tsai
/
ImageSharp
mirror of https://github.com/SixLabors/ImageSharp
1
0
Fork 0
Code Issues Projects Releases Wiki Activity
Browse Source

Added tests for 420 rgb -> ycbcr subsampling

pull/1632/head
Dmitry Pentin 5 years ago
parent
01f44a839e
commit
fcf202a913
1 changed files with 152 additions and 13 deletions
Whitespace
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
Split View
Diff Options
Show Stats Download Patch File Download Diff File
  1. 165
      tests/ImageSharp.Tests/Formats/Jpg/RgbToYCbCrConverterTests.cs

165
tests/ImageSharp.Tests/Formats/Jpg/RgbToYCbCrConverterTests.cs
View File

@ -23,9 +23,10 @@ namespace SixLabors.ImageSharp.Tests.Formats.Jpg
private ITestOutputHelper Output { get; }
[Fact]
public void TestLutConverter()
public void TestConverterLut444()
{
Rgb24[] data = CreateTestData();
int dataSize = 8 * 8;
Rgb24[] data = CreateTestData(dataSize);
var target = RgbToYCbCrConverterLut.Create();
Block8x8F y = default;
@ -34,11 +35,11 @@ namespace SixLabors.ImageSharp.Tests.Formats.Jpg
target.Convert444(data.AsSpan(), ref y, ref cb, ref cr);
Verify(data, ref y, ref cb, ref cr, new ApproximateColorSpaceComparer(1F));
Verify444(data, ref y, ref cb, ref cr, new ApproximateColorSpaceComparer(1F));
}
[Fact]
public void TestVectorizedConverter()
public void TestConverterVectorized444()
{
if (!RgbToYCbCrConverterVectorized.IsSupported)
{
@ -46,7 +47,8 @@ namespace SixLabors.ImageSharp.Tests.Formats.Jpg
return;
}
Rgb24[] data = CreateTestData();
int dataSize = 8 * 8;
Rgb24[] data = CreateTestData(dataSize);
Block8x8F y = default;
Block8x8F cb = default;
@ -54,10 +56,141 @@ namespace SixLabors.ImageSharp.Tests.Formats.Jpg
RgbToYCbCrConverterVectorized.Convert444(data.AsSpan(), ref y, ref cb, ref cr);
Verify(data, ref y, ref cb, ref cr, new ApproximateColorSpaceComparer(0.0001F));
Verify444(data, ref y, ref cb, ref cr, new ApproximateColorSpaceComparer(0.0001F));
}
private static void Verify(ReadOnlySpan<Rgb24> data, ref Block8x8F yResult, ref Block8x8F cbResult, ref Block8x8F crResult, ApproximateColorSpaceComparer comparer)
[Fact]
public void TestConverterLut420()
{
int dataSize = 16 * 16;
Span<Rgb24> data = CreateTestData(dataSize).AsSpan();
var target = RgbToYCbCrConverterLut.Create();
var yBlocks = new Block8x8F[4];
var cb = default(Block8x8F);
var cr = default(Block8x8F);
target.Convert420(data, ref yBlocks[0], ref yBlocks[1], ref cb, ref cr, 0);
target.Convert420(data.Slice(16 * 8), ref yBlocks[2], ref yBlocks[3], ref cb, ref cr, 1);
Verify420(data, yBlocks, ref cb, ref cr, new ApproximateFloatComparer(1F));
}
[Fact]
public void TestConverterVectorized420()
{
if (!RgbToYCbCrConverterVectorized.IsSupported)
{
this.Output.WriteLine("No AVX and/or FMA present, skipping test!");
return;
}
int dataSize = 16 * 16;
Span<Rgb24> data = CreateTestData(dataSize).AsSpan();
var yBlocks = new Block8x8F[4];
var cb = default(Block8x8F);
var cr = default(Block8x8F);
RgbToYCbCrConverterVectorized.Convert420_16x8(data, ref yBlocks[0], ref yBlocks[1], ref cb, ref cr, 0);
RgbToYCbCrConverterVectorized.Convert420_16x8(data.Slice(16 * 8), ref yBlocks[2], ref yBlocks[3], ref cb, ref cr, 1);
Verify420(data, yBlocks, ref cb, ref cr, new ApproximateFloatComparer(1F));
}
private static void Verify444(
ReadOnlySpan<Rgb24> data,
ref Block8x8F yResult,
ref Block8x8F cbResult,
ref Block8x8F crResult,
ApproximateColorSpaceComparer comparer)
{
Block8x8F y = default;
Block8x8F cb = default;
Block8x8F cr = default;
