зеркало из https://github.com/mozilla/pjs.git
94 строки
3.4 KiB
C++
94 строки
3.4 KiB
C++
// Copyright (c) 2009 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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// This webpage shows layout of YV12 and other YUV formats
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// http://www.fourcc.org/yuv.php
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// The actual conversion is best described here
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// http://en.wikipedia.org/wiki/YUV
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// An article on optimizing YUV conversion using tables instead of multiplies
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// http://lestourtereaux.free.fr/papers/data/yuvrgb.pdf
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//
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// YV12 is a full plane of Y and a half height, half width chroma planes
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// YV16 is a full plane of Y and a full height, half width chroma planes
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// YV24 is a full plane of Y and a full height, full width chroma planes
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//
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// ARGB pixel format is output, which on little endian is stored as BGRA.
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// The alpha is set to 255, allowing the application to use RGBA or RGB32.
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#include "yuv_convert.h"
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// Header for low level row functions.
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#include "yuv_row.h"
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#include "mozilla/SSE.h"
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namespace mozilla {
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namespace gfx {
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// Convert a frame of YUV to 32 bit ARGB.
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NS_GFX_(void) ConvertYCbCrToRGB32(const uint8* y_buf,
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const uint8* u_buf,
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const uint8* v_buf,
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uint8* rgb_buf,
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int pic_x,
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int pic_y,
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int pic_width,
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int pic_height,
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int y_pitch,
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int uv_pitch,
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int rgb_pitch,
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YUVType yuv_type) {
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unsigned int y_shift = yuv_type == YV12 ? 1 : 0;
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unsigned int x_shift = yuv_type == YV24 ? 0 : 1;
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// Test for SSE because the optimized code uses movntq, which is not part of MMX.
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bool has_sse = supports_mmx() && supports_sse();
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// There is no optimized YV24 SSE routine so we check for this and
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// fall back to the C code.
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has_sse &= yuv_type != YV24;
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bool odd_pic_x = yuv_type != YV24 && pic_x % 2 != 0;
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int x_width = odd_pic_x ? pic_width - 1 : pic_width;
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for (int y = pic_y; y < pic_height + pic_y; ++y) {
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uint8* rgb_row = rgb_buf + (y - pic_y) * rgb_pitch;
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const uint8* y_ptr = y_buf + y * y_pitch + pic_x;
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const uint8* u_ptr = u_buf + (y >> y_shift) * uv_pitch + (pic_x >> x_shift);
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const uint8* v_ptr = v_buf + (y >> y_shift) * uv_pitch + (pic_x >> x_shift);
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if (odd_pic_x) {
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// Handle the single odd pixel manually and use the
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// fast routines for the remaining.
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FastConvertYUVToRGB32Row_C(y_ptr++,
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u_ptr++,
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v_ptr++,
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rgb_row,
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1,
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x_shift);
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rgb_row += 4;
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}
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if (has_sse)
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FastConvertYUVToRGB32Row(y_ptr,
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u_ptr,
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v_ptr,
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rgb_row,
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x_width);
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else
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FastConvertYUVToRGB32Row_C(y_ptr,
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u_ptr,
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v_ptr,
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rgb_row,
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x_width,
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x_shift);
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}
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#ifdef ARCH_CPU_X86_FAMILY
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// SSE used for FastConvertYUVToRGB32Row requires emms instruction.
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if (has_sse)
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EMMS();
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#endif
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}
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} // namespace gfx
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} // namespace mozilla
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