Additionally to this, they decided to provide garbage in AM_MEDIA_TYPE::formattype field of IAMStreamConfig::SetFormat. They perhaps learned that standard Audio Capture Filter will ignore it anyway, so why bother then?

Having fixed that, Tone Source Filter based virtual audio device is now compatible with Adobe Flash Media Live Encoder 3.1 and it is possible to send audio to remote Flash Media Server, e.g. such as Ustream.tv service (over RTMP protocol, as implemented by FMLE).

The filters behind that empower the sample are described in another post.

RenderHttpMjpegVideoIntoFiles01 sample takes an URL on the input to generate image/jpeg JPEG or multipart/x-mixed-replace M-JPEG stream. For example, it might be http://demo1.stardotcams.com/nph-mjpeg.cgi feed from a demo StarDot Technologies IP camera.

The application will create a new directory to write files into, and will save each new video frame received into new JPEG file.

Z:\MediaTools\Samples\RenderHttpMjpegVideoIntoFiles01\Release>RenderHttpMjpegVideoIntoFiles01.exe http://demo1.stardotcams.com/nph-mjpeg.cgi
URL: http://demo1.stardotcams.com/nph-mjpeg.cgi
Writing to directory: Z:\MediaTools\Samples\RenderHttpMjpegVideoIntoFiles01\Release\2010-05-12 22-07-37
Event: nCode EC_CLOCK_CHANGED 0xD, nParameter1 0x00000000, nParameter2 0x00000000
Event: nCode EC_PAUSED 0xE, nResult 0x00000000, nParameter2 0x00000000
[...]
^C

The application will generate the files and convert media sample time stamps into file time.

The DirectShow graph that implements the operation is the following:

The other sample RenderJpegFiles01 takes a directory path to look for JPEG files, e.g. generated by previous sample, and pushes them into DirectShow graph as a video feed. File times will be converted [back] to media sample times.

Z:\MediaTools\Samples\RenderJpegFiles01\Release>RenderJpegFiles01 "Z:\MediaTools\Samples\RenderHttpMjpegVideoIntoFiles01\Release\2010-05-12 22-07-37"
Directory: Z:\MediaTools\Samples\RenderHttpMjpegVideoIntoFiles01\Release\2010-05-12 22-07-37
Event: nCode EC_CLOCK_CHANGED 0xD, nParameter1 0x00000000, nParameter2 0x00000000
Event: nCode EC_PAUSED 0xE, nResult 0x00000000, nParameter2 0x00000000
Event: nCode EC_VMR_RECONNECTION_FAILED 0x55, nResult 0x80004005, nParameter2 0x00000000
Event: nCode EC_VMR_RENDERDEVICE_SET 0x53, RendererDeviceType 0x2, nParameter2 0x00000000
Event: nCode EC_VIDEO_SIZE_CHANGED 0xA, Extent 384x240, nParameter2 0x00000000
Event: nCode EC_COMPLETE 0x1, nResult 0x00000000, nParameter2 0x00000000
Event: nCode EC_ERRORABORT 0x3, nResult 0x80004005, nParameter2 0x00000000
Detected resolution change, new resolution is 1024x768, recreating filter graph...
Event: nCode EC_VMR_RECONNECTION_FAILED 0x55, nResult 0x80004005, nParameter2 0x00000000
Event: nCode EC_VMR_RENDERDEVICE_SET 0x53, RendererDeviceType 0x2, nParameter2 0x00000000
Event: nCode EC_VIDEO_SIZE_CHANGED 0xA, Extent 384x240, nParameter2 0x00000000
Event: nCode EC_CLOCK_CHANGED 0xD, nParameter1 0x00000000, nParameter2 0x00000000
Event: nCode EC_PAUSED 0xE, nResult 0x00000000, nParameter2 0x00000000

Download links:

• RenderHttpMjpegVideoIntoFiles01: source code, binary
• RenderJpegFiles01: source code, binary

Partial Visual C++ .NET 2008 source code is available from SVN, release binary included (Win32, x64); installation instructions are in another post.

