DirectX.Capture Class Library

I came across the following:[i]
Version 0.9 of the WindowsMediaLib library is the result of work done by: David Wohlferd (snarfle@users.SourceForge.net)[/i]. I did some more digging and I know it will not be an easy job. Most of the work will be in the area of "user friendelyness" ... There is one positive part, I did already implemented an ASF writer for saving audio and video. It seems I can use that also for WMA.

Did you do already some investigations on WMA (and Asf)? I am getting a bit confused about valid ways to change between different formats.
- When reading MSDN: use WMProfile, ConfigureFilterUsingProfileId became obsolete
- When reading MSDN:
- DirectShowLib says: use WMProfile, ConfigureFilterUsingProfileId, ConfigureFilterUsingProfileGuid became obsolete

The Guid method is not that difficult. However I did not find a way yet to find the correct naming for a specific format. Furthermore it is not really clear whether a specific format supports audio+video, audio only or video only. It is important because the graph fails if the rendering of audio and/or video does not match the selected format.
Of course it is handy to know what the relation is between WMProfile and the Guid method, and it is handy to know whether MSDN is more correct or DirectShowLib. For now I would choose the easy way.

hi almere,
I have NOT tried the wma recording yet now ..becoz i dont know ... simply i am wondering that why even there is no Header information is present in that recorded .WAV file. Is it a Junk file ... Taking 400 MB per minute ... Even though i have set the sampling rate and etc .. what is the use of properties like ...
capture.AudioSamplingRate = 44100; capture.AudioSampleSize = 16; capture.AudioChannels = 2;

I set these values or not the output is a junk file ... If i can able to read the header part it will be useful to me.. Any help ..

hello

-- modified at 6:55 Wednesday 8th March, 2006

Well, I think you are saving an Avi file and you name it as a Wav file. Just rename your Wav into an Avi file and I think it will play. For Avi, 400MB per minute is quite normal.
What the best thing to is start reading the audio capture articles on MSDN http://msdn.microsoft.com/library/default.asp?url=/library/en-us/directshow/htm/creatinganaudiocapturegraph.asp[^].
Currently I am digging in the WMProfile stuff. Yesterday I did not know what to do with that, today, well it looks promishing. Just start digging, the answers and solutions will come.
Most important for Wav is that the renderstream for video is not included in the graph. In addition, it is not possible to use SetOutputFileName. That information is available on MSDN and in quite a lot coding examples (unfortunately hardly no C# ...).

Did you check if the captured was Avi and not Wav (by renaming)? THat would explain why the header is not a Wav header.

I just made my first WMA (Asf audio) file save. That was though, and the coding is not very user friendly yet. I also noticed that the Asf filter does not like to be added temporary (at least that is my impression). It causes 0x80004005, pretty severe. Happily the error can be catched smoothly.
Now, I know that it takes some more coding than I thought. So first I will try to get the Wav and Mp3 part covered. For good Asf processing some extra functionality is needed. Partly that functionality is in yeti.wmfsdk.dll and in WindowsMediaLib.dll (only one of the libraries is needed). The other part is smart thinking, just some checks if audio/video saving would be possible. I do not know how official the status of the libraries are. In fact only some data and interfaces are needed. Data could als be hard-coded (=not future proof). The advantage is that the subject will be WMA or Asf and not IWMProfile or the libraries.

I just made a quick (and no to dirty) solution for saving Wma files. It is 'untested', but I am quite sure that it does what it should do! Save a file in the current implementation. Without all kind of checks whether file save is really allowed. It means that there is a risk on some strange errors. This is not the problem caused by me! It is the way the DirectX.Capture example have been implemented. At least, that is my opinion. Thanks to DirectX.Capture this file save solution exist so there is nothing wrong with the idea behind DirectX.Capture, that is just great! I will see if I am able to submit it today or tomorrow. I want to add some advise (and warnings). I also do not know if I should write it in more general format, as a sort of article.

I made this solution for Wma because I noticed that SetFileOutputName can be used for Asf (windows media formats).
This means that it can be added with only little extra code. The Wav and Mp3 file save option is something more complicated.

Hi almere,
congrats ..Thats good to see ...... Please Post it for reference .. I think after your post Directx.capture will attain its fullfillment in Radio part .. So that everyone can record audio from FM in WMA format...
regards . ,

hello

The full article on Audio file saving for DirectX.Capture can be found here:
http://www.codeproject.com/cs/media/audiosav.asp[^]

I deleted the text in this message to the information at one place. Also the original information in this message is more or less out of date.
xplain first the current implementation that implements the audio/video capturing to file. This functionality can be found in the function renderGraph in Capture.cs.

