我跟着this修改了NAudio演示以播放ShoutCast。
在我的完整代码中，我必须对传入的音频进行重新采样，然后通过网络再次将其传输到网络播放器。由于我获得了许多点击和弹出＆＃34;，我回到了演示代码，我发现这些工件是在解码块之后产生的。 如果我以mp3格式保存传入的流，很明显。 当我保存原始解码数据（没有除解码器之外的其他处理）时，我得到许多音频伪像。
我想知道我是否正在做一些错误，即使我的代码几乎等于NAudio演示。
这里的例子中的函数由我修改以保存原始数据。它被称为新线程。
private void StreamMP3(object state)
{
//Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
//SettingsSection section = (SettingsSection)config.GetSection("system.net/settings");
this.fullyDownloaded = false;
string url = "http://icestreaming.rai.it/5.mp3";//(string)state;
webRequest = (HttpWebRequest)WebRequest.Create(url);
int metaInt = 0; // blocksize of mp3 data
int framesize = 0;
webRequest.Headers.Clear();
webRequest.Headers.Add("GET", "/ HTTP/1.0");
// needed to receive metadata informations
webRequest.Headers.Add("Icy-MetaData", "1");
webRequest.UserAgent = "WinampMPEG/5.09";
HttpWebResponse resp = null;
try
{
resp = (HttpWebResponse)webRequest.GetResponse();
}
catch (WebException e)
{
if (e.Status != WebExceptionStatus.RequestCanceled)
{
ShowError(e.Message);
}
return;
}
byte[] buffer = new byte[16384 * 4]; // needs to be big enough to hold a decompressed frame
try
{
// read blocksize to find metadata block
metaInt = Convert.ToInt32(resp.GetResponseHeader("icy-metaint"));
}
catch
{
}
IMp3FrameDecompressor decompressor = null;
byteOut = createNewFile(destPath, "salva", "raw");
try
{
using (var responseStream = resp.GetResponseStream())
{
var readFullyStream = new ReadFullyStream(responseStream);
readFullyStream.metaInt = metaInt;
do
{
if (mybufferedWaveProvider != null && mybufferedWaveProvider.BufferLength - mybufferedWaveProvider.BufferedBytes < mybufferedWaveProvider.WaveFormat.AverageBytesPerSecond / 4)
{
Debug.WriteLine("Buffer getting full, taking a break");
Thread.Sleep(500);
}
else
{
Mp3Frame frame = null;
try
{
frame = Mp3Frame.LoadFromStream(readFullyStream, true);
if (metaInt > 0)
UpdateSongName(readFullyStream.SongName);
else
UpdateSongName("No Song Info in Stream...");
}
catch (EndOfStreamException)
{
this.fullyDownloaded = true;
// reached the end of the MP3 file / stream
break;
}
catch (WebException)
{
// probably we have aborted download from the GUI thread
break;
}
if (decompressor == null)
{
// don't think these details matter too much - just help ACM select the right codec
// however, the buffered provider doesn't know what sample rate it is working at
// until we have a frame
WaveFormat waveFormat = new Mp3WaveFormat(frame.SampleRate, frame.ChannelMode == ChannelMode.Mono ? 1 : 2, frame.FrameLength, frame.BitRate);
decompressor = new AcmMp3FrameDecompressor(waveFormat);
this.mybufferedWaveProvider = new BufferedWaveProvider(decompressor.OutputFormat);
this.mybufferedWaveProvider.BufferDuration = TimeSpan.FromSeconds(200); // allow us to get well ahead of ourselves
framesize = (decompressor.OutputFormat.Channels * decompressor.OutputFormat.SampleRate * (decompressor.OutputFormat.BitsPerSample / 8) * 20) / 1000;
//this.bufferedWaveProvider.BufferedDuration = 250;
}
int decompressed = decompressor.DecompressFrame(frame, buffer, 0);
//Debug.WriteLine(String.Format("Decompressed a frame {0}", decompressed));
mybufferedWaveProvider.AddSamples(buffer, 0, decompressed);
while (mybufferedWaveProvider.BufferedDuration.Milliseconds >= 20)
{
byte[] read = new byte[framesize];
mybufferedWaveProvider.Read(read, 0, framesize);
byteOut.Write(read, 0, framesize);
}
}
} while (playbackState != StreamingPlaybackState.Stopped);
Debug.WriteLine("Exiting");
// was doing this in a finally block, but for some reason
// we are hanging on response stream .Dispose so never get there
decompressor.Dispose();
}
}
finally
{
if (decompressor != null)
{
decompressor.Dispose();
}
}
}
答案 0 :(得分：0)
好的，我发现了问题。我将shoutcast元数据包含在MP3Frame中。 请参阅评论＆＃34;这里我收集MP3框架的字样＆＃34;找到正确的点来获取没有流式元数据的MP3帧。
以下代码在没有音频工件的情况下运行：
private void SHOUTcastReceiverThread()
{
//-*- String server = "http://216.235.80.18:8285/stream";
