Add video capture on Android.

media/video/capture/android/video_capture_device_android.cc

+// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "media/video/capture/android/video_capture_device_android.h"
+
+#include <string>
+
+#include "base/android/jni_android.h"
+#include "base/android/scoped_java_ref.h"
+#include "base/string_number_conversions.h"
+#include "base/stringprintf.h"
+#include "jni/Camera_jni.h"
+#include "jni/VideoCapture_jni.h"
+
+using base::android::AttachCurrentThread;
+using base::android::CheckException;
+using base::android::GetClass;
+using base::android::MethodID;
+using base::android::JavaRef;
+using base::android::ScopedJavaLocalRef;
+
+namespace {
+
+// TODO(wjia): add stride as part of buffer parameter.
+void ResetBufferI420(uint8* buffer, int width, int height) {
+  int y_size = width * height;
+  memset(buffer, 0, y_size);
+  buffer += y_size;
+  memset(buffer, 128, y_size / 2);
+}
+
+// TODO(wjia): add test for this function.
+void RotatePlaneByPixels(
+    uint8* src,
+    uint8* dest,
+    int width,
+    int height,
+    int rotation,  // Clockwise.
+    bool flip_vert,
+    bool flip_horiz) {
+  // Consolidate cases. Only 0 and 90 are left.
+  if (rotation == 180 || rotation == 270) {
+    rotation -= 180;
+    flip_vert = !flip_vert;
+    flip_horiz = !flip_horiz;
+  }
+
+  int num_rows = height;
+  int num_cols = width;
+  int src_stride = width;
+  // During pixel copying, the corresponding incremental of dest pointer
+  // when src pointer moves to next row.
+  int dest_row_step = width;
+  // During pixel copying, the corresponding incremental of dest pointer
+  // when src pointer moves to next column.
+  int dest_col_step = 1;
+
+  if (rotation == 0) {
+    if (flip_horiz) {
+      // Use pixel copying.
+      dest_col_step = -1;
+      if (flip_vert) {
+        // Rotation 180.
+        dest_row_step = -width;
+        dest += height * width - 1;
+      } else {
+        dest += width - 1;
+      }
+    } else {
+      if (flip_vert) {
+        // Fast copy by rows.
+        dest += width * (height - 1);
+        for (int row = 0; row < height; ++row) {
+          memcpy(dest, src, width);
+          src += width;
+          dest -= width;
+        }
+      } else {
+        memcpy(dest, src, width * height);
+      }
+      return;
+    }
+  } else if (rotation == 90) {
+    int offset = (width - height) / 2;

[Ami GONE FROM CHROMIUM, 2013/02/07 05:37:34]

the initialization value seems to me to belong in the then clause below (l.87).

[wjia(left Chromium), 2013/02/12 00:23:45]

Done.

+    if (width > height) {
+      src += offset;
+      num_rows = num_cols = height;
+    } else {
+      offset = (height - width) / 2;
+      src += width * offset;
+      num_rows = num_cols = width;

[Ami GONE FROM CHROMIUM, 2013/02/07 05:37:34]

If the camera starts out rotated 90deg then a single OnFrameInfo is enough, but
you're still messing up the frame.

What actually happens when you rotate the camera on android with this patch?  Do
you just capture square previews with a black (width-height) x height size? 
That doesn't seem shippable to me.

[wjia(left Chromium), 2013/02/12 00:23:45]

This comes from the restriction that current video capture framework doesn't
support resolution change in a capture session. We will improve that. Then this
rotation will include full image, instead of just the square portion.

+    }
+
+    dest_col_step = (flip_vert ? -width : width);
+    if (flip_horiz) {
+      dest_row_step = 1;

[Ami GONE FROM CHROMIUM, 2013/02/07 05:37:34]

I think you misunderstood me.
I was just suggesting you could set dest_row_step using a ?: expression like at
l.95.

[wjia(left Chromium), 2013/02/12 00:23:45]

Changed to ?: expression. I thought since flip_horiz will be checked anyway,
putting assignment of dest_row_step in each branch doesn't require second
checking on flip_horiz.