FilterMapperSpy.h(186): CFilterMapperSpy::EnumMatchingFilters: nFlags 0x0, bExactMatch 0, nMinimalMerit 0x00200001, bInputNeeded 1, nInputTypeCount 1, pInputPinCategory NULL, bRender 1, bOutputNeeded 0, nOutputTypeCount 0, pOutputPinCategory NULL
FilterMapperSpy.h(191): CFilterMapperSpy::EnumMatchingFilters: nInputTypeIndex 0, MajorType {73647561-0000-0010-8000-00AA00389B71}, Subtype {00000000-0000-0000-0000-000000000000}
FilterMapperSpy.h(212): CFilterMapperSpy::EnumMatchingFilters: pMoniker @device:sw:{083863F1-70DE-11D0-BD40-00A0C911CE86}\{AB9D6472-752F-43F6-B29E-61207BDA8E06}
FilterMapperSpy.h(220): CFilterMapperSpy::EnumMatchingFilters: sFriendlyName "RDP DShow Redirection Filter", sDescription "", sDevicePath ""
FilterMapperSpy.h(212): CFilterMapperSpy::EnumMatchingFilters: pMoniker @device:cm:{E0F158E1-CB04-11D0-BD4E-00A0C911CE86}\Default DirectSound Device
FilterMapperSpy.h(220): CFilterMapperSpy::EnumMatchingFilters: sFriendlyName "Default DirectSound Device", sDescription "", sDevicePath ""

Important is that DirectShow’s internals are using the mapper through COM instantiation and this provides a safe method to override default behavior process wide in order to, for example, extend Intelligent Connect functionality onto custom, unregistered globally, private filters.

Also, the binary is renamed from FilterGraphSpy.dll to DirectShowSpy.dll.

Partial Visual C++ .NET 2008 source code is available from SVN, release binary included (Win32, x64); installation instructions are in another post.

Filter Graph Spy is offering three new interfaces that provide extensibility of the spy:

• IFilterGraphAddRemoveHook
• IFilterGraphConnectHook
• IFilterGraphStateControlHook

The interfaces are contained in the type library and can be imported using #import directive. An implementation of one or more of these interfaces will receive hook style calls corresponding to respective Filter Graph Manager calls, system wide including in context of other applications.

A COM object may be registered as a hook object with Spy and NoThreadSpy COM classes under predefined registry keys:

Spy will instantiate the registered hook objects and forward them the calls it receive, before passing them to system Filter Graph Manager object. A hook object has an option to override default processing, including, for example, inserting its own filter in between. For example, IFilterGraph::Reconnect call is implemented the following way:

STDMETHOD(Reconnect)(IPin* pPin) throw()
{
    _Z4(atlTraceCOM, 4, _T("...\n"));
    HOOK_PROLOG(CFilterGraphConnectHookHost)
        OnReconnect(pT, pPin, &bDefault);
    HOOK_EPILOG()
    return m_pInnerFilterGraph2->Reconnect(pPin);
}

Before passing the call to original Reconnect method, spy is iterating through associated hooks, passing them IFilterGraphConnectHook::OnReconnect call. Setting bDefault parameter to FALSE will prevent spy from passing the call to original method.

Included BdaHooks project shows a sample implementation of the hooking COM classes (note .rgs registration).

Filter Graph Spy is compatible with all current Windows operating systems, 32-bit and 64-bit (x64), in particular including:

• Windows 7
• Windows Server 2008
• Windows Vista
• Windows Server 2003
• Windows XP
• Windows 2000

NOTE: DirectShow Filter Graph Spy is NOT suitable for production environment, it is NOT licensed to be redistributed to be a part of production state software item.

Partial Visual C++ .NET 2008 source code is available from SVN, release binary included (Win32, x64); installation instructions are in another post.

However, for Video Mixing Renderers, version 7 and 9, the preferred and recommended mode is windowless, where no IVideoWindow interface is available.

Note The IVMRWindowlessControl or IVMRWindowlessControl9 interface is now preferred over IVideoWindow. For more information, see Using Windowless Mode.

So in order to implement full screen mode it takes the application to attach Video Mixing Renderer filter to a private frameless window, to its entire client area and expand the window to entire monitor area.

The sample project FullScreenWindowlessVmrSample01 is illustrating this technique.

