On Tuesday, December 22, 2015 at 12:14:37 AM UTC-8, gjs wrote: > > Hi, > > Ok here's two simple example (sine wave) tone generators, one uses the > 'streaming' method and the other uses the 'static' method, this relates to > how the associated memory is allocated / managed. > > The information / tradeoffs - > > 'streaming' is useful where sounds might be changed dynamically as they > are being played, where they are long duration more than a few seconds, not > suitable for allocating a large amount of static memory, where you don't > mind having some latency before sound is heard, don't need to be > synchronized accurately with an animation for example. > > 'static' is suitable for short duration sounds, don't require a lot of > memory, have less latency, are somewhat easier to synchronize. > > That said, 'streaming' is usually adequate for most ordinary purposes > where accuracy < 100ms is not important, such as in a countdown timer > before a camera shutter is fired. >
For what I'm doing, it sounds like static makes more sense. Is the AudioTrack itself reusable? Can I simply construct it and set its properties and then play it multiple times? > These are just java examples, high performance low(er) latency sounds > would probably use C/C++ code / libraries, eg as discussed here > http://superpowered.com/androidaudiopathlatency > > If you hear a 'clicking' sound after each tone is played try adding code > to dynamically reduce the volume (or amplitude) before stopping the > AudioTrack... > > Regards > > > private void playToneStreaming(final int frequency, final long duration) // > duration in milliseconds > > { > new Thread(new Runnable() { > @Override > public void run() { > try { > > final int sampleRate = 8000; > > final int amplitude = 32000; > > final double twoPI = Math.PI * 2.0; > > int minBufferSize = AudioTrack.getMinBufferSize(sampleRate, > AudioFormat.CHANNEL_OUT_MONO, AudioFormat.ENCODING_PCM_16BIT); > > final AudioTrack audioTrack = new > AudioTrack(AudioManager.STREAM_MUSIC, > sampleRate, AudioFormat.CHANNEL_OUT_MONO, > AudioFormat.ENCODING_PCM_16BIT, minBufferSize, > AudioTrack.MODE_STREAM); > > int sampleSize = minBufferSize / 2; > > short samples[] = new short[sampleSize]; > > double phase = 0.0; > > audioTrack.setStereoVolume(1, 1); > > audioTrack.play(); > > long end = System.currentTimeMillis() + duration; > > while (System.currentTimeMillis() < end) > { > for (int i = 0; i < sampleSize; i++) > { > phase += twoPI * frequency / sampleRate; > > samples[i] = (short) (amplitude * Math.sin(phase)); > } > > audioTrack.write(samples, 0, sampleSize); > } > > audioTrack.setStereoVolume(0, 0); > > audioTrack.stop(); > > audioTrack.release(); > > } catch (Exception e) { > e.printStackTrace(); > } > } > > }).start(); > } > > private void playToneStatic(final int frequency, final long duration) // > duration in milliseconds > { > new Thread(new Runnable() > { > @Override > public void run() > { > try { > > final int sampleRate = 8000; > > final int amplitude = 32000; > > final double twoPI = Math.PI * 2.0; > > int sampleSize = (sampleRate / 1000) * (int) duration; > > short samples[] = new short[sampleSize]; > > double phase = 0.0; > > for (int i = 0; i < sampleSize; i++) > { > phase += twoPI * frequency / sampleRate; > > samples[i] = (short) (amplitude * Math.sin(phase)); > } > > final AudioTrack audioTrack = new > AudioTrack(AudioManager.STREAM_MUSIC, > sampleRate, AudioFormat.CHANNEL_OUT_MONO, > AudioFormat.ENCODING_PCM_16BIT, sampleSize * 2, > AudioTrack.MODE_STATIC); > > audioTrack.write(samples, 0, sampleSize); > > audioTrack.setStereoVolume(1, 1); > > audioTrack.play(); > > try { > Thread.sleep(duration); > } catch (Exception ignore) { > } > > audioTrack.setStereoVolume(0, 0); > > audioTrack.stop(); > > audioTrack.release(); > > } catch (Exception e) { > e.printStackTrace(); > } > } > > }).start(); > } > > private void testTones() > { > new Thread(new Runnable() > { > @Override > public void run () > { > long sleep = 500; > > for ( int frequency = 3000; frequency >= 300; frequency -= 300 ) > { > playToneStreaming(frequency, sleep); > > try { > Thread.sleep(sleep); > } catch (Exception ignore) { > } > > if ( frequency < 1000 ) > { > sleep = 250; > } > } > > sleep = 500; > > for ( int frequency = 3000; frequency >= 300; frequency -= 300 ) > { > playToneStatic(frequency, sleep); > > try { > Thread.sleep(sleep); > } catch (Exception ignore) { > } > > if ( frequency < 1000 ) > { > sleep = 250; > } > } > } > > }).start(); > } > > > On Tuesday, December 22, 2015 at 5:25:07 AM UTC+11, David Karr wrote: >> >> On Sunday, December 20, 2015 at 11:27:14 PM UTC-8, gjs wrote: >>> >>> Hi, >>> >>> Here's some examples of using AudioTrack >>> http://www.programcreek.com/java-api-examples/index.php?api=android.media.AudioTrack >>> >>> Just be sure to run in a separate thread. >>> >>> Regards >>> >> >> Note that I did already say that I'd found multiple ways to do this, and >> I was looking for advice on the actual best (or at least better) way to do >> this, and you pointed me to a selection of choices, with no information on >> tradeoffs. >> >> In any case, I tried the first one (creating an AudioTrack and then >> playing it), and wrapping it with a Runnable and a started Thread, and I >> heard no sound from my device when the code executed. >> >> If it matters, here's the method I ended up with: >> >> private void playTone() { >> new Thread(new Runnable() { >> @Override >> public void run() { >> int minSize = AudioTrack.getMinBufferSize(8000, >> AudioFormat.CHANNEL_CONFIGURATION_MONO, AudioFormat.ENCODING_PCM_16BIT); >> AudioTrack audioTrack = new >> AudioTrack(AudioManager.STREAM_MUSIC, 8000, >> AudioFormat.CHANNEL_CONFIGURATION_MONO, >> AudioFormat.ENCODING_PCM_16BIT, minSize, >> AudioTrack.MODE_STREAM); >> audioTrack.play(); >> } >> }).start(); >> } >> >> >> >> -- You received this message because you are subscribed to the Google Groups "Android Developers" group. 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