Add FaceDetector iOS API

PiperOrigin-RevId: 534858193

mediapipe/tasks/ios/BUILD

@@ -49,11 +49,12 @@ OBJC_TASK_COMMON_DEPS = [
 ]
 
 CALCULATORS_AND_GRAPHS = [
-    "//mediapipe/tasks/cc/vision/image_classifier:image_classifier_graph",
+    "//mediapipe/calculators/core:flow_limiter_calculator",
-    "//mediapipe/tasks/cc/vision/object_detector:object_detector_graph",
     "//mediapipe/tasks/cc/text/text_classifier:text_classifier_graph",
     "//mediapipe/tasks/cc/text/text_embedder:text_embedder_graph",
-    "//mediapipe/calculators/core:flow_limiter_calculator",
+    "//mediapipe/tasks/cc/vision/face_detector:face_detector_graph",
+    "//mediapipe/tasks/cc/vision/image_classifier:image_classifier_graph",
+    "//mediapipe/tasks/cc/vision/object_detector:object_detector_graph",
 ]
 
 strip_api_include_path_prefix(
@@ -76,6 +77,9 @@ strip_api_include_path_prefix(
         "//mediapipe/tasks/ios/text/text_embedder:sources/MPPTextEmbedderResult.h",
         "//mediapipe/tasks/ios/vision/core:sources/MPPRunningMode.h",
         "//mediapipe/tasks/ios/vision/core:sources/MPPImage.h",
+        "//mediapipe/tasks/ios/vision/face_detector:sources/MPPFaceDetector.h",
+        "//mediapipe/tasks/ios/vision/face_detector:sources/MPPFaceDetectorOptions.h",
+        "//mediapipe/tasks/ios/vision/face_detector:sources/MPPFaceDetectorResult.h",
         "//mediapipe/tasks/ios/vision/image_classifier:sources/MPPImageClassifier.h",
         "//mediapipe/tasks/ios/vision/image_classifier:sources/MPPImageClassifierOptions.h",
         "//mediapipe/tasks/ios/vision/image_classifier:sources/MPPImageClassifierResult.h",
@@ -157,6 +161,9 @@ apple_static_xcframework(
         ":MPPTaskResult.h",
         ":MPPImage.h",
         ":MPPRunningMode.h",
+        ":MPPFaceDetector.h",
+        ":MPPFaceDetectorOptions.h",
+        ":MPPFaceDetectorResult.h",
         ":MPPImageClassifier.h",
         ":MPPImageClassifierOptions.h",
         ":MPPImageClassifierResult.h",
@@ -165,6 +172,7 @@ apple_static_xcframework(
         ":MPPObjectDetectorResult.h",
     ],
     deps = [
+        "//mediapipe/tasks/ios/vision/face_detector:MPPFaceDetector",
         "//mediapipe/tasks/ios/vision/image_classifier:MPPImageClassifier",
         "//mediapipe/tasks/ios/vision/object_detector:MPPObjectDetector",
     ],

mediapipe/tasks/ios/vision/face_detector/BUILD

@@ -0,0 +1,62 @@
+# Copyright 2023 The MediaPipe Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+package(default_visibility = ["//mediapipe/tasks:internal"])
+
+licenses(["notice"])
+
+objc_library(
+    name = "MPPFaceDetectorResult",
+    srcs = ["sources/MPPFaceDetectorResult.m"],
+    hdrs = ["sources/MPPFaceDetectorResult.h"],
+    deps = [
+        "//mediapipe/tasks/ios/components/containers:MPPDetection",
+        "//mediapipe/tasks/ios/core:MPPTaskResult",
+    ],
+)
+
+objc_library(
+    name = "MPPFaceDetectorOptions",
+    srcs = ["sources/MPPFaceDetectorOptions.m"],
+    hdrs = ["sources/MPPFaceDetectorOptions.h"],
+    deps = [
+        ":MPPFaceDetectorResult",
+        "//mediapipe/tasks/ios/core:MPPTaskOptions",
+        "//mediapipe/tasks/ios/vision/core:MPPRunningMode",
+    ],
+)
+
+objc_library(
+    name = "MPPFaceDetector",
+    srcs = ["sources/MPPFaceDetector.mm"],
+    hdrs = ["sources/MPPFaceDetector.h"],
+    copts = [
+        "-ObjC++",
+        "-std=c++17",
+        "-x objective-c++",
+    ],
+    deps = [
+        ":MPPFaceDetectorOptions",
+        ":MPPFaceDetectorResult",
+        "//mediapipe/tasks/cc/vision/face_detector:face_detector_graph",
+        "//mediapipe/tasks/ios/common/utils:MPPCommonUtils",
+        "//mediapipe/tasks/ios/common/utils:NSStringHelpers",
+        "//mediapipe/tasks/ios/core:MPPTaskInfo",
+        "//mediapipe/tasks/ios/vision/core:MPPImage",
+        "//mediapipe/tasks/ios/vision/core:MPPVisionPacketCreator",
+        "//mediapipe/tasks/ios/vision/core:MPPVisionTaskRunner",
+        "//mediapipe/tasks/ios/vision/face_detector/utils:MPPFaceDetectorOptionsHelpers",
+        "//mediapipe/tasks/ios/vision/face_detector/utils:MPPFaceDetectorResultHelpers",
+    ],
+)

