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using System;
using System.Diagnostics;
using System.IO;
using System.Net;
using System.Threading;
using System.Windows.Forms;
using NAudio.Wave;
namespace NAudioDemo.Mp3StreamingDemo
{
public partial class Mp3StreamingPanel : UserControl
{
enum StreamingPlaybackState
{
Stopped,
Playing,
Buffering,
Paused
}
public Mp3StreamingPanel()
{
InitializeComponent();
volumeSlider1.VolumeChanged += OnVolumeSliderChanged;
Disposed += MP3StreamingPanel_Disposing;
}
void OnVolumeSliderChanged(object sender, EventArgs e)
{
if (volumeProvider != null)
{
volumeProvider.Volume = volumeSlider1.Volume;
}
}
private BufferedWaveProvider bufferedWaveProvider;
private IWavePlayer waveOut;
private volatile StreamingPlaybackState playbackState;
private volatile bool fullyDownloaded;
private HttpWebRequest webRequest;
private VolumeWaveProvider16 volumeProvider;
delegate void ShowErrorDelegate(string message);
private void ShowError(string message)
{
if (InvokeRequired)
{
BeginInvoke(new ShowErrorDelegate(ShowError), message);
}
else
{
MessageBox.Show(message);
}
}
private void StreamMp3(object state)
{
fullyDownloaded = false;
var url = (string)state;
webRequest = (HttpWebRequest)WebRequest.Create(url);
HttpWebResponse resp;
try
{
resp = (HttpWebResponse)webRequest.GetResponse();
}
catch(WebException e)
{
if (e.Status != WebExceptionStatus.RequestCanceled)
{
ShowError(e.Message);
}
return;
}
var buffer = new byte[16384 * 4]; // needs to be big enough to hold a decompressed frame
IMp3FrameDecompressor decompressor = null;
try
{
using (var responseStream = resp.GetResponseStream())
{
var readFullyStream = new ReadFullyStream(responseStream);
do
{
if (IsBufferNearlyFull)
{
Debug.WriteLine("Buffer getting full, taking a break");
Thread.Sleep(500);
}
else
{
Mp3Frame frame;
try
{
frame = Mp3Frame.LoadFromStream(readFullyStream);
}
catch (EndOfStreamException)
{
fullyDownloaded = true;
// reached the end of the MP3 file / stream
break;
}
catch (WebException)
{
// probably we have aborted download from the GUI thread
break;
}
if (frame == null) 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
decompressor = CreateFrameDecompressor(frame);
bufferedWaveProvider = new BufferedWaveProvider(decompressor.OutputFormat);
bufferedWaveProvider.BufferDuration =
TimeSpan.FromSeconds(20); // allow us to get well ahead of ourselves
//this.bufferedWaveProvider.BufferedDuration = 250;
}
int decompressed = decompressor.DecompressFrame(frame, buffer, 0);
//Debug.WriteLine(String.Format("Decompressed a frame {0}", decompressed));
bufferedWaveProvider.AddSamples(buffer, 0, decompressed);
}
} 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();
}
}
}
private static IMp3FrameDecompressor CreateFrameDecompressor(Mp3Frame frame)
{
WaveFormat waveFormat = new Mp3WaveFormat(frame.SampleRate, frame.ChannelMode == ChannelMode.Mono ? 1 : 2,
frame.FrameLength, frame.BitRate);
return new AcmMp3FrameDecompressor(waveFormat);
}
private bool IsBufferNearlyFull
{
get
{
return bufferedWaveProvider != null &&
bufferedWaveProvider.BufferLength - bufferedWaveProvider.BufferedBytes
< bufferedWaveProvider.WaveFormat.AverageBytesPerSecond / 4;
}
}
private void buttonPlay_Click(object sender, EventArgs e)
{
if (playbackState == StreamingPlaybackState.Stopped)
