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Use the pcm volume to add finer steps between every android stream volume step.

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git-svn-id: svn://svn.rockbox.org/rockbox/trunk@29573 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Björn Stenberg 2011-03-11 20:40:19 +00:00
parent 0b18522cd0
commit 00f75c92bf
1 changed files with 37 additions and 14 deletions
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51
android/src/org/rockbox/RockboxPCM.java
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@ -23,6 +23,7 @@ package org.rockbox;
import java.util.Arrays;
import android.content.Context;
import android.content.Intent;
import android.media.AudioFormat;
import android.media.AudioManager;
@ -38,6 +39,7 @@ public class RockboxPCM extends AudioTrack
private PCMListener l;
private HandlerThread ht;
private Handler h = null;
private static final int streamtype = AudioManager.STREAM_MUSIC;
private static final int samplerate = 44100;
/* should be CHANNEL_OUT_STEREO in 2.0 and above */
private static final int channels =
@ -48,6 +50,11 @@ public class RockboxPCM extends AudioTrack
private static final int buf_len =
Math.max(24<<10, getMinBufferSize(samplerate, channels, encoding));
private AudioManager audiomanager;
private int maxstreamvolume;
private float minpcmvolume;
private float pcmrange;
private void LOG(CharSequence text)
{
Log.d("Rockbox", (String) text);
@ -55,7 +62,7 @@ public class RockboxPCM extends AudioTrack
public RockboxPCM()
{
super(AudioManager.STREAM_MUSIC, samplerate, channels, encoding,
super(streamtype, samplerate, channels, encoding,
buf_len, AudioTrack.MODE_STREAM);
ht = new HandlerThread("audio thread",
Process.THREAD_PRIORITY_URGENT_AUDIO);
@ -63,6 +70,15 @@ public class RockboxPCM extends AudioTrack
raw_data = new byte[buf_len]; /* in shorts */
Arrays.fill(raw_data, (byte) 0);
l = new PCMListener(buf_len);
/* find cleaner way to get context? */
final RockboxService rb = RockboxService.get_instance();
audiomanager =
(AudioManager) rb.getSystemService(Context.AUDIO_SERVICE);
maxstreamvolume = audiomanager.getStreamMaxVolume(streamtype);
minpcmvolume = getMinVolume();
pcmrange = getMaxVolume() - minpcmvolume;
}
private int bytes2frames(int bytes)
@ -130,19 +146,26 @@ public class RockboxPCM extends AudioTrack
private void set_volume(int volume)
{
/* volume comes from 0..-990 from Rockbox */
/* TODO:
* volume is in dB, but this code acts as if it were in %, convert? */
float fvolume;
/* special case min and max volume to not suffer from
* floating point accuracy */
if (volume == 0)
fvolume = 1.0f;
else if (volume == -990)
fvolume = 0.0f;
else
fvolume = (volume + 990)/990.0f;
setStereoVolume(fvolume, fvolume);
/* Rockbox 'volume' is 0..-990 deci-dB attenuation.
Android streams have rather low resolution volume control,
typically 8 or 15 steps.
Therefore we use the pcm volume to add finer steps between
every android stream volume step.
It's not "real" dB, but it gives us 100 volume steps.
*/
float fraction = 1 - (volume / -990.0f);
int streamvolume = (int)Math.ceil(maxstreamvolume * fraction);
if (streamvolume > 0) {
float streamfraction = (float)streamvolume / maxstreamvolume;
float pcmvolume =
(fraction / streamfraction) * pcmrange + minpcmvolume;
setStereoVolume(pcmvolume, pcmvolume);
}
int oldstreamvolume = audiomanager.getStreamVolume(streamtype);
if (streamvolume != oldstreamvolume)
audiomanager.setStreamVolume(streamtype, streamvolume, 0);
}
public native void pcmSamplesToByteArray(byte[] dest);