From a8a590c3052d342e824e0da881d6a32598e5e672 Mon Sep 17 00:00:00 2001
From: huangdarwin <huangdarwin@google.com>
Date: Tue, 24 Oct 2023 06:10:36 -0700
Subject: [PATCH] Effect: Clarify flush behavior in javadoc

PiperOrigin-RevId: 576118064
---
 .../androidx/media3/effect/DefaultVideoFrameProcessor.java     | 3 +++
 .../src/main/java/androidx/media3/effect/GlShaderProgram.java  | 2 ++
 2 files changed, 5 insertions(+)

diff --git a/libraries/effect/src/main/java/androidx/media3/effect/DefaultVideoFrameProcessor.java b/libraries/effect/src/main/java/androidx/media3/effect/DefaultVideoFrameProcessor.java
index 8a00c8ca7a..67ab19bac2 100644
--- a/libraries/effect/src/main/java/androidx/media3/effect/DefaultVideoFrameProcessor.java
+++ b/libraries/effect/src/main/java/androidx/media3/effect/DefaultVideoFrameProcessor.java
@@ -554,10 +554,13 @@ public final class DefaultVideoFrameProcessor implements VideoFrameProcessor {
     }
     try {
       videoFrameProcessingTaskExecutor.flush();
+
+      // Flush from the end of the GlShaderProgram pipeline up to the start.
       CountDownLatch latch = new CountDownLatch(1);
       inputSwitcher.activeTextureManager().setOnFlushCompleteListener(latch::countDown);
       videoFrameProcessingTaskExecutor.submit(finalShaderProgramWrapper::flush);
       latch.await();
+
       inputSwitcher.activeTextureManager().setOnFlushCompleteListener(null);
     } catch (InterruptedException e) {
       Thread.currentThread().interrupt();
diff --git a/libraries/effect/src/main/java/androidx/media3/effect/GlShaderProgram.java b/libraries/effect/src/main/java/androidx/media3/effect/GlShaderProgram.java
index 7cce832618..f7148344d5 100644
--- a/libraries/effect/src/main/java/androidx/media3/effect/GlShaderProgram.java
+++ b/libraries/effect/src/main/java/androidx/media3/effect/GlShaderProgram.java
@@ -78,6 +78,8 @@ public interface GlShaderProgram {
      *
      * <p>The implementation shall not assume the {@link GlShaderProgram} is {@linkplain
      * #onReadyToAcceptInputFrame ready to accept another input frame} when this method is called.
+     * If the implementation manages a limited input capacity, it must clear all prior {@linkplain
+     * #onReadyToAcceptInputFrame input frame capacity}.
      */
     default void onFlush() {}
   }