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Merge branch 'feature/112' into develop
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@kekyo
kekyo committed Nov 11, 2023
2 parents 7ee39fd + 0ba0918 commit 6522ab1
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Showing 2 changed files with 166 additions and 51 deletions.
215 changes: 165 additions & 50 deletions FlashCap.Core/Internal/BitmapTranscoder.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -13,60 +13,134 @@

namespace FlashCap.Internal;

public enum YUV2RGBConversionStandard
{
Auto,
BT_601,
BT_709,
BT_2020,
}
internal static class BitmapTranscoder
{
private static readonly int scatteringBase = Environment.ProcessorCount;

// Preffered article: https://docs.microsoft.com/en-us/windows/win32/medfound/recommended-8-bit-yuv-formats-for-video-rendering#420-formats-16-bits-per-pixel
// Prefered article: https://docs.microsoft.com/en-us/windows/win32/medfound/recommended-8-bit-yuv-formats-for-video-rendering#420-formats-16-bits-per-pixel

private static unsafe void TranscodeFromUYVY(
int width, int height, bool performFullRange,
byte* pFrom, byte* pTo)
// some interesting code references:
// https://chromium.googlesource.com/libyuv/libyuv/+/HEAD/unit_test/color_test.cc
// performFullRange = true means that we suppose Y is in [16..235] range and UV in [16..240]
// performFullRange = false means that we suppose Y U and V are in [0..255] range
private static unsafe void TranscodeFromYUVInternal(
int width, int height,
YUV2RGBConversionStandard conversionStandard,
bool performFullRange, bool isUYVY,
byte* pFrom, byte* pTo)
{
var scatter = height / scatteringBase;
Parallel.For(0, (height + scatter - 1) / scatter, ys =>
{
var y = ys * scatter;
var myi = Math.Min(height - y, scatter);
// default values BT.601
int multY = 255;
int multUB = 516;
int multUG = 100;
int multVG = 208;
int multVR = 409;
int offsetY = 0;

for (var yi = 0; yi < myi; yi++)
{
byte* pFromBase = pFrom + (height - (y + yi) - 1) * width * 2;
byte* pToBase = pTo + (y + yi) * width * 3;
// set constants for the color conversion
switch (conversionStandard)
{
case YUV2RGBConversionStandard.BT_601:
//Color profile ITU-R BT.601 Limited Range
//matrix 1.0, 1.0, 1.0,
// 0.0, -0.39173, 2.0170,
// 1.5958,-0.81290, 0.0
//converts to rounded int (multiply by 256)
//256, 256, 256,
//0 ,-100, 516
//409, -208, 0

for (var x = 0; x < width; x += 2)
if (performFullRange)
{
var d = pFromBase[0] - 128; // U
var c1 = pFromBase[1] - 16; // Y1
var e = pFromBase[2] - 128; // V
var c2 = pFromBase[3] - 16; // Y2
// YUV limited range
// (Y is in [16..235], rescale to [0..255])
// (UV is in [16..240], rescale to [0..255])

var cc1 = 298 * c1;
var cc2 = 298 * c2;
*pToBase++ = Clip((cc1 + 516 * d + 128) >> 8); // B1
*pToBase++ = Clip((cc1 - 100 * d - 208 * e + 128) >> 8); // G1
*pToBase++ = Clip((cc1 + 409 * e + 128) >> 8); // R1
// multiply Y by 1.16438
// multiply UV by 1.13839
multY = 298;
multUB = 587;
multUG = 114;
multVG = 237;
multVR = 466;
offsetY = 16;
}
break;
case YUV2RGBConversionStandard.BT_709:
//Color profile ITU-R BT.709 Limited Range
//matrix 1.0, 1.0, 1.0,
// 0.0, -0.1873, 1.8556,
// 1.5748, -0.4681, 0.0
// converts to rounded int (multiply by 256)
//256, 256, 256,
//0 ,-48, 475
//403,-120, 0

*pToBase++ = Clip((cc2 + 516 * d + 128) >> 8); // B1
*pToBase++ = Clip((cc2 - 100 * d - 208 * e + 128) >> 8); // G1
*pToBase++ = Clip((cc2 + 409 * e + 128) >> 8); // R1
if (performFullRange)
{
// YUV limited range
// (Y is in [16..235], rescale to [0..255])
// (UV is in [16..240], rescale to [0..255])

pFromBase += 4;
// multiply Y by 1.16438
// multiply UV by 1.13839
multY = 298;
multUB = 541;
multUG = 55;
multVG = 137;
multVR = 459;
offsetY = 16;
}
}
});
}
else
{
multY = 298;
multUB = 475;
multUG = 48;
multVG = 120;
multVR = 403;
offsetY = 0;
}
break;
case YUV2RGBConversionStandard.BT_2020:
if (performFullRange)
{
// YUV limited range
// (Y is in [16..235], rescale to [0..255])
// (UV is in [16..240], rescale to [0..255])

