common_video/libyuv/webrtc_libyuv.cc - src.git - Git at Google

 /*
  *  Copyright (c) 2012 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.
  */

 #include "common_video/libyuv/include/webrtc_libyuv.h"

 #include <string.h>

 #include "api/video/i420_buffer.h"
 #include "rtc_base/checks.h"
 #include "third_party/libyuv/include/libyuv.h"

 namespace webrtc {

 size_t CalcBufferSize(VideoType type, int width, int height) {
   RTC_DCHECK_GE(width, 0);
   RTC_DCHECK_GE(height, 0);
   size_t buffer_size = 0;
   switch (type) {
     case VideoType::kI420:
     case VideoType::kNV12:
     case VideoType::kNV21:
     case VideoType::kIYUV:
     case VideoType::kYV12: {
       int half_width = (width + 1) >> 1;
       int half_height = (height + 1) >> 1;
       buffer_size = width * height + half_width * half_height * 2;
       break;
     }
     case VideoType::kARGB4444:
     case VideoType::kRGB565:
     case VideoType::kARGB1555:
     case VideoType::kYUY2:
     case VideoType::kUYVY:
       buffer_size = width * height * 2;
       break;
     case VideoType::kRGB24:
       buffer_size = width * height * 3;
       break;
     case VideoType::kBGRA:
     case VideoType::kARGB:
       buffer_size = width * height * 4;
       break;
     default:
       RTC_NOTREACHED();
       break;
   }
   return buffer_size;
 }

 static int PrintPlane(const uint8_t* buf,
                       int width,
                       int height,
                       int stride,
                       FILE* file) {
   for (int i = 0; i < height; i++, buf += stride) {
     if (fwrite(buf, 1, width, file) != static_cast<unsigned int>(width))
       return -1;
   }
   return 0;
 }

 // TODO(nisse): Belongs with the test code?
 int PrintVideoFrame(const I420BufferInterface& frame, FILE* file) {
   int width = frame.width();
   int height = frame.height();
   int chroma_width = frame.ChromaWidth();
   int chroma_height = frame.ChromaHeight();

   if (PrintPlane(frame.DataY(), width, height,
                  frame.StrideY(), file) < 0) {
     return -1;
   }
   if (PrintPlane(frame.DataU(),
                  chroma_width, chroma_height,
                  frame.StrideU(), file) < 0) {
     return -1;
   }
   if (PrintPlane(frame.DataV(),
                  chroma_width, chroma_height,
                  frame.StrideV(), file) < 0) {
     return -1;
   }
   return 0;
 }

 int PrintVideoFrame(const VideoFrame& frame, FILE* file) {
   return PrintVideoFrame(*frame.video_frame_buffer()->ToI420(), file);
 }

 int ExtractBuffer(const rtc::scoped_refptr<I420BufferInterface>& input_frame,
                   size_t size,
                   uint8_t* buffer) {
   RTC_DCHECK(buffer);
   if (!input_frame)
     return -1;
   int width = input_frame->width();
   int height = input_frame->height();
   size_t length = CalcBufferSize(VideoType::kI420, width, height);
   if (size < length) {
      return -1;
   }

   int chroma_width = input_frame->ChromaWidth();
   int chroma_height = input_frame->ChromaHeight();

   libyuv::I420Copy(input_frame->DataY(),
                    input_frame->StrideY(),
                    input_frame->DataU(),
                    input_frame->StrideU(),
                    input_frame->DataV(),
                    input_frame->StrideV(),
                    buffer, width,
                    buffer + width*height, chroma_width,
                    buffer + width*height + chroma_width*chroma_height,
                    chroma_width,
                    width, height);

   return static_cast<int>(length);
 }

 int ExtractBuffer(const VideoFrame& input_frame, size_t size, uint8_t* buffer) {
   return ExtractBuffer(input_frame.video_frame_buffer()->ToI420(), size,
                        buffer);
 }

 int ConvertNV12ToRGB565(const uint8_t* src_frame,
                         uint8_t* dst_frame,
                         int width, int height) {
   int abs_height = (height < 0) ? -height : height;
   const uint8_t* yplane = src_frame;
   const uint8_t* uvInterlaced = src_frame + (width * abs_height);

