[camera_avfoundation] Implementation swift migration - part 9 (#9645)

Migrates camera implementation as part of flutter/flutter#119109

This PR migrates the 6th chunk of `FLTCam` class to Swift:
* `startVideoRecording`
* `setUpVideoRecording`
* `setupWriter`

Some properties of the `FLTCam` have to be temporarily made public so that they are accessible in `DefaultCamera`.

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Author: RobertOdrowaz

packages/camera/camera_avfoundation/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.9.20+5
+
+* Migrates `startVideoRecording`, `setUpVideoRecording`, and `setupWriter` methods to Swift.
+
 ## 0.9.20+4
 
 * Migrates `setVideoFormat`,`stopVideoRecording`, and `stopImageStream` methods to Swift.

packages/camera/camera_avfoundation/ios/camera_avfoundation/Sources/camera_avfoundation/DefaultCamera.swift

@@ -122,6 +122,153 @@ final class DefaultCamera: FLTCam, Camera {
     audioCaptureSession.stopRunning()
   }
 
+  func startVideoRecording(
+    completion: @escaping (FlutterError?) -> Void,
+    messengerForStreaming messenger: FlutterBinaryMessenger?
+  ) {
+    guard !isRecording else {
+      completion(
+        FlutterError(
+          code: "Error",
+          message: "Video is already recording",
+          details: nil))
+      return
+    }
+
+    if let messenger = messenger {
+      startImageStream(with: messenger) { [weak self] error in
+        self?.setUpVideoRecording(completion: completion)
+      }
+      return
+    }
+
+    setUpVideoRecording(completion: completion)
+  }
+
+  /// Main logic to setup the video recording.
+  private func setUpVideoRecording(completion: @escaping (FlutterError?) -> Void) {
+    let videoRecordingPath: String
+    do {
+      videoRecordingPath = try getTemporaryFilePath(
+        withExtension: "mp4",
+        subfolder: "videos",
+        prefix: "REC_")
+      self.videoRecordingPath = videoRecordingPath
+    } catch let error as NSError {
+      completion(DefaultCamera.flutterErrorFromNSError(error))
+      return
+    }
+
+    guard setupWriter(forPath: videoRecordingPath) else {
+      completion(
+        FlutterError(
+          code: "IOError",
+          message: "Setup Writer Failed",
+          details: nil))
+      return
+    }
+
+    // startWriting should not be called in didOutputSampleBuffer where it can cause state
+    // in which isRecording is true but videoWriter.status is .unknown
+    // in stopVideoRecording if it is called after startVideoRecording but before
+    // didOutputSampleBuffer had chance to call startWriting and lag at start of video
+    // https://github.com/flutter/flutter/issues/132016
+    // https://github.com/flutter/flutter/issues/151319
+    videoWriter?.startWriting()
+    isFirstVideoSample = true
+    isRecording = true
+    isRecordingPaused = false
+    videoTimeOffset = CMTime.zero
+    audioTimeOffset = CMTime.zero
+    videoIsDisconnected = false
+    audioIsDisconnected = false
+    completion(nil)
+  }
+
+  private func setupWriter(forPath path: String) -> Bool {
+    setUpCaptureSessionForAudioIfNeeded()
+
+    var error: NSError?
+    videoWriter = assetWriterFactory(URL(fileURLWithPath: path), AVFileType.mp4, &error)
+
+    guard let videoWriter = videoWriter else {
+      if let error = error {
+        reportErrorMessage(error.description)
+      }
+      return false
+    }
+
+    var videoSettings = mediaSettingsAVWrapper.recommendedVideoSettingsForAssetWriter(
+      withFileType:
+        AVFileType.mp4,
+      for: captureVideoOutput
+    )
+
+    if mediaSettings.videoBitrate != nil || mediaSettings.framesPerSecond != nil {
+      var compressionProperties: [String: Any] = [:]
+
+      if let videoBitrate = mediaSettings.videoBitrate {
+        compressionProperties[AVVideoAverageBitRateKey] = videoBitrate
+      }
+
+      if let framesPerSecond = mediaSettings.framesPerSecond {
+        compressionProperties[AVVideoExpectedSourceFrameRateKey] = framesPerSecond
+      }
+
+      videoSettings?[AVVideoCompressionPropertiesKey] = compressionProperties
+    }
+
+    let videoWriterInput = mediaSettingsAVWrapper.assetWriterVideoInput(
+      withOutputSettings: videoSettings)
+    self.videoWriterInput = videoWriterInput
+
+    let sourcePixelBufferAttributes: [String: Any] = [
+      kCVPixelBufferPixelFormatTypeKey as String: videoFormat
+    ]
+
+    videoAdaptor = inputPixelBufferAdaptorFactory(videoWriterInput, sourcePixelBufferAttributes)
+
+    videoWriterInput.expectsMediaDataInRealTime = true
+
+    // Add the audio input
+    if mediaSettings.enableAudio {
+      var audioChannelLayout = AudioChannelLayout()
+      audioChannelLayout.mChannelLayoutTag = kAudioChannelLayoutTag_Mono
+
+      let audioChannelLayoutData = withUnsafeBytes(of: &audioChannelLayout) { Data($0) }
+
+      var audioSettings: [String: Any] = [
+        AVFormatIDKey: kAudioFormatMPEG4AAC,
+        AVSampleRateKey: 44100.0,
+        AVNumberOfChannelsKey: 1,
+        AVChannelLayoutKey: audioChannelLayoutData,
+      ]
+
+      if let audioBitrate = mediaSettings.audioBitrate {
+        audioSettings[AVEncoderBitRateKey] = audioBitrate
+      }
+
+      let newAudioWriterInput = mediaSettingsAVWrapper.assetWriterAudioInput(
+        withOutputSettings: audioSettings)
+      newAudioWriterInput.expectsMediaDataInRealTime = true
+      mediaSettingsAVWrapper.addInput(newAudioWriterInput, to: videoWriter)
+      self.audioWriterInput = newAudioWriterInput
+      audioOutput.setSampleBufferDelegate(self, queue: captureSessionQueue)
+    }
+
+    if flashMode == .torch {
+      try? captureDevice.lockForConfiguration()
+      captureDevice.torchMode = .on
+      captureDevice.unlockForConfiguration()
+    }
+
+    mediaSettingsAVWrapper.addInput(videoWriterInput, to: videoWriter)
+
+    captureVideoOutput.setSampleBufferDelegate(self, queue: captureSessionQueue)
+
+    return true
+  }
+
   func pauseVideoRecording() {
     isRecordingPaused = true
     videoIsDisconnected = true

