third_party/chromium/media/capture/video/fake_video_capture_device_factory.cc - cobalt - Git at Google

 // Copyright 2014 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/capture/video/fake_video_capture_device_factory.h"

 #include <array>

 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_split.h"
 #include "base/strings/string_tokenizer.h"
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 #include "build/build_config.h"
 #include "gpu/ipc/common/gpu_memory_buffer_support.h"
 #include "media/base/media_switches.h"

 namespace {

 // Cap the frame rate command line input to reasonable values.
 static const float kFakeCaptureMinFrameRate = 5.0f;
 static const float kFakeCaptureMaxFrameRate = 60.0f;

 // Cap the device count command line input to reasonable values.
 static const int kFakeCaptureMinDeviceCount = 0;
 static const int kFakeCaptureMaxDeviceCount = 10;
 static const int kDefaultDeviceCount = 1;

 static const char* kDefaultDeviceIdMask = "/dev/video%d";
 static const media::FakeVideoCaptureDevice::DeliveryMode kDefaultDeliveryMode =
     media::FakeVideoCaptureDevice::DeliveryMode::USE_DEVICE_INTERNAL_BUFFERS;
 static constexpr std::array<gfx::Size, 6> kDefaultResolutions{
     {gfx::Size(96, 96), gfx::Size(320, 240), gfx::Size(640, 480),
      gfx::Size(1280, 720), gfx::Size(1920, 1080), gfx::Size(3840, 2160)}};
 static constexpr std::array<float, 1> kDefaultFrameRates{{20.0f}};

 static const double kInitialPan = 100.0;
 static const double kInitialTilt = 100.0;
 static const double kInitialZoom = 100.0;
 static const double kInitialExposureTime = 50.0;
 static const double kInitialFocusDistance = 50.0;

 static const media::VideoPixelFormat kSupportedPixelFormats[] = {
     media::PIXEL_FORMAT_I420, media::PIXEL_FORMAT_Y16,
     media::PIXEL_FORMAT_MJPEG};

 template <typename TElement, size_t TSize>
 std::vector<TElement> ArrayToVector(const std::array<TElement, TSize>& arr) {
   return std::vector<TElement>(arr.begin(), arr.end());
 }

 media::VideoPixelFormat GetPixelFormatFromDeviceIndex(int device_index) {
   if (device_index == 1)
     return media::PIXEL_FORMAT_Y16;
   if (device_index == 2)
     return media::PIXEL_FORMAT_MJPEG;
   return media::PIXEL_FORMAT_I420;
 }

 void AppendAllCombinationsToFormatsContainer(
     const std::vector<media::VideoPixelFormat>& pixel_formats,
     const std::vector<gfx::Size>& resolutions,
     const std::vector<float>& frame_rates,
     media::VideoCaptureFormats* output) {
   for (const auto& pixel_format : pixel_formats) {
     for (const auto& resolution : resolutions) {
       for (const auto& frame_rate : frame_rates)
         output->emplace_back(resolution, frame_rate, pixel_format);
     }
   }
 }

 class ErrorFakeDevice : public media::VideoCaptureDevice {
  public:
   // VideoCaptureDevice implementation.
   void AllocateAndStart(const media::VideoCaptureParams& params,
                         std::unique_ptr<Client> client) override {
     client->OnError(media::VideoCaptureError::
                         kErrorFakeDeviceIntentionallyEmittingErrorEvent,
                     FROM_HERE, "Device has no supported formats.");
   }

   void StopAndDeAllocate() override {}
   void GetPhotoState(GetPhotoStateCallback callback) override {}
   void SetPhotoOptions(media::mojom::PhotoSettingsPtr settings,
                        SetPhotoOptionsCallback callback) override {}
   void TakePhoto(TakePhotoCallback callback) override {}
 };

 }  // anonymous namespace

 namespace media {

 FakeVideoCaptureDeviceSettings::FakeVideoCaptureDeviceSettings() = default;

 FakeVideoCaptureDeviceSettings::~FakeVideoCaptureDeviceSettings() = default;

