// Copyright 2023 The MediaPipe Authors.
//
// 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 MEDIAPIPE_UTIL_FRAME_BUFFER_YUV_BUFFER_H_
#define MEDIAPIPE_UTIL_FRAME_BUFFER_YUV_BUFFER_H_
#include <memory>
#include "HalideBuffer.h"
#include "HalideRuntime.h"
namespace mediapipe {
namespace frame_buffer {
class RgbBuffer;
// YuvBuffer represents a view over a YUV 4:2:0 image.
//
// YuvBuffers may be copied and moved efficiently; their backing buffers are
// shared and never deep copied.
//
// YuvBuffer requires a minimum image width depending on the natural vector
// size of the platform, e.g., 16px. This is not validated by YuvBuffer.
class YuvBuffer {
public:
// YUV formats. Rather than supporting every possible format, we prioritize
// formats with broad hardware/platform support.
//
// Enum values are FourCC codes; see http://fourcc.org/yuv.php for more.
enum Format {
NV21 = 0x3132564E, // YUV420SP (VU interleaved)
YV12 = 0x32315659, // YUV420P (VU planar)
};
// Returns the size (in bytes) of a YUV image of the given dimensions.
static int ByteSize(int width, int height) {
// 1 byte per pixel in the Y plane, 2 bytes per 2x2 block in the UV plane.
// Dimensions with odd sizes are rounded up.
const int y_size = width * height;
const int uv_size = ((width + 1) / 2) * ((height + 1) / 2) * 2;
return y_size + uv_size;
}
// Builds a generic YUV420 YuvBuffer with the given backing buffers,
// dimensions and strides. Supports both interleaved or planar UV with
// custom strides.
//
// Does not take ownership of any backing buffers, which must be large
// enough to fit their contents.
YuvBuffer(uint8_t* y_plane, uint8_t* u_plane, uint8_t* v_plane, int width,
int height, int row_stride_y, int row_stride_uv,
int pixel_stride_uv);
// Builds a YuvBuffer using the given backing buffer, dimensions, and format.
// Expects an NV21- or YV12-format image only.
//
// Does not take ownership of the backing buffer (provided in 'data'), which
// must be sized to hold at least the amount indicated by ByteSize().
YuvBuffer(uint8_t* data, int width, int height, Format format);
// Builds a YuvBuffer using the given dimensions and format. Expects
// an NV21- or YV12-format image only.
//
// The underlying backing buffer is allocated and owned by this YuvBuffer.
YuvBuffer(int width, int height, Format format);
// YuvBuffer is copyable. The source retains ownership of its backing buffers.
YuvBuffer(const YuvBuffer& other);
// YuvBuffer is moveable. The source loses ownership of any backing buffers.
YuvBuffer(YuvBuffer&& other);
// YuvBuffer is assignable.
YuvBuffer& operator=(const YuvBuffer& other);
YuvBuffer& operator=(YuvBuffer&& other);
~YuvBuffer();
// Performs an in-place crop. Modifies this buffer so that the new extent
// matches that of the given crop rectangle -- (x0, y0) becomes (0, 0) and
// the new width and height are x1 - x0 + 1 and y1 - y0 + 1, respectively.
//
// Note that the top-left corner (x0, y0) coordinates must be even to
// maintain alignment between the Y and UV grids.
bool Crop(int x0, int y0, int x1, int y1);
// Resize this image to match the dimensions of the given output YuvBuffer
// and places the result into its backing buffer.
//
// Performs a resize with bilinear interpolation (over four source pixels).
bool Resize(YuvBuffer* output);
// Rotate this image into the given buffer by the given angle (90, 180, 270).
//
// Rotation is specified in degrees counter-clockwise such that when rotating
// by 90 degrees, the top-right corner of the source becomes the top-left of
// the output. The output buffer must have its height and width swapped when
// rotating by 90 or 270.
//
// Any angle values other than (90, 180, 270) are invalid.
bool Rotate(int angle, YuvBuffer* output);
// Flip this image horizontally/vertically into the given buffer. Both buffer
// dimensions must match.
bool FlipHorizontally(YuvBuffer* output);
bool FlipVertically(YuvBuffer* output);
// Performs a YUV-to-RGB color format conversion and places the result
// in the given output RgbBuffer. Both buffer dimensions must match.
//
// When halve is true, the converted output is downsampled by a factor of
// two by discarding three of four luminance values in every 2x2 block.
bool Convert(bool halve, RgbBuffer* output);
// Release ownership of the owned backing buffer.
uint8_t* Release() { return owned_buffer_.release(); }
// Returns the halide_buffer_t* for the Y plane.
const halide_buffer_t* y_buffer() const { return y_buffer_.raw_buffer(); }
// Returns the halide_buffer_t* for the UV plane(s).
const halide_buffer_t* uv_buffer() const { return uv_buffer_.raw_buffer(); }
// Returns the halide_buffer_t* for the Y plane.
halide_buffer_t* y_buffer() { return y_buffer_.raw_buffer(); }
// Returns the halide_buffer_t* for the UV plane(s).
halide_buffer_t* uv_buffer() { return uv_buffer_.raw_buffer(); }
// Returns the image width.
const int width() const { return y_buffer_.dim(0).extent(); }
// Returns the image height.
const int height() const { return y_buffer_.dim(1).extent(); }
private:
void Initialize(uint8_t* data, int width, int height, Format format);
// Non-NULL iff this YuvBuffer owns its buffer.
std::unique_ptr<uint8_t[]> owned_buffer_;
// Y (luminance) backing buffer: layout is always width x height.
Halide::Runtime::Buffer<uint8_t> y_buffer_;
// UV (chrominance) backing buffer; width/2 x height/2 x 2 (channel).
// May be interleaved or planar.
//
// Note that the planes are in the reverse of the usual order: channel 0 is V
// and channel 1 is U.
Halide::Runtime::Buffer<uint8_t> uv_buffer_;
};
} // namespace frame_buffer
} // namespace mediapipe
#endif // MEDIAPIPE_UTIL_FRAME_BUFFER_YUV_BUFFER_H_
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