public void CreateMonoIEEE()
{
var properties = new AudioProperties(1, 44100, 16, AudioFormat.IEEE);
var stream = new MemoryWriterStream(new System.IO.MemoryStream(), properties);
new OLA(stream, 1000, 500);
}
public void MonoOverlapAddRectangle()
{
var properties = new AudioProperties(1, 44100, 32, AudioFormat.IEEE);
var sourceStream = new SineGeneratorStream(44100, 440, TimeSpan.FromSeconds(1));
var targetStream = new MemoryWriterStream(new System.IO.MemoryStream(), properties);
// Rectangular window (samples unchanged) with no overlap should just reconstruct the original stream
int windowSize = 100;
int hopSize = 100;
var window = WindowType.Rectangle;
var sw = new StreamWindower(sourceStream, windowSize, hopSize, window);
var ola = new OLA(targetStream, windowSize, hopSize);
var frameBuffer = new float[windowSize];
while (sw.HasNext())
{
sw.ReadFrame(frameBuffer);
ola.WriteFrame(frameBuffer);
}
ola.Flush();
Assert.AreEqual(sourceStream.Length, targetStream.Length);
// Validate ola target stream content
sourceStream.Position = targetStream.Position = 0;
long similarFloats = StreamUtil.CompareFloats(sourceStream, targetStream);
Assert.AreEqual(sourceStream.Length / sourceStream.SampleBlockSize, similarFloats);
}
public void CreateOverlapTooLarge()
{
var properties = new AudioProperties(1, 44100, 16, AudioFormat.IEEE);
var stream = new MemoryWriterStream(new System.IO.MemoryStream(), properties);
new OLA(stream, 1000, 1001);
}
public void MonoOverlapAddHann()
{
var properties = new AudioProperties(1, 44100, 32, AudioFormat.IEEE);
IAudioStream sourceStream = new SineGeneratorStream(44100, 440, TimeSpan.FromSeconds(1));
IAudioWriterStream targetStream = new MemoryWriterStream(new System.IO.MemoryStream(), properties);
// 50% overlap with a Hann window is an optimal combination, Hann window is optimally uneven with a 1 as middle point
int windowSize = 21;
int hopSize = 11;
var window = WindowType.Hann;
// Adjust source length to window/hop size so no samples remain at the end
// (a potential last incomplete frame is not returned by the stream windower)
// With remaining samples, the source and target length cannot be compared
sourceStream = new CropStream(sourceStream, 0,
sourceStream.Length
- (sourceStream.Length - windowSize * sourceStream.SampleBlockSize)
% (hopSize * sourceStream.SampleBlockSize));
var sw = new StreamWindower(sourceStream, windowSize, hopSize, window);
var ola = new OLA(targetStream, windowSize, hopSize);
var frameBuffer = new float[windowSize];
while (sw.HasNext())
{
sw.ReadFrame(frameBuffer);
ola.WriteFrame(frameBuffer);
}
ola.Flush();
Assert.AreEqual(sourceStream.Length, targetStream.Length);
// Validate ola target stream content
// Crop the streams to ignore windowed start and end when no overlap-add is performed and content definitely differs
var sourceStreamCropped = new CropStream(sourceStream,
hopSize * sourceStream.SampleBlockSize * 2,
sourceStream.Length - hopSize * sourceStream.SampleBlockSize);
var targetStreamCropped = new CropStream(targetStream,
hopSize * sourceStream.SampleBlockSize * 2,
sourceStream.Length - hopSize * sourceStream.SampleBlockSize);
sourceStreamCropped.Position = targetStreamCropped.Position = 0;
long similarFloats = StreamUtil.CompareFloats(sourceStreamCropped, targetStreamCropped);
Assert.AreEqual(sourceStreamCropped.Length / sourceStreamCropped.SampleBlockSize, similarFloats);
}
public void Write()
{
var stream = new MemoryStream();
var properties = new AudioProperties(2, 44100, 16, AudioFormat.IEEE);
var writer = new MemoryWriterStream(stream, properties);
Assert.AreEqual(0, writer.Length);
int size = writer.SampleBlockSize * 1000;
writer.Write(new byte[size], 0, size);
Assert.AreEqual(size, writer.Length);
}
/// <summary>
/// Creates a Wave format proxy file in the same directory and with the same name as the specified file,
/// if no storage directory is specified (i.e. if it is null). If a storage directory is specified, the proxy
/// file will be stored in the specified directory with a hashed file name to avoid name collisions and
/// file overwrites. The story directory option is convenient for the usage of temporary or working directories.
/// </summary>
/// <param name="fileInfo">the file for which a proxy file should be created</param>
/// <param name="storageDirectory">optional directory where the proxy file will be stored, can be null</param>
/// <returns>the FileInfo of the proxy file</returns>
public static FileInfo CreateWaveProxy(FileInfo fileInfo, DirectoryInfo storageDirectory)
{
FileInfo outputFileInfo;
if (storageDirectory == null)
{
// Without a storage directory, store the proxy file beside the original file
outputFileInfo = new FileInfo(fileInfo.FullName + ".ffproxy.wav");
}
else
{
// With a storage directory specified, store the proxy file with a hashed name
// (to avoid name collision / overwrites) in the target directory (e.g. a temp or working directory)
using (var sha256 = SHA256.Create()) {
byte[] hash = sha256.ComputeHash(Encoding.Unicode.GetBytes(fileInfo.FullName));
string hashString = BitConverter.ToString(hash).Replace("-", "").ToLowerInvariant();
outputFileInfo = new FileInfo(Path.Combine(storageDirectory.FullName, hashString + ".ffproxy.wav"));
}
}
if (outputFileInfo.Exists)
{
Console.WriteLine("Proxy already existing, using " + outputFileInfo.Name);
return(outputFileInfo);
}
var reader = new FFmpegReader(fileInfo, FFmpeg.Type.Audio);
var writer = new MemoryWriterStream(new AudioProperties(
reader.AudioOutputConfig.format.channels,
reader.AudioOutputConfig.format.sample_rate,
reader.AudioOutputConfig.format.sample_size * 8,
reader.AudioOutputConfig.format.sample_size == 4 ? AudioFormat.IEEE : AudioFormat.LPCM));
int output_buffer_size = reader.AudioOutputConfig.frame_size * writer.SampleBlockSize;
byte[] output_buffer = new byte[output_buffer_size];
int samplesRead;
long timestamp;
FFmpeg.Type type;
// sequentially read samples from decoder and write it to wav file
while ((samplesRead = reader.ReadFrame(out timestamp, output_buffer, output_buffer_size, out type)) > 0)
{
int bytesRead = samplesRead * writer.SampleBlockSize;
writer.Write(output_buffer, 0, bytesRead);
}
reader.Dispose();
writer.Position = 0;
AudioStreamFactory.WriteToFile(writer, outputFileInfo.FullName);
writer.Close();
return(outputFileInfo);
}