 FakeVideoCaptureDeviceSettings::FakeVideoCaptureDeviceSettings(
     const FakeVideoCaptureDeviceSettings& other) = default;

 constexpr char
     FakeVideoCaptureDeviceFactory::kDeviceConfigForGetPhotoStateFails[];
 constexpr char
     FakeVideoCaptureDeviceFactory::kDeviceConfigForSetPhotoOptionsFails[];
 constexpr char FakeVideoCaptureDeviceFactory::kDeviceConfigForTakePhotoFails[];

 FakeVideoCaptureDeviceFactory::FakeVideoCaptureDeviceFactory() {
   // The default |devices_config_| is the one obtained from an empty options
   // string.
   ParseFakeDevicesConfigFromOptionsString("", &devices_config_);
 }

 FakeVideoCaptureDeviceFactory::~FakeVideoCaptureDeviceFactory() = default;

 // static
 std::unique_ptr<VideoCaptureDevice>
 FakeVideoCaptureDeviceFactory::CreateDeviceWithSettings(
     const FakeVideoCaptureDeviceSettings& settings,
     std::unique_ptr<gpu::GpuMemoryBufferSupport> gmb_support) {
   if (settings.supported_formats.empty())
     return CreateErrorDevice();

   for (const auto& entry : settings.supported_formats) {
     bool pixel_format_supported = false;
     for (const auto& supported_pixel_format : kSupportedPixelFormats) {
       if (entry.pixel_format == supported_pixel_format) {
         pixel_format_supported = true;
         break;
       }
     }
     if (!pixel_format_supported) {
       DLOG(ERROR) << "Requested an unsupported pixel format "
                   << VideoPixelFormatToString(entry.pixel_format);
       return nullptr;
     }
   }

   const VideoCaptureFormat& initial_format = settings.supported_formats.front();
   auto device_state = std::make_unique<FakeDeviceState>(
       kInitialPan, kInitialTilt, kInitialZoom, kInitialExposureTime,
       kInitialFocusDistance, initial_format.frame_rate,
       initial_format.pixel_format);

   auto photo_frame_painter = std::make_unique<PacmanFramePainter>(
       PacmanFramePainter::Format::SK_N32, device_state.get());
   auto photo_device = std::make_unique<FakePhotoDevice>(
       std::move(photo_frame_painter), device_state.get(),
       settings.photo_device_config);

   return std::make_unique<FakeVideoCaptureDevice>(
       settings.supported_formats,
       std::make_unique<FrameDelivererFactory>(
           settings.delivery_mode, device_state.get(), std::move(gmb_support)),
       std::move(photo_device), std::move(device_state));
 }

 // static
 std::unique_ptr<VideoCaptureDevice>
 FakeVideoCaptureDeviceFactory::CreateDeviceWithDefaultResolutions(
     VideoPixelFormat pixel_format,
     FakeVideoCaptureDevice::DeliveryMode delivery_mode,
     float frame_rate,
     std::unique_ptr<gpu::GpuMemoryBufferSupport> gmb_support) {
   FakeVideoCaptureDeviceSettings settings;
   settings.delivery_mode = delivery_mode;
   for (const gfx::Size& resolution : kDefaultResolutions)
     settings.supported_formats.emplace_back(resolution, frame_rate,
                                             pixel_format);
   return CreateDeviceWithSettings(settings, std::move(gmb_support));
 }

 // static
 std::unique_ptr<VideoCaptureDevice>
 FakeVideoCaptureDeviceFactory::CreateErrorDevice() {
   return std::make_unique<ErrorFakeDevice>();
 }

 void FakeVideoCaptureDeviceFactory::SetToDefaultDevicesConfig(
     int device_count) {
   devices_config_.clear();
   ParseFakeDevicesConfigFromOptionsString(
       base::StringPrintf("device-count=%d", device_count), &devices_config_);
 }

 void FakeVideoCaptureDeviceFactory::SetToCustomDevicesConfig(
     const std::vector<FakeVideoCaptureDeviceSettings>& config) {
   devices_config_ = config;
 }

 std::unique_ptr<VideoCaptureDevice> FakeVideoCaptureDeviceFactory::CreateDevice(
     const VideoCaptureDeviceDescriptor& device_descriptor) {
   DCHECK(thread_checker_.CalledOnValidThread());

