What does "deep buffer" mean in the audio system/driver?

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尹豪雲

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May 21, 2015, 3:32:39 PM5/21/15
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Hello Experts,

I am studying the Audio Framework recently.
And I found the "deep buffer" playback which is used when playing MUSIC stream. Right?

I wonder to know what is the difference by comparing with other playback.

1. Deep Buffer
2. Codec Offload
3. Normal Tracks

I think I know what are Codec Offload & Normal Tracks for.
But I don't understand "deep buffer"

1. How does "deep buffer" work?
2. Why music stream plays as "deep buffer" way?
3. What is the benefit of the "deep buffer"
5. Where can I find any reference data about "deep buffer"

Thanks & Best Regards.

Glenn Kasten

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May 22, 2015, 9:30:14 PM5/22/15
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normal tracks - PCM, typical buffer size is ~20 ms, higher latency
fast tracks - PCM, typical buffer size is 5 ms or less, lower latency
deep buffer - PCM, typical buffer size is >= 100 ms, very high latency, intended to save power
codec offload - MP3/AAC/etc., very high latency, intended to save even more power than deep buffer

grep -r DEEP_BUFFER in frameworks/av/* is a starting point for details

Neil Agarwal

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Jun 18, 2017, 7:18:01 PM6/18/17
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Thanks a lot!
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