Determine The State of MIC in android

Question

can we determine the state of MIC that any type of Voice is going in to MIC?

Or

how Voice Recognition APP decide that we have complete our word and it start it's process of searching words?

Answer 1

Reading samples from input device (Microphone) and detecting a linear amplitude of a signal is one way.

There are more sophisticated ways to do this, like applying "Fourier transform" and detecting amplitude of specific range of "voice" frequencies, but that is harder and requires some knowledge of signal processing.

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You can read raw LPCM sample data using AndroidRecord class.