In the code the mediaSubtype is set, than SetOutputFileName() is called to add the Avi multiplexor and the file writer. Furthermore the filename is stored. The next step is to initialize the video rendering. A possible compressor filter is taken into account. After this the audio rendering is initialized. Upon a call of mediaControl.Run() in the function StartPreviewIfNeeded(), the capture graph starts.

<br />
//Original code fragment renderGraph Capture.cs<br />
<br />
Guid mediaSubType = MediaSubType.Avi;<br />
hr = captureGraphBuilder.SetOutputFileName( ref mediaSubType, Filename, out <br />
<br />
muxFilter, out fileWriterFilter );<br />
if( hr < 0 ) Marshal.ThrowExceptionForHR( hr );<br />
<br />
// Render video (video -> mux)<br />
if ( VideoDevice != null )<br />
{<br />
	// Try interleaved first, because if the device supports it,<br />
	// it's the only way to get audio as well as video<br />
	cat = PinCategory.Capture;<br />
	med = MediaType.Interleaved;<br />
	hr = captureGraphBuilder.RenderStream( ref cat, ref med, videoDeviceFilter, videoCompressorFilter, muxFilter ); <br />
	if( hr < 0 ) <br />
	{<br />
		med = MediaType.Video;<br />
		hr = captureGraphBuilder.RenderStream( ref cat, ref med, videoDeviceFilter, videoCompressorFilter, muxFilter ); <br />
		if ( hr == -2147220969 ) throw new DeviceInUseException( "Video device", hr );<br />
		if( hr < 0 ) Marshal.ThrowExceptionForHR( hr );<br />
	}<br />
}<br />
<br />
// Render audio (audio -> mux)<br />
if ( AudioDevice != null )<br />
{<br />
	cat = PinCategory.Capture;<br />
	med = MediaType.Audio;<br />
	hr = captureGraphBuilder.RenderStream( ref cat, ref med, audioDeviceFilter, audioCompressorFilter, muxFilter );<br />
	if( hr < 0 ) Marshal.ThrowExceptionForHR( hr );<br />
}<br />
<br />
isCaptureRendered = true;<br />
didSomething = true;<br />

Well now the enhancements:
The enumeration RecFileModeType is declared which specifies the possible audio/video recording file choices. The choices are Avi, Wmv and Wma. The Wma choice is default because this example is about Audio file saving. The Avi choice was added, so the original functionality is still there and could be used if needed. The Wmv is not explained in this article. It is a good learning goal to figure out how to use that.
The variable recFileMode contains the audio/video recording file mode, so this variable gets value RecFileModeType.Wma. The variable recFileMode should be accessed via RecFileMode. There is a check added that prevents changing the file mode during file capturing. This to prevent strange side effects. It also shows that other functionality could executed upon changing the value of recFileMode. A nice feature would be the change of the filename extension. This code should be put in Capture.cs, preferable in the beginning because there you can find more declarations.

<br />
/// <summary><br />
/// Recording file mode type enumerations<br />
/// </summary><br />
public enum RecFileModeType<br />
{<br />
	/// <summary> Avi video (+ audio) </summary><br />
	Avi,<br />
	/// <summary> Wmv video (+ audio) </summary><br />
	Wmv,<br />
	/// <summary> Wma audio </summary><br />
	Wma,<br />
}<br />
<br />
private RecFileModeType recFileMode = RecFileModeType.wma;<br />
<br />
/// <summary><br />
/// Recording file modes<br />
/// </summary><br />
public RecFileModeType RecFileMode<br />
{<br />
	get { return(recFileMode); }<br />
	set<br />
	{<br />
		if(this.graphState == GraphState.Capturing)<br />
		{<br />
			// Value may not be changed now<br />
			return;<br />
		}<br />
		recFileMode = value;<br />
	}<br />
}<br />

The most interesting part is the modifications of the capture specific code to renderGraph(), mentioned earlier. The major difference is that the file recording mode is taken into account. Still this example is kept simple, so for saving a specific audio and/or video file settings might be important.