   return libyuv::NV12ToRGB565(yplane, width,
                               uvInterlaced, (width + 1) >> 1,
                               dst_frame, width,
                               width, height);
 }

 int ConvertRGB24ToARGB(const uint8_t* src_frame, uint8_t* dst_frame,
                        int width, int height, int dst_stride) {
   if (dst_stride == 0)
     dst_stride = width;
   return libyuv::RGB24ToARGB(src_frame, width,
                              dst_frame, dst_stride,
                              width, height);
 }

 int ConvertVideoType(VideoType video_type) {
   switch (video_type) {
     case VideoType::kUnknown:
       return libyuv::FOURCC_ANY;
     case VideoType::kI420:
       return libyuv::FOURCC_I420;
     case VideoType::kIYUV:  // same as VideoType::kYV12
     case VideoType::kYV12:
       return libyuv::FOURCC_YV12;
     case VideoType::kRGB24:
       return libyuv::FOURCC_24BG;
     case VideoType::kABGR:
       return libyuv::FOURCC_ABGR;
     case VideoType::kRGB565:
       return libyuv::FOURCC_RGBP;
     case VideoType::kYUY2:
       return libyuv::FOURCC_YUY2;
     case VideoType::kUYVY:
       return libyuv::FOURCC_UYVY;
     case VideoType::kMJPEG:
       return libyuv::FOURCC_MJPG;
     case VideoType::kNV21:
       return libyuv::FOURCC_NV21;
     case VideoType::kNV12:
       return libyuv::FOURCC_NV12;
     case VideoType::kARGB:
       return libyuv::FOURCC_ARGB;
     case VideoType::kBGRA:
       return libyuv::FOURCC_BGRA;
     case VideoType::kARGB4444:
       return libyuv::FOURCC_R444;
     case VideoType::kARGB1555:
       return libyuv::FOURCC_RGBO;
   }
   RTC_NOTREACHED();
   return libyuv::FOURCC_ANY;
 }

 int ConvertFromI420(const VideoFrame& src_frame,
                     VideoType dst_video_type,
                     int dst_sample_size,
                     uint8_t* dst_frame) {
   rtc::scoped_refptr<I420BufferInterface> i420_buffer =
       src_frame.video_frame_buffer()->ToI420();
   return libyuv::ConvertFromI420(
       i420_buffer->DataY(), i420_buffer->StrideY(), i420_buffer->DataU(),
       i420_buffer->StrideU(), i420_buffer->DataV(), i420_buffer->StrideV(),
       dst_frame, dst_sample_size, src_frame.width(), src_frame.height(),
       ConvertVideoType(dst_video_type));
 }

 // Compute PSNR for an I420 frame (all planes). Can upscale test frame.
 double I420PSNR(const I420BufferInterface& ref_buffer,
                 const I420BufferInterface& test_buffer) {
   RTC_DCHECK_GE(ref_buffer.width(), test_buffer.width());
   RTC_DCHECK_GE(ref_buffer.height(), test_buffer.height());
   if ((ref_buffer.width() != test_buffer.width()) ||
       (ref_buffer.height() != test_buffer.height())) {
     rtc::scoped_refptr<I420Buffer> scaled_buffer =
         I420Buffer::Create(ref_buffer.width(), ref_buffer.height());
     scaled_buffer->ScaleFrom(test_buffer);
     return I420PSNR(ref_buffer, *scaled_buffer);
   }
   double psnr = libyuv::I420Psnr(
       ref_buffer.DataY(), ref_buffer.StrideY(), ref_buffer.DataU(),
       ref_buffer.StrideU(), ref_buffer.DataV(), ref_buffer.StrideV(),
       test_buffer.DataY(), test_buffer.StrideY(), test_buffer.DataU(),
       test_buffer.StrideU(), test_buffer.DataV(), test_buffer.StrideV(),
       test_buffer.width(), test_buffer.height());
   // LibYuv sets the max psnr value to 128, we restrict it here.
   // In case of 0 mse in one frame, 128 can skew the results significantly.
   return (psnr > kPerfectPSNR) ? kPerfectPSNR : psnr;
 }

