Merge pull request #5010 from kinaryml:c-hand-landmarker-api

PiperOrigin-RevId: 588900627

mediapipe/tasks/c/vision/BUILD

@@ -17,6 +17,7 @@ package(default_visibility = ["//mediapipe/tasks:internal"])
 licenses(["notice"])
 
 VISION_LIBRARIES = [
+    "//mediapipe/tasks/c/vision/hand_landmarker:hand_landmarker_lib",
     "//mediapipe/tasks/c/vision/image_classifier:image_classifier_lib",
     "//mediapipe/tasks/c/vision/image_embedder:image_embedder_lib",
     "//mediapipe/tasks/c/vision/object_detector:object_detector_lib",

mediapipe/tasks/c/vision/gesture_recognizer/gesture_recognizer.cc

@@ -228,7 +228,7 @@ int CppGestureRecognizerRecognizeAsync(void* recognizer, const MpImage& image,
   auto cpp_recognizer = static_cast<GestureRecognizer*>(recognizer);
   auto cpp_result = cpp_recognizer->RecognizeAsync(*img, timestamp_ms);
   if (!cpp_result.ok()) {
-    ABSL_LOG(ERROR) << "Data preparation for the image classification failed: "
+    ABSL_LOG(ERROR) << "Data preparation for the gesture recognition failed: "
                     << cpp_result;
     return CppProcessError(cpp_result, error_msg);
   }

mediapipe/tasks/c/vision/gesture_recognizer/gesture_recognizer_result_converter_test.cc

@@ -95,6 +95,22 @@ TEST(GestureRecognizerResultConverterTest, ConvertsCustomResult) {
     }
   }
 
+  // Verify conversion of handedness
+  EXPECT_NE(c_result.handedness, nullptr);
+  EXPECT_EQ(c_result.handedness_count, cpp_result.handedness.size());
+
+  for (uint32_t i = 0; i < c_result.handedness_count; ++i) {
+    EXPECT_EQ(c_result.handedness[i].categories_count,
+              cpp_result.handedness[i].classification_size());
+    for (uint32_t j = 0; j < c_result.handedness[i].categories_count; ++j) {
+      auto handedness = cpp_result.handedness[i].classification(j);
+      EXPECT_EQ(std::string(c_result.handedness[i].categories[j].category_name),
+                handedness.label());
+      EXPECT_FLOAT_EQ(c_result.handedness[i].categories[j].score,
+                      handedness.score());
+    }
+  }
+
   // Verify conversion of hand_landmarks
   EXPECT_NE(c_result.hand_landmarks, nullptr);
   EXPECT_EQ(c_result.hand_landmarks_count, cpp_result.hand_landmarks.size());

mediapipe/tasks/c/vision/hand_landmarker/BUILD

@@ -0,0 +1,144 @@
+# 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"])
+
+cc_library(
+    name = "hand_landmarker_result",
+    hdrs = ["hand_landmarker_result.h"],
+    visibility = ["//visibility:public"],
+    deps = [
+        "//mediapipe/tasks/c/components/containers:category",
+        "//mediapipe/tasks/c/components/containers:landmark",
+    ],
+)
+
+cc_library(
+    name = "hand_landmarker_result_converter",
+    srcs = ["hand_landmarker_result_converter.cc"],
+    hdrs = ["hand_landmarker_result_converter.h"],
+    deps = [
+        ":hand_landmarker_result",
+        "//mediapipe/tasks/c/components/containers:category",
+        "//mediapipe/tasks/c/components/containers:category_converter",
+        "//mediapipe/tasks/c/components/containers:landmark",
+        "//mediapipe/tasks/c/components/containers:landmark_converter",
+        "//mediapipe/tasks/cc/components/containers:category",
+        "//mediapipe/tasks/cc/components/containers:landmark",
+        "//mediapipe/tasks/cc/vision/hand_landmarker:hand_landmarker_result",
+    ],
+)
+
+cc_test(
+    name = "hand_landmarker_result_converter_test",
+    srcs = ["hand_landmarker_result_converter_test.cc"],
+    linkstatic = 1,
+    deps = [
+        ":hand_landmarker_result",
+        ":hand_landmarker_result_converter",
+        "//mediapipe/framework/port:gtest",
+        "//mediapipe/tasks/c/components/containers:landmark",
+        "//mediapipe/tasks/cc/components/containers:category",
+        "//mediapipe/tasks/cc/components/containers:classification_result",
+        "//mediapipe/tasks/cc/components/containers:landmark",
+        "//mediapipe/tasks/cc/vision/hand_landmarker:hand_landmarker_result",
+        "@com_google_googletest//:gtest_main",
+    ],
+)
+
+cc_library(
+    name = "hand_landmarker_lib",
+    srcs = ["hand_landmarker.cc"],
+    hdrs = ["hand_landmarker.h"],
+    visibility = ["//visibility:public"],
+    deps = [
+        ":hand_landmarker_result",
+        ":hand_landmarker_result_converter",
+        "//mediapipe/framework/formats:image",
+        "//mediapipe/framework/formats:image_frame",
+        "//mediapipe/tasks/c/core:base_options",
+        "//mediapipe/tasks/c/core:base_options_converter",
+        "//mediapipe/tasks/c/vision/core:common",
+        "//mediapipe/tasks/cc/vision/core:running_mode",
+        "//mediapipe/tasks/cc/vision/hand_landmarker",
+        "//mediapipe/tasks/cc/vision/hand_landmarker:hand_landmarker_result",
+        "//mediapipe/tasks/cc/vision/utils:image_utils",
+        "@com_google_absl//absl/log:absl_log",
+        "@com_google_absl//absl/status",
+        "@com_google_absl//absl/status:statusor",
+    ],
+    alwayslink = 1,
+)
+
+cc_test(
+    name = "hand_landmarker_test",
+    srcs = ["hand_landmarker_test.cc"],
+    data = [
+        "//mediapipe/framework/formats:image_frame_opencv",
+        "//mediapipe/framework/port:opencv_core",
+        "//mediapipe/framework/port:opencv_imgproc",
+        "//mediapipe/tasks/testdata/vision:test_images",
+        "//mediapipe/tasks/testdata/vision:test_models",
+    ],
+    linkstatic = 1,
+    deps = [
+        ":hand_landmarker_lib",
+        ":hand_landmarker_result",
+        "//mediapipe/framework/deps:file_path",
+        "//mediapipe/framework/formats:image",
+        "//mediapipe/framework/port:gtest",
+        "//mediapipe/tasks/c/components/containers:landmark",
+        "//mediapipe/tasks/c/vision/core:common",
+        "//mediapipe/tasks/cc/vision/utils:image_utils",
+        "@com_google_absl//absl/flags:flag",
+        "@com_google_absl//absl/strings",
+        "@com_google_googletest//:gtest_main",
+    ],
+)
+
+# bazel build -c opt --linkopt -s --strip always --define MEDIAPIPE_DISABLE_GPU=1 \
+# //mediapipe/tasks/c/vision/hand_landmarker:libhand_landmarker.so
+cc_binary(
+    name = "libhand_landmarker.so",
+    linkopts = [
+        "-Wl,-soname=libhand_landmarker.so",
+        "-fvisibility=hidden",
+    ],
+    linkshared = True,
+    tags = [
+        "manual",
+        "nobuilder",
+        "notap",
+    ],
+    deps = [":hand_landmarker_lib"],
+)
+
+# bazel build --config darwin_arm64 -c opt --strip always --define MEDIAPIPE_DISABLE_GPU=1 \
+# //mediapipe/tasks/c/vision/hand_landmarker:libhand_landmarker.dylib
+cc_binary(
+    name = "libhand_landmarker.dylib",
+    linkopts = [
+        "-Wl,-install_name,libhand_landmarker.dylib",
+        "-fvisibility=hidden",
+    ],
+    linkshared = True,
+    tags = [
+        "manual",
+        "nobuilder",
+        "notap",
+    ],
+    deps = [":hand_landmarker_lib"],
+)

