Frames to milliseconds conversion in android

Question

In Android the getPlaybackHeadPosition() method of AudioTrack class returns the playback head position expressed in frames ,what is its equivalent value in milli seconds?

Nick · Accepted Answer · 2012-05-01T11:40:58.343

21

I'm guessing that it would be

( track.getPlaybackHeadPosition( ) / track.getSampleRate( ) ) * 1000.0

In other words, the number of frames played divided by the number of frames per second. You then multiply the result by 1000 to get milliseconds.

A frame consists of one sample per channel and so should be equivalent to sample rate.

For example, if getPlaybackHeadPosition( ) returns 8654 and getSampleRate( ) returns 8000 then the time since the start of the track would be ( 8654 / 8000 ) * 1000 or 1081.75ms. (Assuming floating point arithmetic)

edited May 01 '12 at 11:40

answered May 01 '12 at 10:06

Nick

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for example, if the audio has 8000 samples/sec, (track.getPlaybackHeadPosition( )/8) gives you current playback head position in milli seconds. – Raneez Ahmed May 01 '12 at 11:32
Correct. I'll add an example to the answer. – Nick May 01 '12 at 11:37
So a "frame" is the same as a sample? – Edward Falk Dec 20 '12 at 00:32
Or with plain integer math (no floats): track.getPlaybackHeadPosition() * 1000 / track.getSampleRate() – Pointer Null Apr 22 '14 at 16:23

score 0 · Answer 2 · answered Dec 20 '17 at 08:32

The answer by @Nike is right。

But there is a problem。

If we call the MediaExtractor.seekTo method, AudioTrack.getPlaybackHeadPosition() returns accumulate value。

MediaExtractor.getSampleTime() / 1000 is the right ms for current position.

You can check it out!

Frames to milliseconds conversion in android

2 Answers2