Keep in mind that saving of Wma file is needed:
- No audio compressor
- Filename with filename extension .wma (or .asf)
- RecFileMode = RecFileModeType.Wma

Keep in mind that saving of Wmv file is needed:
- No video compressor
- No audio compressor
- Filename with filename extension .wmv (or .asf)
- Some video formats do not have an audio stream, video capturing will fail
in the current implementation
- RecFileMode = RecFileModeType.Wmv

Keep in mind that saving of Avi file is needed:
- Video compressor, eg DV Avi
- Filename with filename extension .avi
- RecFileMode = RecFileModeType.Avi

The code explains itselfs (I hope). There are checks added so depending on the file format specific actions can be performed. The first action is the initialization of mediaSubtype. The next action is to configure the Asf file writer. The configuration is a one-liner. The alternative coding with IWMProfile is much more complex and is surely no one-liner. Interesting is the type casting of the file writer pointer. This solution is specific for .Net, it gives an easy solution for changing the prefered audio/video profile. There is one question left, I think,
what does WMProfile_V80_64StereoAudio means? WMProfile_V80_64StereoAudio is the audio recording format I choosed as default. THere are more choices possible. For a different choice, a different value must be used. Also, if you want to save video, just select a Windows media video format.
The audio and video rendering sections looks the same, with one major difference.
Upon entering the video rendering section there is a check on the file format, for audio capturing, no video must be rendered so that section must be ignored!

<br />
// Record captured audio/video in Avi, Wmv or Wma format<br />
<br />
Guid mediaSubType; // Media sub type<br />
<br />
// Set media sub type<br />
if(RecFileMode == RecFileModeType.Avi)<br />
{<br />
	mediaSubType = MediaSubType.Avi;<br />
}<br />
else<br />
{<br />
	mediaSubType = MediaSubType.Asf;<br />
}<br />
<br />
// Intialize the Avi or Asf file writer<br />
hr = captureGraphBuilder.SetOutputFileName( ref mediaSubType, Filename, out muxFilter, out fileWriterFilter );<br />
if( hr < 0 )<br />
{<br />
	Marshal.ThrowExceptionForHR( hr );<br />
}<br />
<br />
// For Wma (and Wmv) a suitable profile must be selected. This can be done<br />
// via a property window, however the muxFilter is just created. if needed, the<br />
// property windows should show up right now!<br />
// Another solution is to configure the Asf file writer, however DShowNet does not<br />
// have the interface that is needed. Please ensure it is added. <br />
if(RecFileMode == RecFileModeType.Wma)<br />
{<br />
	IConfigAsfWriter lConfig = asfMuxFilter as IConfigAsfWriter;<br />
<br />
	// Obsolete interface?<br />
	// According to MSDN no, according to DirectShowLib yes.<br />
	// For simplicity, it will be used ...<br />
	hr = lConfig.ConfigureFilterUsingProfileGuid(WMProfile_V80_64StereoAudio);<br />
	if(hr < 0)<br />
	{<br />
		// Problems with selecting video write format<br />
		// Release resources ... (not done yet)<br />
		Marshal.ThrowExceptionForHR( hr );<br />
	}<br />
}<br />
<br />
// Render video (video -> mux) if needed or possible<br />
if((VideoDevice != null)&&(RecFileMode != RecFileModeType.Wma))<br />
{<br />
	// Try interleaved first, because if the device supports it,<br />
	// it's the only way to get audio as well as video<br />
	cat = PinCategory.Capture;<br />
	med = MediaType.Interleaved;<br />
	hr = captureGraphBuilder.RenderStream( ref cat, ref med, videoDeviceFilter, videoCompressorFilter, muxFilter ); <br />
	if( hr < 0 ) <br />
	{<br />
		med = MediaType.Video;<br />
		hr = captureGraphBuilder.RenderStream( ref cat, ref med, videoDeviceFilter, videoCompressorFilter, muxFilter ); <br />
		if ( hr == -2147220969 )<br />
		{<br />
			throw new DeviceInUseException( "Video device", hr );<br />
		}<br />
		if( hr < 0 )<br />
		{<br />
			Marshal.ThrowExceptionForHR( hr );<br />
		}<br />
	}<br />
}<br />
<br />
// Render audio (audio -> mux) if possible<br />
if ( AudioDevice != null )<br />
{<br />
	// Keep in mind that for certain Wmw formats do not have an audio stream,<br />
	// so when using this code, please ensure you use a format which supports<br />
	// audio!<br />
	cat = PinCategory.Capture;<br />
	med = MediaType.Audio;<br />
	hr = captureGraphBuilder.RenderStream( ref cat, ref med, audioDeviceFilter, audioCompressorFilter, muxFilter );<br />
	if( hr < 0 )<br />
	{<br />
		 Marshal.ThrowExceptionForHR( hr );<br />
	}<br />
}<br />
<br />
isCaptureRendered = true;<br />
didSomething = true;<br />