mediapipe/tasks/c/vision/hand_landmarker/hand_landmarker.cc

@@ -0,0 +1,284 @@
+/* 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.
+==============================================================================*/
+
+#include "mediapipe/tasks/c/vision/hand_landmarker/hand_landmarker.h"
+
+#include <cstdint>
+#include <cstdlib>
+#include <memory>
+#include <utility>
+
+#include "absl/log/absl_log.h"
+#include "absl/status/status.h"
+#include "absl/status/statusor.h"
+#include "mediapipe/framework/formats/image.h"
+#include "mediapipe/framework/formats/image_frame.h"
+#include "mediapipe/tasks/c/core/base_options_converter.h"
+#include "mediapipe/tasks/c/vision/core/common.h"
+#include "mediapipe/tasks/c/vision/hand_landmarker/hand_landmarker_result.h"
+#include "mediapipe/tasks/c/vision/hand_landmarker/hand_landmarker_result_converter.h"
+#include "mediapipe/tasks/cc/vision/core/running_mode.h"
+#include "mediapipe/tasks/cc/vision/hand_landmarker/hand_landmarker.h"
+#include "mediapipe/tasks/cc/vision/hand_landmarker/hand_landmarker_result.h"
+#include "mediapipe/tasks/cc/vision/utils/image_utils.h"
+
+namespace mediapipe::tasks::c::vision::hand_landmarker {
+
+namespace {
+
+using ::mediapipe::tasks::c::components::containers::
+    CppCloseHandLandmarkerResult;
+using ::mediapipe::tasks::c::components::containers::
+    CppConvertToHandLandmarkerResult;
+using ::mediapipe::tasks::c::core::CppConvertToBaseOptions;
+using ::mediapipe::tasks::vision::CreateImageFromBuffer;
+using ::mediapipe::tasks::vision::core::RunningMode;
+using ::mediapipe::tasks::vision::hand_landmarker::HandLandmarker;
+typedef ::mediapipe::tasks::vision::hand_landmarker::HandLandmarkerResult
+    CppHandLandmarkerResult;
+
+int CppProcessError(absl::Status status, char** error_msg) {
+  if (error_msg) {
+    *error_msg = strdup(status.ToString().c_str());
+  }
+  return status.raw_code();
+}
+
+}  // namespace
+
+void CppConvertToHandLandmarkerOptions(
+    const HandLandmarkerOptions& in,
+    mediapipe::tasks::vision::hand_landmarker::HandLandmarkerOptions* out) {
+  out->num_hands = in.num_hands;
+  out->min_hand_detection_confidence = in.min_hand_detection_confidence;
+  out->min_hand_presence_confidence = in.min_hand_presence_confidence;
+  out->min_tracking_confidence = in.min_tracking_confidence;
+}
+
+HandLandmarker* CppHandLandmarkerCreate(const HandLandmarkerOptions& options,
+                                        char** error_msg) {
+  auto cpp_options = std::make_unique<
+      ::mediapipe::tasks::vision::hand_landmarker::HandLandmarkerOptions>();
+
+  CppConvertToBaseOptions(options.base_options, &cpp_options->base_options);
+  CppConvertToHandLandmarkerOptions(options, cpp_options.get());
+  cpp_options->running_mode = static_cast<RunningMode>(options.running_mode);
+
+  // Enable callback for processing live stream data when the running mode is
+  // set to RunningMode::LIVE_STREAM.
+  if (cpp_options->running_mode == RunningMode::LIVE_STREAM) {
+    if (options.result_callback == nullptr) {
+      const absl::Status status = absl::InvalidArgumentError(
+          "Provided null pointer to callback function.");
+      ABSL_LOG(ERROR) << "Failed to create HandLandmarker: " << status;
+      CppProcessError(status, error_msg);
+      return nullptr;
+    }
+
+    HandLandmarkerOptions::result_callback_fn result_callback =
+        options.result_callback;
+    cpp_options->result_callback =
+        [result_callback](absl::StatusOr<CppHandLandmarkerResult> cpp_result,
+                          const Image& image, int64_t timestamp) {
+          char* error_msg = nullptr;
+
+          if (!cpp_result.ok()) {
+            ABSL_LOG(ERROR) << "Recognition failed: " << cpp_result.status();
+            CppProcessError(cpp_result.status(), &error_msg);
+            result_callback(nullptr, MpImage(), timestamp, error_msg);
+            free(error_msg);
+            return;
+          }
+
+          // Result is valid for the lifetime of the callback function.
+          HandLandmarkerResult result;
+          CppConvertToHandLandmarkerResult(*cpp_result, &result);
+
+          const auto& image_frame = image.GetImageFrameSharedPtr();
+          const MpImage mp_image = {
+              .type = MpImage::IMAGE_FRAME,
+              .image_frame = {
+                  .format = static_cast<::ImageFormat>(image_frame->Format()),
+                  .image_buffer = image_frame->PixelData(),
+                  .width = image_frame->Width(),
+                  .height = image_frame->Height()}};
+
+          result_callback(&result, mp_image, timestamp,
+                          /* error_msg= */ nullptr);
+
+          CppCloseHandLandmarkerResult(&result);
+        };
+  }
+
+  auto landmarker = HandLandmarker::Create(std::move(cpp_options));
+  if (!landmarker.ok()) {
+    ABSL_LOG(ERROR) << "Failed to create HandLandmarker: "
+                    << landmarker.status();
+    CppProcessError(landmarker.status(), error_msg);
+    return nullptr;
+  }
+  return landmarker->release();
+}
+
+int CppHandLandmarkerDetect(void* landmarker, const MpImage& image,
+                            HandLandmarkerResult* result, char** error_msg) {
+  if (image.type == MpImage::GPU_BUFFER) {
+    const absl::Status status =
+        absl::InvalidArgumentError("GPU Buffer not supported yet.");
+
+    ABSL_LOG(ERROR) << "Recognition failed: " << status.message();
