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/*
* Copyright (C) 2014 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package android.media;
/**
* The AudioGain describes a gain controller. Gain controllers are exposed by
* audio ports when the gain is configurable at this port's input or output.
* Gain values are expressed in millibels.
* A gain controller has the following attributes:
* - mode: defines modes of operation or features
* MODE_JOINT: all channel gains are controlled simultaneously
* MODE_CHANNELS: each channel gain is controlled individually
* MODE_RAMP: ramps can be applied when gain changes
* - channel mask: indicates for which channels the gain can be controlled
* - min value: minimum gain value in millibel
* - max value: maximum gain value in millibel
* - default value: gain value after reset in millibel
* - step value: granularity of gain control in millibel
* - min ramp duration: minimum ramp duration in milliseconds
* - max ramp duration: maximum ramp duration in milliseconds
*
* This object is always created by the framework and read only by applications.
* Applications get a list of AudioGainDescriptors from AudioPortDescriptor.gains() and can build a
* valid gain configuration from AudioGain.buildConfig()
* @hide
*/
public class AudioGain {
/**
* Bit of AudioGain.mode() field indicating that
* all channel gains are controlled simultaneously
*/
public static final int MODE_JOINT = 1;
/**
* Bit of AudioGain.mode() field indicating that
* each channel gain is controlled individually
*/
public static final int MODE_CHANNELS = 2;
/**
* Bit of AudioGain.mode() field indicating that
* ramps can be applied when gain changes. The type of ramp (linear, log etc...) is
* implementation specific.
*/
public static final int MODE_RAMP = 4;
private final int mIndex;
private final int mMode;
private final int mChannelMask;
private final int mMinValue;
private final int mMaxValue;
private final int mDefaultValue;
private final int mStepValue;
private final int mRampDurationMinMs;
private final int mRampDurationMaxMs;
// The channel mask passed to the constructor is as specified in AudioFormat
// (e.g. AudioFormat.CHANNEL_OUT_STEREO)
AudioGain(int index, int mode, int channelMask,
int minValue, int maxValue, int defaultValue, int stepValue,
int rampDurationMinMs, int rampDurationMaxMs) {
mIndex = index;
mMode = mode;
mChannelMask = channelMask;
mMinValue = minValue;
mMaxValue = maxValue;
mDefaultValue = defaultValue;
mStepValue = stepValue;
mRampDurationMinMs = rampDurationMinMs;
mRampDurationMaxMs = rampDurationMaxMs;
}
/**
* Bit field indicating supported modes of operation
*/
public int mode() {
return mMode;
}
/**
* Indicates for which channels the gain can be controlled
* (e.g. AudioFormat.CHANNEL_OUT_STEREO)
*/
public int channelMask() {
return mChannelMask;
}
/**
* Minimum gain value in millibel
*/
public int minValue() {
return mMinValue;
}
/**
* Maximum gain value in millibel
*/
public int maxValue() {
return mMaxValue;
}
/**
* Default gain value in millibel
*/
public int defaultValue() {
return mDefaultValue;
}
/**
* Granularity of gain control in millibel
*/
public int stepValue() {
return mStepValue;
}
/**
* Minimum ramp duration in milliseconds
* 0 if MODE_RAMP not set
*/
public int rampDurationMinMs() {
return mRampDurationMinMs;
}
/**
* Maximum ramp duration in milliseconds
* 0 if MODE_RAMP not set
*/
public int rampDurationMaxMs() {
return mRampDurationMaxMs;
}
/**
* Build a valid gain configuration for this gain controller for use by
* AudioPortDescriptor.setGain()
* @param mode: desired mode of operation
* @param channelMask: channels of which the gain should be modified.
* @param values: gain values for each channels.
* @param rampDurationMs: ramp duration if mode MODE_RAMP is set.
* ignored if MODE_JOINT.
*/
public AudioGainConfig buildConfig(int mode, int channelMask,
int[] values, int rampDurationMs) {
//TODO: check params here
return new AudioGainConfig(mIndex, this, mode, channelMask, values, rampDurationMs);
}
}
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