+      if (flip_vert) {
+        dest += (width > height ? width * (height - 1) + offset :
+                                  width * (height - offset - 1));
+      } else {
+        dest += (width > height ? offset : width * offset);
+      }
+    } else {
+      dest_row_step = -1;
+      if (flip_vert) {
+        dest += (width > height ?  width * height - offset - 1 :
+                                   width * (height - offset) - 1);
+      } else {
+        dest += (width > height ? width - offset - 1 :
+                                  width * (offset + 1) - 1);
+      }
+    }
+  }

[Ami GONE FROM CHROMIUM, 2013/02/07 05:37:34]

You misunderstood me - I was saying that the outline of
if (rotation == 0) {
} else if (rotation == 90}
} ...
should have an else NOTREACHED clause instead of ... (which is empty now).

[wjia(left Chromium), 2013/02/12 00:23:45]

Done.

+
+  // Copy pixels.
+  for (int row = 0; row < num_rows; ++row) {
+    uint8* src_ptr = src;
+    uint8* dest_ptr = dest;
+    for (int col = 0; col < num_cols; ++col) {
+      *dest_ptr = *src_ptr++;
+      dest_ptr += dest_col_step;
+    }
+    src += src_stride;
+    dest += dest_row_step;
+  }
+}

[Ami GONE FROM CHROMIUM, 2013/02/07 05:37:34]

Testing this should be super-simple.  Please do it as part of this CL.  


(I'd be fine with an initial version of this CL that simply didn't handle
rotation, and then rotation+test in a follow-up, but landing this function
untested seems like a *very* bad idea).