packages/camera/camera_avfoundation/ios/camera_avfoundation/Sources/camera_avfoundation_objc/FLTCam.m

@@ -29,14 +29,11 @@ @interface FLTCam () <AVCaptureVideoDataOutputSampleBufferDelegate,
                       AVCaptureAudioDataOutputSampleBufferDelegate>
 
 @property(readonly, nonatomic) int64_t textureId;
-@property(readonly, nonatomic) FCPPlatformMediaSettings *mediaSettings;
-@property(readonly, nonatomic) FLTCamMediaSettingsAVWrapper *mediaSettingsAVWrapper;
 
 @property(readonly, nonatomic) CGSize captureSize;
 @property(strong, nonatomic)
     NSObject<FLTAssetWriterInputPixelBufferAdaptor> *assetWriterPixelBufferAdaptor;
 @property(strong, nonatomic) AVCaptureVideoDataOutput *videoOutput;
-@property(strong, nonatomic) AVCaptureAudioDataOutput *audioOutput;
 @property(assign, nonatomic) BOOL isAudioSetup;
 
 /// The queue on which captured photos (not videos) are written to disk.
@@ -47,8 +44,6 @@ @interface FLTCam () <AVCaptureVideoDataOutputSampleBufferDelegate,
 @property(nonatomic, copy) VideoDimensionsForFormat videoDimensionsForFormat;
 /// A wrapper for AVCaptureDevice creation to allow for dependency injection in tests.
 @property(nonatomic, copy) AudioCaptureDeviceFactory audioCaptureDeviceFactory;
-@property(nonatomic, copy) AssetWriterFactory assetWriterFactory;
-@property(nonatomic, copy) InputPixelBufferAdaptorFactory inputPixelBufferAdaptorFactory;
 /// Reports the given error message to the Dart side of the plugin.
 ///
 /// Can be called from any thread.
@@ -412,57 +407,6 @@ - (BOOL)setCaptureSessionPreset:(FCPPlatformResolutionPreset)resolutionPreset
   return bestFormat;
 }
 
