public DataFile Compress(DataFile toCompress)
{
var ppmTables = new PPMTables(_maxOrder);
var ac = new ArithmeticCoder();
for (int i = 0; i < toCompress.Length; i++)
{
if (i % _cleanUpLimit == 0)
{
ppmTables.CleanUp();
}
var entry = new Entry(toCompress.GetByte(i), GetContextFromFile(toCompress, i));
ContextTable.ToEncode toEncode;
EncodeInfo encodeInfo;
while ((toEncode = ppmTables.LookUpAndUpdate(entry, out encodeInfo)) !=
ContextTable.ToEncode.EncodeSymbol)
{
if (toEncode == ContextTable.ToEncode.EncodeEscape)
{
ac.Encode(encodeInfo.Count, encodeInfo.CumulativeCount, encodeInfo.TotalCount);
}
entry.NextContext();
}
ac.Encode(encodeInfo.Count, encodeInfo.CumulativeCount, encodeInfo.TotalCount);
}
ac.FinalizeInterval();
var output = ac.GetEncodedBitString().ToArray();
return(new DataFile(output));
}
public void Encode(ArithmeticCoder coder, long budget)
{
_coder = coder;
_budget = budget;
Init();
var thresholdBits = (int)Math.Floor(Math.Log(_threshold) / Math.Log(2) + 0.00001);
_coder.EncodeSymbol(_thresholdModel, thresholdBits);
_threshold = 1 << thresholdBits;
for (; thresholdBits >= 0; thresholdBits--)
{
if (!SortingPass1())
{
break;
}
if (!SortingPass2())
{
break;
}
if (!RefinementPass())
{
break;
}
_threshold >>= 1;
GC.Collect();
}
EndEncoding();
}
/// <summary>
/// Encodes <paramref name="symbol"/> using the <paramref name="coder"/> with
/// the provided <paramref name="model"/>.
/// </summary>
public static void Encode <TSymbolType>(this ArithmeticCoder coder, TSymbolType symbol, IModel <TSymbolType> model,
WriteBitDelegate bitWriter)
where TSymbolType : struct
{
// cumulate frequencies
Range count = model.GetRange(symbol);
// encode symbol
coder.Encode(count, model.TotalFrequencies, bitWriter);
// update model
model.Update(symbol);
}
public void LargeFileTest1()
{
var path = TestUtil.GetTestDataDir(TestPathType.ClassName) + "test.wav";
var inStream = new FileStream(path, FileMode.Open, FileAccess.Read);
var outStream = new MemoryStream();
var stopwatch = Stopwatch.StartNew();
ArithmeticCoder.EncodeStream(inStream, outStream, 65536, 16);
var endpoint = stopwatch.Elapsed;
Console.WriteLine(endpoint);
Console.WriteLine("Encoded size is {0}", outStream.Position);
}
public void TestBasicArithmeticCodingRoundtrip2()
{
const string testString = "ユチエフ-8は素晴らしいです";
var data = Encoding.UTF8.GetBytes(testString);
var frequencies = ArithmeticCoder.CalculateFrequencies(data);
var encodedData = ArithmeticCoder.Encode(data, frequencies);
var decodedData = ArithmeticCoder.Decode(encodedData, frequencies, data.Length);
var resultString = Encoding.UTF8.GetString(decodedData);
Console.WriteLine("{0} {1} {2}", data.Length, encodedData.Length, decodedData.Length);
Console.WriteLine(encodedData.Aggregate("", (s, b) => s + ", " + b));
Console.WriteLine(testString);
Console.WriteLine(resultString);
Assert.LessOrEqual(encodedData.Length, data.Length);
Assert.AreEqual(testString, resultString);
}
/// <summary>
/// Decodes a symbol using the <paramref name="coder"/> with the provided
/// <paramref name="model"/>.