 // Compute PSNR for an I420 frame (all planes)
 double I420PSNR(const VideoFrame* ref_frame, const VideoFrame* test_frame) {
   if (!ref_frame || !test_frame)
     return -1;
   return I420PSNR(*ref_frame->video_frame_buffer()->ToI420(),
                   *test_frame->video_frame_buffer()->ToI420());
 }

 // Compute SSIM for an I420 frame (all planes). Can upscale test_buffer.
 double I420SSIM(const I420BufferInterface& ref_buffer,
                 const I420BufferInterface& test_buffer) {
   RTC_DCHECK_GE(ref_buffer.width(), test_buffer.width());
   RTC_DCHECK_GE(ref_buffer.height(), test_buffer.height());
   if ((ref_buffer.width() != test_buffer.width()) ||
       (ref_buffer.height() != test_buffer.height())) {
     rtc::scoped_refptr<I420Buffer> scaled_buffer =
         I420Buffer::Create(ref_buffer.width(), ref_buffer.height());
     scaled_buffer->ScaleFrom(test_buffer);
     return I420SSIM(ref_buffer, *scaled_buffer);
   }
   return libyuv::I420Ssim(
       ref_buffer.DataY(), ref_buffer.StrideY(), ref_buffer.DataU(),
       ref_buffer.StrideU(), ref_buffer.DataV(), ref_buffer.StrideV(),
       test_buffer.DataY(), test_buffer.StrideY(), test_buffer.DataU(),
       test_buffer.StrideU(), test_buffer.DataV(), test_buffer.StrideV(),
       test_buffer.width(), test_buffer.height());
 }
 double I420SSIM(const VideoFrame* ref_frame, const VideoFrame* test_frame) {
   if (!ref_frame || !test_frame)
     return -1;
   return I420SSIM(*ref_frame->video_frame_buffer()->ToI420(),
                   *test_frame->video_frame_buffer()->ToI420());
 }

 void NV12Scale(uint8_t* tmp_buffer,
                const uint8_t* src_y, int src_stride_y,
                const uint8_t* src_uv, int src_stride_uv,
                int src_width, int src_height,
                uint8_t* dst_y, int dst_stride_y,
                uint8_t* dst_uv, int dst_stride_uv,
                int dst_width, int dst_height) {
   const int src_chroma_width = (src_width + 1) / 2;
   const int src_chroma_height = (src_height + 1) / 2;

   if (src_width == dst_width && src_height == dst_height) {
     // No scaling.
     libyuv::CopyPlane(src_y, src_stride_y, dst_y, dst_stride_y, src_width,
                       src_height);
     libyuv::CopyPlane(src_uv, src_stride_uv, dst_uv, dst_stride_uv,
                       src_chroma_width * 2, src_chroma_height);
     return;
   }

   // Scaling.
   // Allocate temporary memory for spitting UV planes and scaling them.
   const int dst_chroma_width = (dst_width + 1) / 2;
   const int dst_chroma_height = (dst_height + 1) / 2;

   uint8_t* const src_u = tmp_buffer;
   uint8_t* const src_v = src_u + src_chroma_width * src_chroma_height;
   uint8_t* const dst_u = src_v + src_chroma_width * src_chroma_height;
   uint8_t* const dst_v = dst_u + dst_chroma_width * dst_chroma_height;

   // Split source UV plane into separate U and V plane using the temporary data.
   libyuv::SplitUVPlane(src_uv, src_stride_uv,
                        src_u, src_chroma_width,
                        src_v, src_chroma_width,
                        src_chroma_width, src_chroma_height);

   // Scale the planes.
   libyuv::I420Scale(src_y, src_stride_y,
                     src_u, src_chroma_width,
                     src_v, src_chroma_width,
                     src_width, src_height,
                     dst_y, dst_stride_y,
                     dst_u, dst_chroma_width,
                     dst_v, dst_chroma_width,
                     dst_width, dst_height,
                     libyuv::kFilterBox);

   // Merge the UV planes into the destination.
   libyuv::MergeUVPlane(dst_u, dst_chroma_width,
                        dst_v, dst_chroma_width,
                        dst_uv, dst_stride_uv,
                        dst_chroma_width, dst_chroma_height);
 }