mediapipe/tasks/ios/vision/face_detector/sources/MPPFaceDetector.h

@@ -0,0 +1,190 @@
+// Copyright 2023 The MediaPipe Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#import <Foundation/Foundation.h>
+
+#import "mediapipe/tasks/ios/vision/core/sources/MPPImage.h"
+#import "mediapipe/tasks/ios/vision/face_detector/sources/MPPFaceDetectorOptions.h"
+#import "mediapipe/tasks/ios/vision/face_detector/sources/MPPFaceDetectorResult.h"
+
+NS_ASSUME_NONNULL_BEGIN
+
+/**
+ * @brief Class that performs face detection on images.
+ *
+ * The API expects a TFLite model with mandatory TFLite Model Metadata.
+ *
+ * The API supports models with one image input tensor and one or more output tensors. To be more
+ * specific, here are the requirements:
+ *
+ * Input tensor
+ *  (kTfLiteUInt8/kTfLiteFloat32)
+ *  - image input of size `[batch x height x width x channels]`.
+ *  - batch inference is not supported (`batch` is required to be 1).
+ *  - only RGB inputs are supported (`channels` is required to be 3).
+ *  - if type is kTfLiteFloat32, NormalizationOptions are required to be attached to the metadata
+ * for input normalization.
+ *
+ * Output tensors must be the 4 outputs of a `DetectionPostProcess` op, i.e:(kTfLiteFloat32)
+ *  (kTfLiteUInt8/kTfLiteFloat32)
+ *  - locations tensor of size `[num_results x 4]`, the inner array representing bounding boxes
+ *    in the form [top, left, right, bottom].
+ *  - BoundingBoxProperties are required to be attached to the metadata and must specify
+ *    type=BOUNDARIES and coordinate_type=RATIO.
+ *  (kTfLiteFloat32)
+ *  - classes tensor of size `[num_results]`, each value representing the integer index of a
+ *  class.
+ *  - scores tensor of size `[num_results]`, each value representing the score of the detected
+ *    face.
+ *  - optional score calibration can be attached using ScoreCalibrationOptions and an
+ *    AssociatedFile with type TENSOR_AXIS_SCORE_CALIBRATION. See metadata_schema.fbs [1] for more
+ *    details.
+ *  (kTfLiteFloat32)
+ *  - integer num_results as a tensor of size `[1]`
+ */
+NS_SWIFT_NAME(FaceDetector)
+@interface MPPFaceDetector : NSObject
+
+/**
+ * Creates a new instance of `MPPFaceDetector` from an absolute path to a TensorFlow Lite model
+ * file stored locally on the device and the default `MPPFaceDetector`.
+ *
+ * @param modelPath An absolute path to a TensorFlow Lite model file stored locally on the device.
+ * @param error An optional error parameter populated when there is an error in initializing the
+ * face detector.
+ *
+ * @return A new instance of `MPPFaceDetector` with the given model path. `nil` if there is an
+ * error in initializing the face detector.
+ */
+- (nullable instancetype)initWithModelPath:(NSString *)modelPath error:(NSError **)error;
+
+/**
+ * Creates a new instance of `MPPFaceDetector` from the given `MPPFaceDetectorOptions`.
+ *
+ * @param options The options of type `MPPFaceDetectorOptions` to use for configuring the
+ * `MPPFaceDetector`.
+ * @param error An optional error parameter populated when there is an error in initializing the
+ * face detector.
+ *
+ * @return A new instance of `MPPFaceDetector` with the given options. `nil` if there is an error
+ * in initializing the face detector.
+ */
+- (nullable instancetype)initWithOptions:(MPPFaceDetectorOptions *)options
+                                   error:(NSError **)error NS_DESIGNATED_INITIALIZER;
+
+/**
+ * Performs face detection on the provided MPPImage using the whole image as region of
+ * interest. Rotation will be applied according to the `orientation` property of the provided
+ * `MPPImage`. Only use this method when the `MPPFaceDetector` is created with
+ * `MPPRunningModeImage`.
+ *
+ * This method supports classification of RGBA images. If your `MPPImage` has a source type of
+ * `MPPImageSourceTypePixelBuffer` or `MPPImageSourceTypeSampleBuffer`, the underlying pixel buffer
+ * must have one of the following pixel format types:
+ * 1. kCVPixelFormatType_32BGRA
+ * 2. kCVPixelFormatType_32RGBA
+ *
+ * If your `MPPImage` has a source type of `MPPImageSourceTypeImage` ensure that the color space is
+ * RGB with an Alpha channel.
+ *
+ * @param image The `MPPImage` on which face detection is to be performed.
+ * @param error An optional error parameter populated when there is an error in performing face
+ * detection on the input image.
+ *
+ * @return An `MPPFaceDetectorResult` face that contains a list of detections, each detection
