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Merge pull request #1811 from SixLabors/bp/quantizeblocksse 

Add SSE41 version of Quantize block
pull/1820/head
Brian Popow 5 years ago
committed by GitHub
parent
ce7687ba5f 55f859602f
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7495a91d97
No known key found for this signature in database GPG Key ID: 4AEE18F83AFDEB23
5 changed files with 235 additions and 82 deletions
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  1. 204
      src/ImageSharp/Formats/Webp/Lossy/QuantEnc.cs
  2. 8
      src/ImageSharp/Formats/Webp/Lossy/Vp8Encoder.cs
  3. 38
      src/ImageSharp/Formats/Webp/Lossy/Vp8Matrix.cs
  4. 14
      src/ImageSharp/Formats/Webp/Lossy/Vp8SegmentInfo.cs
  5. 53
      tests/ImageSharp.Tests/Formats/WebP/QuantEncTests.cs

204
src/ImageSharp/Formats/Webp/Lossy/QuantEnc.cs
View File

@ -3,13 +3,18 @@
using System;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
#if SUPPORTS_RUNTIME_INTRINSICS
using System.Runtime.Intrinsics;
using System.Runtime.Intrinsics.X86;
#endif
namespace SixLabors.ImageSharp.Formats.Webp.Lossy
{
/// <summary>
/// Quantization methods.
/// </summary>
internal static class QuantEnc
internal static unsafe class QuantEnc
{
private static readonly byte[] Zigzag = { 0, 1, 4, 8, 5, 2, 3, 6, 9, 12, 13, 10, 7, 11, 14, 15 };
@ -17,6 +22,18 @@ namespace SixLabors.ImageSharp.Formats.Webp.Lossy
private const int MaxLevel = 2047;
#if SUPPORTS_RUNTIME_INTRINSICS
private static readonly Vector128<short> MaxCoeff2047 = Vector128.Create((short)MaxLevel);
private static readonly Vector128<byte> CstLo = Vector128.Create(0, 1, 2, 3, 8, 9, 254, 255, 10, 11, 4, 5, 6, 7, 12, 13);
private static readonly Vector128<byte> Cst7 = Vector128.Create(254, 255, 254, 255, 254, 255, 254, 255, 14, 15, 254, 255, 254, 255, 254, 255);
private static readonly Vector128<byte> CstHi = Vector128.Create(2, 3, 8, 9, 10, 11, 4, 5, 254, 255, 6, 7, 12, 13, 14, 15);
private static readonly Vector128<byte> Cst8 = Vector128.Create(254, 255, 254, 255, 254, 255, 0, 1, 254, 255, 254, 255, 254, 255, 254, 255);
#endif
// Diffusion weights. We under-correct a bit (15/16th of the error is actually
// diffused) to avoid 'rainbow' chessboard pattern of blocks at q~=0.
private const int C1 = 7; // fraction of error sent to the 4x4 block below
@ -298,14 +315,14 @@ namespace SixLabors.ImageSharp.Formats.Webp.Lossy
}
Vp8Encoding.FTransformWht(tmp, dcTmp, scratch);
nz |= QuantizeBlock(dcTmp, rd.YDcLevels, dqm.Y2) << 24;
nz |= QuantizeBlock(dcTmp, rd.YDcLevels, ref dqm.Y2) << 24;
for (n = 0; n < 16; n += 2)
{
// Zero-out the first coeff, so that: a) nz is correct below, and
// b) finding 'last' non-zero coeffs in SetResidualCoeffs() is simplified.
tmp[n * 16] = tmp[(n + 1) * 16] = 0;
nz |= Quantize2Blocks(tmp.Slice(n * 16, 32), rd.YAcLevels.AsSpan(n * 16, 32), dqm.Y1) << n;
