Any ability to use web camera STILL image mode to take picture?

[jdredd87]

I want to take a still image. Not just save a random frame from a video stream.

Using the Windows Media Foundation API ( not DirectX )

If you use Windows 10 Camera app, say on a surface pro.
The preview mode is 1920x1080 mode.
But when you take the STILL image, it is 3264x2448 ( 8 MP )

Downloaded latest MF pack and don't see this ability. So not sure if it is there and missing something.
If it does, can a demo be added?

[FactoryXCode]

Hello,

Depending on the hardware a still image, snap-shot or freeze-frame kan be taken from it's still image pin. For this you have to use DirectShow. Capturing an Image From a Still Image Pin

Media Foundation does have this ability.

There are 2 scenarios:

1# In combination with the WIC (which is also part of MfPack), it is possible to pick a frame from the videostream and convert this frame to the proper format. as been suggested here

A good readable "how to" can be found here on Code Project

2# By using the IMFCapturePhotoSink interface (WinApi.MediaFoundationApi.MfCaptureEngine.pas), you can extract still images from a video stream, as explained here.

Greetings, Tony.

[Ciaran3]

I might look into doing a sample project demonstrating webcam to still image capture. It seems like one of the few remaining use cases that is not covered.

[Ciaran3]

Re: Brightness - So far I've only found DXVA2_ProcAmp_Brightness . It works fine when you use that to increase the brightness but it doesn't feel like the correct solution. Back to searching...

[FactoryXCode]

I'm asking myself why my camera on your example exposes 11 formats and mine about 33?

[Ciaran3]

I'm asking myself why my camera on your example exposes 11 formats and mine about 33?

Is it the check 'IsFormatAvailable' in CameraCapture.pas? That filters out lower frame rates and formats that are not supported for conversion.

[FactoryXCode]

Is it the check 'IsFormatAvailable' in CameraCapture.pas?

I'm still getting 6 more.

Another thing: a-synchronous operations have a thread priority of THREAD_PRIORITY_NORMAL. On high CPU usage the thread of an a-synchronous operation can take some while. That means, a calculation for example memory usage or processing a sample may lead to a miscalculation. Therefore it would be a good idea - I think - to give those another thread priority than the default. See here

I don't know if Delhi has a class that is able to get or set thread priorities. Otherwise I will write one.

[Ciaran3]

Thanks for that suggestion regarding thread priority - it sounds like a good idea. Although the sample reader appears to spawn multiple threads to read samples, so i'm not sure it would be efficient setting the priority on each new thread?
Ideally, everything should be outside of the main thread - as it is possible with the current code for the main thread to become unresponsive when using 'burst mode' (continuous capture).

[FactoryXCode]

The downside is no 'live' preview is visible. Although the captured images can be displayed instead.

This can be done by implementing the TCPreview class from sample MfCaptureD3D9. Here the class will show the preview processed by IMFSourceReaderCallback.OnReadSample. The only thing you have to do is create a Window class like for instance TPanel to show the preview.

I'll try to implement this.

[FactoryXCode]

My suggestion is: To adjust camera properties ( like brightness, format etc.) a sink should be implemented in OnReadSample, when a sample is token. Therefore you should use the interfaces from WinApi.MediaFoundationApi.CameraUIControl.pas. I think that is more likely the way to implement a preview and conversion for supported formats see here

[FactoryXCode]

OK, I'd wrote a function that doesn't need a session or d3d9 surface to get a preview. I did not test it yet, but I think in theory it should work with your sample.