 NV12ToI420Scaler::NV12ToI420Scaler() = default;
 NV12ToI420Scaler::~NV12ToI420Scaler() = default;

 void NV12ToI420Scaler::NV12ToI420Scale(
     const uint8_t* src_y, int src_stride_y,
     const uint8_t* src_uv, int src_stride_uv,
     int src_width, int src_height,
     uint8_t* dst_y, int dst_stride_y,
     uint8_t* dst_u, int dst_stride_u,
     uint8_t* dst_v, int dst_stride_v,
     int dst_width, int dst_height) {
   if (src_width == dst_width && src_height == dst_height) {
     // No scaling.
     tmp_uv_planes_.clear();
     tmp_uv_planes_.shrink_to_fit();
     libyuv::NV12ToI420(
         src_y, src_stride_y,
         src_uv, src_stride_uv,
         dst_y, dst_stride_y,
         dst_u, dst_stride_u,
         dst_v, dst_stride_v,
         src_width, src_height);
     return;
   }

   // Scaling.
   // Allocate temporary memory for spitting UV planes.
   const int src_uv_width = (src_width + 1) / 2;
   const int src_uv_height = (src_height + 1) / 2;
   tmp_uv_planes_.resize(src_uv_width * src_uv_height * 2);
   tmp_uv_planes_.shrink_to_fit();

   // Split source UV plane into separate U and V plane using the temporary data.
   uint8_t* const src_u = tmp_uv_planes_.data();
   uint8_t* const src_v = tmp_uv_planes_.data() + src_uv_width * src_uv_height;
   libyuv::SplitUVPlane(src_uv, src_stride_uv,
                        src_u, src_uv_width,
                        src_v, src_uv_width,
                        src_uv_width, src_uv_height);

   // Scale the planes into the destination.
   libyuv::I420Scale(src_y, src_stride_y,
                     src_u, src_uv_width,
                     src_v, src_uv_width,
                     src_width, src_height,
                     dst_y, dst_stride_y,
                     dst_u, dst_stride_u,
                     dst_v, dst_stride_v,
                     dst_width, dst_height,
                     libyuv::kFilterBox);
 }

 }  // namespace webrtc
	/*
	* Copyright (c) 2012 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.
	*/

	#include "common_video/libyuv/include/webrtc_libyuv.h"

	#include <string.h>

	#include "api/video/i420_buffer.h"
	#include "rtc_base/checks.h"
	#include "third_party/libyuv/include/libyuv.h"

	namespace webrtc {

	size_t CalcBufferSize(VideoType type, int width, int height) {
	RTC_DCHECK_GE(width, 0);
	RTC_DCHECK_GE(height, 0);
	size_t buffer_size = 0;
	switch (type) {
	case VideoType::kI420:
	case VideoType::kNV12:
	case VideoType::kNV21:
	case VideoType::kIYUV:
	case VideoType::kYV12: {
	int half_width = (width + 1) >> 1;
	int half_height = (height + 1) >> 1;
	buffer_size = width * height + half_width * half_height * 2;
	break;
	}
	case VideoType::kARGB4444:
	case VideoType::kRGB565:
	case VideoType::kARGB1555:
	case VideoType::kYUY2:
	case VideoType::kUYVY:
	buffer_size = width * height * 2;
	break;
	case VideoType::kRGB24:
	buffer_size = width * height * 3;
	break;
	case VideoType::kBGRA:
	case VideoType::kARGB:
	buffer_size = width * height * 4;
	break;
	default:
	RTC_NOTREACHED();
	break;
	}
	return buffer_size;
	}

	static int PrintPlane(const uint8_t* buf,
	int width,
	int height,
	int stride,
	FILE* file) {
	for (int i = 0; i < height; i++, buf += stride) {
	if (fwrite(buf, 1, width, file) != static_cast<unsigned int>(width))
	return -1;
	}
	return 0;
	}