//String serverPath = "/";
//String destPath = "C:\\temp\\"; // destination path for saved songs
HttpWebRequest request = null; // web request
HttpWebResponse response = null; // web response
int metaInt = 0; // blocksize of mp3 data
int count = 0; // byte counter
int metadataLength = 0; // length of metadata header
string metadataHeader = ""; // metadata header that contains the actual songtitle
string oldMetadataHeader = null; // previous metadata header, to compare with new header and find next song
//CircularQueueStream framestream = new CircularQueueStream(2048);
QueueStream framestream = new QueueStream();
framestream.Position = 0;
bool bNewSong = false;
byte[] buffer = new byte[512]; // receive buffer
byte[] dec_buffer = new byte[decSIZE];
Mp3Frame frame;
IMp3FrameDecompressor decompressor = null;
Stream socketStream = null; // input stream on the web request
// create web request
request = (HttpWebRequest)WebRequest.Create(server);
// clear old request header and build own header to receive ICY-metadata
request.Headers.Clear();
request.Headers.Add("GET", serverPath + " HTTP/1.0");
request.Headers.Add("Icy-MetaData", "1"); // needed to receive metadata informations
request.UserAgent = "WinampMPEG/5.09";
// execute request
try
{
response = (HttpWebResponse)request.GetResponse();
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
return;
}
// read blocksize to find metadata header
metaInt = Convert.ToInt32(response.GetResponseHeader("icy-metaint"));
try
{
// open stream on response
socketStream = response.GetResponseStream();
var readFullyStream = new ReadFullyStream(socketStream);
frame = null;
// rip stream in an endless loop
do
{
if (IsBufferNearlyFull)
{
Debug.WriteLine("Buffer getting full, taking a break");
Thread.Sleep(500);
frame = null;
}
else
{
int bufLen = readFullyStream.Read(buffer, 0, buffer.Length);
try
{
if (framestream.CanRead && framestream.Length > 512)
frame = Mp3Frame.LoadFromStream(framestream);
else
frame = null;
}
catch (Exception ex)
{
frame = null;
}
if (bufLen < 0)
{
Debug.WriteLine("Buffer error 1: exit.");
return;
}
// processing RAW data
for (int i = 0; i < bufLen; i++)
{
// if there is a header, the 'headerLength' would be set to a value != 0. Then we save the header to a string
if (metadataLength != 0)
{
metadataHeader += Convert.ToChar(buffer[i]);
metadataLength--;
if (metadataLength == 0) // all metadata informations were written to the 'metadataHeader' string
{
string fileName = "";
string fileNameRaw = "";
// if songtitle changes, create a new file
if (!metadataHeader.Equals(oldMetadataHeader))
{
// flush and close old byteOut stream
if (byteOut != null)
{
byteOut.Flush();
byteOut.Close();
byteOut = null;
}
if (byteOutRaw != null)
{
byteOutRaw.Flush();
byteOutRaw.Close();
byteOutRaw = null;
}
timeStart = timeEnd;
// extract songtitle from metadata header. Trim was needed, because some stations don't trim the songtitle
//fileName = Regex.Match(metadataHeader, "(StreamTitle=')(.*)(';StreamUrl)").Groups[2].Value.Trim();
fileName = Regex.Match(metadataHeader, "(StreamTitle=')(.*)(';)").Groups[2].Value.Trim();
// write new songtitle to console for information
if (fileName.Length == 0)
fileName = "shoutcast_test";
fileNameRaw = fileName + "_raw";
framestream.reSetPosition();
SongChanged(this, metadataHeader);
bNewSong = true;
// create new file with the songtitle from header and set a stream on this file
timeEnd = DateTime.Now;
if (bWrite_to_file)
{
byteOut = createNewFile(destPath, fileName, "mp3");
byteOutRaw = createNewFile(destPath, fileNameRaw, "raw");
}
timediff = timeEnd - timeStart;
// save new header to 'oldMetadataHeader' string, to compare if there's a new song starting
oldMetadataHeader = metadataHeader;
}
metadataHeader = "";
}
}
else // write mp3 data to file or extract metadata headerlength
{
if (count++ < metaInt) // write bytes to filestream
{
