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/*
* Copyright (c) 2015 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.
*/
#ifndef API_VIDEO_VIDEO_FRAME_BUFFER_H_
#define API_VIDEO_VIDEO_FRAME_BUFFER_H_
#include <stdint.h>
#include "rtc_base/refcount.h"
#include "rtc_base/scoped_ref_ptr.h"
namespace webrtc {
class I420BufferInterface;
class I420ABufferInterface;
class I444BufferInterface;
// Base class for frame buffers of different types of pixel format and storage.
// The tag in type() indicates how the data is represented, and each type is
// implemented as a subclass. To access the pixel data, call the appropriate
// GetXXX() function, where XXX represents the type. There is also a function
// ToI420() that returns a frame buffer in I420 format, converting from the
// underlying representation if necessary. I420 is the most widely accepted
// format and serves as a fallback for video sinks that can only handle I420,
// e.g. the internal WebRTC software encoders. A special enum value 'kNative' is
// provided for external clients to implement their own frame buffer
// representations, e.g. as textures. The external client can produce such
// native frame buffers from custom video sources, and then cast it back to the
// correct subclass in custom video sinks. The purpose of this is to improve
// performance by providing an optimized path without intermediate conversions.
// Frame metadata such as rotation and timestamp are stored in
// webrtc::VideoFrame, and not here.
class VideoFrameBuffer : public rtc::RefCountInterface {
public:
// New frame buffer types will be added conservatively when there is an
// opportunity to optimize the path between some pair of video source and
// video sink.
enum class Type {
kNative,
kI420,
kI420A,
kI444,
};
// This function specifies in what pixel format the data is stored in.
virtual Type type() const = 0;
// The resolution of the frame in pixels. For formats where some planes are
// subsampled, this is the highest-resolution plane.
virtual int width() const = 0;
virtual int height() const = 0;
// Returns a memory-backed frame buffer in I420 format. If the pixel data is
// in another format, a conversion will take place. All implementations must
// provide a fallback to I420 for compatibility with e.g. the internal WebRTC
// software encoders.
virtual rtc::scoped_refptr<I420BufferInterface> ToI420() = 0;
// These functions should only be called if type() is of the correct type.
// Calling with a different type will result in a crash.
// TODO(magjed): Return raw pointers for GetI420 once deprecated interface is
// removed.
rtc::scoped_refptr<I420BufferInterface> GetI420();
rtc::scoped_refptr<const I420BufferInterface> GetI420() const;
I420ABufferInterface* GetI420A();
const I420ABufferInterface* GetI420A() const;
I444BufferInterface* GetI444();
const I444BufferInterface* GetI444() const;
protected:
~VideoFrameBuffer() override {}
};
// This interface represents Type::kI420 and Type::kI444.
class PlanarYuvBuffer : public VideoFrameBuffer {
public:
virtual int ChromaWidth() const = 0;
virtual int ChromaHeight() const = 0;
// Returns pointer to the pixel data for a given plane. The memory is owned by
// the VideoFrameBuffer object and must not be freed by the caller.
virtual const uint8_t* DataY() const = 0;
virtual const uint8_t* DataU() const = 0;
virtual const uint8_t* DataV() const = 0;
// Returns the number of bytes between successive rows for a given plane.
virtual int StrideY() const = 0;
virtual int StrideU() const = 0;
virtual int StrideV() const = 0;
protected:
~PlanarYuvBuffer() override {}
};
class I420BufferInterface : public PlanarYuvBuffer {
public:
Type type() const override;
int ChromaWidth() const final;
int ChromaHeight() const final;
rtc::scoped_refptr<I420BufferInterface> ToI420() final;
protected:
~I420BufferInterface() override {}
};
class I420ABufferInterface : public I420BufferInterface {
public:
Type type() const final;
virtual const uint8_t* DataA() const = 0;
virtual int StrideA() const = 0;
protected:
~I420ABufferInterface() override {}
};
class I444BufferInterface : public PlanarYuvBuffer {
public:
Type type() const final;
int ChromaWidth() const final;
int ChromaHeight() const final;
protected:
~I444BufferInterface() override {}
};
} // namespace webrtc
#endif // API_VIDEO_VIDEO_FRAME_BUFFER_H_