meed to use NDK - which would give you lower latency anyway but last time i checked audio was not really usable in the NDK but this may have changed