The function ConfigureFilterUsingProfileGuid() needs to be called for setting the proper audio format. Which formats exists? In this example there are 7 specific Windows media audio formats provided (hard coded) by means of a Guid. Each Guid stands for a specic format and profile. There are more Windows Media formats, however, those formats supports also video and there are also formats which do not support audio. The best way to get these formats is to use IWMProfile
functionality. Than you will be sure that you get formats that really exists. The formats mentioned next, should exist, but there is no real garantuee they exist really. In a future code sample, the IWMProfile method can be shown. For now, this will be though enough. Thanks to the IWMProfile interface I was able to retrieve all names that belong to a specific file format and profile. I could have typed it over. Besides of the work, the property window does not show the full line ...
The following code should be put somewhere in Capture.cs.

<br />
// Windows Media Audio 8 for Dial-up Modem (Mono, 28.8 Kbps)<br />
private static readonly Guid WMProfile_V80_288MonoAudio = new Guid("7EA3126D-E1BA-4716-89AF-F65CEE0C0C67");<br />
<br />
// Windows Media Audio 8 for Dial-up Modem (FM Radio Stereo, 28.8 Kbps)<br />
private static readonly Guid WMProfile_V80_288StereoAudio = new Guid("7E4CAB5C-35DC-45bb-A7C0-19B28070D0CC");<br />
<br />
// Windows Media Audio 8 for Dial-up Modem (32 Kbps)<br />
private static readonly Guid WMProfile_V80_32StereoAudio = new Guid("60907F9F-B352-47e5-B210-0EF1F47E9F9D");<br />
<br />
// Windows Media Audio 8 for Dial-up Modem (Near CD quality, 48 Kbps)<br />
private static readonly Guid WMProfile_V80_48StereoAudio = new Guid("5EE06BE5-492B-480a-8A8F-12F373ECF9D4");<br />
<br />
// Windows Media Audio 8 for Dial-up Modem (CD quality, 64 Kbps)<br />
private static readonly Guid WMProfile_V80_64StereoAudio = new Guid("09BB5BC4-3176-457f-8DD6-3CD919123E2D");<br />
<br />
// Windows Media Audio 8 for ISDN (Better than CD quality, 96 Kbps)<br />
private static readonly Guid WMProfile_V80_96StereoAudio = new Guid("1FC81930-61F2-436f-9D33-349F2A1C0F10");<br />
<br />
// Windows Media Audio 8 for ISDN (Better than CD quality, 128 Kbps)<br />
private static readonly Guid WMProfile_V80_128StereoAudio = new Guid("407B9450-8BDC-4ee5-88B8-6F527BD941F2");<br />

To get the code working still one interface needs to be addded because DShowNET does not support the interface of IConfigAsfWriter. DirectShowLib supports this interface, os if you use that library than no extra work is needed. There are more libaries which provides this interface, so if I forgot one, please forgive me. This interface can be added to Capture.cs or another suitable place. Keep in mind to change the naming accordingly.

<br />
[Guid("45086030-F7E4-486a-B504-826BB5792A3B"),<br />
InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]<br />
public interface IConfigAsfWriter<br />
{<br />
        /// Obsolete?<br />
        [PreserveSig]<br />
        int ConfigureFilterUsingProfileId([In] int dwProfileId);<br />
<br />
        /// Obsolete?<br />
        [PreserveSig] <br />
        int GetCurrentProfileId([Out] out int pdwProfileId);<br />
<br />
        /// Obsolete?<br />
        [PreserveSig]<br />
        int ConfigureFilterUsingProfileGuid([In, MarshalAs(UnmanagedType.LPStruct)]<br />
Guid guidProfile);<br />
<br />
        [PreserveSig]<br />
        int GetCurrentProfileGuid([Out] out Guid pProfileGuid);<br />
<br />
        /// Obsolete?<br />
        [PreserveSig]<br />
        int ConfigureFilterUsingProfile([In] IntPtr pProfile);<br />
<br />
        /// Obsolete?<br />
        [PreserveSig]<br />
        int GetCurrentProfile([Out] out IntPtr ppProfile);<br />
<br />
        [PreserveSig]<br />
        int SetIndexMode([In, MarshalAs(UnmanagedType.Bool)] bool bIndexFile);<br />
<br />
        [PreserveSig]<br />
        int GetIndexMode([Out, MarshalAs(UnmanagedType.Bool)] out bool pbIndexFile);<br />
}<br />

