Make some audio processors public

ChannelMappingAudioProcessor, TrimmingAudioProcessor and
ToFloatPcmAudioProcessor are currently package-private even
though they might be useful in custom audio processing chains
or custom version of audio sinks.

Issue: androidx/media#2339
PiperOrigin-RevId: 747857815

RELEASENOTES.md

@@ -23,6 +23,9 @@
 *   DataSource:
 *   Audio:
     *   Allow constant power upmixing/downmixing in DefaultAudioMixer.
+    *   Make `ChannelMappingAudioProcessor`, `TrimmingAudioProcessor` and
+        `ToFloatPcmAudioProcessor` public
+        ([#2339](https://github.com/androidx/media/issues/2339)).
 *   Video:
     *   Add experimental `ExoPlayer` API to include the
         `MediaCodec.BUFFER_FLAG_DECODE_ONLY` flag when queuing decode-only input

libraries/exoplayer/src/main/java/androidx/media3/exoplayer/audio/ChannelMappingAudioProcessor.java

@@ -23,6 +23,7 @@ import androidx.media3.common.Format;
 import androidx.media3.common.audio.AudioProcessor;
 import androidx.media3.common.audio.BaseAudioProcessor;
 import androidx.media3.common.util.Assertions;
+import androidx.media3.common.util.UnstableApi;
 import java.nio.ByteBuffer;
 import java.util.Arrays;
 
@@ -30,7 +31,8 @@ import java.util.Arrays;
  * An {@link AudioProcessor} that applies a mapping from input channels onto specified output
  * channels. This can be used to reorder, duplicate or discard channels.
  */
-/* package */ final class ChannelMappingAudioProcessor extends BaseAudioProcessor {
+@UnstableApi
+public final class ChannelMappingAudioProcessor extends BaseAudioProcessor {
 
   @Nullable private int[] pendingOutputChannels;
   @Nullable private int[] outputChannels;

libraries/exoplayer/src/main/java/androidx/media3/exoplayer/audio/ToFloatPcmAudioProcessor.java

@@ -19,6 +19,7 @@ import androidx.media3.common.C;
 import androidx.media3.common.Format;
 import androidx.media3.common.audio.AudioProcessor;
 import androidx.media3.common.audio.BaseAudioProcessor;
+import androidx.media3.common.util.UnstableApi;
 import androidx.media3.common.util.Util;
 import java.nio.ByteBuffer;
 
@@ -34,7 +35,8 @@ import java.nio.ByteBuffer;
  *   <li>{@link C#ENCODING_PCM_FLOAT} ({@link #isActive()} will return {@code false})
  * </ul>
  */
-/* package */ final class ToFloatPcmAudioProcessor extends BaseAudioProcessor {
+@UnstableApi
+public final class ToFloatPcmAudioProcessor extends BaseAudioProcessor {
 
   private static final int FLOAT_NAN_AS_INT = Float.floatToIntBits(Float.NaN);
   private static final double PCM_32_BIT_INT_TO_PCM_32_BIT_FLOAT_FACTOR = 1.0 / 0x7FFFFFFF;

libraries/exoplayer/src/main/java/androidx/media3/exoplayer/audio/TrimmingAudioProcessor.java

@@ -20,11 +20,13 @@ import static java.lang.Math.min;
 import androidx.media3.common.C;
 import androidx.media3.common.Format;
 import androidx.media3.common.audio.BaseAudioProcessor;
+import androidx.media3.common.util.UnstableApi;
 import androidx.media3.common.util.Util;
 import java.nio.ByteBuffer;
 
 /** Audio processor for trimming samples from the start/end of data. */
-/* package */ final class TrimmingAudioProcessor extends BaseAudioProcessor {
+@UnstableApi
+public final class TrimmingAudioProcessor extends BaseAudioProcessor {
 
   private int trimStartFrames;
   private int trimEndFrames;