+ * has a bounding box that is expressed in the unrotated input frame of reference coordinates
+ * system, i.e. in `[0,image_width) x [0,image_height)`, which are the dimensions of the underlying
+ * image data.
+ */
+- (nullable MPPFaceDetectorResult *)detectInImage:(MPPImage *)image
+                                            error:(NSError **)error NS_SWIFT_NAME(detect(image:));
+
+/**
+ * Performs face detection on the provided video frame of type `MPPImage` using the whole
+ * image as region of interest. Rotation will be applied according to the `orientation` property of
+ * the provided `MPPImage`. Only use this method when the `MPPFaceDetector` is created with
+ * `MPPRunningModeVideo`.
+ *
+ * This method supports classification of RGBA images. If your `MPPImage` has a source type of
+ * `MPPImageSourceTypePixelBuffer` or `MPPImageSourceTypeSampleBuffer`, the underlying pixel buffer
+ * must have one of the following pixel format types:
+ * 1. kCVPixelFormatType_32BGRA
+ * 2. kCVPixelFormatType_32RGBA
+ *
+ * If your `MPPImage` has a source type of `MPPImageSourceTypeImage` ensure that the color space is
+ * RGB with an Alpha channel.
+ *
+ * @param image The `MPPImage` on which face detection is to be performed.
+ * @param timestampInMilliseconds The video frame's timestamp (in milliseconds). The input
+ * timestamps must be monotonically increasing.
+ * @param error An optional error parameter populated when there is an error in performing face
+ * detection on the input image.
+ *
+ * @return An `MPPFaceDetectorResult` face that contains a list of detections, each detection
+ * has a bounding box that is expressed in the unrotated input frame of reference coordinates
+ * system, i.e. in `[0,image_width) x [0,image_height)`, which are the dimensions of the underlying
+ * image data.
+ */
+- (nullable MPPFaceDetectorResult *)detectInVideoFrame:(MPPImage *)image
+                               timestampInMilliseconds:(NSInteger)timestampInMilliseconds
+                                                 error:(NSError **)error
+    NS_SWIFT_NAME(detect(videoFrame:timestampInMilliseconds:));
+
+/**
+ * Sends live stream image data of type `MPPImage` to perform face detection using the whole
+ * image as region of interest. Rotation will be applied according to the `orientation` property of
+ * the provided `MPPImage`. Only use this method when the `MPPFaceDetector` is created with
+ * `MPPRunningModeLiveStream`.
+ *
+ * The object which needs to be continuously notified of the available results of face
+ * detection must confirm to `MPPFaceDetectorLiveStreamDelegate` protocol and implement the
+ * `faceDetector:didFinishDetectionWithResult:timestampInMilliseconds:error:` delegate method.
+ *
+ * It's required to provide a timestamp (in milliseconds) to indicate when the input image is sent
+ * to the face detector. The input timestamps must be monotonically increasing.
+ *
+ * This method supports classification of RGBA images. If your `MPPImage` has a source type of
+ * `MPPImageSourceTypePixelBuffer` or `MPPImageSourceTypeSampleBuffer`, the underlying pixel buffer
+ * must have one of the following pixel format types:
+ * 1. kCVPixelFormatType_32BGRA
+ * 2. kCVPixelFormatType_32RGBA
+ *
+ * If the input `MPPImage` has a source type of `MPPImageSourceTypeImage` ensure that the color
+ * space is RGB with an Alpha channel.
+ *
+ * If this method is used for classifying live camera frames using `AVFoundation`, ensure that you
+ * request `AVCaptureVideoDataOutput` to output frames in `kCMPixelFormat_32RGBA` using its
+ * `videoSettings` property.
+ *
+ * @param image A live stream image data of type `MPPImage` on which face detection is to be
+ * performed.
+ * @param timestampInMilliseconds The timestamp (in milliseconds) which indicates when the input
+ * image is sent to the face detector. The input timestamps must be monotonically increasing.
+ * @param error An optional error parameter populated when there is an error in performing face
+ * detection on the input live stream image data.
+ *
+ * @return `YES` if the image was sent to the task successfully, otherwise `NO`.
+ */
+- (BOOL)detectAsyncInImage:(MPPImage *)image
+    timestampInMilliseconds:(NSInteger)timestampInMilliseconds
+                      error:(NSError **)error
+    NS_SWIFT_NAME(detectAsync(image:timestampInMilliseconds:));
+
+- (instancetype)init NS_UNAVAILABLE;
+
++ (instancetype)new NS_UNAVAILABLE;
+
+@end
+
+NS_ASSUME_NONNULL_END

