gecko-dev/content/media/webrtc/MediaEngine.h

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4.3 KiB
C++

/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
* You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef MEDIAENGINE_H_
#define MEDIAENGINE_H_
#include "nsIDOMFile.h"
#include "DOMMediaStream.h"
#include "MediaStreamGraph.h"
namespace mozilla {
/**
* Abstract interface for managing audio and video devices. Each platform
* must implement a concrete class that will map these classes and methods
* to the appropriate backend. For example, on Desktop platforms, these will
* correspond to equivalent webrtc (GIPS) calls, and on B2G they will map to
* a Gonk interface.
*/
class MediaEngineVideoSource;
class MediaEngineAudioSource;
struct MediaEnginePrefs;
enum MediaEngineState {
kAllocated,
kStarted,
kStopped,
kReleased
};
// We only support 1 audio and 1 video track for now.
enum {
kVideoTrack = 1,
kAudioTrack = 2
};
class MediaEngine
{
public:
virtual ~MediaEngine() {}
static const int DEFAULT_VIDEO_FPS = 30;
static const int DEFAULT_VIDEO_MIN_FPS = 10;
static const int DEFAULT_VIDEO_WIDTH = 640;
static const int DEFAULT_VIDEO_HEIGHT = 480;
static const int DEFAULT_AUDIO_TIMER_MS = 10;
/* Populate an array of video sources in the nsTArray. Also include devices
* that are currently unavailable. */
virtual void EnumerateVideoDevices(nsTArray<nsRefPtr<MediaEngineVideoSource> >*) = 0;
/* Populate an array of audio sources in the nsTArray. Also include devices
* that are currently unavailable. */
virtual void EnumerateAudioDevices(nsTArray<nsRefPtr<MediaEngineAudioSource> >*) = 0;
};
/**
* Common abstract base class for audio and video sources.
*/
class MediaEngineSource : public nsISupports
{
public:
virtual ~MediaEngineSource() {}
/* Populate the human readable name of this device in the nsAString */
virtual void GetName(nsAString&) = 0;
/* Populate the UUID of this device in the nsAString */
virtual void GetUUID(nsAString&) = 0;
/* This call reserves but does not start the device. */
virtual nsresult Allocate(const MediaEnginePrefs &aPrefs) = 0;
/* Release the device back to the system. */
virtual nsresult Deallocate() = 0;
/* Start the device and add the track to the provided SourceMediaStream, with
* the provided TrackID. You may start appending data to the track
* immediately after. */
virtual nsresult Start(SourceMediaStream*, TrackID) = 0;
/* Take a snapshot from this source. In the case of video this is a single
* image, and for audio, it is a snippet lasting aDuration milliseconds. The
* duration argument is ignored for a MediaEngineVideoSource.
*/
virtual nsresult Snapshot(uint32_t aDuration, nsIDOMFile** aFile) = 0;
/* Called when the stream wants more data */
virtual void NotifyPull(MediaStreamGraph* aGraph,
SourceMediaStream *aSource,
TrackID aId,
StreamTime aDesiredTime,
TrackTicks &aLastEndTime) = 0;
/* Stop the device and release the corresponding MediaStream */
virtual nsresult Stop(SourceMediaStream *aSource, TrackID aID) = 0;
/* Change device configuration. */
virtual nsresult Config(bool aEchoOn, uint32_t aEcho,
bool aAgcOn, uint32_t aAGC,
bool aNoiseOn, uint32_t aNoise) = 0;
/* Returns true if a source represents a fake capture device and
* false otherwise
*/
virtual bool IsFake() = 0;
/* Return false if device is currently allocated or started */
bool IsAvailable() {
if (mState == kAllocated || mState == kStarted) {
return false;
} else {
return true;
}
}
/* It is an error to call Start() before an Allocate(), and Stop() before
* a Start(). Only Allocate() may be called after a Deallocate(). */
protected:
MediaEngineState mState;
};
/**
* Video source and friends.
*/
struct MediaEnginePrefs {
int32_t mWidth;
int32_t mHeight;
int32_t mFPS;
int32_t mMinFPS;
};
class MediaEngineVideoSource : public MediaEngineSource
{
public:
virtual ~MediaEngineVideoSource() {}
};
/**
* Audio source and friends.
*/
class MediaEngineAudioSource : public MediaEngineSource
{
public:
virtual ~MediaEngineAudioSource() {}
};
}
#endif /* MEDIAENGINE_H_ */