   for (const auto& entry : devices_config_) {
     if (device_descriptor.device_id != entry.device_id)
       continue;
     return CreateDeviceWithSettings(entry);
   }
   return nullptr;
 }

 void FakeVideoCaptureDeviceFactory::GetDevicesInfo(
     GetDevicesInfoCallback callback) {
   DCHECK(thread_checker_.CalledOnValidThread());

   std::vector<VideoCaptureDeviceInfo> devices_info;

   int entry_index = 0;
   for (const auto& entry : devices_config_) {
     VideoCaptureApi api =
 #if defined(OS_LINUX) || defined(OS_CHROMEOS)
         VideoCaptureApi::LINUX_V4L2_SINGLE_PLANE;
 #elif defined(OS_MAC)
         VideoCaptureApi::MACOSX_AVFOUNDATION;
 #elif defined(OS_WIN)
         VideoCaptureApi::WIN_DIRECT_SHOW;
 #elif defined(OS_ANDROID)
         VideoCaptureApi::ANDROID_API2_LEGACY;
 #elif defined(OS_FUCHSIA)
         VideoCaptureApi::FUCHSIA_CAMERA3;
 #else
 #error Unsupported platform
 #endif

     devices_info.emplace_back(VideoCaptureDeviceDescriptor(
         base::StringPrintf("fake_device_%d", entry_index), entry.device_id, api,
         entry.photo_device_config.control_support,
         VideoCaptureTransportType::OTHER_TRANSPORT));

     devices_info.back().supported_formats =
         GetSupportedFormats(entry.device_id);
     entry_index++;
   }

   std::move(callback).Run(std::move(devices_info));
 }

 VideoCaptureFormats FakeVideoCaptureDeviceFactory::GetSupportedFormats(
     const std::string& device_id) {
   DCHECK(thread_checker_.CalledOnValidThread());

   VideoCaptureFormats supported_formats;
   for (const auto& entry : devices_config_) {
     if (device_id != entry.device_id)
       continue;
     supported_formats.insert(supported_formats.end(),
                              entry.supported_formats.begin(),
                              entry.supported_formats.end());
   }

   return supported_formats;
 }

 // static
 void FakeVideoCaptureDeviceFactory::ParseFakeDevicesConfigFromOptionsString(
     const std::string options_string,
     std::vector<FakeVideoCaptureDeviceSettings>* config) {
   base::StringTokenizer option_tokenizer(options_string, ", ");
   option_tokenizer.set_quote_chars("\"");

   FakeVideoCaptureDevice::DeliveryMode delivery_mode = kDefaultDeliveryMode;
   std::vector<gfx::Size> resolutions = ArrayToVector(kDefaultResolutions);
   std::vector<float> frame_rates = ArrayToVector(kDefaultFrameRates);
   int device_count = kDefaultDeviceCount;
   FakePhotoDeviceConfig photo_device_config;
   FakeVideoCaptureDevice::DisplayMediaType display_media_type =
       FakeVideoCaptureDevice::DisplayMediaType::ANY;

   while (option_tokenizer.GetNext()) {
     std::vector<base::StringPiece> param = base::SplitStringPiece(
         option_tokenizer.token_piece(), "=", base::TRIM_WHITESPACE,
         base::SPLIT_WANT_NONEMPTY);

     if (param.size() != 2u) {
       LOG(WARNING) << "Forget a value '" << options_string
                    << "'? Use name=value for "
                    << switches::kUseFakeDeviceForMediaStream << ".";
       return;
     }