-/// Main logic to setup the video recording.
-- (void)setUpVideoRecordingWithCompletion:(void (^)(FlutterError *_Nullable))completion {
-  NSError *error;
-  _videoRecordingPath = [self getTemporaryFilePathWithExtension:@"mp4"
-                                                      subfolder:@"videos"
-                                                         prefix:@"REC_"
-                                                          error:&error];
-  if (error) {
-    completion(FlutterErrorFromNSError(error));
-    return;
-  }
-  if (![self setupWriterForPath:_videoRecordingPath]) {
-    completion([FlutterError errorWithCode:@"IOError" message:@"Setup Writer Failed" details:nil]);
-    return;
-  }
-  // startWriting should not be called in didOutputSampleBuffer where it can cause state
-  // in which _isRecording is YES but _videoWriter.status is AVAssetWriterStatusUnknown
-  // in stopVideoRecording if it is called after startVideoRecording but before
-  // didOutputSampleBuffer had chance to call startWriting and lag at start of video
-  // https://github.com/flutter/flutter/issues/132016
-  // https://github.com/flutter/flutter/issues/151319
-  [_videoWriter startWriting];
-  _isFirstVideoSample = YES;
-  _isRecording = YES;
-  _isRecordingPaused = NO;
-  _videoTimeOffset = CMTimeMake(0, 1);
-  _audioTimeOffset = CMTimeMake(0, 1);
-  _videoIsDisconnected = NO;
-  _audioIsDisconnected = NO;
-  completion(nil);
-}
-
-- (void)startVideoRecordingWithCompletion:(void (^)(FlutterError *_Nullable))completion
-                    messengerForStreaming:(nullable NSObject<FlutterBinaryMessenger> *)messenger {
-  if (!_isRecording) {
-    if (messenger != nil) {
-      [self startImageStreamWithMessenger:messenger
-                               completion:^(FlutterError *_Nullable error) {
-                                 [self setUpVideoRecordingWithCompletion:completion];
-                               }];
-      return;
-    }
-
-    [self setUpVideoRecordingWithCompletion:completion];
-  } else {
-    completion([FlutterError errorWithCode:@"Error"
-                                   message:@"Video is already recording"
-                                   details:nil]);
-  }
-}
-
 - (void)startImageStreamWithMessenger:(NSObject<FlutterBinaryMessenger> *)messenger
                            completion:(void (^)(FlutterError *))completion {
   [self startImageStreamWithMessenger:messenger
@@ -510,91 +454,6 @@ - (void)startImageStreamWithMessenger:(NSObject<FlutterBinaryMessenger> *)messen
   }
 }
 
-- (BOOL)setupWriterForPath:(NSString *)path {
-  NSError *error = nil;
-  NSURL *outputURL;
-  if (path != nil) {
-    outputURL = [NSURL fileURLWithPath:path];
-  } else {
-    return NO;
-  }
-
-  [self setUpCaptureSessionForAudioIfNeeded];
-
-  _videoWriter = _assetWriterFactory(outputURL, AVFileTypeMPEG4, &error);
-
-  NSParameterAssert(_videoWriter);
-  if (error) {
-    [self reportErrorMessage:error.description];
-    return NO;
-  }
-
-  NSMutableDictionary<NSString *, id> *videoSettings = [[_mediaSettingsAVWrapper
-      recommendedVideoSettingsForAssetWriterWithFileType:AVFileTypeMPEG4
-                                               forOutput:_captureVideoOutput] mutableCopy];
-
-  if (_mediaSettings.videoBitrate || _mediaSettings.framesPerSecond) {
-    NSMutableDictionary *compressionProperties = [[NSMutableDictionary alloc] init];
-
-    if (_mediaSettings.videoBitrate) {
-      compressionProperties[AVVideoAverageBitRateKey] = _mediaSettings.videoBitrate;
-    }
-
-    if (_mediaSettings.framesPerSecond) {
-      compressionProperties[AVVideoExpectedSourceFrameRateKey] = _mediaSettings.framesPerSecond;
-    }
-
-    videoSettings[AVVideoCompressionPropertiesKey] = compressionProperties;
-  }
-
-  _videoWriterInput =
-      [_mediaSettingsAVWrapper assetWriterVideoInputWithOutputSettings:videoSettings];
-
-  _videoAdaptor = _inputPixelBufferAdaptorFactory(
-      _videoWriterInput, @{(NSString *)kCVPixelBufferPixelFormatTypeKey : @(_videoFormat)});
-
-  NSParameterAssert(_videoWriterInput);
-
-  _videoWriterInput.expectsMediaDataInRealTime = YES;
-
-  // Add the audio input
-  if (_mediaSettings.enableAudio) {
-    AudioChannelLayout acl;
-    bzero(&acl, sizeof(acl));
-    acl.mChannelLayoutTag = kAudioChannelLayoutTag_Mono;
-    NSMutableDictionary *audioOutputSettings = [@{
-      AVFormatIDKey : [NSNumber numberWithInt:kAudioFormatMPEG4AAC],
-      AVSampleRateKey : [NSNumber numberWithFloat:44100.0],
-      AVNumberOfChannelsKey : [NSNumber numberWithInt:1],
-      AVChannelLayoutKey : [NSData dataWithBytes:&acl length:sizeof(acl)],
-    } mutableCopy];
-
-    if (_mediaSettings.audioBitrate) {
-      audioOutputSettings[AVEncoderBitRateKey] = _mediaSettings.audioBitrate;
-    }
-
-    _audioWriterInput =
-        [_mediaSettingsAVWrapper assetWriterAudioInputWithOutputSettings:audioOutputSettings];
-
-    _audioWriterInput.expectsMediaDataInRealTime = YES;
-
-    [_mediaSettingsAVWrapper addInput:_audioWriterInput toAssetWriter:_videoWriter];
-    [_audioOutput setSampleBufferDelegate:self queue:_captureSessionQueue];
-  }
-
-  if (self.flashMode == FCPPlatformFlashModeTorch) {
-    [self.captureDevice lockForConfiguration:nil];
-    [self.captureDevice setTorchMode:AVCaptureTorchModeOn];
-    [self.captureDevice unlockForConfiguration];
-  }
-
-  [_mediaSettingsAVWrapper addInput:_videoWriterInput toAssetWriter:_videoWriter];
-
-  [_captureVideoOutput setSampleBufferDelegate:self queue:_captureSessionQueue];
-
-  return YES;
-}
-
 // This function, although slightly modified, is also in video_player_avfoundation.
 // Both need to do the same thing and run on the same thread (for example main thread).
 // Configure application wide audio session manually to prevent overwriting flag