+
+int GetIntField(JNIEnv* env,
+                const JavaRef<jclass>& clazz,
+                const JavaRef<jobject>& instance,
+                const char* field_name) {
+  jfieldID field = GetFieldID(env, clazz, field_name, "I");
+  jint int_value = env->GetIntField(instance.obj(), field);
+  return int_value;
+}
+
+}  // namespace
+
+namespace media {
+
+// static
+void VideoCaptureDevice::GetDeviceNames(Names* device_names) {
+  device_names->clear();
+
+  JNIEnv* env = AttachCurrentThread();
+
+  int num_cameras = JNI_Camera::Java_Camera_getNumberOfCameras(env);
+  DVLOG(1) << "VideoCaptureDevice::GetDeviceNames: num_cameras=" << num_cameras;
+  if (num_cameras <= 0)
+    return;
+
+  // TODO(wjia): switch to using same approach as Camera when
+  // jar_file_jni_generator.gypi supports system inner classes.
+  std::string camera_info_string("android/hardware/Camera$CameraInfo");
+
+  ScopedJavaLocalRef<jclass> camera_info_class(
+      GetClass(env, camera_info_string.c_str()));
+  jmethodID constructor = MethodID::Get<MethodID::TYPE_INSTANCE>(
+      env, camera_info_class.obj(), "<init>", "()V");
+
+  ScopedJavaLocalRef<jobject> object_camera_info(
+      env, env->NewObject(camera_info_class.obj(), constructor));
+
+  jfieldID field_facing = GetFieldID(env, camera_info_class, "facing", "I");
+  jfieldID field_facing_front = GetStaticFieldID(
+      env, camera_info_class, "CAMERA_FACING_FRONT", "I");
+
+  for (int camera_id = num_cameras - 1; camera_id >= 0; --camera_id) {
+    JNI_Camera::Java_Camera_getCameraInfo(
+        env, camera_id, object_camera_info.obj());
+
+    Name name;
+    name.unique_id = StringPrintf("%d", camera_id);
+    std::string facing_string;
+    if (env->GetIntField(object_camera_info.obj(), field_facing) ==
+        env->GetStaticIntField(camera_info_class.obj(), field_facing_front)) {
+      facing_string = "front";
+    } else {
+      facing_string = "back";
+    }
+    name.device_name = StringPrintf(
+        "camera %d, facing %s", camera_id, facing_string.c_str());
+    device_names->push_back(name);
+    jfieldID field_orientation = GetFieldID(
+        env, camera_info_class, "orientation", "I");
+    jint orientation = env->GetIntField(object_camera_info.obj(),
+                                        field_orientation);
+    DVLOG(1) << "VideoCaptureDevice::GetDeviceNames: camera device_name="
+             << name.device_name
+             << ", unique_id="
+             << name.unique_id
+             << ", orientation "
+             << orientation;
+  }
+}
+
+// static
+VideoCaptureDevice* VideoCaptureDevice::Create(const Name& device_name) {
+  return VideoCaptureDeviceAndroid::Create(device_name);
+}
+
+// static
+VideoCaptureDevice* VideoCaptureDeviceAndroid::Create(const Name& device_name) {
+  scoped_ptr<VideoCaptureDeviceAndroid> ret(
+      new VideoCaptureDeviceAndroid(device_name));
+  if (ret->Init())
+    return ret.release();
+  return NULL;
+}
+
+// static
+bool VideoCaptureDeviceAndroid::RegisterVideoCaptureDevice(JNIEnv* env) {
+  return RegisterNativesImpl(env) && JNI_Camera::RegisterNativesImpl(env);
+}
+
+VideoCaptureDeviceAndroid::VideoCaptureDeviceAndroid(const Name& device_name)
+    : state_(kIdle),
+      observer_(NULL),
+      device_name_(device_name),
+      current_settings_(),
+      rotation_(0) {
+}
+
+VideoCaptureDeviceAndroid::~VideoCaptureDeviceAndroid() {
+  DeAllocate();
+}
+
+bool VideoCaptureDeviceAndroid::Init() {
+  int id;
+  if (!base::StringToInt(device_name_.unique_id, &id))
+    return false;
+
+  JNIEnv* env = AttachCurrentThread();
+
+  j_capture_.Reset(Java_VideoCapture_createVideoCapture(
+      env, base::android::GetApplicationContext(), id,
+      reinterpret_cast<jlong>(this)));
+
+  return true;
+}
+
+const VideoCaptureDevice::Name& VideoCaptureDeviceAndroid::device_name() {
+  return device_name_;
+}
+
+void VideoCaptureDeviceAndroid::Allocate(
+    int width,
+    int height,
+    int frame_rate,
+    EventHandler* observer) {
+  {
+    base::AutoLock lock(lock_);
+    if (state_ != kIdle)
+      return;
+    observer_ = observer;
+    state_ = kAllocated;
+  }
+
+  JNIEnv* env = AttachCurrentThread();
+
+  jboolean ret = Java_VideoCapture_allocate(env,
+                                            j_capture_.obj(),
+                                            width,
+                                            height,
+                                            frame_rate);
+  if (!ret) {