mediapipe/tasks/ios/vision/face_detector/sources/MPPFaceDetector.mm

@@ -0,0 +1,259 @@
+// Copyright 2023 The MediaPipe Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#import "mediapipe/tasks/ios/vision/face_detector/sources/MPPFaceDetector.h"
+
+#import "mediapipe/tasks/ios/common/utils/sources/MPPCommonUtils.h"
+#import "mediapipe/tasks/ios/common/utils/sources/NSString+Helpers.h"
+#import "mediapipe/tasks/ios/core/sources/MPPTaskInfo.h"
+#import "mediapipe/tasks/ios/vision/core/sources/MPPVisionPacketCreator.h"
+#import "mediapipe/tasks/ios/vision/core/sources/MPPVisionTaskRunner.h"
+#import "mediapipe/tasks/ios/vision/face_detector/utils/sources/MPPFaceDetectorOptions+Helpers.h"
+#import "mediapipe/tasks/ios/vision/face_detector/utils/sources/MPPFaceDetectorResult+Helpers.h"
+
+using ::mediapipe::NormalizedRect;
+using ::mediapipe::Packet;
+using ::mediapipe::Timestamp;
+using ::mediapipe::tasks::core::PacketMap;
+using ::mediapipe::tasks::core::PacketsCallback;
+
+static constexpr int kMicrosecondsPerMillisecond = 1000;
+
+// Constants for the underlying MP Tasks Graph. See
+// https://github.com/google/mediapipe/tree/master/mediapipe/tasks/cc/vision/face_detector/face_detector_graph.cc
+static NSString *const kDetectionsStreamName = @"detections_out";
+static NSString *const kDetectionsTag = @"DETECTIONS";
+static NSString *const kImageInStreamName = @"image_in";
+static NSString *const kImageOutStreamName = @"image_out";
+static NSString *const kImageTag = @"IMAGE";
+static NSString *const kNormRectStreamName = @"norm_rect_in";
+static NSString *const kNormRectTag = @"NORM_RECT";
+static NSString *const kTaskGraphName = @"mediapipe.tasks.vision.face_detector.FaceDetectorGraph";
+static NSString *const kTaskName = @"faceDetector";
+
+#define InputPacketMap(imagePacket, normalizedRectPacket) \
+  {                                                       \
+    {kImageInStreamName.cppString, imagePacket}, {        \
+      kNormRectStreamName.cppString, normalizedRectPacket \
+    }                                                     \
+  }
+
+@interface MPPFaceDetector () {
+  /** iOS Vision Task Runner */
+  MPPVisionTaskRunner *_visionTaskRunner;
+  dispatch_queue_t _callbackQueue;
+}
+@property(nonatomic, weak) id<MPPFaceDetectorLiveStreamDelegate> faceDetectorLiveStreamDelegate;
+
+- (void)processLiveStreamResult:(absl::StatusOr<PacketMap>)liveStreamResult;
+@end
+
+@implementation MPPFaceDetector
+
+- (instancetype)initWithOptions:(MPPFaceDetectorOptions *)options error:(NSError **)error {
+  self = [super init];
+  if (self) {
+    MPPTaskInfo *taskInfo = [[MPPTaskInfo alloc]
+        initWithTaskGraphName:kTaskGraphName
+                 inputStreams:@[
+                   [NSString stringWithFormat:@"%@:%@", kImageTag, kImageInStreamName],
+                   [NSString stringWithFormat:@"%@:%@", kNormRectTag, kNormRectStreamName]
+                 ]
+                outputStreams:@[
+                  [NSString stringWithFormat:@"%@:%@", kDetectionsTag, kDetectionsStreamName],
+                  [NSString stringWithFormat:@"%@:%@", kImageTag, kImageOutStreamName]
+                ]
+                  taskOptions:options
+           enableFlowLimiting:options.runningMode == MPPRunningModeLiveStream
+                        error:error];
+
+    if (!taskInfo) {
+      return nil;
+    }
+
+    PacketsCallback packetsCallback = nullptr;
+
+    if (options.faceDetectorLiveStreamDelegate) {
+      _faceDetectorLiveStreamDelegate = options.faceDetectorLiveStreamDelegate;
+
+      // Create a private serial dispatch queue in which the delegate method will be called
+      // asynchronously. This is to ensure that if the client performs a long running operation in
+      // the delegate method, the queue on which the C++ callbacks is invoked is not blocked and is
+      // freed up to continue with its operations.
+      _callbackQueue = dispatch_queue_create(
+          [MPPVisionTaskRunner uniqueDispatchQueueNameWithSuffix:kTaskName], NULL);
+
+      // Capturing `self` as weak in order to avoid `self` being kept in memory
+      // and cause a retain cycle, after self is set to `nil`.
+      MPPFaceDetector *__weak weakSelf = self;
+      packetsCallback = [=](absl::StatusOr<PacketMap> liveStreamResult) {
+        [weakSelf processLiveStreamResult:liveStreamResult];
+      };
+    }
+
+    _visionTaskRunner =
+        [[MPPVisionTaskRunner alloc] initWithCalculatorGraphConfig:[taskInfo generateGraphConfig]
+                                                       runningMode:options.runningMode
+                                                   packetsCallback:std::move(packetsCallback)
+                                                             error:error];
+
+    if (!_visionTaskRunner) {
+      return nil;
+    }
+  }
+
+  return self;
+}
+
+- (instancetype)initWithModelPath:(NSString *)modelPath error:(NSError **)error {
+  MPPFaceDetectorOptions *options = [[MPPFaceDetectorOptions alloc] init];
+
+  options.baseOptions.modelAssetPath = modelPath;
+
+  return [self initWithOptions:options error:error];
+}
+
+- (std::optional<PacketMap>)inputPacketMapWithMPPImage:(MPPImage *)image
+                               timestampInMilliseconds:(NSInteger)timestampInMilliseconds
+                                                 error:(NSError **)error {
+  std::optional<NormalizedRect> rect =
+      [_visionTaskRunner normalizedRectFromRegionOfInterest:CGRectZero