RgbToYCbCr(data, ref y, ref cb, ref cr);
for (int i = 0; i < Block8x8F.Size; i++)
{
Assert.True(comparer.Equals(new YCbCr(y[i], cb[i], cr[i]), new YCbCr(yResult[i], cbResult[i], crResult[i])), $"Pos {i}, Expected {y[i]} == {yResult[i]}, {cb[i]} == {cbResult[i]}, {cr[i]} == {crResult[i]}");
}
}
private static void Verify420(
ReadOnlySpan<Rgb24> data,
Block8x8F[] yResult,
ref Block8x8F cbResult,
ref Block8x8F crResult,
ApproximateFloatComparer comparer)
{
var tempBlock = default(Block8x8F);
var cbTrue = new Block8x8F[4];
var crTrue = new Block8x8F[4];
Span<Rgb24> tempData = new Rgb24[8 * 8].AsSpan();
// top left
Copy8x8(data, tempData);
RgbToYCbCr(tempData, ref tempBlock, ref cbTrue[0], ref crTrue[0]);
VerifyBlock(ref yResult[0], ref tempBlock, comparer);
// top right
Copy8x8(data.Slice(8), tempData);
RgbToYCbCr(tempData, ref tempBlock, ref cbTrue[1], ref crTrue[1]);
VerifyBlock(ref yResult[1], ref tempBlock, comparer);
// bottom left
Copy8x8(data.Slice(8 * 16), tempData);
RgbToYCbCr(tempData, ref tempBlock, ref cbTrue[2], ref crTrue[2]);
VerifyBlock(ref yResult[2], ref tempBlock, comparer);
// bottom right
Copy8x8(data.Slice((8 * 16) + 8), tempData);
RgbToYCbCr(tempData, ref tempBlock, ref cbTrue[3], ref crTrue[3]);
VerifyBlock(ref yResult[3], ref tempBlock, comparer);
// verify Cb
Scale16X16To8X8(ref tempBlock, cbTrue);
VerifyBlock(ref cbResult, ref tempBlock, comparer);
// verify Cr
Scale16X16To8X8(ref tempBlock, crTrue);
VerifyBlock(ref crResult, ref tempBlock, comparer);
// extracts 8x8 blocks from 16x8 memory region
static void Copy8x8(ReadOnlySpan<Rgb24> source, Span<Rgb24> dest)
{
for (int i = 0; i < 8; i++)
{
source.Slice(i * 16, 8).CopyTo(dest.Slice(i * 8));
}
}
// scales 16x16 to 8x8, used in chroma subsampling tests
static void Scale16X16To8X8(ref Block8x8F dest, ReadOnlySpan<Block8x8F> source)
{
for (int i = 0; i < 4; i++)
{
int dstOff = ((i & 2) << 4) | ((i & 1) << 2);
Block8x8F iSource = source[i];
for (int y = 0; y < 4; y++)
{
for (int x = 0; x < 4; x++)
{
int j = (16 * y) + (2 * x);
float sum = iSource[j] + iSource[j + 1] + iSource[j + 8] + iSource[j + 9];
dest[(8 * y) + x + dstOff] = (sum + 2) * .25F;
}
}
}
}
}
private static void RgbToYCbCr(ReadOnlySpan<Rgb24> data, ref Block8x8F y, ref Block8x8F cb, ref Block8x8F cr)
{
for (int i = 0; i < data.Length; i++)
{
@ -65,17 +198,23 @@ namespace SixLabors.ImageSharp.Tests.Formats.Jpg
int g = data[i].G;
int b = data[i].B;
float y = (0.299F * r) + (0.587F * g) + (0.114F * b);
float cb = 128F + ((-0.168736F * r) - (0.331264F * g) + (0.5F * b));
float cr = 128F + ((0.5F * r) - (0.418688F * g) - (0.081312F * b));
y[i] = (0.299F * r) + (0.587F * g) + (0.114F * b);
cb[i] = 128F + ((-0.168736F * r) - (0.331264F * g) + (0.5F * b));
cr[i] = 128F + ((0.5F * r) - (0.418688F * g) - (0.081312F * b));
}
}
Assert.True(comparer.Equals(new YCbCr(y, cb, cr), new YCbCr(yResult[i], cbResult[i], crResult[i])), $"Pos {i}, Expected {y} == {yResult[i]}, {cb} == {cbResult[i]}, {cr} == {crResult[i]}");
private static void VerifyBlock(ref Block8x8F res, ref Block8x8F target, ApproximateFloatComparer comparer)
{
for (int i = 0; i < Block8x8F.Size; i++)
{
Assert.True(comparer.Equals(res[i], target[i]), $"Pos {i}, Expected {target[i]} == {res[i]}");
}
}
private static Rgb24[] CreateTestData()
private static Rgb24[] CreateTestData(int size)
{
var data = new Rgb24[64];
var data = new Rgb24[size];
var r = new Random();
var random = new byte[3];

Write Preview
Loading…
Cancel
Save