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Add basic volume scaling to the Transformer demo app.

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PiperOrigin-RevId: 553086635
This commit is contained in:
samrobinson 2023-08-02 10:01:15 +00:00 committed by Tianyi Feng
parent 4302102cf0
commit fec6252065
2 changed files with 26 additions and 6 deletions
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7
demos/transformer/src/main/java/androidx/media3/demo/transformer/ConfigurationActivity.java
View File

@ -119,6 +119,7 @@ public final class ConfigurationActivity extends AppCompatActivity {
public static final int SAMPLE_RATE_INDEX = 1;
public static final int SKIP_SILENCE_INDEX = 2;
public static final int CHANNEL_MIXING_INDEX = 3;
public static final int VOLUME_SCALING_INDEX = 4;
// Color filter options.
public static final int COLOR_FILTER_GRAYSCALE = 0;
@ -165,7 +166,11 @@ public final class ConfigurationActivity extends AppCompatActivity {
"720p H264 video with no audio",
};
private static final String[] AUDIO_EFFECTS = {
"High pitched", "Sample rate of 48000Hz", "Skip silence", "Mix channels into mono"
"High pitched",
"Sample rate of 48000Hz",
"Skip silence",
"Mix channels into mono",
"Scale volume to 50%"
};
private static final String[] VIDEO_EFFECTS = {
"Dizzy crop",

25
demos/transformer/src/main/java/androidx/media3/demo/transformer/TransformerActivity.java
View File

@ -414,14 +414,29 @@ public final class TransformerActivity extends AppCompatActivity {
processors.add(silenceSkippingAudioProcessor);
}
if (selectedAudioEffects[ConfigurationActivity.CHANNEL_MIXING_INDEX]) {
boolean mixToMono = selectedAudioEffects[ConfigurationActivity.CHANNEL_MIXING_INDEX];
boolean scaleVolumeToHalf = selectedAudioEffects[ConfigurationActivity.VOLUME_SCALING_INDEX];
if (mixToMono || scaleVolumeToHalf) {
ChannelMixingAudioProcessor mixingAudioProcessor = new ChannelMixingAudioProcessor();
for (int inputChannelCount = 1; inputChannelCount <= 6; inputChannelCount++) {
float[] mixingCoefficients = new float[inputChannelCount];
Arrays.fill(mixingCoefficients, 1f / inputChannelCount);
ChannelMixingMatrix matrix;
if (mixToMono) {
float[] mixingCoefficients = new float[inputChannelCount];
// Each channel is equally weighted in the mix to mono.
Arrays.fill(mixingCoefficients, 1f / inputChannelCount);
matrix =
new ChannelMixingMatrix(
inputChannelCount, /* outputChannelCount= */ 1, mixingCoefficients);
} else {
// Identity matrix.
matrix =
ChannelMixingMatrix.create(
inputChannelCount, /* outputChannelCount= */ inputChannelCount);
}
// Apply the volume adjustment.
mixingAudioProcessor.putChannelMixingMatrix(
new ChannelMixingMatrix(
inputChannelCount, /* outputChannelCount= */ 1, mixingCoefficients));
scaleVolumeToHalf ? matrix.scaleBy(0.5f) : matrix);
}
processors.add(mixingAudioProcessor);
}