Re-add "waiting for keyframe" logic in MediaCodecRenderer

This is a partial revert of https://github.com/google/ExoPlayer/commit/0a2bacb7b7ca9a3e88962dbeaaa86f10f0e83b2a. I've added a comment
explaining why the code path is necessary after all, to avoid
future confusion.

PiperOrigin-RevId: 319822696

library/core/src/main/java/com/google/android/exoplayer2/mediacodec/MediaCodecRenderer.java

@@ -1318,6 +1318,21 @@ public abstract class MediaCodecRenderer extends BaseRenderer {
       return false;
     }
 
+    // This logic is required for cases where the decoder needs to be flushed or re-instantiated
+    // during normal consumption of samples from the source (i.e., without a corresponding
+    // Renderer.enable or Renderer.resetPosition call). This is necessary for certain legacy and
+    // workaround behaviors, for example when switching the output Surface on API levels prior to
+    // the introduction of MediaCodec.setOutputSurface.
+    if (!codecReceivedBuffers && !buffer.isKeyFrame()) {
+      buffer.clear();
+      if (codecReconfigurationState == RECONFIGURATION_STATE_QUEUE_PENDING) {
+        // The buffer we just cleared contained reconfiguration data. We need to re-write this data
+        // into a subsequent buffer (if there is one).
+        codecReconfigurationState = RECONFIGURATION_STATE_WRITE_PENDING;
+      }
+      return true;
+    }
+
     boolean bufferEncrypted = buffer.isEncrypted();
     if (bufferEncrypted) {
       buffer.cryptoInfo.increaseClearDataFirstSubSampleBy(adaptiveReconfigurationBytes);

library/core/src/test/java/com/google/android/exoplayer2/audio/MediaCodecAudioRendererTest.java

@@ -115,13 +115,13 @@ public class MediaCodecAudioRendererTest {
             /* eventDispatcher= */ null,
             /* initialFormat= */ AUDIO_AAC,
             ImmutableList.of(
-                oneByteSample(/* timeUs= */ 0),
-                oneByteSample(/* timeUs= */ 50),
-                oneByteSample(/* timeUs= */ 100),
+                oneByteSample(/* timeUs= */ 0, C.BUFFER_FLAG_KEY_FRAME),
+                oneByteSample(/* timeUs= */ 50, C.BUFFER_FLAG_KEY_FRAME),
+                oneByteSample(/* timeUs= */ 100, C.BUFFER_FLAG_KEY_FRAME),
                 format(changedFormat),
-                oneByteSample(/* timeUs= */ 150),
-                oneByteSample(/* timeUs= */ 200),
-                oneByteSample(/* timeUs= */ 250),
+                oneByteSample(/* timeUs= */ 150, C.BUFFER_FLAG_KEY_FRAME),
+                oneByteSample(/* timeUs= */ 200, C.BUFFER_FLAG_KEY_FRAME),
+                oneByteSample(/* timeUs= */ 250, C.BUFFER_FLAG_KEY_FRAME),
                 END_OF_STREAM_ITEM));
 
     mediaCodecAudioRenderer.enable(
@@ -162,13 +162,13 @@ public class MediaCodecAudioRendererTest {
             /* eventDispatcher= */ null,
             /* initialFormat= */ AUDIO_AAC,
             ImmutableList.of(
-                oneByteSample(/* timeUs= */ 0),
-                oneByteSample(/* timeUs= */ 50),
-                oneByteSample(/* timeUs= */ 100),
+                oneByteSample(/* timeUs= */ 0, C.BUFFER_FLAG_KEY_FRAME),
+                oneByteSample(/* timeUs= */ 50, C.BUFFER_FLAG_KEY_FRAME),
+                oneByteSample(/* timeUs= */ 100, C.BUFFER_FLAG_KEY_FRAME),
                 format(changedFormat),
-                oneByteSample(/* timeUs= */ 150),
-                oneByteSample(/* timeUs= */ 200),
-                oneByteSample(/* timeUs= */ 250),
+                oneByteSample(/* timeUs= */ 150, C.BUFFER_FLAG_KEY_FRAME),
+                oneByteSample(/* timeUs= */ 200, C.BUFFER_FLAG_KEY_FRAME),
+                oneByteSample(/* timeUs= */ 250, C.BUFFER_FLAG_KEY_FRAME),
                 END_OF_STREAM_ITEM));
 
     mediaCodecAudioRenderer.enable(
@@ -228,7 +228,8 @@ public class MediaCodecAudioRendererTest {
             DrmSessionManager.DUMMY,
             /* eventDispatcher= */ null,
             /* initialFormat= */ AUDIO_AAC,
-            ImmutableList.of(oneByteSample(/* timeUs= */ 0), END_OF_STREAM_ITEM));
+            ImmutableList.of(
+                oneByteSample(/* timeUs= */ 0, C.BUFFER_FLAG_KEY_FRAME), END_OF_STREAM_ITEM));
 
     exceptionThrowingRenderer.enable(
         RendererConfiguration.DEFAULT,

library/core/src/test/java/com/google/android/exoplayer2/video/MediaCodecVideoRendererTest.java

