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Support 32-bit FP to 16-bit Int audio resampling

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This is a no-op for DefaultAudioSink for now, because DefaultAudioSink
currently disables processing anyway if the input uses ENCODING_PCM_FLOAT.

Issue: #7134
PiperOrigin-RevId: 302670534
This commit is contained in:
olly 2020-03-24 15:32:52 +00:00 committed by Oliver Woodman
parent 05fb211121
commit 9ed471651e
1 changed files with 23 additions and 5 deletions
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28
library/core/src/main/java/com/google/android/exoplayer2/audio/ResamplingAudioProcessor.java
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@ -20,8 +20,17 @@ import com.google.android.exoplayer2.Format;
import java.nio.ByteBuffer;
/**
* An {@link AudioProcessor} that converts 8-bit, 24-bit and 32-bit integer PCM audio to 16-bit
* integer PCM audio.
* An {@link AudioProcessor} that converts different PCM audio encodings to 16-bit integer PCM. The
* following encodings are supported as input:
*
* <ul>
* <li>{@link C#ENCODING_PCM_8BIT}
* <li>{@link C#ENCODING_PCM_16BIT} ({@link #isActive()} will return {@code false})
* <li>{@link C#ENCODING_PCM_16BIT_BIG_ENDIAN}
* <li>{@link C#ENCODING_PCM_24BIT}
* <li>{@link C#ENCODING_PCM_32BIT}
* <li>{@link C#ENCODING_PCM_FLOAT}
* </ul>
*/
/* package */ final class ResamplingAudioProcessor extends BaseAudioProcessor {
@ -33,7 +42,8 @@ import java.nio.ByteBuffer;
&& encoding != C.ENCODING_PCM_16BIT
&& encoding != C.ENCODING_PCM_16BIT_BIG_ENDIAN
&& encoding != C.ENCODING_PCM_24BIT
&& encoding != C.ENCODING_PCM_32BIT) {
&& encoding != C.ENCODING_PCM_32BIT
&& encoding != C.ENCODING_PCM_FLOAT) {
throw new UnhandledAudioFormatException(inputAudioFormat);
}
return encoding != C.ENCODING_PCM_16BIT
@ -60,10 +70,10 @@ import java.nio.ByteBuffer;
resampledSize = (size / 3) * 2;
break;
case C.ENCODING_PCM_32BIT:
case C.ENCODING_PCM_FLOAT:
resampledSize = size / 2;
break;
case C.ENCODING_PCM_16BIT:
case C.ENCODING_PCM_FLOAT:
case C.ENCODING_INVALID:
case Format.NO_VALUE:
default:
@ -101,8 +111,16 @@ import java.nio.ByteBuffer;
buffer.put(inputBuffer.get(i + 3));
}
break;
case C.ENCODING_PCM_16BIT:
case C.ENCODING_PCM_FLOAT:
// 32 bit floating point -> 16 bit resampling. Floating point values are in the range
// [-1.0, 1.0], so need to be scaled by Short.MAX_VALUE.
for (int i = position; i < limit; i += 4) {
short value = (short) (inputBuffer.getFloat(i) * Short.MAX_VALUE);
buffer.put((byte) (value & 0xFF));
buffer.put((byte) ((value >> 8) & 0xFF));
}
break;
case C.ENCODING_PCM_16BIT:
case C.ENCODING_INVALID:
case Format.NO_VALUE:
default: