[video_player] foundation - reduce seek accuracy to fix seek to end bug (flutter#3784)

Reduces avplayer seek accuracy when seeking to end of video to fix `seekToTime` never running completion handler.

fixes flutter#124475

Author: tarrinneal

packages/video_player/video_player_avfoundation/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 2.4.6
+
+* Fixes hang when seeking to end of video.
+
 ## 2.4.5
 
 * Updates functions without a prototype to avoid deprecation warning.

packages/video_player/video_player_avfoundation/example/integration_test/video_player_test.dart

@@ -71,13 +71,27 @@ void main() {
       expect(await controller.position, greaterThan(Duration.zero));
     });
 
-    testWidgets('can seek', (WidgetTester tester) async {
-      await controller.initialize();
+    testWidgets(
+      'can seek',
+      (WidgetTester tester) async {
+        await controller.initialize();
 
-      await controller.seekTo(const Duration(seconds: 3));
+        await controller.seekTo(const Duration(seconds: 3));
 
-      expect(await controller.position, const Duration(seconds: 3));
-    });
+        expect(controller.value.position, const Duration(seconds: 3));
+      },
+    );
+
+    testWidgets(
+      'can seek to end',
+      (WidgetTester tester) async {
+        await controller.initialize();
+
+        await controller.seekTo(controller.value.duration);
+
+        expect(controller.value.duration, controller.value.position);
+      },
+    );
 
     testWidgets('can be paused', (WidgetTester tester) async {
       await controller.initialize();

packages/video_player/video_player_avfoundation/example/ios/RunnerTests/VideoPlayerTests.m

@@ -8,6 +8,7 @@
 
 #import <OCMock/OCMock.h>
 #import <video_player_avfoundation/AVAssetTrackUtils.h>
+#import <video_player_avfoundation/FLTVideoPlayerPlugin_Test.h>
 
 @interface FLTVideoPlayer : NSObject <FlutterStreamHandler>
 @property(readonly, nonatomic) AVPlayer *player;
@@ -61,6 +62,46 @@ - (CGAffineTransform)preferredTransform {
 @interface VideoPlayerTests : XCTestCase
 @end
 
+@interface StubAVPlayer : AVPlayer
+@property(readonly, nonatomic) NSNumber *beforeTolerance;
+@property(readonly, nonatomic) NSNumber *afterTolerance;
+@end
+
+@implementation StubAVPlayer
+
+- (void)seekToTime:(CMTime)time
+      toleranceBefore:(CMTime)toleranceBefore
+       toleranceAfter:(CMTime)toleranceAfter
+    completionHandler:(void (^)(BOOL finished))completionHandler {
+  _beforeTolerance = [NSNumber numberWithLong:toleranceBefore.value];
+  _afterTolerance = [NSNumber numberWithLong:toleranceAfter.value];
+  completionHandler(YES);
+}
+
+@end
+
+@interface StubFVPPlayerFactory : NSObject <FVPPlayerFactory>
+
+@property(nonatomic, strong) StubAVPlayer *stubAVPlayer;
+
+- (instancetype)initWithPlayer:(StubAVPlayer *)stubAVPlayer;
+
+@end
+
+@implementation StubFVPPlayerFactory
+
+- (instancetype)initWithPlayer:(StubAVPlayer *)stubAVPlayer {
+  self = [super init];
+  _stubAVPlayer = stubAVPlayer;
+  return self;
+}
+
+- (AVPlayer *)playerWithPlayerItem:(AVPlayerItem *)playerItem {
+  return _stubAVPlayer;
+}
+
+@end
+
 @implementation VideoPlayerTests
 
 - (void)testBlankVideoBugWithEncryptedVideoStreamAndInvertedAspectRatioBugForSomeVideoStream {
@@ -226,6 +267,81 @@ - (void)testTransformFix {
   [self validateTransformFixForOrientation:UIImageOrientationRightMirrored];
 }
 
+- (void)testSeekToleranceWhenNotSeekingToEnd {
+  NSObject<FlutterPluginRegistry> *registry =
+      (NSObject<FlutterPluginRegistry> *)[[UIApplication sharedApplication] delegate];
+  NSObject<FlutterPluginRegistrar> *registrar = [registry registrarForPlugin:@"TestSeekTolerance"];
+
+  StubAVPlayer *stubAVPlayer = [[StubAVPlayer alloc] init];
+  StubFVPPlayerFactory *stubFVPPlayerFactory =
+      [[StubFVPPlayerFactory alloc] initWithPlayer:stubAVPlayer];
+  FLTVideoPlayerPlugin *pluginWithMockAVPlayer =
+      [[FLTVideoPlayerPlugin alloc] initWithPlayerFactory:stubFVPPlayerFactory registrar:registrar];
+
+  FlutterError *error;
+  [pluginWithMockAVPlayer initialize:&error];
+  XCTAssertNil(error);
+
+  FLTCreateMessage *create = [FLTCreateMessage
+      makeWithAsset:nil
+                uri:@"https://flutter.github.io/assets-for-api-docs/assets/videos/bee.mp4"
+        packageName:nil
+         formatHint:nil
+        httpHeaders:@{}];
+  FLTTextureMessage *textureMessage = [pluginWithMockAVPlayer create:create error:&error];
+  NSNumber *textureId = textureMessage.textureId;
+
+  XCTestExpectation *initializedExpectation =
+      [self expectationWithDescription:@"seekTo has zero tolerance when seeking not to end"];
+  FLTPositionMessage *message = [FLTPositionMessage makeWithTextureId:textureId position:@1234];
+  [pluginWithMockAVPlayer seekTo:message
+                      completion:^(FlutterError *_Nullable error) {
+                        [initializedExpectation fulfill];
+                      }];
+
+  [self waitForExpectationsWithTimeout:30.0 handler:nil];
+  XCTAssertEqual([stubAVPlayer.beforeTolerance intValue], 0);
+  XCTAssertEqual([stubAVPlayer.afterTolerance intValue], 0);
+}
+
+- (void)testSeekToleranceWhenSeekingToEnd {
+  NSObject<FlutterPluginRegistry> *registry =
+      (NSObject<FlutterPluginRegistry> *)[[UIApplication sharedApplication] delegate];
+  NSObject<FlutterPluginRegistrar> *registrar =
+      [registry registrarForPlugin:@"TestSeekToEndTolerance"];
+
+  StubAVPlayer *stubAVPlayer = [[StubAVPlayer alloc] init];
+  StubFVPPlayerFactory *stubFVPPlayerFactory =
+      [[StubFVPPlayerFactory alloc] initWithPlayer:stubAVPlayer];
+  FLTVideoPlayerPlugin *pluginWithMockAVPlayer =
+      [[FLTVideoPlayerPlugin alloc] initWithPlayerFactory:stubFVPPlayerFactory registrar:registrar];
+
+  FlutterError *error;
+  [pluginWithMockAVPlayer initialize:&error];
+  XCTAssertNil(error);
+
+  FLTCreateMessage *create = [FLTCreateMessage
+      makeWithAsset:nil
+                uri:@"https://flutter.github.io/assets-for-api-docs/assets/videos/bee.mp4"
+        packageName:nil
+         formatHint:nil
+        httpHeaders:@{}];
+  FLTTextureMessage *textureMessage = [pluginWithMockAVPlayer create:create error:&error];
+  NSNumber *textureId = textureMessage.textureId;
+
+  XCTestExpectation *initializedExpectation =
+      [self expectationWithDescription:@"seekTo has non-zero tolerance when seeking to end"];
+  // The duration of this video is "0" due to the non standard initiliatazion process.
+  FLTPositionMessage *message = [FLTPositionMessage makeWithTextureId:textureId position:@0];
+  [pluginWithMockAVPlayer seekTo:message
+                      completion:^(FlutterError *_Nullable error) {
+                        [initializedExpectation fulfill];
+                      }];
+  [self waitForExpectationsWithTimeout:30.0 handler:nil];
+  XCTAssertGreaterThan([stubAVPlayer.beforeTolerance intValue], 0);
+  XCTAssertGreaterThan([stubAVPlayer.afterTolerance intValue], 0);
+}
+
 - (NSDictionary<NSString *, id> *)testPlugin:(FLTVideoPlayerPlugin *)videoPlayerPlugin
                                          uri:(NSString *)uri {
   FlutterError *error;

packages/video_player/video_player_avfoundation/ios/Classes/FLTVideoPlayerPlugin.m

@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 #import "FLTVideoPlayerPlugin.h"
+#import "FLTVideoPlayerPlugin_Test.h"
 
 #import <AVFoundation/AVFoundation.h>
 #import <GLKit/GLKit.h>
@@ -33,6 +34,16 @@ - (void)onDisplayLink:(CADisplayLink *)link {
 }
 @end
 