	// TODO(nisse): Belongs with the test code?
	int PrintVideoFrame(const I420BufferInterface& frame, FILE* file) {
	int width = frame.width();
	int height = frame.height();
	int chroma_width = frame.ChromaWidth();
	int chroma_height = frame.ChromaHeight();

	if (PrintPlane(frame.DataY(), width, height,
	frame.StrideY(), file) < 0) {
	return -1;
	}
	if (PrintPlane(frame.DataU(),
	chroma_width, chroma_height,
	frame.StrideU(), file) < 0) {
	return -1;
	}
	if (PrintPlane(frame.DataV(),
	chroma_width, chroma_height,
	frame.StrideV(), file) < 0) {
	return -1;
	}
	return 0;
	}

	int PrintVideoFrame(const VideoFrame& frame, FILE* file) {
	return PrintVideoFrame(*frame.video_frame_buffer()->ToI420(), file);
	}

	int ExtractBuffer(const rtc::scoped_refptr<I420BufferInterface>& input_frame,
	size_t size,
	uint8_t* buffer) {
	RTC_DCHECK(buffer);
	if (!input_frame)
	return -1;
	int width = input_frame->width();
	int height = input_frame->height();
	size_t length = CalcBufferSize(VideoType::kI420, width, height);
	if (size < length) {
	return -1;
	}

	int chroma_width = input_frame->ChromaWidth();
	int chroma_height = input_frame->ChromaHeight();

	libyuv::I420Copy(input_frame->DataY(),
	input_frame->StrideY(),
	input_frame->DataU(),
	input_frame->StrideU(),
	input_frame->DataV(),
	input_frame->StrideV(),
	buffer, width,
	buffer + width*height, chroma_width,
	buffer + widthheight + chroma_widthchroma_height,
	chroma_width,
	width, height);

	return static_cast<int>(length);
	}

	int ExtractBuffer(const VideoFrame& input_frame, size_t size, uint8_t* buffer) {
	return ExtractBuffer(input_frame.video_frame_buffer()->ToI420(), size,
	buffer);
	}

	int ConvertNV12ToRGB565(const uint8_t* src_frame,
	uint8_t* dst_frame,
	int width, int height) {
	int abs_height = (height < 0) ? -height : height;
	const uint8_t* yplane = src_frame;
	const uint8_t* uvInterlaced = src_frame + (width * abs_height);

	return libyuv::NV12ToRGB565(yplane, width,
	uvInterlaced, (width + 1) >> 1,
	dst_frame, width,
	width, height);
	}

	int ConvertRGB24ToARGB(const uint8_t* src_frame, uint8_t* dst_frame,
	int width, int height, int dst_stride) {
	if (dst_stride == 0)
	dst_stride = width;
	return libyuv::RGB24ToARGB(src_frame, width,
	dst_frame, dst_stride,
	width, height);
	}

	int ConvertVideoType(VideoType video_type) {
	switch (video_type) {
	case VideoType::kUnknown:
	return libyuv::FOURCC_ANY;
	case VideoType::kI420:
	return libyuv::FOURCC_I420;
	case VideoType::kIYUV: // same as VideoType::kYV12
	case VideoType::kYV12:
	return libyuv::FOURCC_YV12;
	case VideoType::kRGB24:
	return libyuv::FOURCC_24BG;
	case VideoType::kABGR:
	return libyuv::FOURCC_ABGR;
	case VideoType::kRGB565:
	return libyuv::FOURCC_RGBP;
	case VideoType::kYUY2:
	return libyuv::FOURCC_YUY2;
	case VideoType::kUYVY:
	return libyuv::FOURCC_UYVY;
	case VideoType::kMJPEG:
	return libyuv::FOURCC_MJPG;
	case VideoType::kNV21:
	return libyuv::FOURCC_NV21;
	case VideoType::kNV12:
	return libyuv::FOURCC_NV12;
	case VideoType::kARGB:
	return libyuv::FOURCC_ARGB;
	case VideoType::kBGRA:
	return libyuv::FOURCC_BGRA;
	case VideoType::kARGB4444:
	return libyuv::FOURCC_R444;
	case VideoType::kARGB1555:
	return libyuv::FOURCC_RGBO;
	}
	RTC_NOTREACHED();
	return libyuv::FOURCC_ANY;
	}

	int ConvertFromI420(const VideoFrame& src_frame,
	VideoType dst_video_type,
	int dst_sample_size,
	uint8_t* dst_frame) {
	rtc::scoped_refptr<I420BufferInterface> i420_buffer =
	src_frame.video_frame_buffer()->ToI420();
	return libyuv::ConvertFromI420(
	i420_buffer->DataY(), i420_buffer->StrideY(), i420_buffer->DataU(),
	i420_buffer->StrideU(), i420_buffer->DataV(), i420_buffer->StrideV(),
	dst_frame, dst_sample_size, src_frame.width(), src_frame.height(),
	ConvertVideoType(dst_video_type));
	}

