Add function to clear the cached list of encoders

EncoderUtil using a static list to cache encoders means it's not possible to
use a different set of encoders for different tests when running all
robolectric tests together.

PiperOrigin-RevId: 491959350

libraries/transformer/src/main/java/androidx/media3/transformer/EncoderUtil.java

@@ -16,7 +16,6 @@
 
 package androidx.media3.transformer;
 
-import static androidx.media3.common.util.Assertions.checkNotNull;
 import static java.lang.Math.max;
 import static java.lang.Math.round;
 
@@ -29,8 +28,10 @@ import android.util.Pair;
 import android.util.Range;
 import android.util.Size;
 import androidx.annotation.DoNotInline;
+import androidx.annotation.GuardedBy;
 import androidx.annotation.Nullable;
 import androidx.annotation.RequiresApi;
+import androidx.annotation.VisibleForTesting;
 import androidx.media3.common.C;
 import androidx.media3.common.C.ColorTransfer;
 import androidx.media3.common.ColorInfo;
@@ -40,10 +41,8 @@ import androidx.media3.common.util.MediaFormatUtil;
 import androidx.media3.common.util.UnstableApi;
 import androidx.media3.common.util.Util;
 import com.google.common.base.Ascii;
-import com.google.common.base.Supplier;
+import com.google.common.collect.ArrayListMultimap;
-import com.google.common.base.Suppliers;
 import com.google.common.collect.ImmutableList;
-import com.google.common.collect.ImmutableListMultimap;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.primitives.Ints;
 
@@ -54,20 +53,29 @@ public final class EncoderUtil {
   /** A value to indicate the encoding level is not set. */
   public static final int LEVEL_UNSET = Format.NO_VALUE;
 
-  private static final Supplier<ImmutableListMultimap<String, MediaCodecInfo>>
+  @GuardedBy("EncoderUtil.class")
-      MIME_TYPE_TO_ENCODERS = Suppliers.memoize(EncoderUtil::populateEncoderInfos);
+  private static final ArrayListMultimap<String, MediaCodecInfo> mimeTypeToEncoders =
+      ArrayListMultimap.create();
 
   /**
    * Returns a list of {@linkplain MediaCodecInfo encoders} that support the given {@code mimeType},
    * or an empty list if there is none.
    */
-  public static ImmutableList<MediaCodecInfo> getSupportedEncoders(String mimeType) {
+  public static synchronized ImmutableList<MediaCodecInfo> getSupportedEncoders(String mimeType) {
-    return checkNotNull(MIME_TYPE_TO_ENCODERS.get()).get(Ascii.toLowerCase(mimeType));
+    maybePopulateEncoderInfo();
+    return ImmutableList.copyOf(mimeTypeToEncoders.get(Ascii.toLowerCase(mimeType)));
   }
 
   /** Returns a list of video {@linkplain MimeTypes MIME types} that can be encoded. */
-  public static ImmutableSet<String> getSupportedVideoMimeTypes() {
+  public static synchronized ImmutableSet<String> getSupportedVideoMimeTypes() {
-    return checkNotNull(MIME_TYPE_TO_ENCODERS.get()).keySet();
+    maybePopulateEncoderInfo();
+    return ImmutableSet.copyOf(mimeTypeToEncoders.keySet());
+  }
+
+  /** Clears the cached list of encoders. */
+  @VisibleForTesting
+  public static synchronized void clearCachedEncoders() {
+    mimeTypeToEncoders.clear();
   }
 
   /**
@@ -433,9 +441,10 @@ public final class EncoderUtil {
         : alignment * Math.round((float) size / alignment);
   }
 
-  private static ImmutableListMultimap<String, MediaCodecInfo> populateEncoderInfos() {
+  private static synchronized void maybePopulateEncoderInfo() {
-    ImmutableListMultimap.Builder<String, MediaCodecInfo> encoderInfosBuilder =
+    if (!mimeTypeToEncoders.isEmpty()) {
-        new ImmutableListMultimap.Builder<>();
+      return;
+    }
 
