private void HuffmanEncode(BitList bits, int[,] block8, HuffmanTable huffmanDC, HuffmanTable huffmanAC, int DCIndex) {
short diff = (short)(block8[0, 0] - _lastDc[DCIndex]);
_lastDc[DCIndex] += diff;
if (diff != 0) {
byte category = _bitCost(diff);
HuffmanElement huffmanCode = huffmanDC.GetElementFromRunSize(0, category);
_ushortToBits(bits, huffmanCode.CodeWord, huffmanCode.Length);
_ushortToBits(bits, _numberEncoder(diff), category);
} else {
HuffmanElement EOB = huffmanDC.GetElementFromRunSize(0x00, 0x00);
_ushortToBits(bits, EOB.CodeWord, EOB.Length);
}
int zeroesCounter = 0;
for (int i = 1; i < 64; i++) {
int x = QuantizationTable.RoadPoints[i, 0], y = QuantizationTable.RoadPoints[i, 1];
if (block8[x, y] == 0) {
zeroesCounter++;
continue;
}
while (zeroesCounter >= 16) {
HuffmanElement ZRL = huffmanAC.GetElementFromRunSize(0x0F, 0x00);
_ushortToBits(bits, ZRL.CodeWord, ZRL.Length);
zeroesCounter -= 16;
}
byte cost = _bitCost((short)Math.Abs(block8[x, y]));
HuffmanElement codeElement = huffmanAC.GetElementFromRunSize((byte)zeroesCounter, cost);
zeroesCounter = 0;
_ushortToBits(bits, codeElement.CodeWord, codeElement.Length);
_ushortToBits(bits, _numberEncoder((short)block8[x, y]), cost);
}
if (zeroesCounter != 0) { //EOB
HuffmanElement EOB = huffmanAC.GetElementFromRunSize(0x00, 0x00);
_ushortToBits(bits, EOB.CodeWord, EOB.Length);
}
}
public void GetElementFromRunSize_Test()
{
byte runSizeInput1 = 0x00;
ushort codeWordInput1 = 2; // 10 in base 2
byte lengthInput1 = 8; // 1000 in base 2
byte runSizeInput2 = 0x01;
ushort codeWordInput2 = 3; // 11 in base 2
byte lengthInput2 = 8; // 1000 in base 2
HuffmanElement huffmanTestElement1 = new HuffmanElement(runSizeInput1, codeWordInput1, lengthInput1);
HuffmanElement huffmanTestElement2 = new HuffmanElement(runSizeInput2, codeWordInput2, lengthInput2);
HuffmanTable huffTable1 = new HuffmanTable(huffmanTestElement1, huffmanTestElement2);
Assert.AreEqual(huffmanTestElement2, huffTable1.GetElementFromRunSize(0x0, 0x1)); //combines to 0x01
}