     if (base::EqualsCaseInsensitiveASCII(param.front(), "ownership") &&
         base::EqualsCaseInsensitiveASCII(param.back(), "client")) {
       delivery_mode =
           FakeVideoCaptureDevice::DeliveryMode::USE_CLIENT_PROVIDED_BUFFERS;
     } else if (base::EqualsCaseInsensitiveASCII(param.front(), "fps")) {
       double parsed_fps = 0;
       if (base::StringToDouble(param.back(), &parsed_fps)) {
         float capped_frame_rate =
             std::max(kFakeCaptureMinFrameRate, static_cast<float>(parsed_fps));
         capped_frame_rate =
             std::min(kFakeCaptureMaxFrameRate, capped_frame_rate);
         frame_rates.clear();
         frame_rates.push_back(capped_frame_rate);
       }
     } else if (base::EqualsCaseInsensitiveASCII(param.front(),
                                                 "device-count")) {
       unsigned int count = 0;
       if (base::StringToUint(param.back(), &count)) {
         device_count = std::min(
             kFakeCaptureMaxDeviceCount,
             std::max(kFakeCaptureMinDeviceCount, static_cast<int>(count)));
       }
     } else if (base::EqualsCaseInsensitiveASCII(param.front(), "config")) {
       const int device_index = 0;
       std::vector<VideoPixelFormat> pixel_formats;
       pixel_formats.push_back(GetPixelFormatFromDeviceIndex(device_index));
       FakeVideoCaptureDeviceSettings settings;
       settings.delivery_mode = delivery_mode;
       settings.device_id =
           base::StringPrintf(kDefaultDeviceIdMask, device_index);
       AppendAllCombinationsToFormatsContainer(
           pixel_formats, resolutions, frame_rates, &settings.supported_formats);

       if (param.back() == kDeviceConfigForGetPhotoStateFails) {
         settings.photo_device_config.should_fail_get_photo_capabilities = true;
         config->push_back(settings);
         return;
       }
       if (param.back() == kDeviceConfigForSetPhotoOptionsFails) {
         settings.photo_device_config.should_fail_set_photo_options = true;
         config->push_back(settings);
         return;
       }
       if (param.back() == kDeviceConfigForTakePhotoFails) {
         settings.photo_device_config.should_fail_take_photo = true;
         config->push_back(settings);
         return;
       }
       LOG(WARNING) << "Unknown config " << param.back();
       return;
     } else if (base::EqualsCaseInsensitiveASCII(param.front(),
                                                 "display-media-type")) {
       if (base::EqualsCaseInsensitiveASCII(param.back(), "any")) {
         display_media_type = FakeVideoCaptureDevice::DisplayMediaType::ANY;
       } else if (base::EqualsCaseInsensitiveASCII(param.back(), "monitor")) {
         display_media_type = FakeVideoCaptureDevice::DisplayMediaType::MONITOR;
       } else if (base::EqualsCaseInsensitiveASCII(param.back(), "window")) {
         display_media_type = FakeVideoCaptureDevice::DisplayMediaType::WINDOW;
       } else if (base::EqualsCaseInsensitiveASCII(param.back(), "browser")) {
         display_media_type = FakeVideoCaptureDevice::DisplayMediaType::BROWSER;
       }
     } else if (base::EqualsCaseInsensitiveASCII(param.front(),
                                                 "hardware-support")) {
       photo_device_config.control_support = VideoCaptureControlSupport();
       if (!base::EqualsCaseInsensitiveASCII(param.back(), "none")) {
         for (const std::string& support :
              base::SplitString(param.back(), "-", base::KEEP_WHITESPACE,
                                base::SPLIT_WANT_NONEMPTY)) {
           if (base::EqualsCaseInsensitiveASCII(support, "pan"))
             photo_device_config.control_support.pan = true;
           else if (base::EqualsCaseInsensitiveASCII(support, "tilt"))
             photo_device_config.control_support.tilt = true;
           else if (base::EqualsCaseInsensitiveASCII(support, "zoom"))
             photo_device_config.control_support.zoom = true;
           else
             LOG(WARNING) << "Unsupported hardware support " << support;
         }
       }
     }
   }

   for (int device_index = 0; device_index < device_count; device_index++) {
     std::vector<VideoPixelFormat> pixel_formats;
     pixel_formats.push_back(GetPixelFormatFromDeviceIndex(device_index));
     FakeVideoCaptureDeviceSettings settings;
     settings.delivery_mode = delivery_mode;
     settings.device_id = base::StringPrintf(kDefaultDeviceIdMask, device_index);
     AppendAllCombinationsToFormatsContainer(
         pixel_formats, resolutions, frame_rates, &settings.supported_formats);
     settings.photo_device_config = photo_device_config;
     settings.display_media_type = display_media_type;
     config->push_back(settings);
   }
 }

