media/video/capture/video_capture_device.h - platform/external/chromium_org - Git at Google

 // Copyright (c) 2012 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.
 //
 // VideoCaptureDevice is the abstract base class for realizing video capture
 // device support in Chromium. It provides the interface for OS dependent
 // implementations.
 // The class is created and functions are invoked on a thread owned by
 // VideoCaptureManager. Capturing is done on other threads, depending on the OS
 // specific implementation.

 #ifndef MEDIA_VIDEO_CAPTURE_VIDEO_CAPTURE_DEVICE_H_
 #define MEDIA_VIDEO_CAPTURE_VIDEO_CAPTURE_DEVICE_H_

 #include <list>
 #include <string>

 #include "base/logging.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/single_thread_task_runner.h"
 #include "base/time/time.h"
 #include "media/base/media_export.h"
 #include "media/base/video_frame.h"
 #include "media/video/capture/video_capture_types.h"

 namespace media {

 class MEDIA_EXPORT VideoCaptureDevice {
  public:
   // Represents a capture device name and ID.
   // You should not create an instance of this class directly by e.g. setting
   // various properties directly.  Instead use
   // VideoCaptureDevice::GetDeviceNames to do this for you and if you need to
   // cache your own copy of a name, you can do so via the copy constructor.
   // The reason for this is that a device name might contain platform specific
   // settings that are relevant only to the platform specific implementation of
   // VideoCaptureDevice::Create.
   class MEDIA_EXPORT Name {
    public:
     Name() {}
     Name(const std::string& name, const std::string& id)
         : device_name_(name), unique_id_(id) {}

 #if defined(OS_WIN)
     // Windows targets Capture Api type: it can only be set on construction.
     enum CaptureApiType {
       MEDIA_FOUNDATION,
       DIRECT_SHOW,
       API_TYPE_UNKNOWN
     };
 #endif
 #if defined(OS_MACOSX)
     // Mac targets Capture Api type: it can only be set on construction.
     enum CaptureApiType {
       AVFOUNDATION,
       QTKIT,
       API_TYPE_UNKNOWN
     };
 #endif
 #if defined(OS_WIN) || defined(OS_MACOSX)
     Name(const std::string& name,
          const std::string& id,
          const CaptureApiType api_type)
         : device_name_(name), unique_id_(id), capture_api_class_(api_type) {}
 #endif
     ~Name() {}

     // Friendly name of a device
     const std::string& name() const { return device_name_; }

     // Unique name of a device. Even if there are multiple devices with the same
     // friendly name connected to the computer this will be unique.
     const std::string& id() const { return unique_id_; }

     // The unique hardware model identifier of the capture device. Returns
     // "[vid]:[pid]" when a USB device is detected, otherwise "".
     // The implementation of this method is platform-dependent.
     const std::string GetModel() const;

     // Friendly name of a device, plus the model identifier in parentheses.
     const std::string GetNameAndModel() const;

     // These operators are needed due to storing the name in an STL container.
     // In the shared build, all methods from the STL container will be exported
     // so even though they're not used, they're still depended upon.
     bool operator==(const Name& other) const {
       return other.id() == unique_id_;
     }
     bool operator<(const Name& other) const {
       return unique_id_ < other.id();
     }

 #if defined(OS_WIN) || defined(OS_MACOSX)
     CaptureApiType capture_api_type() const {
       return capture_api_class_.capture_api_type();
     }
 #endif  // if defined(OS_WIN)

    private:
     std::string device_name_;
     std::string unique_id_;
 #if defined(OS_WIN) || defined(OS_MACOSX)
     // This class wraps the CaptureApiType to give it a by default value if not
     // initialized.
     class CaptureApiClass {
      public:
       CaptureApiClass(): capture_api_type_(API_TYPE_UNKNOWN) {}
       CaptureApiClass(const CaptureApiType api_type)
           : capture_api_type_(api_type) {}
       CaptureApiType capture_api_type() const {
         DCHECK_NE(capture_api_type_, API_TYPE_UNKNOWN);
         return capture_api_type_;
       }
      private:
       CaptureApiType capture_api_type_;
     };

     CaptureApiClass capture_api_class_;
 #endif
     // Allow generated copy constructor and assignment.
   };