nz |= Quantize2Blocks(tmp.Slice(n * 16, 32), rd.YAcLevels.AsSpan(n * 16, 32), ref dqm.Y1) << n;
}
// Transform back.
@ -326,7 +343,7 @@ namespace SixLabors.ImageSharp.Formats.Webp.Lossy
tmp.Clear();
scratch.Clear();
Vp8Encoding.FTransform(src, reference, tmp, scratch);
int nz = QuantizeBlock(tmp, levels, dqm.Y1);
int nz = QuantizeBlock(tmp, levels, ref dqm.Y1);
Vp8Encoding.ITransform(reference, tmp, yuvOut, false, scratch);
return nz;
@ -353,11 +370,11 @@ namespace SixLabors.ImageSharp.Formats.Webp.Lossy
scratch);
}
CorrectDcValues(it, dqm.Uv, tmp, rd);
CorrectDcValues(it, ref dqm.Uv, tmp, rd);
for (n = 0; n < 8; n += 2)
{
nz |= Quantize2Blocks(tmp.Slice(n * 16, 32), rd.UvLevels.AsSpan(n * 16, 32), dqm.Uv) << n;
nz |= Quantize2Blocks(tmp.Slice(n * 16, 32), rd.UvLevels.AsSpan(n * 16, 32), ref dqm.Uv) << n;
}
for (n = 0; n < 8; n += 2)
@ -508,58 +525,155 @@ namespace SixLabors.ImageSharp.Formats.Webp.Lossy
}
[MethodImpl(InliningOptions.ShortMethod)]
public static int Quantize2Blocks(Span<short> input, Span<short> output, Vp8Matrix mtx)
public static int Quantize2Blocks(Span<short> input, Span<short> output, ref Vp8Matrix mtx)
{
int nz = QuantizeBlock(input, output, mtx) << 0;
nz |= QuantizeBlock(input.Slice(1 * 16), output.Slice(1 * 16), mtx) << 1;
int nz = QuantizeBlock(input.Slice(0, 16), output.Slice(0, 16), ref mtx) << 0;
nz |= QuantizeBlock(input.Slice(1 * 16, 16), output.Slice(1 * 16, 16), ref mtx) << 1;
return nz;
}
public static int QuantizeBlock(Span<short> input, Span<short> output, Vp8Matrix mtx)
public static int QuantizeBlock(Span<short> input, Span<short> output, ref Vp8Matrix mtx)
{
int last = -1;
int n;
for (n = 0; n < 16; ++n)
#if SUPPORTS_RUNTIME_INTRINSICS
if (Sse41.IsSupported)
{
int j = Zigzag[n];
bool sign = input[j] < 0;
uint coeff = (uint)((sign ? -input[j] : input[j]) + mtx.Sharpen[j]);
if (coeff > mtx.ZThresh[j])
// Load all inputs.
Vector128<short> input0 = Unsafe.As<short, Vector128<short>>(ref MemoryMarshal.GetReference(input));
Vector128<short> input8 = Unsafe.As<short, Vector128<short>>(ref MemoryMarshal.GetReference(input.Slice(8, 8)));
Vector128<ushort> iq0 = Unsafe.As<ushort, Vector128<ushort>>(ref mtx.IQ[0]);
Vector128<ushort> iq8 = Unsafe.As<ushort, Vector128<ushort>>(ref mtx.IQ[8]);
Vector128<ushort> q0 = Unsafe.As<ushort, Vector128<ushort>>(ref mtx.Q[0]);
Vector128<ushort> q8 = Unsafe.As<ushort, Vector128<ushort>>(ref mtx.Q[8]);
// coeff = abs(in)
Vector128<ushort> coeff0 = Ssse3.Abs(input0);
Vector128<ushort> coeff8 = Ssse3.Abs(input8);
// coeff = abs(in) + sharpen
Vector128<short> sharpen0 = Unsafe.As<short, Vector128<short>>(ref mtx.Sharpen[0]);
Vector128<short> sharpen8 = Unsafe.As<short, Vector128<short>>(ref mtx.Sharpen[8]);
Sse2.Add(coeff0.AsInt16(), sharpen0);
Sse2.Add(coeff8.AsInt16(), sharpen8);
// out = (coeff * iQ + B) >> QFIX
// doing calculations with 32b precision (QFIX=17)
// out = (coeff * iQ)