 }  // namespace media
	// Copyright 2014 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/capture/video/fake_video_capture_device_factory.h"

	#include <array>

	#include "base/strings/string_number_conversions.h"
	#include "base/strings/string_split.h"
	#include "base/strings/string_tokenizer.h"
	#include "base/strings/string_util.h"
	#include "base/strings/stringprintf.h"
	#include "build/build_config.h"
	#include "gpu/ipc/common/gpu_memory_buffer_support.h"
	#include "media/base/media_switches.h"

	namespace {

	// Cap the frame rate command line input to reasonable values.
	static const float kFakeCaptureMinFrameRate = 5.0f;
	static const float kFakeCaptureMaxFrameRate = 60.0f;

	// Cap the device count command line input to reasonable values.
	static const int kFakeCaptureMinDeviceCount = 0;
	static const int kFakeCaptureMaxDeviceCount = 10;
	static const int kDefaultDeviceCount = 1;

	static const char* kDefaultDeviceIdMask = "/dev/video%d";
	static const media::FakeVideoCaptureDevice::DeliveryMode kDefaultDeliveryMode =
	media::FakeVideoCaptureDevice::DeliveryMode::USE_DEVICE_INTERNAL_BUFFERS;
	static constexpr std::array<gfx::Size, 6> kDefaultResolutions{
	{gfx::Size(96, 96), gfx::Size(320, 240), gfx::Size(640, 480),
	gfx::Size(1280, 720), gfx::Size(1920, 1080), gfx::Size(3840, 2160)}};
	static constexpr std::array<float, 1> kDefaultFrameRates{{20.0f}};

	static const double kInitialPan = 100.0;
	static const double kInitialTilt = 100.0;
	static const double kInitialZoom = 100.0;
	static const double kInitialExposureTime = 50.0;
	static const double kInitialFocusDistance = 50.0;

	static const media::VideoPixelFormat kSupportedPixelFormats[] = {
	media::PIXEL_FORMAT_I420, media::PIXEL_FORMAT_Y16,
	media::PIXEL_FORMAT_MJPEG};

	template <typename TElement, size_t TSize>
	std::vector<TElement> ArrayToVector(const std::array<TElement, TSize>& arr) {
	return std::vector<TElement>(arr.begin(), arr.end());
	}

	media::VideoPixelFormat GetPixelFormatFromDeviceIndex(int device_index) {
	if (device_index == 1)
	return media::PIXEL_FORMAT_Y16;
	if (device_index == 2)
	return media::PIXEL_FORMAT_MJPEG;
	return media::PIXEL_FORMAT_I420;
	}

	void AppendAllCombinationsToFormatsContainer(
	const std::vector<media::VideoPixelFormat>& pixel_formats,
	const std::vector<gfx::Size>& resolutions,
	const std::vector<float>& frame_rates,
	media::VideoCaptureFormats* output) {
	for (const auto& pixel_format : pixel_formats) {
	for (const auto& resolution : resolutions) {
	for (const auto& frame_rate : frame_rates)
	output->emplace_back(resolution, frame_rate, pixel_format);
	}
	}
	}

	class ErrorFakeDevice : public media::VideoCaptureDevice {
	public:
	// VideoCaptureDevice implementation.
	void AllocateAndStart(const media::VideoCaptureParams& params,
	std::unique_ptr<Client> client) override {
	client->OnError(media::VideoCaptureError::
	kErrorFakeDeviceIntentionallyEmittingErrorEvent,
	FROM_HERE, "Device has no supported formats.");
	}

	void StopAndDeAllocate() override {}
	void GetPhotoState(GetPhotoStateCallback callback) override {}
	void SetPhotoOptions(media::mojom::PhotoSettingsPtr settings,
	SetPhotoOptionsCallback callback) override {}
	void TakePhoto(TakePhotoCallback callback) override {}
	};

	} // anonymous namespace

	namespace media {

	FakeVideoCaptureDeviceSettings::FakeVideoCaptureDeviceSettings() = default;

	FakeVideoCaptureDeviceSettings::~FakeVideoCaptureDeviceSettings() = default;