+                                                  imageSize:CGSizeMake(image.width, image.height)
+                                           imageOrientation:image.orientation
+                                                 ROIAllowed:NO
+                                                      error:error];
+  if (!rect.has_value()) {
+    return std::nullopt;
+  }
+
+  Packet imagePacket = [MPPVisionPacketCreator createPacketWithMPPImage:image
+                                                timestampInMilliseconds:timestampInMilliseconds
+                                                                  error:error];
+  if (imagePacket.IsEmpty()) {
+    return std::nullopt;
+  }
+
+  Packet normalizedRectPacket =
+      [MPPVisionPacketCreator createPacketWithNormalizedRect:rect.value()
+                                     timestampInMilliseconds:timestampInMilliseconds];
+
+  PacketMap inputPacketMap = InputPacketMap(imagePacket, normalizedRectPacket);
+  return inputPacketMap;
+}
+
+- (nullable MPPFaceDetectorResult *)detectInImage:(MPPImage *)image error:(NSError **)error {
+  std::optional<NormalizedRect> rect =
+      [_visionTaskRunner normalizedRectFromRegionOfInterest:CGRectZero
+                                                  imageSize:CGSizeMake(image.width, image.height)
+                                           imageOrientation:image.orientation
+                                                 ROIAllowed:NO
+                                                      error:error];
+  if (!rect.has_value()) {
+    return nil;
+  }
+
+  Packet imagePacket = [MPPVisionPacketCreator createPacketWithMPPImage:image error:error];
+  if (imagePacket.IsEmpty()) {
+    return nil;
+  }
+
+  Packet normalizedRectPacket =
+      [MPPVisionPacketCreator createPacketWithNormalizedRect:rect.value()];
+
+  PacketMap inputPacketMap = InputPacketMap(imagePacket, normalizedRectPacket);
+
+  std::optional<PacketMap> outputPacketMap = [_visionTaskRunner processImagePacketMap:inputPacketMap
+                                                                                error:error];
+  if (!outputPacketMap.has_value()) {
+    return nil;
+  }
+
+  return [MPPFaceDetectorResult
+      faceDetectorResultWithDetectionsPacket:outputPacketMap
+                                                 .value()[kDetectionsStreamName.cppString]];
+}
+
+- (nullable MPPFaceDetectorResult *)detectInVideoFrame:(MPPImage *)image
+                               timestampInMilliseconds:(NSInteger)timestampInMilliseconds
+                                                 error:(NSError **)error {
+  std::optional<PacketMap> inputPacketMap = [self inputPacketMapWithMPPImage:image
+                                                     timestampInMilliseconds:timestampInMilliseconds
+                                                                       error:error];
+  if (!inputPacketMap.has_value()) {
+    return nil;
+  }
+
+  std::optional<PacketMap> outputPacketMap =
+      [_visionTaskRunner processVideoFramePacketMap:inputPacketMap.value() error:error];
+
+  if (!outputPacketMap.has_value()) {
+    return nil;
+  }
+
+  return [MPPFaceDetectorResult
+      faceDetectorResultWithDetectionsPacket:outputPacketMap
+                                                 .value()[kDetectionsStreamName.cppString]];
+}
+
+- (BOOL)detectAsyncInImage:(MPPImage *)image
+    timestampInMilliseconds:(NSInteger)timestampInMilliseconds
+                      error:(NSError **)error {
+  std::optional<PacketMap> inputPacketMap = [self inputPacketMapWithMPPImage:image
+                                                     timestampInMilliseconds:timestampInMilliseconds
+                                                                       error:error];
+  if (!inputPacketMap.has_value()) {
+    return NO;
+  }
+
+  return [_visionTaskRunner processLiveStreamPacketMap:inputPacketMap.value() error:error];
+}
+
+- (void)processLiveStreamResult:(absl::StatusOr<PacketMap>)liveStreamResult {
+  if (![self.faceDetectorLiveStreamDelegate
+          respondsToSelector:@selector(faceDetector:
+                                 didFinishDetectionWithResult:timestampInMilliseconds:error:)]) {
+    return;
+  }
+  NSError *callbackError = nil;
+  if (![MPPCommonUtils checkCppError:liveStreamResult.status() toError:&callbackError]) {
+    dispatch_async(_callbackQueue, ^{
+      [self.faceDetectorLiveStreamDelegate faceDetector:self
+                           didFinishDetectionWithResult:nil
+                                timestampInMilliseconds:Timestamp::Unset().Value()
+                                                  error:callbackError];
+    });
+    return;
+  }
+
+  PacketMap &outputPacketMap = liveStreamResult.value();
+  if (outputPacketMap[kImageOutStreamName.cppString].IsEmpty()) {
+    return;
+  }
+
+  MPPFaceDetectorResult *result = [MPPFaceDetectorResult
+      faceDetectorResultWithDetectionsPacket:liveStreamResult
+                                                 .value()[kDetectionsStreamName.cppString]];
+
+  NSInteger timeStampInMilliseconds =
+      outputPacketMap[kImageOutStreamName.cppString].Timestamp().Value() /
+      kMicrosecondsPerMillisecond;
+  dispatch_async(_callbackQueue, ^{
+    [self.faceDetectorLiveStreamDelegate faceDetector:self
+                         didFinishDetectionWithResult:result
+                              timestampInMilliseconds:timeStampInMilliseconds
+                                                error:callbackError];
+  });
+}
+
+@end

