directshow, fails to renderstream connecting still pin to samplegrabber

1
votes

have a problem with still pin capture,

we have a basic video and picture capturing project, capturing images and videos from capture pin is okay, but once i try to connect still pin (which is found succesfully by FindPin) to samplegrabber, it fails with hresult = E_FAIL/Unspecified failure/0x80004005,

the steps of the alrorythm is as follows (written in delphi, i have deleted the names of the variables):

  • initializing interfaces, succesful search for the device, adding video capture filter;

  • FindPin( 'capture filter' , // Filter. PINDIR_OUTPUT, // Look for an output pin. @PIN_CATEGORY_STILL, // Pin category. Nil, // Media type (don't care). False, // Pin must be unconnected. 0, // Get the 0'th pin. 'still pin' // Receives a pointer to thepin. ); this procedure finds pin succesfully;

  • CoCreateInstance(CLSID_SampleGrabber, NIL, CLSCTX_INPROC_SERVER, IID_IBaseFilter, 'sample grabber filter'); succesful;

  • 'sample grabber filter'.QueryInterface(IID_ISampleGrabber, 'isamplegrabber object'); succesful;

  • 'graph builder'.AddFilter (VCOISampleGrabFilter, 'Sample Grabber'); succesful;

  • CoCreateInstance(CLSID_NullRenderer, NIL, CLSCTX_INPROC_SERVER, IID_IBaseFilter, 'null renderer filter'); succesful;

  • 'graph builder'.AddFilter (VCONullRendererFilter, 'Null Renderer'); succesful;

  • 'isamplegrabber object'.SetBufferSamples(True); 'isamplegrabber object'.SetOneShot(False); succesful;

  • 'graph builder 2'.RenderStream (@PIN_CATEGORY_STILL, @MEDIATYPE_Video, 'video capture filter', 'sample grabber filter', 'null renderer filter'); there is where it is fails, after this alrotythm, if i look at the graph (have wrote the procedure for this), it looks like just 3 unconnected filters;

didn't use callback function for sample grabber, just get shots by using GetCurrentBuffer,

actually, this algorythm (only for capture pin) works alright,

algorythm was adopted from http://msdn.microsoft.com/ru-ru/library/windows/desktop/dd318622%28v=vs.85%29.aspx,

also have tried another parameters for RenderStream, the same error occurs,

also tried using 'graph builder'.Connect function with 2 finded pins (out-still, in-samplegrabber), it also fails,

have anyone experienced the same? it is weird, at the first sight i thought that it is enough just to change PIN_CATEGORY_CAPTURE to PIN_CATEGORY_STILL and it will be fine,

the camera is 100% have working still pin (it is working with another programs),

i am rewriting microsoft's AmCap to try the same for now, but, unfortunately it is not finished yet,

thanks, igor.

2
imagegraphdirectshowcapturescreen-capture

2 Answers

0
votes

RenderStream is a wrapper method which [supposedly easily] connects stuff together into workable state. Unfortunately, the price for this is lack of detail for failures. You are interested in connecting pins directly using IGraphBuilder.Connect and isolating the failure to specific graph building step.

0
votes

have found the solution for this problem, maybe someone will find this helpful: you should renderstream a renderer first, then a samplegrabber :)