+    SetErrorState("failed to allocate");
+    return;
+  }
+
+  // Store current width and height.
+  current_settings_.width =
+      Java_VideoCapture_queryWidth(env, j_capture_.obj());
+  current_settings_.height =
+      Java_VideoCapture_queryHeight(env, j_capture_.obj());
+  current_settings_.frame_rate =
+      Java_VideoCapture_queryFrameRate(env, j_capture_.obj());
+  current_settings_.color = VideoCaptureCapability::kYV12;
+  CHECK(current_settings_.width > 0 && !(current_settings_.width % 2));
+  CHECK(current_settings_.height > 0 && !(current_settings_.height % 2));
+
+  DVLOG(1) << "VideoCaptureDeviceAndroid::Allocate: queried width="
+           << current_settings_.width
+           << ", height="
+           << current_settings_.height
+           << ", frame_rate="
+           << current_settings_.frame_rate;
+  // Report the frame size to the observer.
+  observer_->OnFrameInfo(current_settings_);
+
+  int y_size = current_settings_.width * current_settings_.height;
+  rotation_buffer_.reset(new uint8[y_size * 3 / 2]);
+  ResetBufferI420(rotation_buffer_.get(),
+                  current_settings_.width,
+                  current_settings_.height);
+}
+
+void VideoCaptureDeviceAndroid::Start() {
+  DVLOG(1) << "VideoCaptureDeviceAndroid::Start";
+  {
+    base::AutoLock lock(lock_);
+    DCHECK_EQ(state_, kAllocated);
+  }
+
+  JNIEnv* env = AttachCurrentThread();
+
+  jint ret = Java_VideoCapture_startCapture(env, j_capture_.obj());
+  if (ret < 0) {
+    SetErrorState("failed to start capture");
+    return;
+  }
+
+  {
+    base::AutoLock lock(lock_);
+    state_ = kCapturing;
+  }
+}
+
+void VideoCaptureDeviceAndroid::Stop() {
+  DVLOG(1) << "VideoCaptureDeviceAndroid::Stop";
+  {
+    base::AutoLock lock(lock_);
+    if (state_ != kCapturing && state_ != kError)
+      return;
+    if (state_ == kCapturing)
+      state_ = kAllocated;
+  }
+
+  JNIEnv* env = AttachCurrentThread();
+
+  jint ret = Java_VideoCapture_stopCapture(env, j_capture_.obj());
+  if (ret < 0) {
+    SetErrorState("failed to stop capture");
+    return;
+  }
+}
+
+void VideoCaptureDeviceAndroid::DeAllocate() {
+  DVLOG(1) << "VideoCaptureDeviceAndroid::DeAllocate";
+  {
+    base::AutoLock lock(lock_);
+    if (state_ == kIdle)
+      return;
+
+    if (state_ == kCapturing) {
+      base::AutoUnlock unlock(lock_);
+      Stop();
+    }
+
+    if (state_ == kAllocated)
+      state_ = kIdle;
+
+    observer_ = NULL;
+  }
+
+  JNIEnv* env = AttachCurrentThread();
+
+  Java_VideoCapture_deallocate(env, j_capture_.obj());
+}
+
+void VideoCaptureDeviceAndroid::OnFrameAvailable(
+    JNIEnv* env,
+    jobject obj,
+    jbyteArray data,
+    jint length,
+    jint rotation,
+    jboolean flip_vert,
+    jboolean flip_horiz) {
+  DVLOG(3) << "VideoCaptureDeviceAndroid::OnFrameAvailable: length =" << length;
+
+  base::AutoLock lock(lock_);
+  if (state_ != kCapturing || !observer_)
+    return;
+
+  jbyte* buffer = env->GetByteArrayElements(data, NULL);
+  if (!buffer) {
+    LOG(ERROR) << "VideoCaptureDeviceAndroid::OnFrameAvailable: "
+                  "failed to GetByteArrayElements";
+    return;
+  }
+
+  // TODO(wjia): move rotation into VideoCaptureController to remove
+  // one buffer copying.
+  // Rotate the buffer when needed.
+  int width = current_settings_.width;
+  int height = current_settings_.height;
+  if (rotation_ != rotation) {
+    rotation_ = rotation;
+    ResetBufferI420(rotation_buffer_.get(), width, height);
+  }
+
+  uint8* src = reinterpret_cast<uint8*>(buffer);
+  uint8* dest = rotation_buffer_.get();
+
+  RotatePlaneByPixels(src, dest, width, height, rotation, flip_vert,
+                      flip_horiz);
+  int y_size = width * height;
+  src += y_size;
+  dest += y_size;
+  RotatePlaneByPixels(src, dest, width/2, height/2, rotation, flip_vert,
+                      flip_horiz);
+  src += y_size/4;
+  dest += y_size/4;
+  RotatePlaneByPixels(src, dest, width/2, height/2, rotation, flip_vert,
+                      flip_horiz);
+  observer_->OnIncomingCapturedFrame(rotation_buffer_.get(), length,
+                                     base::Time::Now());
+
+  env->ReleaseByteArrayElements(data, buffer, JNI_ABORT);
+}
+
+void VideoCaptureDeviceAndroid::SetErrorState(const std::string& reason) {
+  LOG(ERROR) << "VideoCaptureDeviceAndroid::SetErrorState: " << reason;
+  {
+    base::AutoLock lock(lock_);
+    state_ = kError;
+  }
+  observer_->OnError();
+}
+
+}  // namespace media