packages/camera/camera_avfoundation/ios/camera_avfoundation/Sources/camera_avfoundation_objc/include/camera_avfoundation/FLTCam.h

@@ -60,27 +60,29 @@ NS_ASSUME_NONNULL_BEGIN
 @property(readonly, nonatomic) NSObject<FLTCaptureDeviceInputFactory> *captureDeviceInputFactory;
 /// All FLTCam's state access and capture session related operations should be on run on this queue.
 @property(strong, nonatomic) dispatch_queue_t captureSessionQueue;
+@property(nonatomic, copy) AssetWriterFactory assetWriterFactory;
+@property(readonly, nonatomic) FLTCamMediaSettingsAVWrapper *mediaSettingsAVWrapper;
+@property(readonly, nonatomic) FCPPlatformMediaSettings *mediaSettings;
+@property(nonatomic, copy) InputPixelBufferAdaptorFactory inputPixelBufferAdaptorFactory;
+@property(strong, nonatomic) AVCaptureAudioDataOutput *audioOutput;
 
 /// Initializes an `FLTCam` instance with the given configuration.
 /// @param error report to the caller if any error happened creating the camera.
 - (instancetype)initWithConfiguration:(FLTCamConfiguration *)configuration error:(NSError **)error;
 
 - (void)captureToFileWithCompletion:(void (^)(NSString *_Nullable,
                                               FlutterError *_Nullable))completion;
-/// Starts recording a video with an optional streaming messenger.
-/// If the messenger is non-nil then it will be called for each
-/// captured frame, allowing streaming concurrently with recording.
-///
-/// @param messenger Nullable messenger for capturing each frame.
-- (void)startVideoRecordingWithCompletion:(void (^)(FlutterError *_Nullable))completion
-                    messengerForStreaming:(nullable NSObject<FlutterBinaryMessenger> *)messenger;
 
 - (void)startImageStreamWithMessenger:(NSObject<FlutterBinaryMessenger> *)messenger
                            completion:(nonnull void (^)(FlutterError *_Nullable))completion;
 - (void)setUpCaptureSessionForAudioIfNeeded;
 
 // Methods exposed for the Swift DefaultCamera subclass
 - (void)updateOrientation;
+- (nullable NSString *)getTemporaryFilePathWithExtension:(NSString *)extension
+                                               subfolder:(NSString *)subfolder
+                                                  prefix:(NSString *)prefix
+                                                   error:(NSError **)error;
 
 @end
 

packages/camera/camera_avfoundation/pubspec.yaml

@@ -2,7 +2,7 @@ name: camera_avfoundation
 description: iOS implementation of the camera plugin.
 repository: https://github.com/flutter/packages/tree/main/packages/camera/camera_avfoundation
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+camera%22
-version: 0.9.20+4
+version: 0.9.20+5
 
 environment:
   sdk: ^3.6.0