+    return CppProcessError(status, error_msg);
+  }
+
+  const auto img = CreateImageFromBuffer(
+      static_cast<ImageFormat::Format>(image.image_frame.format),
+      image.image_frame.image_buffer, image.image_frame.width,
+      image.image_frame.height);
+
+  if (!img.ok()) {
+    ABSL_LOG(ERROR) << "Failed to create Image: " << img.status();
+    return CppProcessError(img.status(), error_msg);
+  }
+
+  auto cpp_landmarker = static_cast<HandLandmarker*>(landmarker);
+  auto cpp_result = cpp_landmarker->Detect(*img);
+  if (!cpp_result.ok()) {
+    ABSL_LOG(ERROR) << "Recognition failed: " << cpp_result.status();
+    return CppProcessError(cpp_result.status(), error_msg);
+  }
+  CppConvertToHandLandmarkerResult(*cpp_result, result);
+  return 0;
+}
+
+int CppHandLandmarkerDetectForVideo(void* landmarker, const MpImage& image,
+                                    int64_t timestamp_ms,
+                                    HandLandmarkerResult* result,
+                                    char** error_msg) {
+  if (image.type == MpImage::GPU_BUFFER) {
+    absl::Status status =
+        absl::InvalidArgumentError("GPU Buffer not supported yet");
+
+    ABSL_LOG(ERROR) << "Recognition failed: " << status.message();
+    return CppProcessError(status, error_msg);
+  }
+
+  const auto img = CreateImageFromBuffer(
+      static_cast<ImageFormat::Format>(image.image_frame.format),
+      image.image_frame.image_buffer, image.image_frame.width,
+      image.image_frame.height);
+
+  if (!img.ok()) {
+    ABSL_LOG(ERROR) << "Failed to create Image: " << img.status();
+    return CppProcessError(img.status(), error_msg);
+  }
+
+  auto cpp_landmarker = static_cast<HandLandmarker*>(landmarker);
+  auto cpp_result = cpp_landmarker->DetectForVideo(*img, timestamp_ms);
+  if (!cpp_result.ok()) {
+    ABSL_LOG(ERROR) << "Recognition failed: " << cpp_result.status();
+    return CppProcessError(cpp_result.status(), error_msg);
+  }
+  CppConvertToHandLandmarkerResult(*cpp_result, result);
+  return 0;
+}
+
+int CppHandLandmarkerDetectAsync(void* landmarker, const MpImage& image,
+                                 int64_t timestamp_ms, char** error_msg) {
+  if (image.type == MpImage::GPU_BUFFER) {
+    absl::Status status =
+        absl::InvalidArgumentError("GPU Buffer not supported yet");
+
+    ABSL_LOG(ERROR) << "Recognition failed: " << status.message();
+    return CppProcessError(status, error_msg);
+  }
+
+  const auto img = CreateImageFromBuffer(
+      static_cast<ImageFormat::Format>(image.image_frame.format),
+      image.image_frame.image_buffer, image.image_frame.width,
+      image.image_frame.height);
+
+  if (!img.ok()) {
+    ABSL_LOG(ERROR) << "Failed to create Image: " << img.status();
+    return CppProcessError(img.status(), error_msg);
+  }
+
+  auto cpp_landmarker = static_cast<HandLandmarker*>(landmarker);
+  auto cpp_result = cpp_landmarker->DetectAsync(*img, timestamp_ms);
+  if (!cpp_result.ok()) {
+    ABSL_LOG(ERROR) << "Data preparation for the landmark detection failed: "
+                    << cpp_result;
+    return CppProcessError(cpp_result, error_msg);
+  }
+  return 0;
+}
+
+void CppHandLandmarkerCloseResult(HandLandmarkerResult* result) {
+  CppCloseHandLandmarkerResult(result);
+}
+
+int CppHandLandmarkerClose(void* landmarker, char** error_msg) {
+  auto cpp_landmarker = static_cast<HandLandmarker*>(landmarker);
+  auto result = cpp_landmarker->Close();
+  if (!result.ok()) {
+    ABSL_LOG(ERROR) << "Failed to close HandLandmarker: " << result;
+    return CppProcessError(result, error_msg);
+  }
+  delete cpp_landmarker;
+  return 0;
+}
+
+}  // namespace mediapipe::tasks::c::vision::hand_landmarker
+
+extern "C" {
+
+void* hand_landmarker_create(struct HandLandmarkerOptions* options,
+                             char** error_msg) {
+  return mediapipe::tasks::c::vision::hand_landmarker::CppHandLandmarkerCreate(
+      *options, error_msg);
+}
+
+int hand_landmarker_detect_image(void* landmarker, const MpImage& image,
+                                 HandLandmarkerResult* result,
+                                 char** error_msg) {
+  return mediapipe::tasks::c::vision::hand_landmarker::CppHandLandmarkerDetect(
+      landmarker, image, result, error_msg);
+}
+
+int hand_landmarker_detect_for_video(void* landmarker, const MpImage& image,
+                                     int64_t timestamp_ms,
+                                     HandLandmarkerResult* result,
+                                     char** error_msg) {
+  return mediapipe::tasks::c::vision::hand_landmarker::
+      CppHandLandmarkerDetectForVideo(landmarker, image, timestamp_ms, result,
+                                      error_msg);
+}
+
+int hand_landmarker_detect_async(void* landmarker, const MpImage& image,
+                                 int64_t timestamp_ms, char** error_msg) {
+  return mediapipe::tasks::c::vision::hand_landmarker::
+      CppHandLandmarkerDetectAsync(landmarker, image, timestamp_ms, error_msg);
+}
+
+void hand_landmarker_close_result(HandLandmarkerResult* result) {
+  mediapipe::tasks::c::vision::hand_landmarker::CppHandLandmarkerCloseResult(
+      result);
+}
+
+int hand_landmarker_close(void* landmarker, char** error_ms) {
+  return mediapipe::tasks::c::vision::hand_landmarker::CppHandLandmarkerClose(
+      landmarker, error_ms);
+}
+
+}  // extern "C"