Vector128<ushort> coeffiQ0H = Sse2.MultiplyHigh(coeff0, iq0);
Vector128<ushort> coeffiQ0L = Sse2.MultiplyLow(coeff0, iq0);
Vector128<ushort> coeffiQ8H = Sse2.MultiplyHigh(coeff8, iq8);
Vector128<ushort> coeffiQ8L = Sse2.MultiplyLow(coeff8, iq8);
Vector128<ushort> out00 = Sse2.UnpackLow(coeffiQ0L, coeffiQ0H);
Vector128<ushort> out04 = Sse2.UnpackHigh(coeffiQ0L, coeffiQ0H);
Vector128<ushort> out08 = Sse2.UnpackLow(coeffiQ8L, coeffiQ8H);
Vector128<ushort> out12 = Sse2.UnpackHigh(coeffiQ8L, coeffiQ8H);
// out = (coeff * iQ + B)
Vector128<uint> bias00 = Unsafe.As<uint, Vector128<uint>>(ref mtx.Bias[0]);
Vector128<uint> bias04 = Unsafe.As<uint, Vector128<uint>>(ref mtx.Bias[4]);
Vector128<uint> bias08 = Unsafe.As<uint, Vector128<uint>>(ref mtx.Bias[8]);
Vector128<uint> bias12 = Unsafe.As<uint, Vector128<uint>>(ref mtx.Bias[12]);
out00 = Sse2.Add(out00.AsInt32(), bias00.AsInt32()).AsUInt16();
out04 = Sse2.Add(out04.AsInt32(), bias04.AsInt32()).AsUInt16();
out08 = Sse2.Add(out08.AsInt32(), bias08.AsInt32()).AsUInt16();
out12 = Sse2.Add(out12.AsInt32(), bias12.AsInt32()).AsUInt16();
// out = QUANTDIV(coeff, iQ, B, QFIX)
out00 = Sse2.ShiftRightArithmetic(out00.AsInt32(), WebpConstants.QFix).AsUInt16();
out04 = Sse2.ShiftRightArithmetic(out04.AsInt32(), WebpConstants.QFix).AsUInt16();
out08 = Sse2.ShiftRightArithmetic(out08.AsInt32(), WebpConstants.QFix).AsUInt16();
out12 = Sse2.ShiftRightArithmetic(out12.AsInt32(), WebpConstants.QFix).AsUInt16();
// pack result as 16b
Vector128<short> out0 = Sse2.PackSignedSaturate(out00.AsInt32(), out04.AsInt32());
Vector128<short> out8 = Sse2.PackSignedSaturate(out08.AsInt32(), out12.AsInt32());
// if (coeff > 2047) coeff = 2047
out0 = Sse2.Min(out0, MaxCoeff2047);
out8 = Sse2.Min(out8, MaxCoeff2047);
// put sign back
out0 = Ssse3.Sign(out0, input0);
out8 = Ssse3.Sign(out8, input8);
// in = out * Q
input0 = Sse2.MultiplyLow(out0, q0.AsInt16());
input8 = Sse2.MultiplyLow(out8, q8.AsInt16());
// in = out * Q
ref short inputRef = ref MemoryMarshal.GetReference(input);
Unsafe.As<short, Vector128<short>>(ref inputRef) = input0;
Unsafe.As<short, Vector128<short>>(ref Unsafe.Add(ref inputRef, 8)) = input8;
// zigzag the output before storing it. The re-ordering is:
// 0 1 2 3 4 5 6 7 | 8 9 10 11 12 13 14 15
// -> 0 1 4[8]5 2 3 6 | 9 12 13 10 [7]11 14 15
// There's only two misplaced entries ([8] and [7]) that are crossing the
// reg's boundaries.
// We use pshufb instead of pshuflo/pshufhi.
Vector128<byte> tmpLo = Ssse3.Shuffle(out0.AsByte(), CstLo);
Vector128<byte> tmp7 = Ssse3.Shuffle(out0.AsByte(), Cst7); // extract #7
Vector128<byte> tmpHi = Ssse3.Shuffle(out8.AsByte(), CstHi);
Vector128<byte> tmp8 = Ssse3.Shuffle(out8.AsByte(), Cst8); // extract #8
Vector128<byte> outZ0 = Sse2.Or(tmpLo, tmp8);
Vector128<byte> outZ8 = Sse2.Or(tmpHi, tmp7);
ref short outputRef = ref MemoryMarshal.GetReference(output);
