webrtc/video_engine/main/interface/vie_capture.h

/*
 *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE file in the root of the source
 *  tree. An additional intellectual property rights grant can be found
 *  in the file PATENTS.  All contributing project authors may
 *  be found in the AUTHORS file in the root of the source tree.
 */

// This sub-API supports the following functionalities:
//
//  - Allocating capture devices.
//  - Connect a capture device with one or more channels.
//  - Start and stop capture devices.
//  - Getting capture device capabilities.


#ifndef WEBRTC_VIDEO_ENGINE_MAIN_INTERFACE_VIE_CAPTURE_H_
#define WEBRTC_VIDEO_ENGINE_MAIN_INTERFACE_VIE_CAPTURE_H_

#include "common_types.h"

namespace webrtc
{

class VideoEngine;
class VideoCaptureModule;

// This structure describes one set of the supported capabilities for a capture
// device.
struct CaptureCapability
{
    unsigned int width;
    unsigned int height;
    unsigned int maxFPS;
    RawVideoType rawType;
    VideoCodecType codecType;
    unsigned int expectedCaptureDelay;
    bool interlaced;
    CaptureCapability()
    {
        width = 0;
        height = 0;
        maxFPS = 0;
        rawType = kVideoI420;
        codecType = kVideoCodecUnknown;
        expectedCaptureDelay = 0;
        interlaced = false;
    }
};

// This enumerator tells the current brightness alarm mode.
enum Brightness
{
    Normal = 0,
    Bright = 1,
    Dark = 2
};

// This enumerator describes the capture alarm mode.
enum CaptureAlarm
{
    AlarmRaised = 0,
    AlarmCleared = 1
};

enum RotateCapturedFrame
{
    RotateCapturedFrame_0 = 0,
    RotateCapturedFrame_90 = 90,
    RotateCapturedFrame_180 = 180,
    RotateCapturedFrame_270 = 270
};

// This class declares an abstract interface to be used when using an external
// capture device. The user implemented derived class is registered using
// AllocateExternalCaptureDevice and is released using ReleaseCaptureDevice.
class WEBRTC_DLLEXPORT ViEExternalCapture
{
public:
    ViEExternalCapture() {}
    virtual ~ViEExternalCapture() {}

    // This method is called by the user to deliver a new captured frame to
    // VideoEngine.
    virtual int IncomingFrame(unsigned char* videoFrame,
                              unsigned int videoFrameLength,
                              unsigned short width, unsigned short height,
                              RawVideoType videoType,
                              unsigned long long captureTime = 0) = 0;
};

// ----------------------------------------------------------------------------
//	ViECaptureObserver
// ----------------------------------------------------------------------------

// This class declares an abstract interface for a user defined observer. It is
// up to the VideoEngine user to implement a derived class which implements the
// observer class. The observer is registered using RegisterObserver() and
// deregistered using DeregisterObserver().
class WEBRTC_DLLEXPORT ViECaptureObserver
{
public:
    // This method is called if a bright or dark captured image is detected.
    virtual void BrightnessAlarm(const int captureId,
                                 const Brightness brightness) = 0;

    // This method is called periodically telling the capture device frame rate.
    virtual void CapturedFrameRate(const int captureId,
                                   const unsigned char frameRate) = 0;

    // This method is called if the capture device stops delivering images to
    // VideoEngine.
    virtual void NoPictureAlarm(const int captureId,
                                const CaptureAlarm alarm) = 0;

protected:
    virtual ~ViECaptureObserver()
    {
    }
};

// ----------------------------------------------------------------------------
//	ViECapture
// ----------------------------------------------------------------------------

class WEBRTC_DLLEXPORT ViECapture
{
public:
    // Factory for the ViECapture sub‐API and increases an internal reference
    // counter if successful. Returns NULL if the API is not supported or if
    // construction fails.
    static ViECapture* GetInterface(VideoEngine* videoEngine);

    // Releases the ViECapture sub-API and decreases an internal reference
    // counter.
    // Returns the new reference count. This value should be zero
    // for all sub-API:s before the VideoEngine object can be safely deleted.
    virtual int Release() = 0;