mediapipe/tasks/c/vision/hand_landmarker/hand_landmarker.h

@@ -0,0 +1,146 @@
+/* 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 MEDIAPIPE_TASKS_C_VISION_HAND_LANDMARKER_HAND_LANDMARKER_H_
+#define MEDIAPIPE_TASKS_C_VISION_HAND_LANDMARKER_HAND_LANDMARKER_H_
+
+#include "mediapipe/tasks/c/core/base_options.h"
+#include "mediapipe/tasks/c/vision/core/common.h"
+#include "mediapipe/tasks/c/vision/hand_landmarker/hand_landmarker_result.h"
+
+#ifndef MP_EXPORT
+#define MP_EXPORT __attribute__((visibility("default")))
+#endif  // MP_EXPORT
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// The options for configuring a MediaPipe hand landmarker task.
+struct HandLandmarkerOptions {
+  // Base options for configuring MediaPipe Tasks, such as specifying the model
+  // file with metadata, accelerator options, op resolver, etc.
+  struct BaseOptions base_options;
+
+  // The running mode of the task. Default to the image mode.
+  // HandLandmarker has three running modes:
+  // 1) The image mode for recognizing hand landmarks on single image inputs.
+  // 2) The video mode for recognizing hand landmarks on the decoded frames of a
+  //    video.
+  // 3) The live stream mode for recognizing hand landmarks on the live stream
+  //    of input data, such as from camera. In this mode, the "result_callback"
+  //    below must be specified to receive the detection results asynchronously.
+  RunningMode running_mode;
+
+  // The maximum number of hands can be detected by the HandLandmarker.
+  int num_hands = 1;
+
+  // The minimum confidence score for the hand detection to be considered
+  // successful.
+  float min_hand_detection_confidence = 0.5;
+
+  // The minimum confidence score of hand presence score in the hand landmark
+  // detection.
+  float min_hand_presence_confidence = 0.5;
+
+  // The minimum confidence score for the hand tracking to be considered
+  // successful.
+  float min_tracking_confidence = 0.5;
+
+  // The user-defined result callback for processing live stream data.
+  // The result callback should only be specified when the running mode is set
+  // to RunningMode::LIVE_STREAM. Arguments of the callback function include:
+  // the pointer to recognition result, the image that result was obtained
+  // on, the timestamp relevant to recognition results and pointer to error
+  // message in case of any failure. The validity of the passed arguments is
+  // true for the lifetime of the callback function.
+  //
+  // A caller is responsible for closing hand landmarker result.
+  typedef void (*result_callback_fn)(HandLandmarkerResult* result,
+                                     const MpImage& image, int64_t timestamp_ms,
+                                     char* error_msg);
+  result_callback_fn result_callback;
+};
+
+// Creates an HandLandmarker from the provided `options`.
+// Returns a pointer to the hand landmarker on success.
+// If an error occurs, returns `nullptr` and sets the error parameter to an
+// an error message (if `error_msg` is not `nullptr`). You must free the memory
+// allocated for the error message.
+MP_EXPORT void* hand_landmarker_create(struct HandLandmarkerOptions* options,
+                                       char** error_msg);
+
+// Performs hand landmark detection on the input `image`. Returns `0` on
+// success. If an error occurs, returns an error code and sets the error
+// parameter to an an error message (if `error_msg` is not `nullptr`). You must
+// free the memory allocated for the error message.
+MP_EXPORT int hand_landmarker_detect_image(void* landmarker,
+                                           const MpImage& image,
+                                           HandLandmarkerResult* result,
+                                           char** error_msg);
+
+// Performs hand landmark detection on the provided video frame.
+// Only use this method when the HandLandmarker is created with the video
+// running mode.
+// The image can be of any size with format RGB or RGBA. It's required to
+// provide the video frame's timestamp (in milliseconds). The input timestamps
+// must be monotonically increasing.
+// If an error occurs, returns an error code and sets the error parameter to an
+// an error message (if `error_msg` is not `nullptr`). You must free the memory
+// allocated for the error message.
+MP_EXPORT int hand_landmarker_detect_for_video(void* landmarker,
+                                               const MpImage& image,
+                                               int64_t timestamp_ms,
+                                               HandLandmarkerResult* result,
+                                               char** error_msg);
+
+// Sends live image data to hand landmark detection, and the results will be
+// available via the `result_callback` provided in the HandLandmarkerOptions.
+// Only use this method when the HandLandmarker is created with the live
+// stream running mode.
+// The image can be of any size with format RGB or RGBA. It's required to
+// provide a timestamp (in milliseconds) to indicate when the input image is
+// sent to the hand landmarker. The input timestamps must be monotonically
+// increasing.
+// The `result_callback` provides:
+//   - The recognition results as an HandLandmarkerResult object.
+//   - The const reference to the corresponding input image that the hand
+//     landmarker runs on. Note that the const reference to the image will no
+//     longer be valid when the callback returns. To access the image data
+//     outside of the callback, callers need to make a copy of the image.
+//   - The input timestamp in milliseconds.
+// If an error occurs, returns an error code and sets the error parameter to an
+// an error message (if `error_msg` is not `nullptr`). You must free the memory
+// allocated for the error message.
+MP_EXPORT int hand_landmarker_detect_async(void* landmarker,
+                                           const MpImage& image,
+                                           int64_t timestamp_ms,
+                                           char** error_msg);
+
+// Frees the memory allocated inside a HandLandmarkerResult result.
+// Does not free the result pointer itself.
+MP_EXPORT void hand_landmarker_close_result(HandLandmarkerResult* result);
+
+// Frees hand landmarker.
+// If an error occurs, returns an error code and sets the error parameter to an
+// an error message (if `error_msg` is not `nullptr`). You must free the memory
+// allocated for the error message.
+MP_EXPORT int hand_landmarker_close(void* landmarker, char** error_msg);
+
+#ifdef __cplusplus
+}  // extern C
+#endif
+
+#endif  // MEDIAPIPE_TASKS_C_VISION_HAND_LANDMARKER_HAND_LANDMARKER_H_