mediapipe/tasks/ios/vision/face_detector/sources/MPPFaceDetectorOptions.h

@@ -0,0 +1,101 @@
+// Copyright 2023 The MediaPipe Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#import <Foundation/Foundation.h>
+
+#import "mediapipe/tasks/ios/core/sources/MPPTaskOptions.h"
+#import "mediapipe/tasks/ios/vision/core/sources/MPPRunningMode.h"
+#import "mediapipe/tasks/ios/vision/face_detector/sources/MPPFaceDetectorResult.h"
+
+NS_ASSUME_NONNULL_BEGIN
+
+@class MPPFaceDetector;
+
+/**
+ * This protocol defines an interface for the delegates of `MPPFaceDetector` face to receive
+ * results of performing asynchronous face detection on images (i.e, when `runningMode` =
+ * `MPPRunningModeLiveStream`).
+ *
+ * The delegate of `MPPFaceDetector` must adopt `MPPFaceDetectorLiveStreamDelegate` protocol.
+ * The methods in this protocol are optional.
+ */
+NS_SWIFT_NAME(FaceDetectorLiveStreamDelegate)
+@protocol MPPFaceDetectorLiveStreamDelegate <NSObject>
+
+@optional
+
+/**
+ * This method notifies a delegate that the results of asynchronous face detection of
+ * an image submitted to the `MPPFaceDetector` is available.
+ *
+ * This method is called on a private serial dispatch queue created by the `MPPFaceDetector`
+ * for performing the asynchronous delegates calls.
+ *
+ * @param faceDetector The face detector which performed the face detection.
+ * This is useful to test equality when there are multiple instances of `MPPFaceDetector`.
+ * @param result The `MPPFaceDetectorResult` object that contains a list of detections, each
+ * detection has a bounding box that is expressed in the unrotated input frame of reference
+ * coordinates system, i.e. in `[0,image_width) x [0,image_height)`, which are the dimensions of the
+ * underlying image data.
+ * @param timestampInMilliseconds The timestamp (in milliseconds) which indicates when the input
+ * image was sent to the face detector.
+ * @param error An optional error parameter populated when there is an error in performing face
+ * detection on the input live stream image data.
+ */
+- (void)faceDetector:(MPPFaceDetector *)faceDetector
+    didFinishDetectionWithResult:(nullable MPPFaceDetectorResult *)result
+         timestampInMilliseconds:(NSInteger)timestampInMilliseconds
+                           error:(nullable NSError *)error
+    NS_SWIFT_NAME(faceDetector(_:didFinishDetection:timestampInMilliseconds:error:));
+@end
+
+/** Options for setting up a `MPPFaceDetector`. */
+NS_SWIFT_NAME(FaceDetectorOptions)
+@interface MPPFaceDetectorOptions : MPPTaskOptions <NSCopying>
+
+/**
+ * Running mode of the face detector task. Defaults to `MPPRunningModeImage`.
+ * `MPPFaceDetector` can be created with one of the following running modes:
+ *  1. `MPPRunningModeImage`: The mode for performing face detection on single image inputs.
+ *  2. `MPPRunningModeVideo`: The mode for performing face detection on the decoded frames of a
+ *      video.
+ *  3. `MPPRunningModeLiveStream`: The mode for performing face detection on a live stream of
+ *      input data, such as from the camera.
+ */
+@property(nonatomic) MPPRunningMode runningMode;
+
+/**
+ * An object that confirms to `MPPFaceDetectorLiveStreamDelegate` protocol. This object must
+ * implement `faceDetector:didFinishDetectionWithResult:timestampInMilliseconds:error:` to receive
+ * the results of performing asynchronous face detection on images (i.e, when `runningMode` =
+ * `MPPRunningModeLiveStream`).
+ */
+@property(nonatomic, weak, nullable) id<MPPFaceDetectorLiveStreamDelegate>
+    faceDetectorLiveStreamDelegate;
+
+/**
+ * The minimum confidence score for the face detection to be considered successful. Defaults to
+ * 0.5.
+ */
+@property(nonatomic) float minDetectionConfidence;
+
+/**
+ * The minimum non-maximum-suppression threshold for face detection to be considered overlapped.
+ * Defaults to 0.3.
+ */
+@property(nonatomic) float minSuppressionThreshold;
+
+@end
+
+NS_ASSUME_NONNULL_END