//HERE I COLLECT THE BYTES OF THE MP3 FRAME
framestream.Write(buffer, i, 1);
}
else // get headerlength from lengthbyte and multiply by 16 to get correct headerlength
{
metadataLength = Convert.ToInt32(buffer[i]) * 16;
count = 0;
}
}
}//for
if (bNewSong)
{
decompressor = createDecompressor(frame);
bNewSong = false;
}
if (frame != null && decompressor != null)
{
framedec(decompressor, frame);
}
// fine Processing dati RAW
}//Buffer is not full
SHOUTcastStatusProcess();
} while (playbackState != StreamingPlaybackState.Stopped);
} //try
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
finally
{
if (byteOut != null)
byteOut.Close();
if (socketStream != null)
socketStream.Close();
if (decompressor != null)
{
decompressor.Dispose();
decompressor = null;
}
if (null != request)
request.Abort();
if (null != framestream)
framestream.Dispose();
if (null != bufferedWaveProvider)
bufferedWaveProvider.ClearBuffer();
//if (null != bufferedWaveProviderOut)
// bufferedWaveProviderOut.ClearBuffer();
if (null != mono16bitFsinStream)
{
mono16bitFsinStream.Close();
mono16bitFsinStream.Dispose();
}
if (null != middleStream2)
{
middleStream2.Close();
middleStream2.Dispose();
}
if (null != resampler)
resampler.Dispose();
}
}
public class QueueStream : MemoryStream
{
long ReadPosition = 0;
long WritePosition = 0;
public QueueStream() : base() { }
public override int Read(byte[] buffer, int offset, int count)
{
Position = ReadPosition;
var temp = base.Read(buffer, offset, count);
ReadPosition = Position;
return temp;
}
public override void Write(byte[] buffer, int offset, int count)
{
Position = WritePosition;
base.Write(buffer, offset, count);
WritePosition = Position;
}
public void reSetPosition()
{
WritePosition = 0;
ReadPosition = 0;
Position = 0;
}
}
private void framedec(IMp3FrameDecompressor decompressor, Mp3Frame frame)
{
int Ndecoded_samples = 0;
byte[] dec_buffer = new byte[decSIZE];
Ndecoded_samples = decompressor.DecompressFrame(frame, dec_buffer, 0);
bufferedWaveProvider.AddSamples(dec_buffer, 0, Ndecoded_samples);
NBufferedSamples += Ndecoded_samples;
brcnt_in.incSamples(Ndecoded_samples);
if (Ndecoded_samples > decSIZE)
{
Debug.WriteLine(String.Format("Too many samples {0}", Ndecoded_samples));
}
if (byteOut != null)
byteOut.Write(frame.RawData, 0, frame.RawData.Length);
if (byteOutRaw != null) // as long as we don't have a songtitle, we don't open a new file and don't write any bytes
byteOutRaw.Write(dec_buffer, 0, Ndecoded_samples);
frame = null;
}
private IMp3FrameDecompressor createDecompressor(Mp3Frame frame)
{
IMp3FrameDecompressor dec = null;
if (frame != null)
{
// don't think these details matter too much - just help ACM select the right codec
// however, the buffered provider doesn't know what sample rate it is working at
// until we have a frame
WaveFormat srcwaveFormat = new Mp3WaveFormat(frame.SampleRate, frame.ChannelMode == ChannelMode.Mono ? 1 : 2, frame.FrameLength, frame.BitRate);
dec = new AcmMp3FrameDecompressor(srcwaveFormat);
bufferedWaveProvider = new BufferedWaveProvider(dec.OutputFormat);// decompressor.OutputFormat
bufferedWaveProvider.BufferDuration = TimeSpan.FromSeconds(400); // allow us to get well ahead of ourselves
// ------------------------------------------------
//Create an intermediate format with same sampling rate, 16 bit, mono
middlewavformat = new WaveFormat(dec.OutputFormat.SampleRate, 16, 1);
outwavFormat = new WaveFormat(Fs_out, 16, 1);
// wave16ToFloat = new Wave16ToFloatProvider(provider); // I have tried with and without this converter.
wpws = new WaveProviderToWaveStream(bufferedWaveProvider);
//Check middlewavformat.Encoding == WaveFormatEncoding.Pcm;
mono16bitFsinStream = new WaveFormatConversionStream(middlewavformat, wpws);
middleStream2 = new BlockAlignReductionStream(mono16bitFsinStream);
resampler = new MediaFoundationResampler(middleStream2, outwavFormat);
}
return dec;
}