Main application dialog owns a special window to host renderer, implemented by CRendererDialog class.

class CRendererDialog :
    public CDialogImpl<CRendererDialog>
{
public:

    enum { IDD = IDD_RENDERER };

BEGIN_MSG_MAP_EX(CRendererDialog)
    MSG_WM_INITDIALOG(OnInitDialog)
    MSG_WM_DESTROY(OnDestroy)
    MSG_WM_ERASEBKGND(OnEraseBkgnd)
    MSG_WM_PAINT(OnPaint)
    MSG_WM_DISPLAYCHANGE(OnDisplayChange)
    MSG_WM_KEYDOWN(OnKeyDown)
    COMMAND_ID_HANDLER_EX(IDCANCEL, OnCancel)
END_MSG_MAP()

private:
    CMainDialog& m_Owner;
//...

The dialog template does not have a caption, it has no frame and has its window rectangle equal to client area. As a result, spanning the Video Mixing Renderer to the entire client area and proper positioning of the dialog window is showing video on the entire monitor.

ATLVERIFY(m_RendererDialog.Create(m_hWnd));
ATLVERIFY(m_RendererDialog.MoveWindow(MonitorData.m_Position));
m_RendererDialog.ShowWindow(SW_SHOWNORMAL);
// ...
ATLENSURE_SUCCEEDED(pVmrWindowlessControl->SetVideoClippingWindow(m_RendererDialog));
ATLENSURE_SUCCEEDED(pVmrWindowlessControl->SetVideoPosition(NULL, m_RendererDialog.GetVideoPosition()));

Visual C++ .NET 2008 source code is available from SVN, release binary included. The project is using ATL and WTL libraries.

I have a video stream with variable frame rate, I want to make this in to a constant  frame rate. Do you know of any filters that could help me with this?

Such filter is actually quite easy. You only need to update time stamps of the media samples that are going through. I am not aware of  an “out of the box” ready filter, but you can even do it without special filter: if you build your graph with Sample Grabber Filter in it in  the place of interest, and initialize it to have a callback for each sample, then in SampleCB method you will be able to update time stamps using methods of IMediaSample interface. This is sufficient to redistribute the frames on the timeline, so that they go at constant frame rate.

In your opinion what is the best way to scale the video?

The best depends on what is the criteria (speed, quality etc). The simplest for me while very efficient – and I did this a number of times – is to use a custom filter which inside it uses StretchBlt function on a per frame basis to scale input RGB video into output RGB video of a different resolution.

As the goal was to find out details about connection media types between the filters being spied over, the spy received a new feature of logging graph details each time the graph is going to running state:

Filter 7: Name "[1BDADev]", Class {17CCA71B-ECD7-11D0-B908-00A0C9223196}, State 2
 Pin 1: Name "MPEG2 Transport", Direction "Input", Peer "[0BDATnr].MPEG2 Transport"
 Connection media type:
 majortype {E436EB83-524F-11CE-9F53-0020AF0BA770}, subtype {E06D8023-DB46-11CF-B4D1-00805F6CBBEA}, pUnk 0x00000000
 bFixedSizeSamples 0, bTemporalCompression 0, lSampleSize 1
 formattype {8DEDA6FD-AC5F-4334-8ECF-A4BA8FA7D0F0}, cbFormat 24, pbFormat 0x00350868
 [0x0000] BC 00 00 00 38 9A 00 00 00 00 00 00 00 00 00 00
 [0x0010] 00 00 00 00 00 00 00 00
 Pin 2: Name "MPEG2 Transport", Direction "Output", Peer "Infinite Pin Tee Filter[BDATsIft].Input"
 Connection media type:
 majortype {E436EB83-524F-11CE-9F53-0020AF0BA770}, subtype {F4AEB342-0329-4FDD-A8FD-4AFF4926C978}, pUnk 0x00000000
 bFixedSizeSamples 1, bTemporalCompression 0, lSampleSize 39480
 formattype {0F6417D6-C318-11D0-A43F-00A0C9223196}, cbFormat 0, pbFormat 0x00000000
Filter 8: Name "[0BDATnr]", Class {17CCA71B-ECD7-11D0-B908-00A0C9223196}, State 2
 Pin 1: Name "Input0", Direction "Input", Peer "Microsoft Network Provider[NwPvd].Antenna Out"
 Connection media type:
 majortype {71985F41-1CA1-11D3-9CC8-00C04F7971E0}, subtype {E436EB8E-524F-11CE-9F53-0020AF0BA770}, pUnk 0x00000000
 bFixedSizeSamples 0, bTemporalCompression 0, lSampleSize 1
 formattype {0F6417D6-C318-11D0-A43F-00A0C9223196}, cbFormat 0, pbFormat 0x00000000
 Pin 2: Name "MPEG2 Transport", Direction "Output", Peer "[1BDADev].MPEG2 Transport"
 Connection media type:
 majortype {E436EB83-524F-11CE-9F53-0020AF0BA770}, subtype {E06D8023-DB46-11CF-B4D1-00805F6CBBEA}, pUnk 0x00000000
 bFixedSizeSamples 0, bTemporalCompression 0, lSampleSize 1
 formattype {8DEDA6FD-AC5F-4334-8ECF-A4BA8FA7D0F0}, cbFormat 24, pbFormat 0x00350868
 [0x0000] BC 00 00 00 38 9A 00 00 00 00 00 00 00 00 00 00
 [0x0010] 00 00 00 00 00 00 00 00