Unsafe.As<short, Vector128<short>>(ref outputRef) = outZ0.AsInt16();
Unsafe.As<short, Vector128<short>>(ref Unsafe.Add(ref outputRef, 8)) = outZ8.AsInt16();
Vector128<sbyte> packedOutput = Sse2.PackSignedSaturate(outZ0.AsInt16(), outZ8.AsInt16());
// Detect if all 'out' values are zeros or not.
Vector128<sbyte> cmpeq = Sse2.CompareEqual(packedOutput, Vector128<sbyte>.Zero);
return Sse2.MoveMask(cmpeq) != 0xffff ? 1 : 0;
}
else
#endif
{
int last = -1;
int n;
for (n = 0; n < 16; ++n)
{
uint q = mtx.Q[j];
uint iQ = mtx.IQ[j];
uint b = mtx.Bias[j];
int level = QuantDiv(coeff, iQ, b);
if (level > MaxLevel)
int j = Zigzag[n];
bool sign = input[j] < 0;
uint coeff = (uint)((sign ? -input[j] : input[j]) + mtx.Sharpen[j]);
if (coeff > mtx.ZThresh[j])
{
level = MaxLevel;
}
uint q = mtx.Q[j];
uint iQ = mtx.IQ[j];
uint b = mtx.Bias[j];
int level = QuantDiv(coeff, iQ, b);
if (level > MaxLevel)
{
level = MaxLevel;
}
if (sign)
{
level = -level;
}
if (sign)
{
level = -level;
}
input[j] = (short)(level * (int)q);
output[n] = (short)level;
if (level != 0)
input[j] = (short)(level * (int)q);
output[n] = (short)level;
if (level != 0)
{
last = n;
}
}
else
{
last = n;
output[n] = 0;
input[j] = 0;
}
}
else
{
output[n] = 0;
input[j] = 0;
}
}
return last >= 0 ? 1 : 0;
return last >= 0 ? 1 : 0;
}
}
// Quantize as usual, but also compute and return the quantization error.
// Error is already divided by DSHIFT.
public static int QuantizeSingle(Span<short> v, Vp8Matrix mtx)
public static int QuantizeSingle(Span<short> v, ref Vp8Matrix mtx)
{
int v0 = v[0];
bool sign = v0 < 0;
@ -580,7 +694,7 @@ namespace SixLabors.ImageSharp.Formats.Webp.Lossy
return (sign ? -v0 : v0) >> DSCALE;
}
public static void CorrectDcValues(Vp8EncIterator it, Vp8Matrix mtx, Span<short> tmp, Vp8ModeScore rd)
public static void CorrectDcValues(Vp8EncIterator it, ref Vp8Matrix mtx, Span<short> tmp, Vp8ModeScore rd)
{
#pragma warning disable SA1005 // Single line comments should begin with single space
// | top[0] | top[1]
@ -597,13 +711,13 @@ namespace SixLabors.ImageSharp.Formats.Webp.Lossy
Span<sbyte> left = it.LeftDerr.AsSpan(ch, 2);
Span<short> c = tmp.Slice(ch * 4 * 16, 4 * 16);
c[0] += (short)(((C1 * top[0]) + (C2 * left[0])) >> (DSHIFT - DSCALE));
int err0 = QuantizeSingle(c, mtx);
int err0 = QuantizeSingle(c, ref mtx);
c[1 * 16] += (short)(((C1 * top[1]) + (C2 * err0)) >> (DSHIFT - DSCALE));
int err1 = QuantizeSingle(c.Slice(1 * 16), mtx);
int err1 = QuantizeSingle(c.Slice(1 * 16), ref mtx);
c[2 * 16] += (short)(((C1 * err0) + (C2 * left[1])) >> (DSHIFT - DSCALE));
int err2 = QuantizeSingle(c.Slice(2 * 16), mtx);
int err2 = QuantizeSingle(c.Slice(2 * 16), ref mtx);
c[3 * 16] += (short)(((C1 * err1) + (C2 * err2)) >> (DSHIFT - DSCALE));
int err3 = QuantizeSingle(c.Slice(3 * 16), mtx);
int err3 = QuantizeSingle(c.Slice(3 * 16), ref mtx);
rd.Derr[ch, 0] = err1;
rd.Derr[ch, 1] = err2;

