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Audio latency is the time delay as an audio signal passes through a system. There are many kinds of audio latency metrics. One useful metric is the round trip latency, which is the sum of output latency and input latency. The measurement step works like below: 1. Listen and measure the average loudness of the environment for one second; 2. Create a threshold value 16 decibels higher than the average loudness; 3. Begin playing a ~1000 Hz sine wave and start counting the samples elapsed; 4. Stop counting and playing if the input's loudness is higher than the threshold, as the output wave is probably coming back; 5. Calculate the audio latency value in milliseconds. Signed-off-by: Zhang Vivian <vivian.zhang@intel.com> Signed-off-by: Takashi Iwai <tiwai@suse.de>
18 lines
696 B
C
18 lines
696 B
C
/*
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* Copyright (C) 2013-2015 Intel Corporation
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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*/
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void roundtrip_latency_init(struct bat *);
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int handleinput(struct bat *, void *, int);
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int handleoutput(struct bat *, void *, int, int);
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