	FakeVideoCaptureDeviceSettings::FakeVideoCaptureDeviceSettings(
	const FakeVideoCaptureDeviceSettings& other) = default;

	constexpr char
	FakeVideoCaptureDeviceFactory::kDeviceConfigForGetPhotoStateFails[];
	constexpr char
	FakeVideoCaptureDeviceFactory::kDeviceConfigForSetPhotoOptionsFails[];
	constexpr char FakeVideoCaptureDeviceFactory::kDeviceConfigForTakePhotoFails[];

	FakeVideoCaptureDeviceFactory::FakeVideoCaptureDeviceFactory() {
	// The default \|devices_config_\| is the one obtained from an empty options
	// string.
	ParseFakeDevicesConfigFromOptionsString("", &devices_config_);
	}

	FakeVideoCaptureDeviceFactory::~FakeVideoCaptureDeviceFactory() = default;

	// static
	std::unique_ptr<VideoCaptureDevice>
	FakeVideoCaptureDeviceFactory::CreateDeviceWithSettings(
	const FakeVideoCaptureDeviceSettings& settings,
	std::unique_ptr<gpu::GpuMemoryBufferSupport> gmb_support) {
	if (settings.supported_formats.empty())
	return CreateErrorDevice();

	for (const auto& entry : settings.supported_formats) {
	bool pixel_format_supported = false;
	for (const auto& supported_pixel_format : kSupportedPixelFormats) {
	if (entry.pixel_format == supported_pixel_format) {
	pixel_format_supported = true;
	break;
	}
	}
	if (!pixel_format_supported) {
	DLOG(ERROR) << "Requested an unsupported pixel format "
	<< VideoPixelFormatToString(entry.pixel_format);
	return nullptr;
	}
	}

	const VideoCaptureFormat& initial_format = settings.supported_formats.front();
	auto device_state = std::make_unique<FakeDeviceState>(
	kInitialPan, kInitialTilt, kInitialZoom, kInitialExposureTime,
	kInitialFocusDistance, initial_format.frame_rate,
	initial_format.pixel_format);

	auto photo_frame_painter = std::make_unique<PacmanFramePainter>(
	PacmanFramePainter::Format::SK_N32, device_state.get());
	auto photo_device = std::make_unique<FakePhotoDevice>(
	std::move(photo_frame_painter), device_state.get(),
	settings.photo_device_config);

	return std::make_unique<FakeVideoCaptureDevice>(
	settings.supported_formats,
	std::make_unique<FrameDelivererFactory>(
	settings.delivery_mode, device_state.get(), std::move(gmb_support)),
	std::move(photo_device), std::move(device_state));
	}

	// static
	std::unique_ptr<VideoCaptureDevice>
	FakeVideoCaptureDeviceFactory::CreateDeviceWithDefaultResolutions(
	VideoPixelFormat pixel_format,
	FakeVideoCaptureDevice::DeliveryMode delivery_mode,
	float frame_rate,
	std::unique_ptr<gpu::GpuMemoryBufferSupport> gmb_support) {
	FakeVideoCaptureDeviceSettings settings;
	settings.delivery_mode = delivery_mode;
	for (const gfx::Size& resolution : kDefaultResolutions)
	settings.supported_formats.emplace_back(resolution, frame_rate,
	pixel_format);
	return CreateDeviceWithSettings(settings, std::move(gmb_support));
	}

	// static
	std::unique_ptr<VideoCaptureDevice>
	FakeVideoCaptureDeviceFactory::CreateErrorDevice() {
	return std::make_unique<ErrorFakeDevice>();
	}

	void FakeVideoCaptureDeviceFactory::SetToDefaultDevicesConfig(
	int device_count) {
	devices_config_.clear();
	ParseFakeDevicesConfigFromOptionsString(
	base::StringPrintf("device-count=%d", device_count), &devices_config_);
	}

	void FakeVideoCaptureDeviceFactory::SetToCustomDevicesConfig(
	const std::vector<FakeVideoCaptureDeviceSettings>& config) {
	devices_config_ = config;
	}

	std::unique_ptr<VideoCaptureDevice> FakeVideoCaptureDeviceFactory::CreateDevice(
	const VideoCaptureDeviceDescriptor& device_descriptor) {
	DCHECK(thread_checker_.CalledOnValidThread());

