tenfourfox/dom/media/webrtc/GonkCameraImage.h

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2017-04-19 07:56:45 +00:00
/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* 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 GONKCAMERAIMAGE_H
#define GONKCAMERAIMAGE_H
#include "mozilla/ReentrantMonitor.h"
#include "ImageLayers.h"
#include "ImageContainer.h"
#include "GrallocImages.h"
namespace android {
class MOZ_EXPORT MediaBuffer;
}
namespace mozilla {
/**
* GonkCameraImage has two parts. One is preview image which will be saved in
* GrallocImage, another kind is the MediaBuffer keeps in mMediaBuffer
* which is from gonk camera recording callback. The data in MediaBuffer is Gonk
* shared memory based on android binder (IMemory), the actual format in IMemory
* is platform dependent.
* This instance is created in MediaEngine when the preview image arrives.
* The MediaBuffer is attached to the current created GonkCameraImage via SetMediaBuffer().
* After sending this image to MediaStreamGraph by AppendToTrack(), ClearMediaBuffer()
* must be called to clear MediaBuffer to avoid MediaBuffer be kept in MSG thread.
* The reason to keep MediaBuffer be accessed from MSG thread is MediaBuffer is
* limited resource and it could cause frame rate jitter if MediaBuffer stay too
* long in other threads.
* So there will be 3 threads to accessed this class. First is camera preview
* thread which creates an instance of this class and initialize the preview
* image in the base class GrallocImage. Second is the camera recording
* thread which attaches MediaBuffer and sends this image to MediaStreamDirectListener.
* Third is the MSG thread via NotifyPull, the image should have preview image
* only in NotifyPull.
*
* Note: SetMediaBuffer() and GetMediaBuffer() should be called from the same
* thread. It is forbidden to call GetMediaBuffer() from other threads.
*/
class GonkCameraImage : public layers::GrallocImage
{
public:
GonkCameraImage();
// The returned aBuffer has called aBuffer->add_ref() already, so it is caller's
// duty to release aBuffer. It should be called from the same thread which
// called SetMediaBuffer().
nsresult GetMediaBuffer(android::MediaBuffer** aBuffer);
// Set MediaBuffer to image. It is caller's responsibility to call ClearMediaBuffer()
// after the MediaBuffer is sent via MediaStreamGraph.
nsresult SetMediaBuffer(android::MediaBuffer* aBuffer);
// It should be called from the same thread which called SetMediaBuffer().
nsresult ClearMediaBuffer();
bool HasMediaBuffer();
protected:
virtual ~GonkCameraImage();
// mMonitor protects mMediaBuffer and mThread.
ReentrantMonitor mMonitor;
android::MediaBuffer* mMediaBuffer;
// Check if current thread is the same one which called SetMediaBuffer().
// It doesn't need to hold reference count.
DebugOnly<nsIThread*> mThread;
};
} // namespace mozilla
#endif /* GONKCAMERAIMAGE_H */