     MediaCodecList mediaCodecList = new MediaCodecList(MediaCodecList.REGULAR_CODECS);
     MediaCodecInfo[] allCodecInfos = mediaCodecList.getCodecInfos();
@@ -446,10 +455,9 @@ public final class EncoderUtil {
       }
       String[] supportedMimeTypes = mediaCodecInfo.getSupportedTypes();
       for (String mimeType : supportedMimeTypes) {
-        encoderInfosBuilder.put(Ascii.toLowerCase(mimeType), mediaCodecInfo);
+        mimeTypeToEncoders.put(Ascii.toLowerCase(mimeType), mediaCodecInfo);
       }
     }
-    return encoderInfosBuilder.build();
   }
 
   @RequiresApi(29)

libraries/transformer/src/test/java/androidx/media3/transformer/DefaultEncoderFactoryTest.java

@@ -28,11 +28,13 @@ import androidx.media3.common.Format;
 import androidx.media3.common.MimeTypes;
 import androidx.test.ext.junit.runners.AndroidJUnit4;
 import com.google.common.collect.ImmutableList;
+import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.robolectric.annotation.Config;
 import org.robolectric.shadows.MediaCodecInfoBuilder;
+import org.robolectric.shadows.ShadowMediaCodec;
 import org.robolectric.shadows.ShadowMediaCodecList;
 
 /** Unit test for {@link DefaultEncoderFactory}. */
@@ -45,6 +47,13 @@ public class DefaultEncoderFactoryTest {
     createShadowH264Encoder();
   }
 
+  @After
+  public void tearDown() {
+    ShadowMediaCodec.clearCodecs();
+    ShadowMediaCodecList.reset();
+    EncoderUtil.clearCachedEncoders();
+  }
+
   private static void createShadowH264Encoder() {
     MediaFormat avcFormat = new MediaFormat();
     avcFormat.setString(MediaFormat.KEY_MIME, MediaFormat.MIMETYPE_VIDEO_AVC);

libraries/transformer/src/test/java/androidx/media3/transformer/EncoderUtilTest.java

@@ -27,11 +27,13 @@ import androidx.media3.common.ColorInfo;
 import androidx.media3.common.MimeTypes;
 import androidx.test.ext.junit.runners.AndroidJUnit4;
 import com.google.common.collect.ImmutableList;
+import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.robolectric.annotation.Config;
 import org.robolectric.shadows.MediaCodecInfoBuilder;
+import org.robolectric.shadows.ShadowMediaCodec;
 import org.robolectric.shadows.ShadowMediaCodecList;
 
 /** Unit test for {@link EncoderUtil}. */
@@ -64,6 +66,13 @@ public class EncoderUtilTest {
             .build());
   }
 
+  @After
+  public void tearDown() {
+    ShadowMediaCodecList.reset();
+    ShadowMediaCodec.clearCodecs();
+    EncoderUtil.clearCachedEncoders();
+  }
+
   @Test
   public void getSupportedResolution_withSupportedResolution_succeeds() {
     ImmutableList<MediaCodecInfo> supportedEncoders = EncoderUtil.getSupportedEncoders(MIME_TYPE);

libraries/transformer/src/test/java/androidx/media3/transformer/TransformerEndToEndTest.java

@@ -898,6 +898,8 @@ public final class TransformerEndToEndTest {
 
   private static void removeEncodersAndDecoders() {
     ShadowMediaCodec.clearCodecs();
+    ShadowMediaCodecList.reset();
+    EncoderUtil.clearCachedEncoders();
   }
 
   private static String getDumpFileName(String originalFileName) {

libraries/transformer/src/test/java/androidx/media3/transformer/VideoEncoderWrapperTest.java

@@ -32,10 +32,12 @@ import androidx.media3.common.util.Clock;
 import androidx.media3.common.util.ListenerSet;
 import androidx.test.ext.junit.runners.AndroidJUnit4;
 import com.google.common.collect.ImmutableList;
+import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.robolectric.shadows.MediaCodecInfoBuilder;
+import org.robolectric.shadows.ShadowMediaCodec;
 import org.robolectric.shadows.ShadowMediaCodecList;
 
 /** Unit tests for {@link VideoTranscodingSamplePipeline.EncoderWrapper}. */
@@ -63,6 +65,13 @@ public final class VideoEncoderWrapperTest {
     createShadowH264Encoder();
   }
 
+  @After
+  public void tearDown() {
+    ShadowMediaCodec.clearCodecs();
+    ShadowMediaCodecList.reset();
+    EncoderUtil.clearCachedEncoders();
+  }
+
   @Test
   public void getSurfaceInfo_landscape_leavesOrientationUnchanged() throws Exception {
     int inputWidth = 200;