如何使用DirectShow.NET C#访问音频流
4
- Hauke
2
你需要哪种类型的文件（mp3、wav、wma）？ - Shay Erlichmen
它应该可以处理 DirectShow 能够处理的任何内容；mp3、mp2、wma。DirectShow 可以处理所有这些，我只是没有找到接口来获取流。 - Hauke
3个回答
5
我想与您分享我解决自己问题的方法（我的重点是异国情调的bwf文件格式。因此得名）：
using System;
using System.Collections.Generic;
using System.Text;
using DirectShowLib;
using System.Runtime.InteropServices;
using System.IO;
namespace ConvertBWF2WAV
{
public class BWF2WavConverter : ISampleGrabberCB
{
IFilterGraph2 gb = null;
ICaptureGraphBuilder2 icgb = null;
IBaseFilter ibfSrcFile = null;
DsROTEntry m_rot = null;
IMediaControl m_mediaCtrl = null;
ISampleGrabber sg = null;
public BWF2WavConverter()
{
// Initialize
int hr;
icgb = (ICaptureGraphBuilder2)new CaptureGraphBuilder2();
gb = (IFilterGraph2) new FilterGraph();
sg = (ISampleGrabber)new SampleGrabber();
#if DEBUG
m_rot = new DsROTEntry(gb);
#endif
hr = icgb.SetFiltergraph(gb);
DsError.ThrowExceptionForHR(hr);
}
public void reset()
{
gb = null;
icgb = null;
ibfSrcFile = null;
m_rot = null;
m_mediaCtrl = null;
}
public void convert(object obj)
{
string[] pair = obj as string[];
string srcfile = pair[0];
string targetfile = pair[1];
int hr;
ibfSrcFile = (IBaseFilter)new AsyncReader();
hr = gb.AddFilter(ibfSrcFile, "Reader");
DsError.ThrowExceptionForHR(hr);
IFileSourceFilter ifileSource = (IFileSourceFilter)ibfSrcFile;
hr = ifileSource.Load(srcfile, null);
DsError.ThrowExceptionForHR(hr);
// the guid is the one from ffdshow
Type fftype = Type.GetTypeFromCLSID(new Guid("0F40E1E5-4F79-4988-B1A9-CC98794E6B55"));
object ffdshow = Activator.CreateInstance(fftype);
hr = gb.AddFilter((IBaseFilter)ffdshow, "ffdshow");
DsError.ThrowExceptionForHR(hr);
// the guid is the one from the WAV Dest sample in the SDK
Type type = Type.GetTypeFromCLSID(new Guid("3C78B8E2-6C4D-11d1-ADE2-0000F8754B99"));
object wavedest = Activator.CreateInstance(type);
hr = gb.AddFilter((IBaseFilter)wavedest, "WAV Dest");
DsError.ThrowExceptionForHR(hr);
// manually tell the graph builder to try to hook up the pin that is left
IPin pWaveDestOut = null;
hr = icgb.FindPin(wavedest, PinDirection.Output, null, null, true, 0, out pWaveDestOut);
DsError.ThrowExceptionForHR(hr);
// render step 1
hr = icgb.RenderStream(null, null, ibfSrcFile, (IBaseFilter)ffdshow, (IBaseFilter)wavedest);
DsError.ThrowExceptionForHR(hr);
// Configure the sample grabber
IBaseFilter baseGrabFlt = sg as IBaseFilter;
ConfigSampleGrabber(sg);
IPin pGrabberIn = DsFindPin.ByDirection(baseGrabFlt, PinDirection.Input, 0);
IPin pGrabberOut = DsFindPin.ByDirection(baseGrabFlt, PinDirection.Output, 0);
hr = gb.AddFilter((IBaseFilter)sg, "SampleGrabber");
DsError.ThrowExceptionForHR(hr);
AMMediaType mediatype = new AMMediaType();
sg.GetConnectedMediaType(mediatype);
hr = gb.Connect(pWaveDestOut, pGrabberIn);
DsError.ThrowExceptionForHR(hr);
// file writer
FileWriter file_writer = new FileWriter();
IFileSinkFilter fs = (IFileSinkFilter)file_writer;
fs.SetFileName(targetfile, null);
hr = gb.AddFilter((DirectShowLib.IBaseFilter)file_writer, "File Writer");
DsError.ThrowExceptionForHR(hr);
// render step 2
AMMediaType mediatype2 = new AMMediaType();
pWaveDestOut.ConnectionMediaType(mediatype2);
gb.Render(pGrabberOut);
// alternatively to the file writer use the NullRenderer() to just discard the rest
// assign control
m_mediaCtrl = gb as IMediaControl;
// run
hr = m_mediaCtrl.Run();
DsError.ThrowExceptionForHR(hr);
}
//
// configure the SampleGrabber filter of the graph
//
void ConfigSampleGrabber(ISampleGrabber sampGrabber)
{
AMMediaType media;
// set the media type. works with "stream" somehow...
media = new AMMediaType();
media.majorType = MediaType.Stream;
//media.subType = MediaSubType.WAVE;
//media.formatType = FormatType.WaveEx;
// that's the call to the ISampleGrabber interface
sg.SetMediaType(media);
DsUtils.FreeAMMediaType(media);
media = null;
// set BufferCB as the desired Callback function
sg.SetCallback(this, 1);
}
public int SampleCB(double a, IMediaSample b)
{
return 0;
}
/// <summary>
/// Called on each SampleGrabber hit.
/// </summary>
/// <param name="SampleTime">Starting time of the sample, in seconds.</param>
/// <param name="pBuffer">Pointer to a buffer that contains the sample data.</param>
/// <param name="BufferLen">Length of the buffer pointed to by pBuffer, in bytes.</param>
/// <returns></returns>
public int BufferCB(double SampleTime, IntPtr pBuffer, int BufferLen)
{
byte[] buffer = new byte[BufferLen];
Marshal.Copy(pBuffer, buffer, 0, BufferLen);
using (BinaryWriter binWriter = new BinaryWriter(File.Open(@"C:\directshowoutput.pcm", FileMode.Append)))
{
binWriter.Write(buffer);
}
return 0;
}
}
}
- Hauke
1
这个（AVILibrary Wrapper）可能会带领你找到解决方案，它不是基于DirectSound的（我感觉这很偏向于将你的代码与播放硬件进行接口），但可能是答案。
另一种方法可以在这里找到。
- Lazarus
1
NAudio怎么样？http://www.codeplex.com/naudio 它有一个流实现。
- Jesper Palm
2
我发现NAudio对文件类型太过限制。 - Hauke
NAudio目前可以访问任何已安装的ACM编解码器以及DirectX媒体对象（DMOs）。我希望将DirectShow过滤器添加到其中。 - Mark Heath
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