mediapipe/tasks/ios/vision/face_detector/sources/MPPFaceDetectorOptions.m

@@ -0,0 +1,38 @@
+// Copyright 2023 The MediaPipe Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#import "mediapipe/tasks/ios/vision/face_detector/sources/MPPFaceDetectorOptions.h"
+
+@implementation MPPFaceDetectorOptions
+
+- (instancetype)init {
+  self = [super init];
+  if (self) {
+    _minDetectionConfidence = 0.5;
+    _minSuppressionThreshold = 0.3;
+  }
+  return self;
+}
+
+- (id)copyWithZone:(NSZone *)zone {
+  MPPFaceDetectorOptions *faceDetectorOptions = [super copyWithZone:zone];
+
+  faceDetectorOptions.minDetectionConfidence = self.minDetectionConfidence;
+  faceDetectorOptions.minSuppressionThreshold = self.minSuppressionThreshold;
+  faceDetectorOptions.faceDetectorLiveStreamDelegate = self.faceDetectorLiveStreamDelegate;
+
+  return faceDetectorOptions;
+}
+
+@end

mediapipe/tasks/ios/vision/face_detector/sources/MPPFaceDetectorResult.h

@@ -0,0 +1,49 @@
+// Copyright 2023 The MediaPipe Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#import <Foundation/Foundation.h>
+#import "mediapipe/tasks/ios/components/containers/sources/MPPDetection.h"
+#import "mediapipe/tasks/ios/core/sources/MPPTaskResult.h"
+
+NS_ASSUME_NONNULL_BEGIN
+
+/** Represents the detection results generated by `MPPFaceDetector`. */
+NS_SWIFT_NAME(FaceDetectorResult)
+@interface MPPFaceDetectorResult : MPPTaskResult
+
+/**
+ * The array of `MPPDetection` objects each of which has a bounding box that is expressed in the
+ * unrotated input frame of reference coordinates system, i.e. in `[0,image_width) x
+ * [0,image_height)`, which are the dimensions of the underlying image data.
+ */
+@property(nonatomic, readonly) NSArray<MPPDetection *> *detections;
+
+/**
+ * Initializes a new `MPPFaceDetectorResult` with the given array of detections and timestamp (in
+ * milliseconds).
+ *
+ * @param detections An array of `MPPDetection` objects each of which has a bounding box that is
+ * expressed in the unrotated input frame of reference coordinates system, i.e. in `[0,image_width)
+ * x [0,image_height)`, which are the dimensions of the underlying image data.
+ * @param timestampInMilliseconds The timestamp (in milliseconds) for this result.
+ *
+ * @return An instance of `MPPFaceDetectorResult` initialized with the given array of detections
+ * and timestamp (in milliseconds).
+ */
+- (instancetype)initWithDetections:(NSArray<MPPDetection *> *)detections
+           timestampInMilliseconds:(NSInteger)timestampInMilliseconds;
+
+@end
+
+NS_ASSUME_NONNULL_END

mediapipe/tasks/ios/vision/face_detector/sources/MPPFaceDetectorResult.m

@@ -0,0 +1,28 @@
+// Copyright 2023 The MediaPipe Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#import "mediapipe/tasks/ios/vision/face_detector/sources/MPPFaceDetectorResult.h"
+
+@implementation MPPFaceDetectorResult
+
+- (instancetype)initWithDetections:(NSArray<MPPDetection *> *)detections
+           timestampInMilliseconds:(NSInteger)timestampInMilliseconds {
+  self = [super initWithTimestampInMilliseconds:timestampInMilliseconds];
+  if (self) {
+    _detections = [detections copy];
+  }
+  return self;
+}
+
+@end

mediapipe/tasks/ios/vision/face_detector/utils/BUILD

@@ -0,0 +1,42 @@
+# Copyright 2023 The MediaPipe Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+package(default_visibility = ["//mediapipe/tasks:internal"])
+
+licenses(["notice"])
+
+objc_library(
+    name = "MPPFaceDetectorOptionsHelpers",
+    srcs = ["sources/MPPFaceDetectorOptions+Helpers.mm"],
+    hdrs = ["sources/MPPFaceDetectorOptions+Helpers.h"],
+    deps = [
+        "//mediapipe/framework:calculator_options_cc_proto",
+        "//mediapipe/tasks/cc/vision/face_detector/proto:face_detector_graph_options_cc_proto",
+        "//mediapipe/tasks/ios/common/utils:NSStringHelpers",
+        "//mediapipe/tasks/ios/core:MPPTaskOptionsProtocol",
+        "//mediapipe/tasks/ios/core/utils:MPPBaseOptionsHelpers",
+        "//mediapipe/tasks/ios/vision/face_detector:MPPFaceDetectorOptions",
+    ],
+)
+
+objc_library(
+    name = "MPPFaceDetectorResultHelpers",
+    srcs = ["sources/MPPFaceDetectorResult+Helpers.mm"],
+    hdrs = ["sources/MPPFaceDetectorResult+Helpers.h"],
+    deps = [
+        "//mediapipe/framework:packet",
+        "//mediapipe/tasks/ios/components/containers/utils:MPPDetectionHelpers",
+        "//mediapipe/tasks/ios/vision/face_detector:MPPFaceDetectorResult",
+    ],
+)

mediapipe/tasks/ios/vision/face_detector/utils/sources/MPPFaceDetectorOptions+Helpers.h