/// </summary>
public static TSymbolType Decode <TSymbolType>(this ArithmeticCoder coder, IModel <TSymbolType> model,
ReadBitDelegate bitReader)
where TSymbolType : struct
{
// read value
uint value = coder.DecodeTarget(model.TotalFrequencies);
// determine symbol
RangeSymbol <TSymbolType> rangeSymbol = model.Decode(value);
// adapt decoder
coder.Decode(rangeSymbol.Range, bitReader);
// update model
model.Update(rangeSymbol.Symbol);
return(rangeSymbol.Symbol);
}
public void TestArithmeticStreamsRoundtrip1()
{
const string testString = "ユチエフ-8は素晴らしいです";
var data = Encoding.UTF8.GetBytes(testString);
var originalStream = new MemoryStream(data, false);
var encodedStream = new MemoryStream();
ArithmeticCoder.EncodeStream(originalStream, encodedStream);
var decodedStream = new MemoryStream();
encodedStream.Position = 0;
ArithmeticCoder.DecodeStream(encodedStream, decodedStream);
var decodedData = decodedStream.ToArray();
var encodedData = encodedStream.ToArray();
var resultString = Encoding.UTF8.GetString(decodedData);
Console.WriteLine("{0} {1} {2}", data.Length, encodedData.Length, decodedData.Length);
Console.WriteLine(encodedData.Aggregate("", (s, b) => s + ", " + b));
Console.WriteLine(testString);
Console.WriteLine(resultString);
Assert.LessOrEqual(encodedData.Length, data.Length + 258);
Assert.AreEqual(testString, resultString);
}
private static void CompressTest(HyperspectralImage image, string tempPath, string restoredPath, double compression)
{
var sw = new Stopwatch();
sw.Start();
IntPtr tempData = Marshal.AllocHGlobal(image.SizeInBytes());
IntPtr restoredData = Marshal.AllocHGlobal(image.SizeInBytes());
var wavelet = new WaveletTransformationController(new Wavelet53RTransformation());
wavelet.Encode3D(image.ToPointer(), image.ImageInfo.Width, image.ImageInfo.Height, image.ImageInfo.Bands,
image.ImageInfo.Width, image.ImageInfo.Height, 0, tempData);
var budget = (long)(compression * image.SizeInBytes() * 8);
using (var stream = File.Open(tempPath, FileMode.Create))
{
var coder = new ArithmeticCoder(stream);
var compressor = new Spiht3DCoder(tempData,
image.ImageInfo.Width,
image.ImageInfo.Height,
image.ImageInfo.Bands);
compressor.Encode(coder, budget);
}
GC.Collect();
using (var stream = File.Open(tempPath, FileMode.Open))
{
var decoder = new ArithmeticDecoder(stream);
var decompressor = new Spiht3DDecoder(tempData,
image.ImageInfo.Width,
image.ImageInfo.Height,
image.ImageInfo.Bands);
decompressor.Decode(decoder, budget);
}
GC.Collect();
wavelet.Decode3D(tempData, image.ImageInfo.Width, image.ImageInfo.Height, image.ImageInfo.Bands,
image.ImageInfo.Width, image.ImageInfo.Height, 0, restoredData);
using (var stream = File.Open(restoredPath, FileMode.Create))
{
HyperspectralImage.Save(HyperspectralImage.Load(restoredData, image.ImageInfo), stream);
}
Console.WriteLine("Compression 1:{0}. PSNR = {1}", 1 / compression, PSNRCalculator.Calculate(image.ToPointer(), restoredData, image.ImageInfo));
Console.WriteLine("Compression 1:{0}. MSE = {1}", 1 / compression, PSNRCalculator.CalculateMSE(image.ToPointer(), restoredData, image.ImageInfo));
sw.Stop();
Console.WriteLine("{0}:{1} (Ticks: {2})", sw.Elapsed.Seconds, sw.Elapsed.Milliseconds, sw.ElapsedTicks);
Marshal.FreeHGlobal(tempData);
Marshal.FreeHGlobal(restoredData);
}