I hope this code helps you in understanding the structure of DirectX.Capture, and I hope this I provided you an enhancement that might be useful to you. Feel free to post comments and questions.
Hans Vosman

Dear Hans,
where can I download these changes/enhancements?
Thx
Clemens

I am preparing on "official" article. I found that it is not that easy as I thought. And I have many ideas for some follow ups. My trial program is an FMRadio program that come quite close to this DirectX.Capture class example. But still there are a number of modifications (specific related to audio capturing via PCI bus and the FMRadio itself, and special additions as MCE remote control) that are not related to the file save topic.
Everything put together is just to much and most of it is also not that interesting I think. I have to re-install the original DirectX.Capture example so I can modify/prepare the original Capture.cs file. What I can do next is putting the Capture.cs file on my website.

I wrote an article and I prepared a file having the included code changes. I also tested the code changes. There are some minor changes. I submitted the article, maye be it will be publiced.

Hi Hans,
What the name you have given for the article so that i can search in the codeproject...

hello

'Audio file saving for the DirectX.Capture class library'. But I do not think it is released yet. When I have some spare time I will put the information also on my homepage.

hi hans,
Thanks and congrats for your posting . Please do the posting in your home page B coz i need that concept urgently . I need to study and want to do recording on it.. Waiting for your posting ...
Regards

hello

The article can be found here: Recording FM radio/TV sound in Wma format using the DirectX.Capture class library[^].
I rephrased the title and added some background information to the article because people who find my website (via Google or other search machine) probably do not know the DirectX Capture class library. Funny, today I used style sheets first time, and I it is also great to use (at least for me).

Article has been released and can be found here: http://www.codeproject.com/cs/media/audiosav.asp[^].

Is able to save to .avi from direct3D scene with timer??

How to convert to DsDevice from Direct3D.device??

really complex...i can not understand Direct...ㅜㅜ

I want to how to do...please.

Thank you very much!!

Ellow guys

Nice article here, the only thing I'd like to see added is an example of
how to control your digital camera when capturing from firewire.
I know it can be done by using MCI but how excactly.

Anyone got ideas???
Thanks a lot

Did you do already some investigation and looked here: http://msdn.microsoft.com/library/default.asp?url=/library/en-us/directshow/htm/msdvdriver.asp
I do not know a good example yet, a number of interfaces are involved so you have to dig in DirectShowLib (or DShowNet).

Yello fellas!

First of all, love the library and lsg's modification to it. 2 irritating problems here though..

1 being that i would like to set the Color Space / Compression of the Video Preview & Video Capture Pin programatically (through code) - is there an easy way to do this? Want it to be the second element listed in each of the drop down boxes.

Also for some reason, i just can't get sound either recorded or through the preview? Tried every combination of Crossbar / Audio Capture Device and it just won't do it. I hear a blocky noise like thumping beats repeatedly.

Actually.. i've just realised that my Audio Crossbar section resets itself even with changes made. The Audio Crossbar defaults to Input: "Video Tuner In" and Output: "Video Tuner Out" and even if i change that to Input: "Audio Tuner In" and Output: "Audio Tuner Out", it resets itself when i go back in.

Even viewing the FilterGraph in Graph Edit is just confusing! Confused | :confused:

Any help would be much appreciated as i'm literally pulling my hair out here!

Regards,

basquille

Sure, it is a nice piece of work! Looking to your wishes I was wondering how much time you spend on this code? I did look at it for some months now and rewrote a big part of the code and added some new functionality such as real tv/fm radio fine tuning, broadcast station selection on broadcast name, MPEG2 and ASF file saving. I stumbled across a lot of caveats such as no sound or getting double sound ... (echo, even that is possible), program crashes ...

My conclusion is that you use DirectShowLib and Lsg's version, I think that is a good start. You started to use graph edit, also very good. Now try to go on! You have to start somewhere and finally you will find all answers. But not in one day ... I think.