@@ -133,7 +133,7 @@ public class MediaCodecVideoRendererTest {
             /* eventDispatcher= */ null,
             /* initialFormat= */ VIDEO_H264,
             ImmutableList.of(
-                oneByteSample(/* timeUs= */ 0), // First buffer.
+                oneByteSample(/* timeUs= */ 0, C.BUFFER_FLAG_KEY_FRAME), // First buffer.
                 oneByteSample(/* timeUs= */ 50_000), // Late buffer.
                 oneByteSample(/* timeUs= */ 100_000), // Last buffer.
                 FakeSampleStreamItem.END_OF_STREAM_ITEM));
@@ -169,7 +169,8 @@ public class MediaCodecVideoRendererTest {
             /* eventDispatcher= */ null,
             /* initialFormat= */ VIDEO_H264,
             ImmutableList.of(
-                oneByteSample(/* timeUs= */ 0), FakeSampleStreamItem.END_OF_STREAM_ITEM)),
+                oneByteSample(/* timeUs= */ 0, C.BUFFER_FLAG_KEY_FRAME),
+                FakeSampleStreamItem.END_OF_STREAM_ITEM)),
         /* positionUs= */ 0,
         /* joining= */ false,
         /* mayRenderStartOfStream= */ true,
@@ -204,7 +205,7 @@ public class MediaCodecVideoRendererTest {
             DrmSessionManager.DUMMY,
             /* eventDispatcher= */ null,
             /* initialFormat= */ pAsp1,
-            ImmutableList.of(oneByteSample(/* timeUs= */ 0)));
+            ImmutableList.of(oneByteSample(/* timeUs= */ 0, C.BUFFER_FLAG_KEY_FRAME)));
 
     mediaCodecVideoRenderer.enable(
         RendererConfiguration.DEFAULT,
@@ -248,7 +249,7 @@ public class MediaCodecVideoRendererTest {
             DrmSessionManager.DUMMY,
             /* eventDispatcher= */ null,
             /* initialFormat= */ VIDEO_H264,
-            ImmutableList.of(oneByteSample(/* timeUs= */ 0)));
+            ImmutableList.of(oneByteSample(/* timeUs= */ 0, C.BUFFER_FLAG_KEY_FRAME)));
     mediaCodecVideoRenderer.enable(
         RendererConfiguration.DEFAULT,
         new Format[] {VIDEO_H264},
@@ -262,7 +263,8 @@ public class MediaCodecVideoRendererTest {
     mediaCodecVideoRenderer.render(/* positionUs= */ 0, SystemClock.elapsedRealtime() * 1000);
     mediaCodecVideoRenderer.resetPosition(0);
     mediaCodecVideoRenderer.setCurrentStreamFinal();
-    fakeSampleStream.addFakeSampleStreamItem(oneByteSample(/* timeUs= */ 0));
+    fakeSampleStream.addFakeSampleStreamItem(
+        oneByteSample(/* timeUs= */ 0, C.BUFFER_FLAG_KEY_FRAME));
     fakeSampleStream.addFakeSampleStreamItem(FakeSampleStreamItem.END_OF_STREAM_ITEM);
     int positionUs = 10;
     do {
@@ -280,7 +282,7 @@ public class MediaCodecVideoRendererTest {
             DrmSessionManager.DUMMY,
             /* eventDispatcher= */ null,
             /* initialFormat= */ VIDEO_H264,
-            ImmutableList.of(oneByteSample(/* timeUs= */ 0)));
+            ImmutableList.of(oneByteSample(/* timeUs= */ 0, C.BUFFER_FLAG_KEY_FRAME)));
 
     mediaCodecVideoRenderer.enable(
         RendererConfiguration.DEFAULT,
@@ -329,7 +331,7 @@ public class MediaCodecVideoRendererTest {
             DrmSessionManager.DUMMY,
             /* eventDispatcher= */ null,
             /* initialFormat= */ VIDEO_H264,
-            ImmutableList.of(oneByteSample(/* timeUs= */ 0)));
+            ImmutableList.of(oneByteSample(/* timeUs= */ 0, C.BUFFER_FLAG_KEY_FRAME)));
 
     mediaCodecVideoRenderer.enable(
         RendererConfiguration.DEFAULT,
@@ -445,16 +447,16 @@ public class MediaCodecVideoRendererTest {
             /* eventDispatcher= */ null,
             /* initialFormat= */ mp4Uhd,
             ImmutableList.of(
-                oneByteSample(/* timeUs= */ 0),
+                oneByteSample(/* timeUs= */ 0, C.BUFFER_FLAG_KEY_FRAME),
                 format(VIDEO_H264),
-                oneByteSample(/* timeUs= */ 50),
+                oneByteSample(/* timeUs= */ 50, C.BUFFER_FLAG_KEY_FRAME),
                 oneByteSample(/* timeUs= */ 100),
                 format(mp4Uhd),
-                oneByteSample(/* timeUs= */ 150),
+                oneByteSample(/* timeUs= */ 150, C.BUFFER_FLAG_KEY_FRAME),
                 oneByteSample(/* timeUs= */ 200),
                 oneByteSample(/* timeUs= */ 250),
                 format(VIDEO_H264),
-                oneByteSample(/* timeUs= */ 300),
+                oneByteSample(/* timeUs= */ 300, C.BUFFER_FLAG_KEY_FRAME),
                 FakeSampleStreamItem.END_OF_STREAM_ITEM));
 
     mediaCodecVideoRenderer.enable(