8
src/ImageSharp/Formats/Webp/Lossy/Vp8Encoder.cs
View File

@ -502,7 +502,7 @@ namespace SixLabors.ImageSharp.Formats.Webp.Lossy
this.ResetStats();
}
private void AdjustFilterStrength()
private unsafe void AdjustFilterStrength()
{
if (this.filterStrength > 0)
{
@ -806,7 +806,7 @@ namespace SixLabors.ImageSharp.Formats.Webp.Lossy
proba.NbSkip = 0;
}
private void SetupMatrices(Vp8SegmentInfo[] dqm)
private unsafe void SetupMatrices(Vp8SegmentInfo[] dqm)
{
int tlambdaScale = this.method >= WebpEncodingMethod.Default ? this.spatialNoiseShaping : 0;
for (int i = 0; i < dqm.Length; i++)
@ -814,10 +814,6 @@ namespace SixLabors.ImageSharp.Formats.Webp.Lossy
Vp8SegmentInfo m = dqm[i];
int q = m.Quant;
m.Y1 = new Vp8Matrix();
m.Y2 = new Vp8Matrix();
m.Uv = new Vp8Matrix();
m.Y1.Q[0] = WebpLookupTables.DcTable[Numerics.Clamp(q + this.DqY1Dc, 0, 127)];
m.Y1.Q[1] = WebpLookupTables.AcTable[Numerics.Clamp(q, 0, 127)];

38
src/ImageSharp/Formats/Webp/Lossy/Vp8Matrix.cs
View File

@ -3,7 +3,7 @@
namespace SixLabors.ImageSharp.Formats.Webp.Lossy
{
internal class Vp8Matrix
internal unsafe struct Vp8Matrix
{
private static readonly int[][] BiasMatrices =
{
@ -23,41 +23,29 @@ namespace SixLabors.ImageSharp.Formats.Webp.Lossy
private const int SharpenBits = 11;
/// <summary>
/// Initializes a new instance of the <see cref="Vp8Matrix"/> class.
/// The quantizer steps.
/// </summary>
public Vp8Matrix()
{
this.Q = new ushort[16];
this.IQ = new ushort[16];
this.Bias = new uint[16];
this.ZThresh = new uint[16];
this.Sharpen = new short[16];
}
/// <summary>
/// Gets the quantizer steps.
/// </summary>
public ushort[] Q { get; }
public fixed ushort Q[16];
/// <summary>
/// Gets the reciprocals, fixed point.
/// The reciprocals, fixed point.
/// </summary>
public ushort[] IQ { get; }
public fixed ushort IQ[16];
/// <summary>
/// Gets the rounding bias.
/// The rounding bias.
/// </summary>
public uint[] Bias { get; }
public fixed uint Bias[16];
/// <summary>
/// Gets the value below which a coefficient is zeroed.
/// The value below which a coefficient is zeroed.
/// </summary>
public uint[] ZThresh { get; }
public fixed uint ZThresh[16];
/// <summary>
/// Gets the frequency boosters for slight sharpening.
/// The frequency boosters for slight sharpening.
/// </summary>
public short[] Sharpen { get; }
public fixed short Sharpen[16];
/// <summary>
/// Returns the average quantizer.
@ -72,7 +60,7 @@ namespace SixLabors.ImageSharp.Formats.Webp.Lossy
int isAcCoeff = i > 0 ? 1 : 0;
int bias = BiasMatrices[type][isAcCoeff];
this.IQ[i] = (ushort)((1 << WebpConstants.QFix) / this.Q[i]);
this.Bias[i] = (uint)this.BIAS(bias);
this.Bias[i] = (uint)BIAS(bias);
// zthresh is the exact value such that QUANTDIV(coeff, iQ, B) is:
// * zero if coeff <= zthresh
@ -106,6 +94,6 @@ namespace SixLabors.ImageSharp.Formats.Webp.Lossy
return (sum + 8) >> 4;
}
private int BIAS(int b) => b << (WebpConstants.QFix - 8);
private static int BIAS(int b) => b << (WebpConstants.QFix - 8);
}
}