	// Compute PSNR for an I420 frame (all planes). Can upscale test frame.
	double I420PSNR(const I420BufferInterface& ref_buffer,
	const I420BufferInterface& test_buffer) {
	RTC_DCHECK_GE(ref_buffer.width(), test_buffer.width());
	RTC_DCHECK_GE(ref_buffer.height(), test_buffer.height());
	if ((ref_buffer.width() != test_buffer.width()) \|\|
	(ref_buffer.height() != test_buffer.height())) {
	rtc::scoped_refptr<I420Buffer> scaled_buffer =
	I420Buffer::Create(ref_buffer.width(), ref_buffer.height());
	scaled_buffer->ScaleFrom(test_buffer);
	return I420PSNR(ref_buffer, *scaled_buffer);
	}
	double psnr = libyuv::I420Psnr(
	ref_buffer.DataY(), ref_buffer.StrideY(), ref_buffer.DataU(),
	ref_buffer.StrideU(), ref_buffer.DataV(), ref_buffer.StrideV(),
	test_buffer.DataY(), test_buffer.StrideY(), test_buffer.DataU(),
	test_buffer.StrideU(), test_buffer.DataV(), test_buffer.StrideV(),
	test_buffer.width(), test_buffer.height());
	// LibYuv sets the max psnr value to 128, we restrict it here.
	// In case of 0 mse in one frame, 128 can skew the results significantly.
	return (psnr > kPerfectPSNR) ? kPerfectPSNR : psnr;
	}

	// Compute PSNR for an I420 frame (all planes)
	double I420PSNR(const VideoFrame* ref_frame, const VideoFrame* test_frame) {
	if (!ref_frame \|\| !test_frame)
	return -1;
	return I420PSNR(*ref_frame->video_frame_buffer()->ToI420(),
	*test_frame->video_frame_buffer()->ToI420());
	}

	// Compute SSIM for an I420 frame (all planes). Can upscale test_buffer.
	double I420SSIM(const I420BufferInterface& ref_buffer,
	const I420BufferInterface& test_buffer) {
	RTC_DCHECK_GE(ref_buffer.width(), test_buffer.width());
	RTC_DCHECK_GE(ref_buffer.height(), test_buffer.height());
	if ((ref_buffer.width() != test_buffer.width()) \|\|
	(ref_buffer.height() != test_buffer.height())) {
	rtc::scoped_refptr<I420Buffer> scaled_buffer =
	I420Buffer::Create(ref_buffer.width(), ref_buffer.height());
	scaled_buffer->ScaleFrom(test_buffer);
	return I420SSIM(ref_buffer, *scaled_buffer);
	}
	return libyuv::I420Ssim(
	ref_buffer.DataY(), ref_buffer.StrideY(), ref_buffer.DataU(),
	ref_buffer.StrideU(), ref_buffer.DataV(), ref_buffer.StrideV(),
	test_buffer.DataY(), test_buffer.StrideY(), test_buffer.DataU(),
	test_buffer.StrideU(), test_buffer.DataV(), test_buffer.StrideV(),
	test_buffer.width(), test_buffer.height());
	}
	double I420SSIM(const VideoFrame* ref_frame, const VideoFrame* test_frame) {
	if (!ref_frame \|\| !test_frame)
	return -1;
	return I420SSIM(*ref_frame->video_frame_buffer()->ToI420(),
	*test_frame->video_frame_buffer()->ToI420());
	}

