如何使用临时文件流式传输mp3文件
本文关键字：传输 mp3 文件 何使用 临时文件 | 更新日期: 2023-09-27 18:07:43
我正在制作Mp3流媒体。为了从url流mp3文件，我想使用一个临时文件。但是当试图读写同一个文件时，会因为File.ReadAllBytes而抛出IOException，因为该文件正在使用中。我怎样才能解出这道题?
long pos = 0;
string path = pathtothetempfile;
MemoryStream ms = new MemoryStream();
FileStream fs = new FileStream(path, FileMode.Create,
FileAccess.ReadWrite, FileShare.ReadWrite);
do
{
bytesRead = responseStream.Read(buffer, 0, buffer.Length);
fs.Write(buffer, 0, bytesRead);
fs.Flush();
byte[] tempBuffer = File.ReadAllBytes(path);
pos = ms.Position;
ms = new MemoryStream(tempBuffer);
ms.Position = pos;
frame = Mp3Frame.LoadFromStream(ms);
//....codes....
}
while(bytesRead > 0)
我通过自己的努力找到了答案。这个答案包含NAudio来控制Mp3，它是RAM友好的部分读取流。我把它分享给其他有同样问题的人。
WaveOut waveOut;
AcmMp3FrameDecompressor decompressor;
BufferedWaveProvider provider;
bool firstPlay = true;
public void Play()
{
Task.Run(() =>
{
#region WebRequest creator
HttpWebResponse response = null;
if (avgbytes < 0)
{
HttpWebRequest req = WebRequest.Create(url) as HttpWebRequest;
req.AllowAutoRedirect = true;
req.UserAgent = "Mozilla/5.0 (Windows NT 6.3; WOW64; rv:31.0) Gecko/20100101 Firefox/31.0";
response = req.GetResponse() as HttpWebResponse;
contentLength = response.ContentLength;
}
else
response = Helper.CreateAudioWebRequest(url, currentTime, avgbytes)
.GetResponse() as HttpWebResponse;
Stream responseStream = response.GetResponseStream();
#endregion
#region Local Variables
byte[] buffer = new byte[17 * 1024];
byte[] bigBuffer = new byte[response.ContentLength];
int bytesRead = 0;
long pos = 0;
long postotal = 0;
string path = System.IO.Path.GetTempPath() + Guid.NewGuid().ToString() + ".mp3";
#endregion
Mp3Frame frame;
FileStream fs = new FileStream(path,
FileMode.Create, FileAccess.ReadWrite, FileShare.ReadWrite);
do
{
bytesRead = responseStream.Read(buffer, 0, buffer.Length);
fs.Write(buffer, 0, bytesRead);
fs.Flush();
using (MemoryStream ms = new MemoryStream(ReadPartial(fs, postotal, 1024 * 10)))
{
ms.Position = 0;
frame = Mp3Frame.LoadFromStream(ms);
if (frame == null)
{
continue;
}
pos = ms.Position;
postotal += pos;
}
#region First Play
if (firstPlay)
{
avgbytes = new Mp3WaveFormat(frame.SampleRate, frame.ChannelMode == ChannelMode.Mono ? 1 : 2,
frame.FrameLength, frame.BitRate).AverageBytesPerSecond;
duration = (int)(response.ContentLength * 1d / avgbytes);
firstPlay = false;
}
#endregion
#region Decompress Frame
if (decompressor == null)
{
decompressor = CreateFrameDecompressor(frame) as AcmMp3FrameDecompressor;
provider = new BufferedWaveProvider(decompressor.OutputFormat);
provider.BufferDuration = TimeSpan.FromSeconds(20);
}
int decompressed = decompressor.DecompressFrame(frame, buffer, 0);
#endregion
#region BufferedWaveProvider Area
if (IsBufferNearlyFull(provider))
{
Thread.Sleep(500);
}
provider.AddSamples(buffer, 0, decompressed);
#endregion
if (provider.BufferedDuration.TotalSeconds >= 2 && waveOut == null)
{
waveOut = new WaveOut();
waveOut.Init(provider);
waveOut.Play();
}
}
while (postotal != contentLength || bytesRead > 0 || waveOut==null ||
(waveOut != null && waveOut.PlaybackState == PlaybackState.Playing));
});
}
public static byte[] ReadStreamPartially(System.IO.Stream stream, long offset, long count)
{
long originalPosition = 0;
if (stream.CanSeek)
{
originalPosition = stream.Position;
stream.Position = offset;
}
try
{
byte[] readBuffer = new byte[4096];
byte[] total = new byte[count];
int totalBytesRead = 0;
int byteRead;
while ((byteRead = stream.ReadByte()) != -1)
{
Buffer.SetByte(total, totalBytesRead, (byte)byteRead);
totalBytesRead++;
if (totalBytesRead == count)
{
stream.Position = originalPosition;
break;
}
}
if (totalBytesRead < count)
{
byte[] temp = new byte[totalBytesRead];
Buffer.BlockCopy(total, 0, temp, 0, totalBytesRead);
stream.Position = originalPosition;
return temp;
}
return total;
}
finally
{
if (stream.CanSeek)
{
stream.Position = originalPosition;
}
}
}
private bool IsBufferNearlyFull(BufferedWaveProvider bufferedWaveProvider)
{
return bufferedWaveProvider != null &&
bufferedWaveProvider.BufferLength - bufferedWaveProvider.BufferedBytes
< bufferedWaveProvider.WaveFormat.AverageBytesPerSecond / 4;
}
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);
}