+@interface FVPDefaultPlayerFactory : NSObject <FVPPlayerFactory>
+@end
+
+@implementation FVPDefaultPlayerFactory
+- (AVPlayer *)playerWithPlayerItem:(AVPlayerItem *)playerItem {
+  return [AVPlayer playerWithPlayerItem:playerItem];
+}
+
+@end
+
 @interface FLTVideoPlayer : NSObject <FlutterTexture, FlutterStreamHandler>
 @property(readonly, nonatomic) AVPlayer *player;
 @property(readonly, nonatomic) AVPlayerItemVideoOutput *videoOutput;
@@ -52,7 +63,8 @@ @interface FLTVideoPlayer : NSObject <FlutterTexture, FlutterStreamHandler>
 @property(nonatomic, readonly) BOOL isInitialized;
 - (instancetype)initWithURL:(NSURL *)url
                frameUpdater:(FLTFrameUpdater *)frameUpdater
-                httpHeaders:(nonnull NSDictionary<NSString *, NSString *> *)headers;
+                httpHeaders:(nonnull NSDictionary<NSString *, NSString *> *)headers
+              playerFactory:(id<FVPPlayerFactory>)playerFactory;
 @end
 
 static void *timeRangeContext = &timeRangeContext;
@@ -65,9 +77,14 @@ - (instancetype)initWithURL:(NSURL *)url
 static void *rateContext = &rateContext;
 
 @implementation FLTVideoPlayer
-- (instancetype)initWithAsset:(NSString *)asset frameUpdater:(FLTFrameUpdater *)frameUpdater {
+- (instancetype)initWithAsset:(NSString *)asset
+                 frameUpdater:(FLTFrameUpdater *)frameUpdater
+                playerFactory:(id<FVPPlayerFactory>)playerFactory {
   NSString *path = [[NSBundle mainBundle] pathForResource:asset ofType:nil];
-  return [self initWithURL:[NSURL fileURLWithPath:path] frameUpdater:frameUpdater httpHeaders:@{}];
+  return [self initWithURL:[NSURL fileURLWithPath:path]
+              frameUpdater:frameUpdater
+               httpHeaders:@{}
+             playerFactory:playerFactory];
 }
 
 - (void)addObserversForItem:(AVPlayerItem *)item player:(AVPlayer *)player {
@@ -203,18 +220,20 @@ - (void)createVideoOutputAndDisplayLink:(FLTFrameUpdater *)frameUpdater {
 
 - (instancetype)initWithURL:(NSURL *)url
                frameUpdater:(FLTFrameUpdater *)frameUpdater
-                httpHeaders:(nonnull NSDictionary<NSString *, NSString *> *)headers {
+                httpHeaders:(nonnull NSDictionary<NSString *, NSString *> *)headers
+              playerFactory:(id<FVPPlayerFactory>)playerFactory {
   NSDictionary<NSString *, id> *options = nil;
   if ([headers count] != 0) {
     options = @{@"AVURLAssetHTTPHeaderFieldsKey" : headers};
   }
   AVURLAsset *urlAsset = [AVURLAsset URLAssetWithURL:url options:options];
   AVPlayerItem *item = [AVPlayerItem playerItemWithAsset:urlAsset];
-  return [self initWithPlayerItem:item frameUpdater:frameUpdater];
+  return [self initWithPlayerItem:item frameUpdater:frameUpdater playerFactory:playerFactory];
 }
 
 - (instancetype)initWithPlayerItem:(AVPlayerItem *)item
-                      frameUpdater:(FLTFrameUpdater *)frameUpdater {
+                      frameUpdater:(FLTFrameUpdater *)frameUpdater
+                     playerFactory:(id<FVPPlayerFactory>)playerFactory {
   self = [super init];
   NSAssert(self, @"super init cannot be nil");
 
@@ -247,7 +266,7 @@ - (instancetype)initWithPlayerItem:(AVPlayerItem *)item
     }
   };
 
-  _player = [AVPlayer playerWithPlayerItem:item];
+  _player = [playerFactory playerWithPlayerItem:item];
   _player.actionAtItemEnd = AVPlayerActionAtItemEndNone;
 
   // This is to fix 2 bugs: 1. blank video for encrypted video streams on iOS 16
@@ -420,9 +439,15 @@ - (int64_t)duration {
 }
 