mediapipe/tasks/c/vision/hand_landmarker/hand_landmarker_result.h

@@ -0,0 +1,58 @@
+/* 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 MEDIAPIPE_TASKS_C_VISION_HAND_LANDMARKER_RESULT_HAND_LANDMARKER_RESULT_H_
+#define MEDIAPIPE_TASKS_C_VISION_HAND_LANDMARKER_RESULT_HAND_LANDMARKER_RESULT_H_
+
+#include <cstdint>
+
+#include "mediapipe/tasks/c/components/containers/category.h"
+#include "mediapipe/tasks/c/components/containers/landmark.h"
+
+#ifndef MP_EXPORT
+#define MP_EXPORT __attribute__((visibility("default")))
+#endif  // MP_EXPORT
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// The hand landmarker result from HandLandmarker, where each vector
+// element represents a single hand detected in the image.
+struct HandLandmarkerResult {
+  // Classification of handedness.
+  struct Categories* handedness;
+
+  // The number of elements in the handedness array.
+  uint32_t handedness_count;
+
+  // Detected hand landmarks in normalized image coordinates.
+  struct NormalizedLandmarks* hand_landmarks;
+
+  // The number of elements in the hand_landmarks array.
+  uint32_t hand_landmarks_count;
+
+  // Detected hand landmarks in world coordinates.
+  struct Landmarks* hand_world_landmarks;
+
+  // The number of elements in the hand_world_landmarks array.
+  uint32_t hand_world_landmarks_count;
+};
+
+#ifdef __cplusplus
+}  // extern C
+#endif
+
+#endif  // MEDIAPIPE_TASKS_C_VISION_HAND_LANDMARKER_RESULT_HAND_LANDMARKER_RESULT_H_

mediapipe/tasks/c/vision/hand_landmarker/hand_landmarker_result_converter.cc

@@ -0,0 +1,103 @@
+/* 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.
+==============================================================================*/
+
+#include "mediapipe/tasks/c/vision/hand_landmarker/hand_landmarker_result_converter.h"
+
+#include <cstdint>
+#include <vector>
+
+#include "mediapipe/tasks/c/components/containers/category.h"
+#include "mediapipe/tasks/c/components/containers/category_converter.h"
+#include "mediapipe/tasks/c/components/containers/landmark.h"
+#include "mediapipe/tasks/c/components/containers/landmark_converter.h"
+#include "mediapipe/tasks/c/vision/hand_landmarker/hand_landmarker_result.h"
+#include "mediapipe/tasks/cc/components/containers/category.h"
+#include "mediapipe/tasks/cc/components/containers/landmark.h"
+#include "mediapipe/tasks/cc/vision/hand_landmarker/hand_landmarker_result.h"
+
+namespace mediapipe::tasks::c::components::containers {
+
+using CppCategory = ::mediapipe::tasks::components::containers::Category;
+using CppLandmark = ::mediapipe::tasks::components::containers::Landmark;
+using CppNormalizedLandmark =
+    ::mediapipe::tasks::components::containers::NormalizedLandmark;
+
+void CppConvertToHandLandmarkerResult(
+    const mediapipe::tasks::vision::hand_landmarker::HandLandmarkerResult& in,
+    HandLandmarkerResult* out) {
+  out->handedness_count = in.handedness.size();
+  out->handedness = new Categories[out->handedness_count];
+
+  for (uint32_t i = 0; i < out->handedness_count; ++i) {
+    uint32_t categories_count = in.handedness[i].categories.size();
+    out->handedness[i].categories_count = categories_count;
+    out->handedness[i].categories = new Category[categories_count];
+
+    for (uint32_t j = 0; j < categories_count; ++j) {
+      const auto& cpp_category = in.handedness[i].categories[j];
+      CppConvertToCategory(cpp_category, &out->handedness[i].categories[j]);
+    }
+  }
+
+  out->hand_landmarks_count = in.hand_landmarks.size();
+  out->hand_landmarks = new NormalizedLandmarks[out->hand_landmarks_count];
+  for (uint32_t i = 0; i < out->hand_landmarks_count; ++i) {
+    std::vector<CppNormalizedLandmark> cpp_normalized_landmarks;
+    for (uint32_t j = 0; j < in.hand_landmarks[i].landmarks.size(); ++j) {
+      const auto& cpp_landmark = in.hand_landmarks[i].landmarks[j];
+      cpp_normalized_landmarks.push_back(cpp_landmark);
+    }
+    CppConvertToNormalizedLandmarks(cpp_normalized_landmarks,
+                                    &out->hand_landmarks[i]);
+  }
+
+  out->hand_world_landmarks_count = in.hand_world_landmarks.size();
+  out->hand_world_landmarks = new Landmarks[out->hand_world_landmarks_count];
+  for (uint32_t i = 0; i < out->hand_world_landmarks_count; ++i) {
+    std::vector<CppLandmark> cpp_landmarks;
+    for (uint32_t j = 0; j < in.hand_world_landmarks[i].landmarks.size(); ++j) {
+      const auto& cpp_landmark = in.hand_world_landmarks[i].landmarks[j];
+      cpp_landmarks.push_back(cpp_landmark);
+    }
+    CppConvertToLandmarks(cpp_landmarks, &out->hand_world_landmarks[i]);
+  }
+}
+
+void CppCloseHandLandmarkerResult(HandLandmarkerResult* result) {
+  for (uint32_t i = 0; i < result->handedness_count; ++i) {
+    CppCloseCategories(&result->handedness[i]);
+  }
+  delete[] result->handedness;
+
+  for (uint32_t i = 0; i < result->hand_landmarks_count; ++i) {
+    CppCloseNormalizedLandmarks(&result->hand_landmarks[i]);
+  }
+  delete[] result->hand_landmarks;
+
+  for (uint32_t i = 0; i < result->hand_world_landmarks_count; ++i) {
+    CppCloseLandmarks(&result->hand_world_landmarks[i]);
+  }
+  delete[] result->hand_world_landmarks;
+
+  result->handedness = nullptr;
+  result->hand_landmarks = nullptr;
+  result->hand_world_landmarks = nullptr;
+
+  result->handedness_count = 0;
+  result->hand_landmarks_count = 0;
+  result->hand_world_landmarks_count = 0;
+}
+
+}  // namespace mediapipe::tasks::c::components::containers