	for (const auto& entry : devices_config_) {
	if (device_descriptor.device_id != entry.device_id)
	continue;
	return CreateDeviceWithSettings(entry);
	}
	return nullptr;
	}

	void FakeVideoCaptureDeviceFactory::GetDevicesInfo(
	GetDevicesInfoCallback callback) {
	DCHECK(thread_checker_.CalledOnValidThread());

	std::vector<VideoCaptureDeviceInfo> devices_info;

	int entry_index = 0;
	for (const auto& entry : devices_config_) {
	VideoCaptureApi api =
	#if defined(OS_LINUX) \|\| defined(OS_CHROMEOS)
	VideoCaptureApi::LINUX_V4L2_SINGLE_PLANE;
	#elif defined(OS_MAC)
	VideoCaptureApi::MACOSX_AVFOUNDATION;
	#elif defined(OS_WIN)
	VideoCaptureApi::WIN_DIRECT_SHOW;
	#elif defined(OS_ANDROID)
	VideoCaptureApi::ANDROID_API2_LEGACY;
	#elif defined(OS_FUCHSIA)
	VideoCaptureApi::FUCHSIA_CAMERA3;
	#else
	#error Unsupported platform
	#endif

	devices_info.emplace_back(VideoCaptureDeviceDescriptor(
	base::StringPrintf("fake_device_%d", entry_index), entry.device_id, api,
	entry.photo_device_config.control_support,
	VideoCaptureTransportType::OTHER_TRANSPORT));

	devices_info.back().supported_formats =
	GetSupportedFormats(entry.device_id);
	entry_index++;
	}

	std::move(callback).Run(std::move(devices_info));
	}

	VideoCaptureFormats FakeVideoCaptureDeviceFactory::GetSupportedFormats(
	const std::string& device_id) {
	DCHECK(thread_checker_.CalledOnValidThread());

	VideoCaptureFormats supported_formats;
	for (const auto& entry : devices_config_) {
	if (device_id != entry.device_id)
	continue;
	supported_formats.insert(supported_formats.end(),
	entry.supported_formats.begin(),
	entry.supported_formats.end());
	}

	return supported_formats;
	}

	// static
	void FakeVideoCaptureDeviceFactory::ParseFakeDevicesConfigFromOptionsString(
	const std::string options_string,
	std::vector<FakeVideoCaptureDeviceSettings>* config) {
	base::StringTokenizer option_tokenizer(options_string, ", ");
	option_tokenizer.set_quote_chars("\"");

	FakeVideoCaptureDevice::DeliveryMode delivery_mode = kDefaultDeliveryMode;
	std::vector<gfx::Size> resolutions = ArrayToVector(kDefaultResolutions);
	std::vector<float> frame_rates = ArrayToVector(kDefaultFrameRates);
	int device_count = kDefaultDeviceCount;
	FakePhotoDeviceConfig photo_device_config;
	FakeVideoCaptureDevice::DisplayMediaType display_media_type =
	FakeVideoCaptureDevice::DisplayMediaType::ANY;

	while (option_tokenizer.GetNext()) {
	std::vector<base::StringPiece> param = base::SplitStringPiece(
	option_tokenizer.token_piece(), "=", base::TRIM_WHITESPACE,
	base::SPLIT_WANT_NONEMPTY);

	if (param.size() != 2u) {
	LOG(WARNING) << "Forget a value '" << options_string
	<< "'? Use name=value for "
	<< switches::kUseFakeDeviceForMediaStream << ".";
	return;
	}

