public static Stream Convert(Stream inputStream)
{
using (var fileReader = new WaveFileReader(inputStream))
{
Pcm8BitToSampleProvider sampleProvider = new Pcm8BitToSampleProvider(fileReader);
SampleToWaveProvider waveProvider = new SampleToWaveProvider(sampleProvider);
var outStream = new MemoryStream();
using (var fileWriter = new LameMP3FileWriter(outStream, waveProvider.WaveFormat, 24))
{
int buff_length = 1024 * 1024;
var buff = new byte[buff_length];
int position = 0;
int length = waveProvider.Read(buff, position, buff_length);
while (length > 0)
{
position += length;
fileWriter.Write(buff, (int)fileWriter.Position, length);
length = waveProvider.Read(buff, position, buff_length);
}
fileWriter.Flush();
return(outStream);
}
}
}
public void CanDownsampleAnMp3File()
{
string testFile = @"D:\Audio\Music\Coldplay\Mylo Xyloto\03 - Paradise.mp3";
if (!File.Exists(testFile))
{
Assert.Ignore(testFile);
}
string outFile = @"d:\test22.wav";
using (var reader = new AudioFileReader(testFile))
{
// downsample to 22kHz
var resampler = new WdlResamplingSampleProvider(reader, 22050);
var wp = new SampleToWaveProvider(resampler);
using (var writer = new WaveFileWriter(outFile, wp.WaveFormat))
{
byte[] b = new byte[wp.WaveFormat.AverageBytesPerSecond];
while (true)
{
int read = wp.Read(b, 0, b.Length);
if (read > 0)
{
writer.Write(b, 0, read);
}
else
{
break;
}
}
}
//WaveFileWriter.CreateWaveFile(outFile, );
}
}
/// <summary>
/// 使用指定的音频流绘制波形图
/// </summary>
/// <param name="stream"></param>
/// <returns></returns>
public OptReturn Draw(WaveStream stream)
{
OptReturn optReturn = new OptReturn();
optReturn.Result = true;
optReturn.Code = Defines.RET_SUCCESS;
try
{
WaveStream reader = stream;
reader.Position = 0;
if (reader.WaveFormat.Encoding != WaveFormatEncoding.Pcm && reader.WaveFormat.Encoding != WaveFormatEncoding.IeeeFloat)
{
reader = WaveFormatConversionStream.CreatePcmStream(reader);
reader = new BlockAlignReductionStream(reader);
}
InitDraw();
var waveChannel = new SampleChannel(reader, true);
int samples = (int)(reader.TotalTime.TotalSeconds) * reader.WaveFormat.SampleRate / mPngWidth;
var postVolumeMeter = new MeteringSampleProvider(waveChannel, samples);
postVolumeMeter.StreamVolume += postVolumeMeter_StreamVolume;
var waveProvider = new SampleToWaveProvider(postVolumeMeter);
while (true)
{
byte[] buffer = new byte[waveProvider.WaveFormat.AverageBytesPerSecond];
int readcount = waveProvider.Read(buffer, 0, waveProvider.WaveFormat.AverageBytesPerSecond);
if (readcount <= 0)
{
break;
}
}
stream.Position = 0;
if (mIsSaveFile)
{
return(GenerateImageFile());
}
Bitmap[] bitmaps = new Bitmap[2];
bitmaps[0] = mBitmap;
bitmaps[1] = mBitmap1;
optReturn.Data = bitmaps;
return(optReturn);
}
catch (Exception ex)
{
optReturn.Result = false;
optReturn.Code = Defines.RET_FAIL;
optReturn.Message = ex.Message;
return(optReturn);
}
}
public static byte[] Generate(this WaveFormat waveFormat, TimeSpan interval,
SignalGeneratorType type = SignalGeneratorType.Sin, double frequency = 1.0)
{
var sampleProvider = new SignalGenerator(waveFormat.SampleRate, waveFormat.Channels)
{
Frequency = frequency, Type = type
};
var waveProvider = new SampleToWaveProvider(sampleProvider);
var numBytes = (int)(interval.TotalSeconds * waveFormat.AverageBytesPerSecond);
var data = new byte[numBytes];
waveProvider.Read(data, 0, data.Length);
return(data);
}
public static byte[] Generate(this TimeSpan interval, int rate = 8000, int channels = 1,
SignalGeneratorType type = SignalGeneratorType.Sin, double frequency = 1.0)
{
var waveFormat = WaveFormat.CreateIeeeFloatWaveFormat(rate, channels);
var sampleProvider = new SignalGenerator(rate, channels)
{
Frequency = frequency, Type = type
};
var waveProvider = new SampleToWaveProvider(sampleProvider);
var numBytes = (int)(interval.TotalSeconds * waveFormat.AverageBytesPerSecond);
var data = new byte[numBytes];
waveProvider.Read(data, 0, data.Length);
return(data);
}
public override int Read(byte[] buffer, int offset, int count)
{
return(sampler.Read(buffer, offset, count));
}
