示例#1
0
文件: JPEG.cs 项目: hrjakobsen/P2-AAU
        private void HuffmanEncode(ref List<byte> 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.getHuffmanCode(0, category);
                ushortToBits(ref bits, huffmanCode.codeWord, huffmanCode.length);

                ushortToBits(ref bits, negativeNumberEncoder(diff), category);
            } else {
                huffmanElement EOB = huffmanDC.getHuffmanCode(0x00, 0x00);
                ushortToBits(ref bits, EOB.codeWord, EOB.length);
            }

            int zeroesCounter = 0;
            for (int i = 1; i < 64; i++) {
                int x = _roadPoints[i, 0], y = _roadPoints[i, 1];
                if (block8[x, y] == 0) {
                    zeroesCounter++;
                    continue;
                }
                while (zeroesCounter >= 16) {
                    huffmanElement ZRL = huffmanAC.getHuffmanCode(0x0F, 0x00);
                    ushortToBits(ref bits, ZRL.codeWord, ZRL.length);
                    zeroesCounter -= 16;
                }

                byte cost = bitCost((short)Math.Abs(block8[x, y]));
                huffmanElement codeElement = huffmanAC.getHuffmanCode((byte)zeroesCounter, cost);
                zeroesCounter = 0;
                ushortToBits(ref bits, codeElement.codeWord, codeElement.length);

                ushortToBits(ref bits, negativeNumberEncoder((short)block8[x, y]), cost);

            }

            if (zeroesCounter != 0) { //EOB
                huffmanElement EOB = huffmanAC.getHuffmanCode(0x00, 0x00);
                ushortToBits(ref bits, EOB.codeWord, EOB.length);
            }
        }
示例#2
0
文件: JPEG.cs 项目: hrjakobsen/P2-AAU
        private void addHuffmanTable(HuffmanTable huffman, byte id, bool dc) {
            writeBytesToStream(0xff, 0xc4); //DHT marker
            ushort len = (ushort)(huffman.combinationsInTable + 19);
            writeBytesToStream((byte)(len >> 8), (byte)(len & 0xff));
            byte combined;
            if (!dc) {
                combined = (byte)((1 << 4) + id);
            } else {
                combined = id;
            }
            writeBytesToStream(combined);

            for (int i = 0; i < 16; i++) {
                writeBytesToStream(huffman.bitLengths[i]);
            }

            for (int i = 0; i < 16; i++) {
                for (int j = 0; j < huffman.combinationsInTable; j++) {
                    if (huffman.elements[j].length == i + 1) {
                        writeBytesToStream(huffman.elements[j].runSize);
                    }
                }
            }

        }