	if (base::EqualsCaseInsensitiveASCII(param.front(), "ownership") &&
	base::EqualsCaseInsensitiveASCII(param.back(), "client")) {
	delivery_mode =
	FakeVideoCaptureDevice::DeliveryMode::USE_CLIENT_PROVIDED_BUFFERS;
	} else if (base::EqualsCaseInsensitiveASCII(param.front(), "fps")) {
	double parsed_fps = 0;
	if (base::StringToDouble(param.back(), &parsed_fps)) {
	float capped_frame_rate =
	std::max(kFakeCaptureMinFrameRate, static_cast<float>(parsed_fps));
	capped_frame_rate =
	std::min(kFakeCaptureMaxFrameRate, capped_frame_rate);
	frame_rates.clear();
	frame_rates.push_back(capped_frame_rate);
	}
	} else if (base::EqualsCaseInsensitiveASCII(param.front(),
	"device-count")) {
	unsigned int count = 0;
	if (base::StringToUint(param.back(), &count)) {
	device_count = std::min(
	kFakeCaptureMaxDeviceCount,
	std::max(kFakeCaptureMinDeviceCount, static_cast<int>(count)));
	}
	} else if (base::EqualsCaseInsensitiveASCII(param.front(), "config")) {
	const int device_index = 0;
	std::vector<VideoPixelFormat> pixel_formats;
	pixel_formats.push_back(GetPixelFormatFromDeviceIndex(device_index));
	FakeVideoCaptureDeviceSettings settings;
	settings.delivery_mode = delivery_mode;
	settings.device_id =
	base::StringPrintf(kDefaultDeviceIdMask, device_index);
	AppendAllCombinationsToFormatsContainer(
	pixel_formats, resolutions, frame_rates, &settings.supported_formats);

	if (param.back() == kDeviceConfigForGetPhotoStateFails) {
	settings.photo_device_config.should_fail_get_photo_capabilities = true;
	config->push_back(settings);
	return;
	}
	if (param.back() == kDeviceConfigForSetPhotoOptionsFails) {
	settings.photo_device_config.should_fail_set_photo_options = true;
	config->push_back(settings);
	return;
	}
	if (param.back() == kDeviceConfigForTakePhotoFails) {
	settings.photo_device_config.should_fail_take_photo = true;
	config->push_back(settings);
	return;
	}
	LOG(WARNING) << "Unknown config " << param.back();
	return;
	} else if (base::EqualsCaseInsensitiveASCII(param.front(),
	"display-media-type")) {
	if (base::EqualsCaseInsensitiveASCII(param.back(), "any")) {
	display_media_type = FakeVideoCaptureDevice::DisplayMediaType::ANY;
	} else if (base::EqualsCaseInsensitiveASCII(param.back(), "monitor")) {
	display_media_type = FakeVideoCaptureDevice::DisplayMediaType::MONITOR;
	} else if (base::EqualsCaseInsensitiveASCII(param.back(), "window")) {
	display_media_type = FakeVideoCaptureDevice::DisplayMediaType::WINDOW;
	} else if (base::EqualsCaseInsensitiveASCII(param.back(), "browser")) {
	display_media_type = FakeVideoCaptureDevice::DisplayMediaType::BROWSER;
	}
	} else if (base::EqualsCaseInsensitiveASCII(param.front(),
	"hardware-support")) {
	photo_device_config.control_support = VideoCaptureControlSupport();
	if (!base::EqualsCaseInsensitiveASCII(param.back(), "none")) {
	for (const std::string& support :
	base::SplitString(param.back(), "-", base::KEEP_WHITESPACE,
	base::SPLIT_WANT_NONEMPTY)) {
	if (base::EqualsCaseInsensitiveASCII(support, "pan"))
	photo_device_config.control_support.pan = true;
	else if (base::EqualsCaseInsensitiveASCII(support, "tilt"))
	photo_device_config.control_support.tilt = true;
	else if (base::EqualsCaseInsensitiveASCII(support, "zoom"))
	photo_device_config.control_support.zoom = true;
	else
	LOG(WARNING) << "Unsupported hardware support " << support;
	}
	}
	}
	}

	for (int device_index = 0; device_index < device_count; device_index++) {
	std::vector<VideoPixelFormat> pixel_formats;
	pixel_formats.push_back(GetPixelFormatFromDeviceIndex(device_index));
	FakeVideoCaptureDeviceSettings settings;
	settings.delivery_mode = delivery_mode;
	settings.device_id = base::StringPrintf(kDefaultDeviceIdMask, device_index);
	AppendAllCombinationsToFormatsContainer(
	pixel_formats, resolutions, frame_rates, &settings.supported_formats);
	settings.photo_device_config = photo_device_config;
	settings.display_media_type = display_media_type;
	config->push_back(settings);
	}
	}

	} // namespace media