@@ -0,0 +1,36 @@
+// Copyright 2023 The MediaPipe Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef __cplusplus
+#error "This file requires Objective-C++."
+#endif  // __cplusplus
+
+#include "mediapipe/framework/calculator_options.pb.h"
+#import "mediapipe/tasks/ios/core/sources/MPPTaskOptionsProtocol.h"
+#import "mediapipe/tasks/ios/vision/face_detector/sources/MPPFaceDetectorOptions.h"
+
+NS_ASSUME_NONNULL_BEGIN
+
+@interface MPPFaceDetectorOptions (Helpers) <MPPTaskOptionsProtocol>
+
+/**
+ * Populates the provided `CalculatorOptions` proto container with the current settings.
+ *
+ * @param optionsProto The `CalculatorOptions` proto object to copy the settings to.
+ */
+- (void)copyToProto:(::mediapipe::CalculatorOptions *)optionsProto;
+
+@end
+
+NS_ASSUME_NONNULL_END

mediapipe/tasks/ios/vision/face_detector/utils/sources/MPPFaceDetectorOptions+Helpers.mm

@@ -0,0 +1,39 @@
+// Copyright 2023 The MediaPipe Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#import "mediapipe/tasks/ios/vision/face_detector/utils/sources/MPPFaceDetectorOptions+Helpers.h"
+
+#import "mediapipe/tasks/ios/common/utils/sources/NSString+Helpers.h"
+#import "mediapipe/tasks/ios/core/utils/sources/MPPBaseOptions+Helpers.h"
+
+#include "mediapipe/tasks/cc/vision/face_detector/proto/face_detector_graph_options.pb.h"
+
+using CalculatorOptionsProto = ::mediapipe::CalculatorOptions;
+using FaceDetectorGraphOptionsProto =
+    ::mediapipe::tasks::vision::face_detector::proto::FaceDetectorGraphOptions;
+
+@implementation MPPFaceDetectorOptions (Helpers)
+
+- (void)copyToProto:(CalculatorOptionsProto *)optionsProto {
+  FaceDetectorGraphOptionsProto *graphOptions =
+      optionsProto->MutableExtension(FaceDetectorGraphOptionsProto::ext);
+
+  graphOptions->Clear();
+
+  [self.baseOptions copyToProto:graphOptions->mutable_base_options()];
+  graphOptions->set_min_detection_confidence(self.minDetectionConfidence);
+  graphOptions->set_min_suppression_threshold(self.minSuppressionThreshold);
+}
+
+@end

mediapipe/tasks/ios/vision/face_detector/utils/sources/MPPFaceDetectorResult+Helpers.h

@@ -0,0 +1,39 @@
+// Copyright 2023 The MediaPipe Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef __cplusplus
+#error "This file requires Objective-C++."
+#endif  // __cplusplus
+
+#include "mediapipe/framework/packet.h"
+#import "mediapipe/tasks/ios/vision/face_detector/sources/MPPFaceDetectorResult.h"
+
+NS_ASSUME_NONNULL_BEGIN
+
+@interface MPPFaceDetectorResult (Helpers)
+
+/**
+ * Creates an `MPPFaceDetectorResult` from a MediaPipe packet containing a
+ * `std::vector<DetectionProto>`.
+ *
+ * @param packet a MediaPipe packet wrapping a `std::vector<DetectionProto>`.
+ *
+ * @return  An `MPPFaceDetectorResult` object that contains a list of detections.
+ */
++ (nullable MPPFaceDetectorResult *)faceDetectorResultWithDetectionsPacket:
+    (const ::mediapipe::Packet &)packet;
+
+@end
+
+NS_ASSUME_NONNULL_END

mediapipe/tasks/ios/vision/face_detector/utils/sources/MPPFaceDetectorResult+Helpers.mm

@@ -0,0 +1,45 @@
+// Copyright 2023 The MediaPipe Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#import "mediapipe/tasks/ios/vision/face_detector/utils/sources/MPPFaceDetectorResult+Helpers.h"
+
+#import "mediapipe/tasks/ios/components/containers/utils/sources/MPPDetection+Helpers.h"
+
+using DetectionProto = ::mediapipe::Detection;
+using ::mediapipe::Packet;
+
+static constexpr int kMicrosecondsPerMillisecond = 1000;
+
+@implementation MPPFaceDetectorResult (Helpers)
+
++ (nullable MPPFaceDetectorResult *)faceDetectorResultWithDetectionsPacket:(const Packet &)packet {
+  NSMutableArray<MPPDetection *> *detections;
+
+  if (packet.ValidateAsType<std::vector<DetectionProto>>().ok()) {
+    const std::vector<DetectionProto> &detectionProtos = packet.Get<std::vector<DetectionProto>>();
+    detections = [NSMutableArray arrayWithCapacity:(NSUInteger)detectionProtos.size()];
+    for (const auto &detectionProto : detectionProtos) {
+      [detections addObject:[MPPDetection detectionWithProto:detectionProto]];
+    }
+  } else {
+    detections = [NSMutableArray arrayWithCapacity:0];
+  }
+
+  return
+      [[MPPFaceDetectorResult alloc] initWithDetections:detections
+                                timestampInMilliseconds:(NSInteger)(packet.Timestamp().Value() /
+                                                                    kMicrosecondsPerMillisecond)];
+}
+
+@end