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Merge pull request #1836 from SixLabors/bp/upscalesse
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Add SSE41 version of UpSample
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@brianpopow
brianpopow authored Nov 25, 2021
2 parents 1713891 + 8f6e9ba commit b67a8db
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Showing 4 changed files with 500 additions and 58 deletions.
4 changes: 4 additions & 0 deletions src/ImageSharp/Formats/Webp/Lossy/Vp8Decoder.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -76,10 +76,14 @@ public Vp8Decoder(Vp8FrameHeader frameHeader, Vp8PictureHeader pictureHeader, Vp
this.TmpVBuffer = memoryAllocator.Allocate<byte>((int)width);
this.Pixels = memoryAllocator.Allocate<byte>((int)(width * height * 4));

#if DEBUG
// Filling those buffers with 205, is only useful for debugging,
// so the default values are the same as the reference libwebp implementation.
this.YuvBuffer.Memory.Span.Fill(205);
this.CacheY.Memory.Span.Fill(205);
this.CacheU.Memory.Span.Fill(205);
this.CacheV.Memory.Span.Fill(205);
#endif

this.Vp8BitReaders = new Vp8BitReader[WebpConstants.MaxNumPartitions];
}
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63 changes: 5 additions & 58 deletions src/ImageSharp/Formats/Webp/Lossy/WebpLossyDecoder.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -692,16 +692,17 @@ private int EmitRgb(Vp8Decoder dec, Vp8Io io)
int mbw = io.MbW;
int uvw = (mbw + 1) / 2;
int y = io.MbY;
byte[] uvBuffer = new byte[(14 * 32) + 15];

if (y == 0)
{
// First line is special cased. We mirror the u/v samples at boundary.
this.UpSample(curY, null, curU, curV, curU, curV, dst, null, mbw);
YuvConversion.UpSample(curY, default, curU, curV, curU, curV, dst, default, mbw, uvBuffer);
}
else
{
// We can finish the left-over line from previous call.
this.UpSample(tmpYBuffer, curY, topU, topV, curU, curV, buf.Slice(dstStartIdx - bufferStride), dst, mbw);
YuvConversion.UpSample(tmpYBuffer, curY, topU, topV, curU, curV, buf.Slice(dstStartIdx - bufferStride), dst, mbw, uvBuffer);
numLinesOut++;
}

Expand All @@ -714,7 +715,7 @@ private int EmitRgb(Vp8Decoder dec, Vp8Io io)
topV = curV;
curU = curU.Slice(io.UvStride);
curV = curV.Slice(io.UvStride);
this.UpSample(curY.Slice(io.YStride), curY.Slice(ioStride2), topU, topV, curU, curV, dst.Slice(bufferStride), dst.Slice(bufferStride2), mbw);
YuvConversion.UpSample(curY.Slice(io.YStride), curY.Slice(ioStride2), topU, topV, curU, curV, dst.Slice(bufferStride), dst.Slice(bufferStride2), mbw, uvBuffer);
curY = curY.Slice(ioStride2);
dst = dst.Slice(bufferStride2);
}
Expand All @@ -736,67 +737,13 @@ private int EmitRgb(Vp8Decoder dec, Vp8Io io)
// Process the very last row of even-sized picture.
if ((yEnd & 1) == 0)
{
this.UpSample(curY, null, curU, curV, curU, curV, dst.Slice(bufferStride), null, mbw);
YuvConversion.UpSample(curY, default, curU, curV, curU, curV, dst.Slice(bufferStride), default, mbw, uvBuffer);
}
}

return numLinesOut;
}

private void UpSample(Span<byte> topY, Span<byte> bottomY, Span<byte> topU, Span<byte> topV, Span<byte> curU, Span<byte> curV, Span<byte> topDst, Span<byte> bottomDst, int len)
{
int xStep = 3;
int lastPixelPair = (len - 1) >> 1;
uint tluv = YuvConversion.LoadUv(topU[0], topV[0]); // top-left sample
uint luv = YuvConversion.LoadUv(curU[0], curV[0]); // left-sample
uint uv0 = ((3 * tluv) + luv + 0x00020002u) >> 2;
YuvConversion.YuvToBgr(topY[0], (int)(uv0 & 0xff), (int)(uv0 >> 16), topDst);

if (bottomY != null)
{
uv0 = ((3 * luv) + tluv + 0x00020002u) >> 2;
YuvConversion.YuvToBgr(bottomY[0], (int)uv0 & 0xff, (int)(uv0 >> 16), bottomDst);
}

for (int x = 1; x <= lastPixelPair; x++)
{
uint tuv = YuvConversion.LoadUv(topU[x], topV[x]); // top sample
uint uv = YuvConversion.LoadUv(curU[x], curV[x]); // sample

// Precompute invariant values associated with first and second diagonals.
uint avg = tluv + tuv + luv + uv + 0x00080008u;
uint diag12 = (avg + (2 * (tuv + luv))) >> 3;
uint diag03 = (avg + (2 * (tluv + uv))) >> 3;
uv0 = (diag12 + tluv) >> 1;
uint uv1 = (diag03 + tuv) >> 1;
int xMul2 = x * 2;
YuvConversion.YuvToBgr(topY[xMul2 - 1], (int)(uv0 & 0xff), (int)(uv0 >> 16), topDst.Slice((xMul2 - 1) * xStep));
YuvConversion.YuvToBgr(topY[xMul2 - 0], (int)(uv1 & 0xff), (int)(uv1 >> 16), topDst.Slice((xMul2 - 0) * xStep));

if (bottomY != null)
{
uv0 = (diag03 + luv) >> 1;
uv1 = (diag12 + uv) >> 1;
YuvConversion.YuvToBgr(bottomY[xMul2 - 1], (int)(uv0 & 0xff), (int)(uv0 >> 16), bottomDst.Slice((xMul2 - 1) * xStep));
YuvConversion.YuvToBgr(bottomY[xMul2 + 0], (int)(uv1 & 0xff), (int)(uv1 >> 16), bottomDst.Slice((xMul2 + 0) * xStep));
}

tluv = tuv;
luv = uv;
}

if ((len & 1) == 0)
{
uv0 = ((3 * tluv) + luv + 0x00020002u) >> 2;
YuvConversion.YuvToBgr(topY[len - 1], (int)(uv0 & 0xff), (int)(uv0 >> 16), topDst.Slice((len - 1) * xStep));
if (bottomY != null)
{
uv0 = ((3 * luv) + tluv + 0x00020002u) >> 2;
YuvConversion.YuvToBgr(bottomY[len - 1], (int)(uv0 & 0xff), (int)(uv0 >> 16), bottomDst.Slice((len - 1) * xStep));
}
}
}

private void DoTransform(uint bits, Span<short> src, Span<byte> dst, Span<int> scratch)
{
switch (bits >> 30)
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