// This method returns a IMFActivate that is able to render to a window or any other visual component that has a THandle (HWND)
function CreateMediaSinkActivateWindowRenderer(pSourceSD: IMFStreamDescriptor;
                                                                                   dwStream: DWORD; 
                                                                                   hVideoWindow: HWND;  // Handle to the video clipping window.
                                                                                   pActivate: IMFActivate): HRESULT;
var
  hr: HResult;
  pmtHandler: IMFMediaTypeHandler;
  pmfActivate: IMFActivate;
  guidMajorType: TGUID;
  pmfStreamSink: IMFStreamSink;
  pmfVideoSink: IMFMediaSink;
  dwID: DWord;

label
  Done;

begin

  // Get the media type handler for the stream.
  hr := pSourceSD.GetMediaTypeHandler(pmtHandler);
  if FAILED(hr) then
    goto done;

  // Get the major media type.
  hr := pmtHandler.GetMajorType(guidMajorType);
  if FAILED(hr) then
    goto Done;

  if (MFMediaType_Video = guidMajorType) then
    begin
      // Create the video renderer.
      hr := MFCreateVideoRendererActivate(hVideoWindow,
                                                                    pActivate);

      hr := pActivate.ActivateObject(IID_IMFMediaSink,
                                                       Pointer(pmfVideoSink));
      if SUCCEEDED(hr) then
        begin
          hr := pmfVideoSink.AddStreamSink(dwStream,
                                                                   nil,
                                                                   pmfStreamSink);
          if SUCCEEDED(hr) then
            begin
              hr := pmfStreamSink.GetIdentifier(dwID);
              if SUCCEEDED(hr) then
                SafeRelease(pmfStreamSink);
            end;
        end;
    end
  else
      begin
        // Invalid or no stream present
        hr := MF_E_CAPTURE_SOURCE_NO_VIDEO_STREAM_PRESENT;
      end;

  if FAILED(hr) then
    goto Done;

  pActivate := pmfActivate;

done:
  Result := hr;
end;

[FactoryXCode]

I checked your sample, but getting a MFVideoFormat_YUY2 format the frame is upside down. the MFVideoFormat_NV12 format is doing well.

[Ciaran3]

I checked your sample, but getting a MFVideoFormat_YUY2 format the frame is upside down. the MFVideoFormat_NV12 format is doing well.

Ah yes, now I remember why I had the negative value for BITMAPINFOHEADER height. I have added that format to an array 'FTopDownFormats' and a 'IsTopDown' function. I'm not 100% sure what other formats provide top-down data - so that array might need to be added to.

I did have a go at adding the Preview with the code you provided previously, but had no luck. I think it involves a fair bit more work and I'm not sure when I'll get to that.

[FactoryXCode]

I'll give it a try.

[FactoryXCode]

I wonder why there is a function IsInputSupported and why the list of supported formats is limited to the list in function SetSupportedInputs();
As I read MfApi.pas (See from line 2610) the list of MF supported formats exceeds the formats defined in SetSupportedInputs().
Maybe the list is a bit behind the MF updates of the last past years?

[Ciaran3]

MfApi

Hi Tony, thanks for your recent changes / fixes on this project.
Those formats are the only ones that are supported by the Video Processor, according to this:
https://docs.microsoft.com/en-us/windows/win32/medfound/video-processor-mft#input-formats
Which is needed to convert the sample to RGB.
I probably should make it clearer by adding a comment.

[FactoryXCode]

Thanks.
I missed that info.
A new APi update is underway: SDK 10.0.22621.0 for windows 11.

[jdredd87]

Checking to see how things on this are progressing?

This issue haunts my dreams for years now. Came back up yesterday.

[Ciaran3]

Hi there, have you checked out these two sample projects?
https://github.com/FactoryXCode/MfPack/tree/Master/MfPack/Samples/MFCaptureEngineVideoCapture
https://github.com/FactoryXCode/MfPack/tree/Master/MfPack/Samples/MfCameraFrameCapture

[FactoryXCode]

Well, the MFCaptureEngineVideo Capture sample has an issue. When changing from camera or accessing the camera again, an error is thrown (80070005 Access Denied) Maybe someone has a clue? I asked MS why this is happening with this particular interface (IMFCaptureEngine) and not for example the IMFSourceReader (like the MfCaptureD3D9 sample).

[FactoryXCode]

MFCaptureEngineVideoCapture sample has been fixed.
Also the different format on a SurfacePro is caused by it's camera pin preview format.
A preview format has always a lower quality than the actual camera format.
So, a clip from a preview snapshot has always a lower quality as a result.
Therefore you should not get a snapshot from a preview, but from the actual camera presentation.