Taking still shots while recording video

[mephistodan]

I hope someone can help me with this, is there an example where I can record
video and at the same time take snapshots from the camera?
I have tried to combine elements from two examples (one for video and one for
still shots) but i failed, I'm not really good with direct show so if there's
an exisint sample someone is aware of I'll greatly appreciate.
If not, could someone describe the basic steps I need to do to achieve this?

Many thanks

[mephistodan]

Here's the code where the graphs are created copied from different samples
this is working fine for recording video but how can I add a still capture?

> Blockquote
>

Guid cat;
Guid med;
int hr;

if (theDevice == null)
return;

// Make a new filter graph
graphBuilder = (IGraphBuilder)new FilterGraph();

//Create the Capture Graph Builder
ICaptureGraphBuilder2 captureGraphBuilder = null;
captureGraphBuilder = (ICaptureGraphBuilder2)new CaptureGraphBuilder2();

// Link the CaptureGraphBuilder to the filter graph
hr = captureGraphBuilder.SetFiltergraph(graphBuilder);
if (hr < 0) Marshal.ThrowExceptionForHR(hr);

//Add the Video input device to the graph
hr = graphBuilder.AddFilter(theDevice, "source filter");
DsError.ThrowExceptionForHR(hr);

if (theAudioDevice != null)
{
////Add the audio device filter to the graph
hr = graphBuilder.AddFilter(theAudioDevice, "audio source filter");
DsError.ThrowExceptionForHR(hr);
}

if (theCompressor != null)
{
////Add the Video compressor filter to the graph
hr = graphBuilder.AddFilter(theCompressor, "compressor filter");
DsError.ThrowExceptionForHR(hr);
}

if (theAudioCompressor != null)
{
////Add the audio device filter to the graph
hr = graphBuilder.AddFilter(theAudioCompressor, "audio source
compressor");
DsError.ThrowExceptionForHR(hr);
}

// Try looking for an interleaved media type
object o;
cat = PinCategory.Capture;
med = MediaType.Interleaved;
Guid iid = typeof(IAMStreamConfig).GUID;
hr = captureGraphBuilder.FindInterface(
cat, med, theDevice, iid, out o);

if (hr != 0)
{
// If not found, try looking for a video media type
med = MediaType.Video;
hr = captureGraphBuilder.FindInterface(
cat, med, theDevice, iid, out o);

if (hr != 0)
o = null;
}
//videoStreamConfig = o as IAMStreamConfig;

// Retrieve the stream control interface for the audio device
o = null;
cat = PinCategory.Capture;
med = MediaType.Audio;
iid = typeof(IAMStreamConfig).GUID;
hr = captureGraphBuilder.FindInterface(
cat, med, theAudioDevice, iid, out o);
if (hr != 0)
o = null;
//audioStreamConfig = o as IAMStreamConfig;

// Retreive the media control interface (for starting/stopping graph)
mediaControl = (IMediaControl)graphBuilder;

Guid mediaSubType = MediaSubType.Avi;
if (isRecordingToFile)
{
// Render the file writer portion of graph (mux -> file)
hr = captureGraphBuilder.SetOutputFileName(mediaSubType, FileName, out
muxFilter, out fileWriterFilter);
if (hr < 0) Marshal.ThrowExceptionForHR(hr);
}
// Render video (video -> mux)
if (theDevice != null)
{
// Try interleaved first, because if the device supports it,
// it's the only way to get audio as well as video
cat = PinCategory.Capture;
med = MediaType.Interleaved;
hr = captureGraphBuilder.RenderStream(cat, med, theDevice, theCompressor,
muxFilter);
if (hr < 0)
{
med = MediaType.Video;
hr = captureGraphBuilder.RenderStream(cat, med, theDevice, theCompressor,
muxFilter);
if (hr == -2147220969) throw new Exception("Video device");
if (hr < 0) Marshal.ThrowExceptionForHR(hr);
}
}

// Render audio (audio -> mux)
if (theAudioDevice != null)
{
cat = PinCategory.Capture;
med = MediaType.Audio;
hr = captureGraphBuilder.RenderStream(cat, med, theAudioDevice,
theAudioCompressor, muxFilter);
if (hr < 0) Marshal.ThrowExceptionForHR(hr);
}

// Render preview (video -> renderer)
cat = PinCategory.Preview;
med = MediaType.Video;
hr = captureGraphBuilder.RenderStream( cat, med, theDevice, null, null);
if (hr < 0) Marshal.ThrowExceptionForHR(hr);

IVideoWindow videoWindow = null;

// Get the IVideoWindow interface
videoWindow = (IVideoWindow)graphBuilder;

// Set the video window to be a child of the main window
hr = videoWindow.put_Owner(this.Handle);
if (hr < 0) Marshal.ThrowExceptionForHR(hr);

// Set video window style
hr = videoWindow.put_WindowStyle(WindowStyle.Child |
WindowStyle.ClipChildren);
if (hr < 0) Marshal.ThrowExceptionForHR(hr);

// Position video window in client rect of main application window
hr = videoWindow.SetWindowPosition(0, 0, this.Width, this.Height);
DsError.ThrowExceptionForHR(hr);

// Make the video window visible
hr = videoWindow.put_Visible(OABool.True);
DsError.ThrowExceptionForHR(hr);

hr = videoWindow.put_MessageDrain(this.Handle);
DsError.ThrowExceptionForHR(hr);

if (muxFilter != null)
Marshal.ReleaseComObject(muxFilter);

//if (sink != null)
// Marshal.ReleaseComObject(sink);

Marshal.ReleaseComObject(captureGraphBuilder);

}

protected override void WndProc(ref Message m)
{
switch (m.Msg)
{
case 0x0201:
OnClick(EventArgs.Empty);
break;
}
base.WndProc(ref m);

> Blockquote

[snarfle]

Have you taken a look at any of the samples that use the SampleGrabber filter?

[mephistodan]

Yes I have looked but the way the capturer is defined and filters created is
different in these examples than the video example, I have tried to combine
them but keep gettting exceptions, I thought it's just as simple as adding a
still pin ? or am i missing something? can you point me to something that can
help?

Many thanks

[Peter_B]

If you use the sample grabber, you can save a bitmap in the BufferCB function.
Something like this: Bitmap.Save(Path, Drawing.Imaging.ImageFormat.Bmp)