root/media/video/capture/android/video_capture_device_android.cc

DEFINITIONS

1. GetDeviceNames
2. GetDeviceSupportedFormats
3. Create
4. Create
5. RegisterVideoCaptureDevice
6. GetModel
7. device_name_
8. Init
9. AllocateAndStart
10. StopAndDeAllocate
11. OnFrameAvailable
12. GetColorspace
13. SetErrorState

// 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/strings/string_number_conversions.h"
#include "jni/VideoCapture_jni.h"
#include "media/video/capture/android/video_capture_device_factory_android.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 media {

//static
void VideoCaptureDevice::GetDeviceNames(Names* device_names) {
  VideoCaptureDeviceFactoryAndroid::GetDeviceNames(device_names);
}

// static
void VideoCaptureDevice::GetDeviceSupportedFormats(
    const Name& device,
    VideoCaptureFormats* capture_formats) {
  VideoCaptureDeviceFactoryAndroid::GetDeviceSupportedFormats(device,
                                                              capture_formats);
}

// 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);
}

const std::string VideoCaptureDevice::Name::GetModel() const {
  // Android cameras are not typically USB devices, and this method is currently
  // only used for USB model identifiers, so this implementation just indicates
  // an unknown device model.
  return "";
}

VideoCaptureDeviceAndroid::VideoCaptureDeviceAndroid(const Name& device_name)
    : state_(kIdle), got_first_frame_(false), device_name_(device_name) {}

VideoCaptureDeviceAndroid::~VideoCaptureDeviceAndroid() {
  StopAndDeAllocate();
}

bool VideoCaptureDeviceAndroid::Init() {
  int id;
  if (!base::StringToInt(device_name_.id(), &id))
    return false;

  j_capture_.Reset(VideoCaptureDeviceFactoryAndroid::createVideoCaptureAndroid(
      id, reinterpret_cast<intptr_t>(this)));
  return true;
}

void VideoCaptureDeviceAndroid::AllocateAndStart(
    const VideoCaptureParams& params,
    scoped_ptr<Client> client) {
  DVLOG(1) << "VideoCaptureDeviceAndroid::AllocateAndStart";
  {
    base::AutoLock lock(lock_);
    if (state_ != kIdle)
      return;
    client_ = client.Pass();
    got_first_frame_ = false;
  }

  JNIEnv* env = AttachCurrentThread();

  jboolean ret = Java_VideoCapture_allocate(
      env,
      j_capture_.obj(),
      params.requested_format.frame_size.width(),
      params.requested_format.frame_size.height(),
      params.requested_format.frame_rate);
  if (!ret) {
    SetErrorState("failed to allocate");
    return;
  }

  // Store current width and height.
  capture_format_.frame_size.SetSize(
      Java_VideoCapture_queryWidth(env, j_capture_.obj()),
      Java_VideoCapture_queryHeight(env, j_capture_.obj()));
  capture_format_.frame_rate =
      Java_VideoCapture_queryFrameRate(env, j_capture_.obj());
  capture_format_.pixel_format = GetColorspace();
  DCHECK_NE(capture_format_.pixel_format, media::PIXEL_FORMAT_UNKNOWN);
  CHECK(capture_format_.frame_size.GetArea() > 0);
  CHECK(!(capture_format_.frame_size.width() % 2));
  CHECK(!(capture_format_.frame_size.height() % 2));

  if (capture_format_.frame_rate > 0) {
    frame_interval_ = base::TimeDelta::FromMicroseconds(
        (base::Time::kMicrosecondsPerSecond + capture_format_.frame_rate - 1) /
        capture_format_.frame_rate);
  }

  DVLOG(1) << "VideoCaptureDeviceAndroid::Allocate: queried frame_size="
           << capture_format_.frame_size.ToString()
           << ", frame_rate=" << capture_format_.frame_rate;

  jint result = Java_VideoCapture_startCapture(env, j_capture_.obj());
  if (result < 0) {
    SetErrorState("failed to start capture");
    return;
  }

  {
    base::AutoLock lock(lock_);
    state_ = kCapturing;
  }
}

void VideoCaptureDeviceAndroid::StopAndDeAllocate() {
  DVLOG(1) << "VideoCaptureDeviceAndroid::StopAndDeAllocate";
  {
    base::AutoLock lock(lock_);
    if (state_ != kCapturing && state_ != kError)
      return;
  }

  JNIEnv* env = AttachCurrentThread();

  jint ret = Java_VideoCapture_stopCapture(env, j_capture_.obj());
  if (ret < 0) {
    SetErrorState("failed to stop capture");
    return;
  }

  {
    base::AutoLock lock(lock_);
    state_ = kIdle;
    client_.reset();
  }

  Java_VideoCapture_deallocate(env, j_capture_.obj());
}

void VideoCaptureDeviceAndroid::OnFrameAvailable(
    JNIEnv* env,
    jobject obj,
    jbyteArray data,
    jint length,
    jint rotation) {
  DVLOG(3) << "VideoCaptureDeviceAndroid::OnFrameAvailable: length =" << length;

  base::AutoLock lock(lock_);
  if (state_ != kCapturing || !client_.get())
    return;

  jbyte* buffer = env->GetByteArrayElements(data, NULL);
  if (!buffer) {
    LOG(ERROR) << "VideoCaptureDeviceAndroid::OnFrameAvailable: "
                  "failed to GetByteArrayElements";
    return;
  }

  base::TimeTicks current_time = base::TimeTicks::Now();
  if (!got_first_frame_) {
    // Set aside one frame allowance for fluctuation.
    expected_next_frame_time_ = current_time - frame_interval_;
    got_first_frame_ = true;
  }

  // Deliver the frame when it doesn't arrive too early.
  if (expected_next_frame_time_ <= current_time) {
    expected_next_frame_time_ += frame_interval_;

    client_->OnIncomingCapturedData(reinterpret_cast<uint8*>(buffer),
                                    length,
                                    capture_format_,
                                    rotation,
                                    base::TimeTicks::Now());
  }

  env->ReleaseByteArrayElements(data, buffer, JNI_ABORT);
}

VideoPixelFormat VideoCaptureDeviceAndroid::GetColorspace() {
  JNIEnv* env = AttachCurrentThread();
  int current_capture_colorspace =
      Java_VideoCapture_getColorspace(env, j_capture_.obj());
  switch (current_capture_colorspace) {
    case ANDROID_IMAGEFORMAT_YV12:
      return media::PIXEL_FORMAT_YV12;
    case ANDROID_IMAGEFORMAT_NV21:
      return media::PIXEL_FORMAT_NV21;
    case ANDROID_IMAGEFORMAT_UNKNOWN:
    default:
      return media::PIXEL_FORMAT_UNKNOWN;
  }
}

void VideoCaptureDeviceAndroid::SetErrorState(const std::string& reason) {
  LOG(ERROR) << "VideoCaptureDeviceAndroid::SetErrorState: " << reason;
  {
    base::AutoLock lock(lock_);
    state_ = kError;
  }
  client_->OnError(reason);
}

}  // namespace media