   // Manages a list of Name entries.
   typedef std::list<Name> Names;

   class MEDIA_EXPORT Client {
    public:
     // Memory buffer returned by Client::ReserveOutputBuffer().
     class Buffer : public base::RefCountedThreadSafe<Buffer> {
      public:
       int id() const { return id_; }
       void* data() const { return data_; }
       size_t size() const { return size_; }

      protected:
       friend class base::RefCountedThreadSafe<Buffer>;

       Buffer(int id, void* data, size_t size)
           : id_(id), data_(data), size_(size) {}
       virtual ~Buffer() {}

       const int id_;
       void* const data_;
       const size_t size_;
     };

     virtual ~Client() {}

     // Reserve an output buffer into which contents can be captured directly.
     // The returned Buffer will always be allocated with a memory size suitable
     // for holding a packed video frame with pixels of |format| format, of
     // |dimensions| frame dimensions. It is permissible for |dimensions| to be
     // zero; in which case the returned Buffer does not guarantee memory
     // backing, but functions as a reservation for external input for the
     // purposes of buffer throttling.
     //
     // The output buffer stays reserved for use until the Buffer object is
     // destroyed.
     virtual scoped_refptr<Buffer> ReserveOutputBuffer(
         media::VideoFrame::Format format,
         const gfx::Size& dimensions) = 0;

     // Captured a new video frame, data for which is pointed to by |data|.
     //
     // The format of the frame is described by |frame_format|, and is assumed to
     // be tightly packed. This method will try to reserve an output buffer and
     // copy from |data| into the output buffer. If no output buffer is
     // available, the frame will be silently dropped.
     virtual void OnIncomingCapturedData(const uint8* data,
                                         int length,
                                         const VideoCaptureFormat& frame_format,
                                         int rotation,  // Clockwise.
                                         base::TimeTicks timestamp) = 0;

     // Captured a new video frame, held in |frame|.
     //
     // As the frame is backed by a reservation returned by
     // ReserveOutputBuffer(), delivery is guaranteed and will require no
     // additional copies in the browser process.
     virtual void OnIncomingCapturedVideoFrame(
         const scoped_refptr<Buffer>& buffer,
         const VideoCaptureFormat& buffer_format,
         const scoped_refptr<media::VideoFrame>& frame,
         base::TimeTicks timestamp) = 0;

     // An error has occurred that cannot be handled and VideoCaptureDevice must
     // be StopAndDeAllocate()-ed. |reason| is a text description of the error.
     virtual void OnError(const std::string& reason) = 0;

     // VideoCaptureDevice requests the |message| to be logged.
     virtual void OnLog(const std::string& message) {}
   };

   // Creates a VideoCaptureDevice object.
   // Return NULL if the hardware is not available.
   static VideoCaptureDevice* Create(
       scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner,
       const Name& device_name);
   virtual ~VideoCaptureDevice();

   // Gets the names of all video capture devices connected to this computer.
   static void GetDeviceNames(Names* device_names);

   // Gets the supported formats of a particular device attached to the system.
   // This method should be called before allocating or starting a device. In
   // case format enumeration is not supported, or there was a problem, the
   // formats array will be empty.
   static void GetDeviceSupportedFormats(const Name& device,
                                         VideoCaptureFormats* supported_formats);

   // Prepares the camera for use. After this function has been called no other
   // applications can use the camera. StopAndDeAllocate() must be called before
   // the object is deleted.
   virtual void AllocateAndStart(const VideoCaptureParams& params,
                                 scoped_ptr<Client> client) = 0;

   // Deallocates the camera, possibly asynchronously.
   //
   // This call requires the device to do the following things, eventually: put
   // camera hardware into a state where other applications could use it, free
   // the memory associated with capture, and delete the |client| pointer passed
   // into AllocateAndStart.
   //
   // If deallocation is done asynchronously, then the device implementation must
   // ensure that a subsequent AllocateAndStart() operation targeting the same ID
   // would be sequenced through the same task runner, so that deallocation
   // happens first.
   virtual void StopAndDeAllocate() = 0;

   // Gets the power line frequency from the current system time zone if this is
   // defined, otherwise returns 0.
   int GetPowerLineFrequencyForLocation() const;

  protected:
   static const int kPowerLine50Hz = 50;
   static const int kPowerLine60Hz = 60;
 };

 }  // namespace media

 #endif  // MEDIA_VIDEO_CAPTURE_VIDEO_CAPTURE_DEVICE_H_
	// Copyright (c) 2012 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.
	//
	// VideoCaptureDevice is the abstract base class for realizing video capture
	// device support in Chromium. It provides the interface for OS dependent
	// implementations.
	// The class is created and functions are invoked on a thread owned by
	// VideoCaptureManager. Capturing is done on other threads, depending on the OS
	// specific implementation.

