如何在Android中收到Audiorecord的硬件时间戳？

Question

I need to retrieve the timestamp of when the AudioRecord class does a read of a buffer. I need to keep track of the time in milliseconds. I have tried to add a timestamp retrieve after I read the buffer, however when I receive the next buffer, the amount of time it takes to retrieve it can fluctuate a lot. Is there a way from a callback to receive the time that the audio was recorded?

int bufferReadResult = audioRecord.read(buffer, 0,blockSize);
            long startTime = System.nanoTime()/ 1000; 

is what I am currently trying.

Answer 1

Audio is sampled realtime by local oscillator. A chunk is sent to you as soon as the operative system has free time to send it to you. I'm not sure, but i think that you can't get the absolute time of the aquired signal. What you can do is to count the samples between 2 events on the recorded audio signal, and get the precise elapsed time, by counting the samples and knowing the sample frequency. Hope this helps.