webrtc/talk/media/base/videoframefactory.h

// libjingle
// Copyright 2014 Google Inc.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
//  1. Redistributions of source code must retain the above copyright notice,
//     this list of conditions and the following disclaimer.
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//     this list of conditions and the following disclaimer in the documentation
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#ifndef TALK_MEDIA_BASE_VIDEOFRAMEFACTORY_H_
#define TALK_MEDIA_BASE_VIDEOFRAMEFACTORY_H_

#include "talk/media/base/videoframe.h"
#include "webrtc/base/scoped_ptr.h"

namespace cricket {

struct CapturedFrame;
class VideoFrame;

// Creates cricket::VideoFrames, or a subclass of cricket::VideoFrame
// depending on the subclass of VideoFrameFactory.
class VideoFrameFactory {
 public:
  VideoFrameFactory() {}
  virtual ~VideoFrameFactory() {}

  // The returned frame aliases the aliased_frame if the input color
  // space allows for aliasing, otherwise a color conversion will
  // occur.  For safety, |input_frame| must outlive the returned
  // frame.  Returns NULL if conversion fails.

  // The returned frame will be a center crop of |input_frame| with
  // size |cropped_width| x |cropped_height|.
  virtual VideoFrame* CreateAliasedFrame(const CapturedFrame* input_frame,
                                         int cropped_width,
                                         int cropped_height) const = 0;

  // The returned frame will be a center crop of |input_frame| with size
  // |cropped_width| x |cropped_height|, scaled to |output_width| x
  // |output_height|. If scaling has taken place, i.e. cropped input
  // resolution != output resolution, the returned frame will remain valid
  // until this function is called again.
  virtual VideoFrame* CreateAliasedFrame(const CapturedFrame* input_frame,
                                         int cropped_input_width,
                                         int cropped_input_height,
                                         int output_width,
                                         int output_height) const;

 private:
  // An internal frame buffer to avoid reallocations. It is mutable because it
  // does not affect behaviour, only performance.
  mutable rtc::scoped_ptr<VideoFrame> output_frame_;
};

}  // namespace cricket

#endif  // TALK_MEDIA_BASE_VIDEOFRAMEFACTORY_H_