From 036a28b292c391ff3c262fabda153e08e3c9edcc Mon Sep 17 00:00:00 2001
From: christosts <christosts@google.com>
Date: Thu, 23 Dec 2021 14:51:17 +0000
Subject: [PATCH] MediaController: stop advancing content position when player
 is paused

MediaController.getContentPosition() estimates the content position
based on the last position info sent by the player and the elapsed
real-time since the position info was received. After calling
MediaController's play/pause/setPlayWhenReady, the position estimation
logic is still applying, therefore advancing the position until the
underlying player's actual position is received. This can make the
MediaController's content position to be out of sync with player's
actual content position.

With this change, MediaController stops making content position
estimations after any of play/pause/setPlayWhenReady is called and
until a new position info is received from the underlying player.

Tested manually with the the session demo app, pausing/resuming content
from the UI.

PiperOrigin-RevId: 418000800
---
 .../session/MediaControllerImplBase.java      | 31 ++++++++++++++++---
 1 file changed, 27 insertions(+), 4 deletions(-)

diff --git a/libraries/session/src/main/java/androidx/media3/session/MediaControllerImplBase.java b/libraries/session/src/main/java/androidx/media3/session/MediaControllerImplBase.java
index 51a8008f5d..47d07b71e2 100644
--- a/libraries/session/src/main/java/androidx/media3/session/MediaControllerImplBase.java
+++ b/libraries/session/src/main/java/androidx/media3/session/MediaControllerImplBase.java
@@ -186,6 +186,8 @@ import org.checkerframework.checker.nullness.qual.NonNull;
   private int surfaceWidth;
   private int surfaceHeight;
   @Nullable private IMediaSession iSession;
+  private long lastReturnedContentPositionMs;
+  private long lastSetPlayWhenReadyCalledTimeMs;
 
   public MediaControllerImplBase(
       Context context, MediaController instance, SessionToken token, Bundle connectionHints) {
@@ -228,6 +230,8 @@ import org.checkerframework.checker.nullness.qual.NonNull;
       this.instance.runOnApplicationLooper(MediaControllerImplBase.this.instance::release);
     }
     flushCommandQueueHandler = new FlushCommandQueueHandler(instance.getApplicationLooper());
+    lastReturnedContentPositionMs = C.TIME_UNSET;
+    lastSetPlayWhenReadyCalledTimeMs = C.TIME_UNSET;
   }
 
   @Override
@@ -662,9 +666,22 @@ import org.checkerframework.checker.nullness.qual.NonNull;
 
   @Override
   public long getContentPosition() {
+    boolean receivedUpdatedPositionInfo =
+        lastSetPlayWhenReadyCalledTimeMs != C.TIME_UNSET
+            && lastSetPlayWhenReadyCalledTimeMs < playerInfo.sessionPositionInfo.eventTimeMs;
     if (!playerInfo.isPlaying || playerInfo.sessionPositionInfo.isPlayingAd) {
-      return playerInfo.sessionPositionInfo.positionInfo.contentPositionMs;
+      if (receivedUpdatedPositionInfo || lastReturnedContentPositionMs == C.TIME_UNSET) {
+        lastReturnedContentPositionMs =
+            playerInfo.sessionPositionInfo.positionInfo.contentPositionMs;
+      }
+      return lastReturnedContentPositionMs;
     }
+
+    if (!receivedUpdatedPositionInfo && lastReturnedContentPositionMs != C.TIME_UNSET) {
+      // We need an updated content position to make a new position estimation.
+      return lastReturnedContentPositionMs;
+    }
+
     long elapsedTimeMs =
         (instance.getTimeDiffMs() != C.TIME_UNSET)
             ? instance.getTimeDiffMs()
@@ -672,9 +689,12 @@ import org.checkerframework.checker.nullness.qual.NonNull;
     long estimatedPositionMs =
         playerInfo.sessionPositionInfo.positionInfo.contentPositionMs
             + (long) (elapsedTimeMs * playerInfo.playbackParameters.speed);
-    return playerInfo.sessionPositionInfo.contentDurationMs == C.TIME_UNSET
-        ? estimatedPositionMs
-        : Math.min(estimatedPositionMs, playerInfo.sessionPositionInfo.contentDurationMs);
+    if (playerInfo.sessionPositionInfo.contentDurationMs != C.TIME_UNSET) {
+      estimatedPositionMs =
+          Math.min(estimatedPositionMs, playerInfo.sessionPositionInfo.contentDurationMs);
+    }
+    lastReturnedContentPositionMs = estimatedPositionMs;
+    return lastReturnedContentPositionMs;
   }
 
   @Override
@@ -2051,6 +2071,9 @@ import org.checkerframework.checker.nullness.qual.NonNull;
         && playerInfo.playbackSuppressionReason == playbackSuppressionReason) {
       return;
     }
+
+    // Stop estimating content position until a new positionInfo arrives from the player
+    lastSetPlayWhenReadyCalledTimeMs = SystemClock.elapsedRealtime();
     PlayerInfo playerInfo =
         this.playerInfo.copyWithPlayWhenReady(
             playWhenReady, playWhenReadyChangeReason, playbackSuppressionReason);