{
playbackState = StreamingPlaybackState.Buffering;
bufferedWaveProvider = null;
ThreadPool.QueueUserWorkItem(StreamMp3, textBoxStreamingUrl.Text);
timer1.Enabled = true;
}
else if (playbackState == StreamingPlaybackState.Paused)
{
playbackState = StreamingPlaybackState.Buffering;
}
}
private void StopPlayback()
{
if (playbackState != StreamingPlaybackState.Stopped)
{
if (!fullyDownloaded)
{
webRequest.Abort();
}
playbackState = StreamingPlaybackState.Stopped;
if (waveOut != null)
{
waveOut.Stop();
waveOut.Dispose();
waveOut = null;
}
timer1.Enabled = false;
// n.b. streaming thread may not yet have exited
Thread.Sleep(500);
ShowBufferState(0);
}
}
private void ShowBufferState(double totalSeconds)
{
labelBuffered.Text = String.Format("{0:0.0}s", totalSeconds);
progressBarBuffer.Value = (int)(totalSeconds * 1000);
}
private void timer1_Tick(object sender, EventArgs e)
{
if (playbackState != StreamingPlaybackState.Stopped)
{
if (waveOut == null && bufferedWaveProvider != null)
{
Debug.WriteLine("Creating WaveOut Device");
waveOut = CreateWaveOut();
waveOut.PlaybackStopped += OnPlaybackStopped;
volumeProvider = new VolumeWaveProvider16(bufferedWaveProvider);
volumeProvider.Volume = volumeSlider1.Volume;
waveOut.Init(volumeProvider);
progressBarBuffer.Maximum = (int)bufferedWaveProvider.BufferDuration.TotalMilliseconds;
}
else if (bufferedWaveProvider != null)
{
var bufferedSeconds = bufferedWaveProvider.BufferedDuration.TotalSeconds;
ShowBufferState(bufferedSeconds);
// make it stutter less if we buffer up a decent amount before playing
if (bufferedSeconds < 0.5 && playbackState == StreamingPlaybackState.Playing && !fullyDownloaded)
{
Pause();
}
else if (bufferedSeconds > 4 && playbackState == StreamingPlaybackState.Buffering)
{
Play();
}
else if (fullyDownloaded && bufferedSeconds == 0)
{
Debug.WriteLine("Reached end of stream");
StopPlayback();
}
}
}
}
private void Play()
{
waveOut.Play();
Debug.WriteLine(String.Format("Started playing, waveOut.PlaybackState={0}", waveOut.PlaybackState));
playbackState = StreamingPlaybackState.Playing;
}
private void Pause()
{
playbackState = StreamingPlaybackState.Buffering;
waveOut.Pause();
Debug.WriteLine(String.Format("Paused to buffer, waveOut.PlaybackState={0}", waveOut.PlaybackState));
}
private IWavePlayer CreateWaveOut()
{
return new WaveOut();
}
private void MP3StreamingPanel_Disposing(object sender, EventArgs e)
{
StopPlayback();
}
private void buttonPause_Click(object sender, EventArgs e)
{
if (playbackState == StreamingPlaybackState.Playing || playbackState == StreamingPlaybackState.Buffering)
{
waveOut.Pause();
Debug.WriteLine(String.Format("User requested Pause, waveOut.PlaybackState={0}", waveOut.PlaybackState));
playbackState = StreamingPlaybackState.Paused;
}
}
private void buttonStop_Click(object sender, EventArgs e)
{
StopPlayback();
}
private void OnPlaybackStopped(object sender, StoppedEventArgs e)
{
Debug.WriteLine("Playback Stopped");
if (e.Exception != null)
{
MessageBox.Show(String.Format("Playback Error {0}", e.Exception.Message));
}
}
}
public class Mp3StreamingPanelPlugin : INAudioDemoPlugin
{
public string Name
{
get { return "MP3 Streaming"; }
}
public Control CreatePanel()
{
return new Mp3StreamingPanel();
}
}
}
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