	#ifndef MEDIA_VIDEO_CAPTURE_VIDEO_CAPTURE_DEVICE_H_
	#define MEDIA_VIDEO_CAPTURE_VIDEO_CAPTURE_DEVICE_H_

	#include <list>
	#include <string>

	#include "base/logging.h"
	#include "base/memory/ref_counted.h"
	#include "base/memory/scoped_ptr.h"
	#include "base/single_thread_task_runner.h"
	#include "base/time/time.h"
	#include "media/base/media_export.h"
	#include "media/base/video_frame.h"
	#include "media/video/capture/video_capture_types.h"

	namespace media {

	class MEDIA_EXPORT VideoCaptureDevice {
	public:
	// Represents a capture device name and ID.
	// You should not create an instance of this class directly by e.g. setting
	// various properties directly. Instead use
	// VideoCaptureDevice::GetDeviceNames to do this for you and if you need to
	// cache your own copy of a name, you can do so via the copy constructor.
	// The reason for this is that a device name might contain platform specific
	// settings that are relevant only to the platform specific implementation of
	// VideoCaptureDevice::Create.
	class MEDIA_EXPORT Name {
	public:
	Name() {}
	Name(const std::string& name, const std::string& id)
	: device_name_(name), unique_id_(id) {}

	#if defined(OS_WIN)
	// Windows targets Capture Api type: it can only be set on construction.
	enum CaptureApiType {
	MEDIA_FOUNDATION,
	DIRECT_SHOW,
	API_TYPE_UNKNOWN
	};
	#endif
	#if defined(OS_MACOSX)
	// Mac targets Capture Api type: it can only be set on construction.
	enum CaptureApiType {
	AVFOUNDATION,
	QTKIT,
	API_TYPE_UNKNOWN
	};
	#endif
	#if defined(OS_WIN) \|\| defined(OS_MACOSX)
	Name(const std::string& name,
	const std::string& id,
	const CaptureApiType api_type)
	: device_name_(name), unique_id_(id), capture_api_class_(api_type) {}
	#endif
	~Name() {}

	// Friendly name of a device
	const std::string& name() const { return device_name_; }

	// Unique name of a device. Even if there are multiple devices with the same
	// friendly name connected to the computer this will be unique.
	const std::string& id() const { return unique_id_; }

	// The unique hardware model identifier of the capture device. Returns
	// "[vid]:[pid]" when a USB device is detected, otherwise "".
	// The implementation of this method is platform-dependent.
	const std::string GetModel() const;

	// Friendly name of a device, plus the model identifier in parentheses.
	const std::string GetNameAndModel() const;

	// These operators are needed due to storing the name in an STL container.
	// In the shared build, all methods from the STL container will be exported
	// so even though they're not used, they're still depended upon.
	bool operator==(const Name& other) const {
	return other.id() == unique_id_;
	}
	bool operator<(const Name& other) const {
	return unique_id_ < other.id();
	}

	#if defined(OS_WIN) \|\| defined(OS_MACOSX)
	CaptureApiType capture_api_type() const {
	return capture_api_class_.capture_api_type();
	}
	#endif // if defined(OS_WIN)

	private:
	std::string device_name_;
	std::string unique_id_;
	#if defined(OS_WIN) \|\| defined(OS_MACOSX)
	// This class wraps the CaptureApiType to give it a by default value if not
	// initialized.
	class CaptureApiClass {
	public:
	CaptureApiClass(): capture_api_type_(API_TYPE_UNKNOWN) {}
	CaptureApiClass(const CaptureApiType api_type)
	: capture_api_type_(api_type) {}
	CaptureApiType capture_api_type() const {
	DCHECK_NE(capture_api_type_, API_TYPE_UNKNOWN);
	return capture_api_type_;
	}
	private:
	CaptureApiType capture_api_type_;
	};

	CaptureApiClass capture_api_class_;
	#endif
	// Allow generated copy constructor and assignment.
	};

