private static double[,] Uncompress(CompressedImage image, int degreeOfParallelism)
{
var allQuantizedBytes = HuffmanCodec.HuffmanCodec.Decode(image.CompressedBytes, image.DecodeTable, image.BitsCount, degreeOfParallelism);
var result = new double[image.Height, image.Width];
for (var y = 0; y < image.Height; y += DCTSize)
{
for (var x = 0; x < image.Width; x += DCTSize)
{
var quantizedBytes = new byte[DCTSize * DCTSize];
Array.Copy(allQuantizedBytes, y * image.Width + x * DCTSize, quantizedBytes, 0, quantizedBytes.Length);
var quantizedFreqs = ZigZagUnScan(quantizedBytes);
var channelFreqs = DeQuantize(quantizedFreqs, image.Quality);
var subMatrix = DCT.IDCT2D(channelFreqs, degreeOfParallelism);
subMatrix.ShiftMatrixValues(128);
result.SetSubmatrix(subMatrix, y, x);
}
}
return(result);
}