 - (void)seekTo:(int)location completionHandler:(void (^)(BOOL))completionHandler {
-  [_player seekToTime:CMTimeMake(location, 1000)
-        toleranceBefore:kCMTimeZero
-         toleranceAfter:kCMTimeZero
+  CMTime locationCMT = CMTimeMake(location, 1000);
+  CMTimeValue duration = _player.currentItem.asset.duration.value;
+  // Without adding tolerance when seeking to duration,
+  // seekToTime will never complete, and this call will hang.
+  // see issue https://github.com/flutter/flutter/issues/124475.
+  CMTime tolerance = location == duration ? CMTimeMake(1, 1000) : kCMTimeZero;
+  [_player seekToTime:locationCMT
+        toleranceBefore:tolerance
+         toleranceAfter:tolerance
       completionHandler:completionHandler];
 }
 
@@ -523,6 +548,7 @@ @interface FLTVideoPlayerPlugin () <FLTAVFoundationVideoPlayerApi>
 @property(readonly, strong, nonatomic)
     NSMutableDictionary<NSNumber *, FLTVideoPlayer *> *playersByTextureId;
 @property(readonly, strong, nonatomic) NSObject<FlutterPluginRegistrar> *registrar;
+@property(nonatomic, strong) id<FVPPlayerFactory> playerFactory;
 @end
 
 @implementation FLTVideoPlayerPlugin
@@ -533,11 +559,17 @@ + (void)registerWithRegistrar:(NSObject<FlutterPluginRegistrar> *)registrar {
 }
 
 - (instancetype)initWithRegistrar:(NSObject<FlutterPluginRegistrar> *)registrar {
+  return [self initWithPlayerFactory:[[FVPDefaultPlayerFactory alloc] init] registrar:registrar];
+}
+
+- (instancetype)initWithPlayerFactory:(id<FVPPlayerFactory>)playerFactory
+                            registrar:(NSObject<FlutterPluginRegistrar> *)registrar {
   self = [super init];
   NSAssert(self, @"super init cannot be nil");
   _registry = [registrar textures];
   _messenger = [registrar messenger];
   _registrar = registrar;
+  _playerFactory = playerFactory;
   _playersByTextureId = [NSMutableDictionary dictionaryWithCapacity:1];
   return self;
 }
@@ -588,12 +620,15 @@ - (FLTTextureMessage *)create:(FLTCreateMessage *)input error:(FlutterError **)e
     } else {
       assetPath = [_registrar lookupKeyForAsset:input.asset];
     }
-    player = [[FLTVideoPlayer alloc] initWithAsset:assetPath frameUpdater:frameUpdater];
+    player = [[FLTVideoPlayer alloc] initWithAsset:assetPath
+                                      frameUpdater:frameUpdater
+                                     playerFactory:_playerFactory];
     return [self onPlayerSetup:player frameUpdater:frameUpdater];
   } else if (input.uri) {
     player = [[FLTVideoPlayer alloc] initWithURL:[NSURL URLWithString:input.uri]
                                     frameUpdater:frameUpdater
-                                     httpHeaders:input.httpHeaders];
+                                     httpHeaders:input.httpHeaders
+                                   playerFactory:_playerFactory];
     return [self onPlayerSetup:player frameUpdater:frameUpdater];
   } else {
     *error = [FlutterError errorWithCode:@"video_player" message:@"not implemented" details:nil];

packages/video_player/video_player_avfoundation/ios/Classes/FLTVideoPlayerPlugin_Test.h

@@ -0,0 +1,18 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#import "FLTVideoPlayerPlugin.h"
+
+#import <AVFoundation/AVFoundation.h>
+
+// Protocol for an AVPlayer instance factory. Used for injecting players in tests.
+@protocol FVPPlayerFactory
+- (AVPlayer *)playerWithPlayerItem:(AVPlayerItem *)playerItem;
+@end
+
+@interface FLTVideoPlayerPlugin ()
+
+- (instancetype)initWithPlayerFactory:(id<FVPPlayerFactory>)playerFactory
+                            registrar:(NSObject<FlutterPluginRegistrar> *)registrar;
+@end

packages/video_player/video_player_avfoundation/pubspec.yaml

@@ -2,7 +2,7 @@ name: video_player_avfoundation
 description: iOS implementation of the video_player plugin.
 repository: https://github.com/flutter/packages/tree/main/packages/video_player/video_player_avfoundation
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+video_player%22
-version: 2.4.5
+version: 2.4.6
 
 environment:
   sdk: ">=2.18.0 <4.0.0"