	// Manages a list of Name entries.
	typedef std::list<Name> Names;

	class MEDIA_EXPORT Client {
	public:
	// Memory buffer returned by Client::ReserveOutputBuffer().
	class Buffer : public base::RefCountedThreadSafe<Buffer> {
	public:
	int id() const { return id_; }
	void* data() const { return data_; }
	size_t size() const { return size_; }

	protected:
	friend class base::RefCountedThreadSafe<Buffer>;

	Buffer(int id, void* data, size_t size)
	: id_(id), data_(data), size_(size) {}
	virtual ~Buffer() {}

	const int id_;
	void* const data_;
	const size_t size_;
	};

	virtual ~Client() {}

	// Reserve an output buffer into which contents can be captured directly.
	// The returned Buffer will always be allocated with a memory size suitable
	// for holding a packed video frame with pixels of \|format\| format, of
	// \|dimensions\| frame dimensions. It is permissible for \|dimensions\| to be
	// zero; in which case the returned Buffer does not guarantee memory
	// backing, but functions as a reservation for external input for the
	// purposes of buffer throttling.
	//
	// The output buffer stays reserved for use until the Buffer object is
	// destroyed.
	virtual scoped_refptr<Buffer> ReserveOutputBuffer(
	media::VideoFrame::Format format,
	const gfx::Size& dimensions) = 0;

	// Captured a new video frame, data for which is pointed to by \|data\|.
	//
	// The format of the frame is described by \|frame_format\|, and is assumed to
	// be tightly packed. This method will try to reserve an output buffer and
	// copy from \|data\| into the output buffer. If no output buffer is
	// available, the frame will be silently dropped.
	virtual void OnIncomingCapturedData(const uint8* data,
	int length,
	const VideoCaptureFormat& frame_format,
	int rotation, // Clockwise.
	base::TimeTicks timestamp) = 0;

	// Captured a new video frame, held in \|frame\|.
	//
	// As the frame is backed by a reservation returned by
	// ReserveOutputBuffer(), delivery is guaranteed and will require no
	// additional copies in the browser process.
	virtual void OnIncomingCapturedVideoFrame(
	const scoped_refptr<Buffer>& buffer,
	const VideoCaptureFormat& buffer_format,
	const scoped_refptr<media::VideoFrame>& frame,
	base::TimeTicks timestamp) = 0;

	// An error has occurred that cannot be handled and VideoCaptureDevice must
	// be StopAndDeAllocate()-ed. \|reason\| is a text description of the error.
	virtual void OnError(const std::string& reason) = 0;

	// VideoCaptureDevice requests the \|message\| to be logged.
	virtual void OnLog(const std::string& message) {}
	};

	// Creates a VideoCaptureDevice object.
	// Return NULL if the hardware is not available.
	static VideoCaptureDevice* Create(
	scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner,
	const Name& device_name);
	virtual ~VideoCaptureDevice();

	// Gets the names of all video capture devices connected to this computer.
	static void GetDeviceNames(Names* device_names);

	// Gets the supported formats of a particular device attached to the system.
	// This method should be called before allocating or starting a device. In
	// case format enumeration is not supported, or there was a problem, the
	// formats array will be empty.
	static void GetDeviceSupportedFormats(const Name& device,
	VideoCaptureFormats* supported_formats);

	// Prepares the camera for use. After this function has been called no other
	// applications can use the camera. StopAndDeAllocate() must be called before
	// the object is deleted.
	virtual void AllocateAndStart(const VideoCaptureParams& params,
	scoped_ptr<Client> client) = 0;

	// Deallocates the camera, possibly asynchronously.
	//
	// This call requires the device to do the following things, eventually: put
	// camera hardware into a state where other applications could use it, free
	// the memory associated with capture, and delete the \|client\| pointer passed
	// into AllocateAndStart.
	//
	// If deallocation is done asynchronously, then the device implementation must
	// ensure that a subsequent AllocateAndStart() operation targeting the same ID
	// would be sequenced through the same task runner, so that deallocation
	// happens first.
	virtual void StopAndDeAllocate() = 0;

	// Gets the power line frequency from the current system time zone if this is
	// defined, otherwise returns 0.
	int GetPowerLineFrequencyForLocation() const;

	protected:
	static const int kPowerLine50Hz = 50;
	static const int kPowerLine60Hz = 60;
	};

	} // namespace media

	#endif // MEDIA_VIDEO_CAPTURE_VIDEO_CAPTURE_DEVICE_H_