    // Gets the number of available capture devices.
    virtual int NumberOfCaptureDevices() = 0;

    // Gets the name and unique id of a capture device.
    virtual int GetCaptureDevice(unsigned int listNumber, char* deviceNameUTF8,
                                 const unsigned int deviceNameUTF8Length,
                                 char* uniqueIdUTF8,
                                 const unsigned int uniqueIdUTF8Length) = 0;

    // Allocates a capture device to be used in VideoEngine.
    virtual int AllocateCaptureDevice(const char* uniqueIdUTF8,
                                      const unsigned int uniqueIdUTF8Length,
                                      int& captureId) = 0;

    // Registers an external capture device to be used in VideoEngine
    virtual int AllocateExternalCaptureDevice(
        int& captureId, ViEExternalCapture *&externalCapture) = 0;

    // Use capture device using external capture module.
    virtual int AllocateCaptureDevice(VideoCaptureModule& captureModule,
                                      int& captureId) = 0;

    // Releases a capture device and makes it available for other applications.
    virtual int ReleaseCaptureDevice(const int captureId) = 0;

    // This function connects a capture device with a channel. Multiple channels
    // can be connected to the same capture device.
    virtual int ConnectCaptureDevice(const int captureId,
                                     const int videoChannel) = 0;

    // Disconnects a capture device as input for a specified channel.
    virtual int DisconnectCaptureDevice(const int videoChannel) = 0;

    // Makes a capture device start capturing video frames.
    virtual int StartCapture(const int captureId,
                             const CaptureCapability captureCapability =
                                 CaptureCapability()) = 0;

    // Stops a started capture device from capturing video frames.
    virtual int StopCapture(const int captureId) = 0;

    // Rotates captured frames before encoding and sending.
    // Used on mobile devices with rotates cameras.
    virtual int SetRotateCapturedFrames(const int captureId,
                                        const RotateCapturedFrame rotation) = 0;

    // This function sets the expected delay from when a video frame is captured
    // to when that frame is delivered to VideoEngine.
    virtual int SetCaptureDelay(const int captureId,
                                const unsigned int captureDelayMs) = 0;

    // Returns the number of sets of capture capabilities the capture device
    // supports.
    virtual int NumberOfCapabilities(const char* uniqueIdUTF8,
                                     const unsigned int uniqueIdUTF8Length) = 0;

    // Gets a set of capture capabilities for a specified capture device.
    virtual int GetCaptureCapability(const char* uniqueIdUTF8,
                                     const unsigned int uniqueIdUTF8Length,
                                     const unsigned int capabilityNumber,
                                     CaptureCapability& capability) = 0;

    // Displays the capture device property dialog box for the specified capture
    // device. Windows only.
    virtual int ShowCaptureSettingsDialogBox(
        const char* uniqueIdUTF8, const unsigned int uniqueIdUTF8Length,
        const char* dialogTitle, void* parentWindow = NULL,
        const unsigned int x = 200, const unsigned int y = 200) = 0;

    // Gets the clockwise angle the frames from the camera must be rotated in
    // order to display the frames correctly if the display is rotated in its
    // natural orientation.
    virtual int GetOrientation(const char* uniqueIdUTF8,
                               RotateCapturedFrame &orientation) = 0;

    // Enables brightness alarm detection and the brightness alarm callback.
    virtual int EnableBrightnessAlarm(const int captureId,
                                      const bool enable) = 0;

    // Registers an instance of a user implementation of the ViECaptureObserver.
    virtual int RegisterObserver(const int captureId,
                                 ViECaptureObserver& observer) = 0;

    // Removes an already registered instance of ViECaptureObserver.
    virtual int DeregisterObserver(const int captureId) = 0;

protected:
    ViECapture() {};
    virtual ~ViECapture() {};
};
} // namespace webrtc
#endif  // WEBRTC_VIDEO_ENGINE_MAIN_INTERFACE_VIE_CAPTURE_H_