	void NV12Scale(uint8_t* tmp_buffer,
	const uint8_t* src_y, int src_stride_y,
	const uint8_t* src_uv, int src_stride_uv,
	int src_width, int src_height,
	uint8_t* dst_y, int dst_stride_y,
	uint8_t* dst_uv, int dst_stride_uv,
	int dst_width, int dst_height) {
	const int src_chroma_width = (src_width + 1) / 2;
	const int src_chroma_height = (src_height + 1) / 2;

	if (src_width == dst_width && src_height == dst_height) {
	// No scaling.
	libyuv::CopyPlane(src_y, src_stride_y, dst_y, dst_stride_y, src_width,
	src_height);
	libyuv::CopyPlane(src_uv, src_stride_uv, dst_uv, dst_stride_uv,
	src_chroma_width * 2, src_chroma_height);
	return;
	}

	// Scaling.
	// Allocate temporary memory for spitting UV planes and scaling them.
	const int dst_chroma_width = (dst_width + 1) / 2;
	const int dst_chroma_height = (dst_height + 1) / 2;

	uint8_t* const src_u = tmp_buffer;
	uint8_t* const src_v = src_u + src_chroma_width * src_chroma_height;
	uint8_t* const dst_u = src_v + src_chroma_width * src_chroma_height;
	uint8_t* const dst_v = dst_u + dst_chroma_width * dst_chroma_height;

	// Split source UV plane into separate U and V plane using the temporary data.
	libyuv::SplitUVPlane(src_uv, src_stride_uv,
	src_u, src_chroma_width,
	src_v, src_chroma_width,
	src_chroma_width, src_chroma_height);

	// Scale the planes.
	libyuv::I420Scale(src_y, src_stride_y,
	src_u, src_chroma_width,
	src_v, src_chroma_width,
	src_width, src_height,
	dst_y, dst_stride_y,
	dst_u, dst_chroma_width,
	dst_v, dst_chroma_width,
	dst_width, dst_height,
	libyuv::kFilterBox);

	// Merge the UV planes into the destination.
	libyuv::MergeUVPlane(dst_u, dst_chroma_width,
	dst_v, dst_chroma_width,
	dst_uv, dst_stride_uv,
	dst_chroma_width, dst_chroma_height);
	}

	NV12ToI420Scaler::NV12ToI420Scaler() = default;
	NV12ToI420Scaler::~NV12ToI420Scaler() = default;

	void NV12ToI420Scaler::NV12ToI420Scale(
	const uint8_t* src_y, int src_stride_y,
	const uint8_t* src_uv, int src_stride_uv,
	int src_width, int src_height,
	uint8_t* dst_y, int dst_stride_y,
	uint8_t* dst_u, int dst_stride_u,
	uint8_t* dst_v, int dst_stride_v,
	int dst_width, int dst_height) {
	if (src_width == dst_width && src_height == dst_height) {
	// No scaling.
	tmp_uv_planes_.clear();
	tmp_uv_planes_.shrink_to_fit();
	libyuv::NV12ToI420(
	src_y, src_stride_y,
	src_uv, src_stride_uv,
	dst_y, dst_stride_y,
	dst_u, dst_stride_u,
	dst_v, dst_stride_v,
	src_width, src_height);
	return;
	}

	// Scaling.
	// Allocate temporary memory for spitting UV planes.
	const int src_uv_width = (src_width + 1) / 2;
	const int src_uv_height = (src_height + 1) / 2;
	tmp_uv_planes_.resize(src_uv_width * src_uv_height * 2);
	tmp_uv_planes_.shrink_to_fit();

	// Split source UV plane into separate U and V plane using the temporary data.
	uint8_t* const src_u = tmp_uv_planes_.data();
	uint8_t* const src_v = tmp_uv_planes_.data() + src_uv_width * src_uv_height;
	libyuv::SplitUVPlane(src_uv, src_stride_uv,
	src_u, src_uv_width,
	src_v, src_uv_width,
	src_uv_width, src_uv_height);

	// Scale the planes into the destination.
	libyuv::I420Scale(src_y, src_stride_y,
	src_u, src_uv_width,
	src_v, src_uv_width,
	src_width, src_height,
	dst_y, dst_stride_y,
	dst_u, dst_stride_u,
	dst_v, dst_stride_v,
	dst_width, dst_height,
	libyuv::kFilterBox);
	}

	} // namespace webrtc