Reapply "InputSurface: InputSurfaceSource from bqhelper"

/*

 * Copyright (C) 2015 The Android Open Source Project

 *

 * Licensed under the Apache License, Version 2.0 (the "License");

 * you may not use this file except in compliance with the License.

 * You may obtain a copy of the License at

 *

 *      http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

#ifndef FRAME_DROPPER_H_

#define FRAME_DROPPER_H_

#include <utils/Errors.h>

#include <utils/RefBase.h>

#include <media/stagefright/foundation/ABase.h>

namespace android {

struct FrameDropper : public RefBase {

    // No frames will be dropped until a valid max frame rate is set.

    FrameDropper();

    // maxFrameRate required to be positive.

    // maxFrameRate negative causes shouldDrop() to always return false

    // maxFrameRate == 0 is illegal

    status_t setMaxFrameRate(float maxFrameRate);

    // Returns false if max frame rate has not been set via setMaxFrameRate.

    bool shouldDrop(int64_t timeUs);

    // Returns true if all frame drop logic should be disabled.

    bool disabled() { return (mMinIntervalUs == -1ll); }

protected:

    virtual ~FrameDropper();

private:

    int64_t mDesiredMinTimeUs;

    int64_t mMinIntervalUs;

    DISALLOW_EVIL_CONSTRUCTORS(FrameDropper);

};

}  // namespace android

#endif  // FRAME_DROPPER_H_