Android ToneGenerator startTone () is very slow on first call

Question

I call ToneGenerator.startTone()several times to produce short bursts of sound. But at the first call, it is blocked for a long period of time. Thus, the first surge is too long. Here is an example:

Membership Variables:

private ToneGenerator mDTMFPlayer

In the constructor:

mDTMFPlayer = new ToneGenerator(AudioManager.STREAM_VOICE_CALL, TONE_RELATIVE_VOLUME);

In Threadstarting with OnClickListener.onClick():

long startTime = System.currentTimeMillis();
mDTMFPlayer.startTone(ToneGenerator.TONE_DTMF_0);
Log.d(TAG,"After 1st: " + (System.currentTimeMillis() - startTime));
try { Thread.sleep(160); } catch (InterruptedException e) { }
mDTMFPlayer.stopTone();

startTime = System.currentTimeMillis();
mDTMFPlayer.startTone(ToneGenerator.TONE_DTMF_0);
Log.d(TAG,"After 2nd: " + (System.currentTimeMillis() - startTime));
try { Thread.sleep(160); } catch (InterruptedException e) { }
mDTMFPlayer.stopTone();

startTime = System.currentTimeMillis();
mDTMFPlayer.startTone(ToneGenerator.TONE_DTMF_0);
Log.d(TAG,"After 3rd: " + (System.currentTimeMillis() - startTime));
try { Thread.sleep(160); } catch (InterruptedException e) { }
mDTMFPlayer.stopTone();

Here is the output with runtime startTone()in milliseconds:

11-16 18:07:35.885 16927-17977/com.my.project D/Ring: After 1st: 454
11-16 18:07:36.502 16927-17977/com.my.project D/Ring: After 2nd: 0
11-16 18:07:36.672 16927-17977/com.my.project D/Ring: After 3rd: 1

The first call is blocked for almost half a second, which is too long for what I need. Any calls after this block for a while. What is strange, if I wait a bit and try again, it slows down again. It seems that there is a period after which a lock occurs.

Please inform.

Answer 1

, AudioManager.STREAM_VOICE_CALL . . init startTone(). , 3 . ", , " , - .

, , / , AudioManager.STREAM_NOTIFICATION 4-10 . : AudioManager ?

:

for (int i = -1; i < 10; i++) {
    System.out.println("AudioSystem stream " + i);
    mDTMFPlayer = new ToneGenerator(i, TONE_RELATIVE_VOLUME);
    long startTime = System.currentTimeMillis();
    mDTMFPlayer.startTone(ToneGenerator.TONE_DTMF_0);
    Log.d(TAG, "After 1st: " + (System.currentTimeMillis() - startTime));
    try {Thread.sleep(160);} catch (InterruptedException e) {}
    mDTMFPlayer.stopTone();

    startTime = System.currentTimeMillis();
    mDTMFPlayer.startTone(ToneGenerator.TONE_DTMF_0);
    Log.d(TAG, "After 2nd: " + (System.currentTimeMillis() - startTime));
    try {Thread.sleep(160);} catch (InterruptedException e) {}
    mDTMFPlayer.stopTone();

    startTime = System.currentTimeMillis();
    mDTMFPlayer.startTone(ToneGenerator.TONE_DTMF_0);
    Log.d(TAG, "After 3rd: " + (System.currentTimeMillis() - startTime));
    try {Thread.sleep(160);} catch (InterruptedException e) {}
    mDTMFPlayer.stopTone();
    mDTMFPlayer.release();
}

:

I/System.out: AudioSystem stream -1 STREAM_DEFAULT
D/com.example.MainActivity: After 1st: 8
D/com.example.MainActivity: After 2nd: 1
D/com.example.MainActivity: After 3rd: 1
I/System.out: AudioSystem stream 0 STREAM_VOICE_CALL
D/com.example.MainActivity: After 1st: 325
D/com.example.MainActivity: After 2nd: 1
D/com.example.MainActivity: After 3rd: 1
I/System.out: AudioSystem stream 1 STREAM_SYSTEM
D/com.example.MainActivity: After 1st: 17
D/com.example.MainActivity: After 2nd: 2
D/com.example.MainActivity: After 3rd: 3
I/System.out: AudioSystem stream 2 STREAM_RING
D/com.example.MainActivity: After 1st: 28
D/com.example.MainActivity: After 2nd: 2
D/com.example.MainActivity: After 3rd: 1
I/System.out: AudioSystem stream 3 STREAM_MUSIC
D/com.example.MainActivity: After 1st: 19
D/com.example.MainActivity: After 2nd: 1
D/com.example.MainActivity: After 3rd: 1
I/System.out: AudioSystem stream 4 STREAM_ALARM
D/com.example.MainActivity: After 1st: 28
D/com.example.MainActivity: After 2nd: 1
D/com.example.MainActivity: After 3rd: 1
I/System.out: AudioSystem stream 5 STREAM_NOTIFICATION
D/com.example.MainActivity: After 1st: 16
D/com.example.MainActivity: After 2nd: 1
D/com.example.MainActivity: After 3rd: 1
I/System.out: AudioSystem stream 6 STREAM_BLUETOOTH_SCO
D/com.example.MainActivity: After 1st: 332
D/com.example.MainActivity: After 2nd: 2
D/com.example.MainActivity: After 3rd: 1
I/System.out: AudioSystem stream 7 STREAM_SYSTEM_ENFORCED
D/com.example.MainActivity: After 1st: 324
D/com.example.MainActivity: After 2nd: 1
D/com.example.MainActivity: After 3rd: 1
I/System.out: AudioSystem stream 8 STREAM_DTMF
D/com.example.MainActivity: After 1st: 26
D/com.example.MainActivity: After 2nd: 2
D/com.example.MainActivity: After 3rd: 4
I/System.out: AudioSystem stream 9 STREAM_TTS
D/com.example.MainActivity: After 1st: 12
D/com.example.MainActivity: After 2nd: 4
D/com.example.MainActivity: After 3rd: 2  

Btw, C-, android_media_ToneGenerator.cpp, ToneGenerator.h, ToneGenerator.cpp AudioService.java