Important to know is which hardware you are using. maybe than I can get a clue what is causing you giving no sound.

What do you want to achieve with the special option for the video preview and video capture pin? Or do you want to changes some compression settings? That are two totally different things. So, in fact I do not understand that question.
What I did was using the capture pin for preview, upon capturing to file I changed that into preview pin for preview and use the capture pin for capture. I also removed the cued, I have mixed feeling on that functionality. For the compressor I added a property view in a different way.

I've spend the best part of a couple of weeks on it but i'm not too up on DirectX Library in terms of . I'm actually extending the OpenHTPC PVR (www.openhtpc.org). Have a TV Guide built but am now working on live TV.

Am trying to built it around my own settings for now. The TV Card i'm using has a built in Audio Renderer, according to the graph (in graphedit) anyways. Sound device is "SoundMAX Digital Audio". I can make an image of my graph in GraphEdit and upload it somewhere if it makes it easier for you to comprehend.

Both the preview and capture look too choppy using the default capture pin so want to change it to use the field DX50 in the Color Space section of both the preview and capture pins, that make more sense?

Have mixed opinion on the cue also.

Thanks for that!

Regards,

Brian

The OpenHTPC project looks promishing. I will look into it to get an idea what it is all about. Interesting is that it also written in C#. SoundMax Digital Audio seems to be a soundcard on a TV-card? It might be possible. Please send me a graph but do it in XML format. There is at least one graph edit program that is able to do that. The normal .grf format I can not use because I do not have the hardware and the software you are using. In others words: with a normal graph I can do nothing (due to fatal error) or very little (no pin and property information).
The Color space section is part of the capture filter, or it is an extra filter? Such as compressor filter or a de-interlace filter? The field DX50 is a special pin or option of a filter? Many questions, sorry, I am not familiar with Color Space. With choppy you mean blocked and/or slow? The capture pin on my TV-card (Hauppauge PVR150-MCE) gives a pretty good picture. The video lines are visible so a de-interlacer is needed to improve the picture quality.

Currently I am testing the software on several systems. I noticed that every computer behaves a little bit different.

Thanks for the quick follow up, almere!

SoundMax Digital Audio is a standard sound-card alright but the TV card (i think) has a built-in Audio Renderer (according to the graph) so if i could use this, it'd be ideal!

The older version of GraphEdit can export to XML but i can't find a copy of that anywhere. Here's the JPEG image of the basic graph i'm getting if that helps you in any way: Graph Capture

And as for the sound, he's a WAV file taken from my sound card of the noise when i start to record something: Sound Capture Any changes i make to the options of the Audio Crossbar seem to reset back to default (of Video In / Video Decoder Out) as i mentioned in my first post.

Any advice would be much appreciated!

Regards,

basquille

Yes the picture of the graph is clear. ANd indeed you can use the audio capture pin on the capture device. That means that you have also a wired connection? Because of the wired connection you do not need the audio renderer. I would also expect an echo during listening to the audio.
Using the audio capture pin would be comparable with my implementation for the Hauppauge TV card. You have to check whether you have a separate audio capture filter for the TV-card exists or not (the older driver of the Hauppauge card has, the newer driver has not). The current DirectX.Capture code supports TV-cards that have an audio capture driver. SO if there is not a separate driver, you have to check the videodevice filter for it and make some additional code changes when rendering. Than you have to check whether the crossbar switches through the related pins properly and of cource DirectX.Capture does a great job in loosing the audio connection, so be careful with a (de)render graph.

The sound is probably caused by a loop. I got it also with an old PCTV card I have. Today I made a fix for that: no audio rendering. The point was that the audio device is still needed for capturing audio, so some coding was needed to get that done properly. Now I have to add an option that switches through the audio to the sound card so there is audible sound while watching TV. That functionality I did not write yet, but I know how to do that. Such functionality is in WIndows so there is no real need to put it in the program unless the program should be user-friendly. In your case you might need two audio devices to control. But of course the capture device for file writing will be more important than for audio rendering.

I noticed that the htpc project uses DShowNet. I did not check if it is exactly the same as the one that was used in this project. I am using DirectShowLib instead. Recently however, I made some changes to the DshowNet version so it handles audio better.

DirectX.Capture Class Library

Introduction

Using the Code

A Second Example

Behind the Scenes

The Least Work Possible

Performance Tips

Credits

Troubleshooting

User Enhancements

DirectX.Capture Wiki

License

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