mediapipe/tasks/c/vision/hand_landmarker/hand_landmarker_result_converter.h

@@ -0,0 +1,32 @@
+/* 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 MEDIAPIPE_TASKS_C_COMPONENTS_CONTAINERS_HAND_LANDMARKER_RESULT_CONVERTER_H_
+#define MEDIAPIPE_TASKS_C_COMPONENTS_CONTAINERS_HAND_LANDMARKER_RESULT_CONVERTER_H_
+
+#include "mediapipe/tasks/c/vision/hand_landmarker/hand_landmarker_result.h"
+#include "mediapipe/tasks/cc/vision/hand_landmarker/hand_landmarker_result.h"
+
+namespace mediapipe::tasks::c::components::containers {
+
+void CppConvertToHandLandmarkerResult(
+    const mediapipe::tasks::vision::hand_landmarker::HandLandmarkerResult& in,
+    HandLandmarkerResult* out);
+
+void CppCloseHandLandmarkerResult(HandLandmarkerResult* result);
+
+}  // namespace mediapipe::tasks::c::components::containers
+
+#endif  // MEDIAPIPE_TASKS_C_COMPONENTS_CONTAINERS_HAND_LANDMARKER_RESULT_CONVERTER_H_

mediapipe/tasks/c/vision/hand_landmarker/hand_landmarker_result_converter_test.cc

@@ -0,0 +1,127 @@
+/* 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.
+==============================================================================*/
+
+#include "mediapipe/tasks/c/vision/hand_landmarker/hand_landmarker_result_converter.h"
+
+#include <cstdint>
+
+#include "mediapipe/framework/port/gtest.h"
+#include "mediapipe/tasks/c/components/containers/landmark.h"
+#include "mediapipe/tasks/c/vision/hand_landmarker/hand_landmarker_result.h"
+#include "mediapipe/tasks/cc/components/containers/category.h"
+#include "mediapipe/tasks/cc/components/containers/classification_result.h"
+#include "mediapipe/tasks/cc/components/containers/landmark.h"
+#include "mediapipe/tasks/cc/vision/hand_landmarker/hand_landmarker_result.h"
+
+namespace mediapipe::tasks::c::components::containers {
+
+void InitHandLandmarkerResult(
+    ::mediapipe::tasks::vision::hand_landmarker::HandLandmarkerResult*
+        cpp_result) {
+  // Initialize handedness
+  mediapipe::tasks::components::containers::Category cpp_category = {
+      /* index= */ 1,
+      /* score= */ 0.8f,
+      /* category_name= */ "handeness_label_1",
+      /* display_name= */ "handeness_display_name_1"};
+  mediapipe::tasks::components::containers::Classifications
+      classifications_for_handedness;
+  classifications_for_handedness.categories.push_back(cpp_category);
+  cpp_result->handedness.push_back(classifications_for_handedness);
+
+  // Initialize hand_landmarks
+  mediapipe::tasks::components::containers::NormalizedLandmark
+      cpp_normalized_landmark = {/* x= */ 0.1f,
+                                 /* y= */ 0.2f,
+                                 /* z= */ 0.3f};
+  mediapipe::tasks::components::containers::NormalizedLandmarks
+      cpp_normalized_landmarks;
+  cpp_normalized_landmarks.landmarks.push_back(cpp_normalized_landmark);
+  cpp_result->hand_landmarks.push_back(cpp_normalized_landmarks);
+
+  // Initialize hand_world_landmarks
+  mediapipe::tasks::components::containers::Landmark cpp_landmark = {
+      /* x= */ 1.0f,
+      /* y= */ 1.1f,
+      /* z= */ 1.2f};
+  mediapipe::tasks::components::containers::Landmarks cpp_landmarks;
+  cpp_landmarks.landmarks.push_back(cpp_landmark);
+  cpp_result->hand_world_landmarks.push_back(cpp_landmarks);
+}
+
+TEST(HandLandmarkerResultConverterTest, ConvertsCustomResult) {
+  ::mediapipe::tasks::vision::hand_landmarker::HandLandmarkerResult cpp_result;
+  InitHandLandmarkerResult(&cpp_result);
+
+  HandLandmarkerResult c_result;
+  CppConvertToHandLandmarkerResult(cpp_result, &c_result);
+
+  // Verify conversion of hand_landmarks
+  EXPECT_NE(c_result.hand_landmarks, nullptr);
+  EXPECT_EQ(c_result.hand_landmarks_count, cpp_result.hand_landmarks.size());
+
+  for (uint32_t i = 0; i < c_result.hand_landmarks_count; ++i) {
+    EXPECT_EQ(c_result.hand_landmarks[i].landmarks_count,
+              cpp_result.hand_landmarks[i].landmarks.size());
+    for (uint32_t j = 0; j < c_result.hand_landmarks[i].landmarks_count; ++j) {
+      const auto& landmark = cpp_result.hand_landmarks[i].landmarks[j];
+      EXPECT_FLOAT_EQ(c_result.hand_landmarks[i].landmarks[j].x, landmark.x);
+      EXPECT_FLOAT_EQ(c_result.hand_landmarks[i].landmarks[j].y, landmark.y);
+      EXPECT_FLOAT_EQ(c_result.hand_landmarks[i].landmarks[j].z, landmark.z);
+    }
+  }
+
+  // Verify conversion of hand_world_landmarks
+  EXPECT_NE(c_result.hand_world_landmarks, nullptr);
+  EXPECT_EQ(c_result.hand_world_landmarks_count,
+            cpp_result.hand_world_landmarks.size());
+
+  for (uint32_t i = 0; i < c_result.hand_landmarks_count; ++i) {
+    EXPECT_EQ(c_result.hand_world_landmarks[i].landmarks_count,
+              cpp_result.hand_world_landmarks[i].landmarks.size());
+    for (uint32_t j = 0; j < c_result.hand_world_landmarks[i].landmarks_count;
+         ++j) {
+      const auto& landmark = cpp_result.hand_world_landmarks[i].landmarks[j];
+      EXPECT_FLOAT_EQ(c_result.hand_world_landmarks[i].landmarks[j].x,
+                      landmark.x);
+      EXPECT_FLOAT_EQ(c_result.hand_world_landmarks[i].landmarks[j].y,
+                      landmark.y);
+      EXPECT_FLOAT_EQ(c_result.hand_world_landmarks[i].landmarks[j].z,
+                      landmark.z);
+    }
+  }
+
+  CppCloseHandLandmarkerResult(&c_result);
+}
+
+TEST(HandLandmarkerResultConverterTest, FreesMemory) {
+  ::mediapipe::tasks::vision::hand_landmarker::HandLandmarkerResult cpp_result;
+  InitHandLandmarkerResult(&cpp_result);
+
+  HandLandmarkerResult c_result;
+  CppConvertToHandLandmarkerResult(cpp_result, &c_result);
+
+  EXPECT_NE(c_result.handedness, nullptr);
+  EXPECT_NE(c_result.hand_landmarks, nullptr);
+  EXPECT_NE(c_result.hand_world_landmarks, nullptr);
+
+  CppCloseHandLandmarkerResult(&c_result);
+
+  EXPECT_EQ(c_result.handedness, nullptr);
+  EXPECT_EQ(c_result.hand_landmarks, nullptr);
+  EXPECT_EQ(c_result.hand_world_landmarks, nullptr);
+}
+
+}  // namespace mediapipe::tasks::c::components::containers