14
src/ImageSharp/Formats/Webp/Lossy/Vp8SegmentInfo.cs
View File

@ -8,19 +8,21 @@ namespace SixLabors.ImageSharp.Formats.Webp.Lossy
internal class Vp8SegmentInfo
{
/// <summary>
/// Gets or sets the quantization matrix y1.
/// Gets the quantization matrix y1.
/// </summary>
public Vp8Matrix Y1 { get; set; }
#pragma warning disable SA1401 // Fields should be private
public Vp8Matrix Y1;
/// <summary>
/// Gets or sets the quantization matrix y2.
/// Gets the quantization matrix y2.
/// </summary>
public Vp8Matrix Y2 { get; set; }
public Vp8Matrix Y2;
/// <summary>
/// Gets or sets the quantization matrix uv.
/// Gets the quantization matrix uv.
/// </summary>
public Vp8Matrix Uv { get; set; }
public Vp8Matrix Uv;
#pragma warning restore SA1401 // Fields should be private
/// <summary>
/// Gets or sets the quant-susceptibility, range [-127,127]. Zero is neutral. Lower values indicate a lower risk of blurriness.

53
tests/ImageSharp.Tests/Formats/WebP/QuantEncTests.cs
View File

@ -0,0 +1,53 @@
// Copyright (c) Six Labors.
// Licensed under the Apache License, Version 2.0.
using System.Linq;
using SixLabors.ImageSharp.Formats.Webp.Lossy;
using SixLabors.ImageSharp.Tests.TestUtilities;
using Xunit;
namespace SixLabors.ImageSharp.Tests.Formats.WebP
{
[Trait("Format", "Webp")]
public class QuantEncTests
{
private static unsafe void RunQuantizeBlockTest()
{
// arrange
short[] input = { 378, 777, -851, 888, 259, 148, 0, -111, -185, -185, -74, -37, 148, 74, 111, 74 };
short[] output = new short[16];
ushort[] q = { 42, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37 };
ushort[] iq = { 3120, 3542, 3542, 3542, 3542, 3542, 3542, 3542, 3542, 3542, 3542, 3542, 3542, 3542, 3542, 3542 };
uint[] bias = { 49152, 55296, 55296, 55296, 55296, 55296, 55296, 55296, 55296, 55296, 55296, 55296, 55296, 55296, 55296, 55296 };
uint[] zthresh = { 26, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21 };
short[] expectedOutput = { 9, 21, 7, -5, 4, -23, 24, 0, -5, 4, 2, -2, -3, -1, 3, 2 };
int expectedResult = 1;
Vp8Matrix vp8Matrix = default;
for (int i = 0; i < 16; i++)
{
vp8Matrix.Q[i] = q[i];
vp8Matrix.IQ[i] = iq[i];
vp8Matrix.Bias[i] = bias[i];
vp8Matrix.ZThresh[i] = zthresh[i];
}
// act
int actualResult = QuantEnc.QuantizeBlock(input, output, ref vp8Matrix);
// assert
Assert.True(output.SequenceEqual(expectedOutput));
Assert.Equal(expectedResult, actualResult);
}
[Fact]
public void QuantizeBlock_Works() => RunQuantizeBlockTest();
#if SUPPORTS_RUNTIME_INTRINSICS
[Fact]
public void QuantizeBlock_WithHardwareIntrinsics_Works() => FeatureTestRunner.RunWithHwIntrinsicsFeature(RunQuantizeBlockTest, HwIntrinsics.AllowAll);
[Fact]
public void QuantizeBlock_WithoutHardwareIntrinsics_Works() => FeatureTestRunner.RunWithHwIntrinsicsFeature(RunQuantizeBlockTest, HwIntrinsics.DisableHWIntrinsic);
#endif
}
}
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