private static unsafe void TranscodeFromYUYV(
int width, int height, bool performFullRange,
byte* pFrom, byte* pTo)
{
// multiply Y by 1.16438
// multiply UV by 1.13839
multY = 298;
multUB = 549;
multUG = 48;
multVG = 166;
multVR = 429;
offsetY = 16;
}
else
{
multY = 298;
multUB = 482;
multUG = 42;
multVG = 146;
multVR = 377;
offsetY = 0;
}
break;
}
var scatter = height / scatteringBase;
Parallel.For(0, (height + scatter - 1) / scatter, ys =>
{
var y = ys * scatter;
var myi = Math.Min(height - y, scatter);
int c1, c2, d, e, cc1, cc2;
for (var yi = 0; yi < myi; yi++)
{
Expand All @@ -75,28 +149,67 @@ internal static class BitmapTranscoder
for (var x = 0; x < width; x += 2)
{
var c1 = pFromBase[0] - 16; // Y1
var d = pFromBase[1] - 128; // U
var c2 = pFromBase[2] - 16; // Y2
var e = pFromBase[3] - 128; // V
if (isUYVY)
{
d = pFromBase[0] - 128; // U
c1 = pFromBase[1] - offsetY; // Y1
e = pFromBase[2] - 128; // V
c2 = pFromBase[3] - offsetY; // Y2
}
else
{
c1 = pFromBase[0] - offsetY; // Y1
d = pFromBase[1] - 128; // U
c2 = pFromBase[2] - offsetY; // Y2
e = pFromBase[3] - 128; // V
}
var cc1 = 298 * c1;
var cc2 = 298 * c2;
cc1 = multY * c1;
cc2 = multY * c2;
*pToBase++ = Clip((cc1 + 516 * d + 128) >> 8); // B1
*pToBase++ = Clip((cc1 - 100 * d - 208 * e + 128) >> 8); // G1
*pToBase++ = Clip((cc1 + 409 * e + 128) >> 8); // R1
*pToBase++ = Clip((cc1 + multUB * d + 128) >> 8); // B1
*pToBase++ = Clip((cc1 - multUG * d - multVG * e + 128) >> 8); // G1
*pToBase++ = Clip((cc1 + multVR * e + 128) >> 8); // R1
*pToBase++ = Clip((cc2 + 516 * d + 128) >> 8); // B1
*pToBase++ = Clip((cc2 - 100 * d - 208 * e + 128) >> 8); // G1
*pToBase++ = Clip((cc2 + 409 * e + 128) >> 8); // R1
*pToBase++ = Clip((cc2 + multUB * d + 128) >> 8); // B2
*pToBase++ = Clip((cc2 - multUG * d - multVG * e + 128) >> 8); // G2
*pToBase++ = Clip((cc2 + multVR * e + 128) >> 8); // R2
pFromBase += 4;
}
}
});
}

private static unsafe void TranscodeFromYUV(
int width, int height,
YUV2RGBConversionStandard conversionStandard,
bool isUYVY,
bool performFullRange,
byte* pFrom, byte* pTo)
{
switch (conversionStandard)
{
case YUV2RGBConversionStandard.BT_601:
case YUV2RGBConversionStandard.BT_709:
case YUV2RGBConversionStandard.BT_2020:
TranscodeFromYUVInternal(width, height, conversionStandard, performFullRange, isUYVY, pFrom, pTo);
break;
case YUV2RGBConversionStandard.Auto:
// determine the color conversion based on the width and height of the frame
if (width > 1920 || height > 1080) // UHD or larger
TranscodeFromYUVInternal(width, height, YUV2RGBConversionStandard.BT_2020, performFullRange, isUYVY, pFrom, pTo);
else if (width > 720 || height > 576) // HD
TranscodeFromYUVInternal(width, height, YUV2RGBConversionStandard.BT_709, performFullRange, isUYVY, pFrom, pTo);
else // SD
TranscodeFromYUVInternal(width, height, YUV2RGBConversionStandard.BT_601, performFullRange, isUYVY, pFrom, pTo);
break;
default:
TranscodeFromYUVInternal(width, height, YUV2RGBConversionStandard.BT_601, performFullRange, isUYVY, pFrom, pTo);
break;
}
}

#if NET45_OR_GREATER || NETSTANDARD || NETCOREAPP
[MethodImpl(MethodImplOptions.AggressiveInlining)]
#endif
Expand All @@ -122,18 +235,20 @@ internal static class BitmapTranscoder

public static unsafe void Transcode(
int width, int height,
NativeMethods.Compression compression, bool performFullRange,
NativeMethods.Compression compression,
YUV2RGBConversionStandard conversionStandard,
bool performFullRange,
byte* pFrom, byte* pTo)
{
switch (compression)
{
case NativeMethods.Compression.UYVY:
case NativeMethods.Compression.HDYC:
TranscodeFromUYVY(width, height, performFullRange, pFrom, pTo);
TranscodeFromYUV(width, height, conversionStandard, true, performFullRange, pFrom, pTo);
break;
case NativeMethods.Compression.YUYV:
case NativeMethods.Compression.YUY2:
TranscodeFromYUYV(width, height, performFullRange, pFrom, pTo);
TranscodeFromYUV(width, height, conversionStandard, false, performFullRange, pFrom, pTo);
break;
default:
throw new ArgumentException();
Expand Down
2 changes: 1 addition & 1 deletion FlashCap.Core/PixelBuffer.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -182,7 +182,7 @@ internal unsafe ArraySegment<byte> InternalExtractImage(BufferStrategies strateg
#endif
BitmapTranscoder.Transcode(
pBih->biWidth, pBih->biHeight,
pBih->biCompression, false,
pBih->biCompression, YUV2RGBConversionStandard.Auto, true,
pImageContainer + pBfh->bfOffBits,
pTranscodedImageContainer + pBfhTo->bfOffBits);

Expand Down

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