mediapipe/tasks/c/vision/hand_landmarker/hand_landmarker_test.cc

@@ -0,0 +1,261 @@
+/* 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.
+==============================================================================*/
+
+#include "mediapipe/tasks/c/vision/hand_landmarker/hand_landmarker.h"
+
+#include <cstdint>
+#include <cstdlib>
+#include <string>
+
+#include "absl/flags/flag.h"
+#include "absl/strings/string_view.h"
+#include "mediapipe/framework/deps/file_path.h"
+#include "mediapipe/framework/formats/image.h"
+#include "mediapipe/framework/port/gmock.h"
+#include "mediapipe/framework/port/gtest.h"
+#include "mediapipe/tasks/c/components/containers/landmark.h"
+#include "mediapipe/tasks/c/vision/core/common.h"
+#include "mediapipe/tasks/c/vision/hand_landmarker/hand_landmarker_result.h"
+#include "mediapipe/tasks/cc/vision/utils/image_utils.h"
+
+namespace {
+
+using ::mediapipe::file::JoinPath;
+using ::mediapipe::tasks::vision::DecodeImageFromFile;
+using testing::HasSubstr;
+
+constexpr char kTestDataDirectory[] = "/mediapipe/tasks/testdata/vision/";
+constexpr char kModelName[] = "hand_landmarker.task";
+constexpr char kImageFile[] = "fist.jpg";
+constexpr float kScorePrecision = 1e-2;
+constexpr float kLandmarkPrecision = 1e-1;
+constexpr int kIterations = 100;
+
+std::string GetFullPath(absl::string_view file_name) {
+  return JoinPath("./", kTestDataDirectory, file_name);
+}
+
+void MatchesHandLandmarkerResult(HandLandmarkerResult* result,
+                                 const float score_precision,
+                                 const float landmark_precision) {
+  // Expects to have the same number of hands detected.
+  EXPECT_EQ(result->handedness_count, 1);
+
+  // Actual handedness matches expected handedness.
+  EXPECT_EQ(std::string{result->handedness[0].categories[0].category_name},
+            "Right");
+  EXPECT_NEAR(result->handedness[0].categories[0].score, 0.9893f,
+              score_precision);
+
+  // Actual landmarks match expected landmarks.
+  EXPECT_NEAR(result->hand_landmarks[0].landmarks[0].x, 0.477f,
+              landmark_precision);
+  EXPECT_NEAR(result->hand_landmarks[0].landmarks[0].y, 0.661f,
+              landmark_precision);
+  EXPECT_NEAR(result->hand_landmarks[0].landmarks[0].z, 0.0f,
+              landmark_precision);
+  EXPECT_NEAR(result->hand_world_landmarks[0].landmarks[0].x, -0.009f,
+              landmark_precision);
+  EXPECT_NEAR(result->hand_world_landmarks[0].landmarks[0].y, 0.082f,
+              landmark_precision);
+  EXPECT_NEAR(result->hand_world_landmarks[0].landmarks[0].z, 0.006f,
+              landmark_precision);
+}
+
+TEST(HandLandmarkerTest, ImageModeTest) {
+  const auto image = DecodeImageFromFile(GetFullPath(kImageFile));
+  ASSERT_TRUE(image.ok());
+
+  const std::string model_path = GetFullPath(kModelName);
+  HandLandmarkerOptions options = {
+      /* base_options= */ {/* model_asset_buffer= */ nullptr,
+                           /* model_asset_buffer_count= */ 0,
+                           /* model_asset_path= */ model_path.c_str()},
+      /* running_mode= */ RunningMode::IMAGE,
+      /* num_hands= */ 1,
+      /* min_hand_detection_confidence= */ 0.5,
+      /* min_hand_presence_confidence= */ 0.5,
+      /* min_tracking_confidence= */ 0.5,
+  };
+
+  void* landmarker = hand_landmarker_create(&options, /* error_msg */ nullptr);
+  EXPECT_NE(landmarker, nullptr);
+
+  const auto& image_frame = image->GetImageFrameSharedPtr();
+  const MpImage mp_image = {
+      .type = MpImage::IMAGE_FRAME,
+      .image_frame = {.format = static_cast<ImageFormat>(image_frame->Format()),
+                      .image_buffer = image_frame->PixelData(),
+                      .width = image_frame->Width(),
+                      .height = image_frame->Height()}};
+
+  HandLandmarkerResult result;
+  hand_landmarker_detect_image(landmarker, mp_image, &result,
+                               /* error_msg */ nullptr);
+  MatchesHandLandmarkerResult(&result, kScorePrecision, kLandmarkPrecision);
+  hand_landmarker_close_result(&result);
+  hand_landmarker_close(landmarker, /* error_msg */ nullptr);
+}
+
+TEST(HandLandmarkerTest, VideoModeTest) {
+  const auto image = DecodeImageFromFile(GetFullPath(kImageFile));
+  ASSERT_TRUE(image.ok());
+
+  const std::string model_path = GetFullPath(kModelName);
+  HandLandmarkerOptions options = {
+      /* base_options= */ {/* model_asset_buffer= */ nullptr,
+                           /* model_asset_buffer_count= */ 0,
+                           /* model_asset_path= */ model_path.c_str()},
+      /* running_mode= */ RunningMode::VIDEO,
+      /* num_hands= */ 1,
+      /* min_hand_detection_confidence= */ 0.5,
+      /* min_hand_presence_confidence= */ 0.5,
+      /* min_tracking_confidence= */ 0.5,
+  };
+
+  void* landmarker = hand_landmarker_create(&options, /* error_msg */ nullptr);
+  EXPECT_NE(landmarker, nullptr);
+
+  const auto& image_frame = image->GetImageFrameSharedPtr();
+  const MpImage mp_image = {
+      .type = MpImage::IMAGE_FRAME,
+      .image_frame = {.format = static_cast<ImageFormat>(image_frame->Format()),
+                      .image_buffer = image_frame->PixelData(),
