Android Audio代码分析17 - setvolume函数
下面来看看音量设置相关的接口。
*****************************************源码*************************************************
//Test case 1: setStereoVolume() with max volume returns SUCCESS
@LargeTest
public void testSetStereoVolumeMax() throws Exception {
// constants for test
final String TEST_NAME = "testSetStereoVolumeMax";
final int TEST_SR = 22050;
final int TEST_CONF = AudioFormat.CHANNEL_OUT_STEREO;
final int TEST_FORMAT = AudioFormat.ENCODING_PCM_16BIT;
final int TEST_MODE = AudioTrack.MODE_STREAM;
final int TEST_STREAM_TYPE = AudioManager.STREAM_MUSIC;
//-------- initialization --------------
int minBuffSize = AudioTrack.getMinBufferSize(TEST_SR, TEST_CONF, TEST_FORMAT);
AudioTrack track = new AudioTrack(TEST_STREAM_TYPE, TEST_SR, TEST_CONF, TEST_FORMAT,
minBuffSize, TEST_MODE);
byte data[] = new byte[minBuffSize/2];
//-------- test --------------
track.write(data, 0, data.length);
track.write(data, 0, data.length);
track.play();
float maxVol = AudioTrack.getMaxVolume();
assertTrue(TEST_NAME, track.setStereoVolume(maxVol, maxVol) == AudioTrack.SUCCESS);
//-------- tear down --------------
track.release();
}
**********************************************************************************************
源码路径：
frameworks\base\media\tests\mediaframeworktest\src\com\android\mediaframeworktest\functional\MediaAudioTrackTest.java
#######################说明################################
//Test case 1: setStereoVolume() with max volume returns SUCCESS
@LargeTest
public void testSetStereoVolumeMax() throws Exception {
// constants for test
final String TEST_NAME = "testSetStereoVolumeMax";
final int TEST_SR = 22050;
final int TEST_CONF = AudioFormat.CHANNEL_OUT_STEREO;
final int TEST_FORMAT = AudioFormat.ENCODING_PCM_16BIT;
final int TEST_MODE = AudioTrack.MODE_STREAM;
final int TEST_STREAM_TYPE = AudioManager.STREAM_MUSIC;
//-------- initialization --------------
int minBuffSize = AudioTrack.getMinBufferSize(TEST_SR, TEST_CONF, TEST_FORMAT);
AudioTrack track = new AudioTrack(TEST_STREAM_TYPE, TEST_SR, TEST_CONF, TEST_FORMAT,
minBuffSize, TEST_MODE);
byte data[] = new byte[minBuffSize/2];
//-------- test --------------
track.write(data, 0, data.length);
track.write(data, 0, data.length);
track.play();
float maxVol = AudioTrack.getMaxVolume();
++++++++++++++++++++++++++++++getMaxVolume++++++++++++++++++++++++++++++++++
/**
* Returns the maximum valid volume value. Volume values set above this one will
* be clamped at this value.
* @return the maximum volume expressed as a linear attenuation.
*/
static public float getMaxVolume() {
return AudioTrack.VOLUME_MAX;
}
------------------------------getMaxVolume----------------------------------
assertTrue(TEST_NAME, track.setStereoVolume(maxVol, maxVol) == AudioTrack.SUCCESS);
++++++++++++++++++++++++++++++setStereoVolume++++++++++++++++++++++++++++++++++
/**
* Sets the specified left/right output volume values on the AudioTrack. Values are clamped
* to the ({@link #getMinVolume()}, {@link #getMaxVolume()}) interval if outside this range.
* @param leftVolume output attenuation for the left channel. A value of 0.0f is silence,
* a value of 1.0f is no attenuation.
* @param rightVolume output attenuation for the right channel
* @return error code or success, see {@link #SUCCESS},
* {@link #ERROR_INVALID_OPERATION}
*/
public int setStereoVolume(float leftVolume, float rightVolume) {
if (mState != STATE_INITIALIZED) {
return ERROR_INVALID_OPERATION;
}
// 确保音量在[min, max]范围之内。
// clamp the volumes
if (leftVolume < getMinVolume()) {
leftVolume = getMinVolume();
}
if (leftVolume > getMaxVolume()) {
leftVolume = getMaxVolume();
}
if (rightVolume < getMinVolume()) {
rightVolume = getMinVolume();
}
if (rightVolume > getMaxVolume()) {
rightVolume = getMaxVolume();
}
native_setVolume(leftVolume, rightVolume);
++++++++
补充：移动开发 , Android ,