Partial Visual C++ .NET 2008 source code is available from SVN, release binary included; installation instructions are in another post.

Protection
A monitor program has been foun drunning in your system. Please unload it from memory and restart your program.

The module which popped up the message chose to not identify itself in a friendly manner, however as nothing goes untraceable it appeared to be MediaLooks MPEG-2 Video Decoder file, Mpeg2DecoderL.dll (version 1.0.3.9). As the message was popped up from a non-GUI thread, there was no way to close the box – the entire application froze…

The problem does not happen in GraphEdit, as the decoder is probably handling this case specifically.

The decoder has an deinstallation batch file located in application directory: C:\Program Files\MediaLooks\Mpeg2Decoder\Uninstall.bat. A curious thing, however, is that running this file in attempt to uninstall the decoder shows the same problem: the decoder refuses to be uninstalled due to mystic “monitor program” running in the system:

After closing the message box the application still continues deinstallation script and removes the decoder from system.

Another issue for this file (and hopefully for today) is that another filter Haali Media Splitter (AR) (splitter.ax, version 1.9.42.1) is crashing the hosting process on being removed from the graph.

Q: I am using Web camera with DirectShow. Camera has only capture pin, so I am looking for the best way to switch resolution on the pin while graph is running. I would like to keep preview with smaller image size and when i would like to capture an image i would like to switch to full resolution. I have to use sample grabber callback since i need access to single image to process them. Is there a way to do that without stopping and starting a graph? This works but very slow between captures.

Is it possible to just reconnect the sample grabber only with new media changes and then resume the graph? Currently i just kill the graph and start it again, but it takes few seconds to do so, so I am looking the way to reduce that time.

There is no way to switch resolution on the running graph. There is a technique to dynamically start/stop individual filters and re-negotiate resolutions (media types), but it does not work for the majority of filters. Additionally to that Sample Grabber Filter cannot change resolution too, as it passes data through.

If you only have to use switched resolution for preview, you can use Geraint’s GMFBridge Toolkit to join two graphs, and a filter that changes resolution. Combining all that you will have a running capture graph that [also] renders video to a bridge sink. In the other graph you have another bridge sink that receives video from first graph and then you resize video to the resolution of interest already in the second graph. You can stop and reconfigure only second graph to update resolution and have first graph running and capturing. This is the best you can do, or just stop your single graph and change resolution this simple way.

So a solution, which is used by many, and I can recommend it too, is to use GMFBridge bridging. Additionally, you can find questions and answers on it on MSDN DirectShow Development Forum (search for “bridge” there). With a certain effort you can duplicate this with your own code but this is more or less ready to use solution and, again, the key advantage you have that you have two graphs which you can top independently.

Would it be possible to use smart tee as a splitter on the capture pin, and then use two sample grabbers on capture and preview, one with smaller resolution and the other one with higher one?

With a Smart Tee Filter you will still have 1 graph, so no individual resolution changes without stopping the graph. Additionally to that, Smart Tee Filter will deliver same frame on its output pins, so they will have to have one resolution and no resizing takes place inside.

Also, is it possible to run 2 graphs in the same time? Same device, 2 graphs, 2 sample grabbers.

Most likely no, for only one reason: you won’t be able to have two running filters for the same device, as source filter will exclusively lock the device. So capture filter will be a single filter. You can use Infinite Tee Pin Filter to split stream between 2+ processing lines. And you can use the same bridge to pass data into another graph for further processing.