+                      .width = image_frame->Width(),
+                      .height = image_frame->Height()}};
+
+  for (int i = 0; i < kIterations; ++i) {
+    HandLandmarkerResult result;
+    hand_landmarker_detect_for_video(landmarker, mp_image, i, &result,
+                                     /* error_msg */ nullptr);
+
+    MatchesHandLandmarkerResult(&result, kScorePrecision, kLandmarkPrecision);
+    hand_landmarker_close_result(&result);
+  }
+  hand_landmarker_close(landmarker, /* error_msg */ nullptr);
+}
+
+// A structure to support LiveStreamModeTest below. This structure holds a
+// static method `Fn` for a callback function of C API. A `static` qualifier
+// allows to take an address of the method to follow API style. Another static
+// struct member is `last_timestamp` that is used to verify that current
+// timestamp is greater than the previous one.
+struct LiveStreamModeCallback {
+  static int64_t last_timestamp;
+  static void Fn(HandLandmarkerResult* landmarker_result, const MpImage& image,
+                 int64_t timestamp, char* error_msg) {
+    ASSERT_NE(landmarker_result, nullptr);
+    ASSERT_EQ(error_msg, nullptr);
+    MatchesHandLandmarkerResult(landmarker_result, kScorePrecision,
+                                kLandmarkPrecision);
+    EXPECT_GT(image.image_frame.width, 0);
+    EXPECT_GT(image.image_frame.height, 0);
+    EXPECT_GT(timestamp, last_timestamp);
+    ++last_timestamp;
+  }
+};
+int64_t LiveStreamModeCallback::last_timestamp = -1;
+
+TEST(HandLandmarkerTest, LiveStreamModeTest) {
+  const auto image = DecodeImageFromFile(GetFullPath(kImageFile));
+  ASSERT_TRUE(image.ok());
+
+  const std::string model_path = GetFullPath(kModelName);
+
+  HandLandmarkerOptions options = {
+      /* base_options= */ {/* model_asset_buffer= */ nullptr,
+                           /* model_asset_buffer_count= */ 0,
+                           /* model_asset_path= */ model_path.c_str()},
+      /* running_mode= */ RunningMode::LIVE_STREAM,
+      /* num_hands= */ 1,
+      /* min_hand_detection_confidence= */ 0.5,
+      /* min_hand_presence_confidence= */ 0.5,
+      /* min_tracking_confidence= */ 0.5,
+      /* result_callback= */ LiveStreamModeCallback::Fn,
+  };
+
+  void* landmarker = hand_landmarker_create(&options, /* error_msg */ nullptr);
+  EXPECT_NE(landmarker, nullptr);
+
+  const auto& image_frame = image->GetImageFrameSharedPtr();
+  const MpImage mp_image = {
+      .type = MpImage::IMAGE_FRAME,
+      .image_frame = {.format = static_cast<ImageFormat>(image_frame->Format()),
+                      .image_buffer = image_frame->PixelData(),
+                      .width = image_frame->Width(),
+                      .height = image_frame->Height()}};
+
+  for (int i = 0; i < kIterations; ++i) {
+    EXPECT_GE(hand_landmarker_detect_async(landmarker, mp_image, i,
+                                           /* error_msg */ nullptr),
+              0);
+  }
+  hand_landmarker_close(landmarker, /* error_msg */ nullptr);
+
+  // Due to the flow limiter, the total of outputs might be smaller than the
+  // number of iterations.
+  EXPECT_LE(LiveStreamModeCallback::last_timestamp, kIterations);
+  EXPECT_GT(LiveStreamModeCallback::last_timestamp, 0);
+}
+
+TEST(HandLandmarkerTest, InvalidArgumentHandling) {
+  // It is an error to set neither the asset buffer nor the path.
+  HandLandmarkerOptions options = {
+      /* base_options= */ {/* model_asset_buffer= */ nullptr,
+                           /* model_asset_buffer_count= */ 0,
+                           /* model_asset_path= */ nullptr},
+      /* running_mode= */ RunningMode::IMAGE,
+      /* num_hands= */ 1,
+      /* min_hand_detection_confidence= */ 0.5,
+      /* min_hand_presence_confidence= */ 0.5,
+      /* min_tracking_confidence= */ 0.5,
+  };
+
+  char* error_msg;
+  void* landmarker = hand_landmarker_create(&options, &error_msg);
+  EXPECT_EQ(landmarker, nullptr);
+
+  EXPECT_THAT(error_msg, HasSubstr("ExternalFile must specify"));
+
+  free(error_msg);
+}
+
+TEST(HandLandmarkerTest, FailedRecognitionHandling) {
+  const std::string model_path = GetFullPath(kModelName);
+  HandLandmarkerOptions options = {
+      /* base_options= */ {/* model_asset_buffer= */ nullptr,
+                           /* model_asset_buffer_count= */ 0,
+                           /* model_asset_path= */ model_path.c_str()},
+      /* running_mode= */ RunningMode::IMAGE,
+      /* num_hands= */ 1,
+      /* min_hand_detection_confidence= */ 0.5,
+      /* min_hand_presence_confidence= */ 0.5,
+      /* min_tracking_confidence= */ 0.5,
+  };
+
+  void* landmarker = hand_landmarker_create(&options, /* error_msg */
+                                            nullptr);
+  EXPECT_NE(landmarker, nullptr);
+
+  const MpImage mp_image = {.type = MpImage::GPU_BUFFER, .gpu_buffer = {}};
+  HandLandmarkerResult result;
+  char* error_msg;
+  hand_landmarker_detect_image(landmarker, mp_image, &result, &error_msg);
+  EXPECT_THAT(error_msg, HasSubstr("GPU Buffer not supported yet"));
+  free(error_msg);
+  hand_landmarker_close(landmarker, /* error_msg */ nullptr);
+}
+
+}  // namespace