Use DirectShow for camera Development

First of all, my system is win7. It is said that win7 comes with DirectX, so you do not need to download DirectX again.

Add in header file# Pragma comment (Lib, "strmiids") <br/> # pragma comment (Lib, "quartz") <br/> # include <dshow. h> /// all required DirectShow applications <br/>

First, find the video device list

Void ccameradlg: getallcapdevices () <br/>{< br/> uint uindex = 0; <br/> // release the video device list <br/> for (INT I = 0; I <numelms (m_rgpmvideomenu); I ++) {<br/> imonrelease (m_rgpmvideomenu [I]); <br/>}</P> <p> // enumerate all video capturing devices <br/> icreatedevenum * pcreatedevenum = 0; <br/> hresult hR = cocreateinstance (clsid_systemdeviceenum, null, clsctx_inproc_server, <br/> iid_icreatedevenum, (void **) & pcreatedevenum ); // create an enumeration for all system devices <br/> If (HR! = Noerror) <br/>{< br/> error (text ("error creatint device enumerator"); <br/> return; <br/>}< br/> ienummoniker * PEM = 0; <br/> hR = pcreatedevenum-> createclassenumerator (clsid_videoinputdevicecategory, & PEM, 0 ); // filter out the video input device <br/> If (HR! = Noerror) <br/>{< br/> error (text ("Sorry, you have no video capture hardware. /R/n/R/N "); <br/>}< br/> PEM-> Reset (); <br/> ulong cfetched; <br/> imoniker * PM; </P> <p> while (hR = PEM-> next (1, & PM, & cfetched) = s_ OK) // loop until the last device <br/>{< br/> ipropertybag * pbag = 0; <br/> hR = PM-> bindtostorage (0, 0, iid_ipropertybag, (void **) & pbag); // bind the object to the corresponding property object <br/> If (succeeded (HR )) <br/>{< br/> variant var; <br/> var. vt = vt_bstr; <br/> hR = pbag-> Read (L "friendlyname", & var, null); <br/> If (hR = noerror) <br/>{< br/> cstring strdevicename = var. bstrval; <br/> // cstring strmenuitem; <br/> // strmenuitem. format ("% d) % s", (uindex + 1), strdevicename); <br/> sysfreestring (var. bstrval); <br/> m_rgpmvideomenu [uindex] = PM; <br/> PM-> addref (); <br/>}< br/> pbag-> release (); <br/>}< br/> PM-> release (); <br/> uindex ++; <br/>}< br/> PEM-> release (); <br/>}< br/> void ccameradlg: imonrelease (imoniker * & pm) <br/>{< br/> If (PM) <br/>{< br/> PM-> release (); <br/> PM = 0; <br/>}< br/>

 

The error function is:

 

Void ccameradlg: Error (tchar * ptext) <br/>{< br/>: MessageBox (null, ptext, text ("error! "), Mb_ OK | mb_taskmodal | mb_setforeground); <br/>}

Connect and display the video:

 Hresult ccameradlg: initandstartpreview () <br/> {<br/> If (numelms (m_rgpmvideomenu)> 0) <br/> {<br/> hresult hR = m_rgpmvideomenu [0]-> bindtoobject (0, 0, iid_ibasefilter, (void **) & m_pvcap ); // bind the selected device to the Source Filter <br/> If (! M_pvcap) <br/>{< br/> error (text ("there is no USB/web camera for video capture! Please check! "); <Br/> return e_fail; <br/>}< br/> hR = m_pcapturegraph.cocreateinstance (clsid_filtergraph); <br/> If (! M_pcapturegraph) <br/>{< br/> error (text ("cocould not create filter graph"); <br/> return e_fail; <br/>}< br/> hR = m_pcapturegraph-> addfilter (m_pvcap, l "videopreview"); <br/> If (failed (HR )) <br/>{< br/> error (text ("cocould not put capture device in graph"); <br/> return e_fail; <br/>}< br/> hR = m_pbuilder.cocreateinstance (clsid_capturegraphbuilder2); <br/> If (! M_pbuilder) <br/>{< br/> error (text ("cocould not create capture graph builder2"); <br/> return hr; <br/>}</P> <p> hR = m_pbuilder-> setfiltergraph (m_pcapturegraph); // <br/> If (HR! = Noerror) <br/>{< br/> error (text ("cannot give graph to builder"); <br/> return e_fail; <br/>}< br/> // connect the filters of the captured video image <br/> hR = m_pbuilder-> renderstream (& pin_category_preview, & mediatype_interleaved, m_pvcap, null, null); <br/> If (failed (HR) <br/>{< br/> hR = m_pbuilder-> renderstream (& pin_category_preview, & mediatype_video, m_pvcap, null, null); <br/> If (failed (HR) <br/>{< br/> hR = m_pbuilder-> renderstream (& Pi N_category_capture, & mediatype_video, m_pvcap, null, null ); <br/>}< br/> // find the video window and stuff it in our window <br/> ccomqiptr <ivideowindow, & iid_ivideowindow> pwindow = m_pcapturegraph; // videowindow interface <br/> If (! Pwindow) <br/>{< br/> error (text ("cocould not get video window interface"); <br/> return e_fail; <br/>}< br/> // set up the preview window to be in our dialog instead of floating popup <br/> hwnd hwndpreview = NULL; <br/> getdlgitem (idc_preview_avi, & hwndpreview); // obtain the hwnd of the preview window control <br/> rect RC; <br/>: getwindowrect (hwndpreview, & rc); <br/> hR = pwindow-> put_owner (oahwnd) hwndpreview); <br/> hR = pwindow-> put_left (0 ); <br/> hR = pwindow-> put_top (0); <br/> hR = pwindow-> put_width (RC. right-rc.left); <br/> hR = pwindow-> put_height (RC. bottom-rc.top); <br/> hR = pwindow-> put_windowstyle (ws_child | ws_clipsiblings); <br/> hR = pwindow-> put_visible (oatrue ); </P> <p> // run the filter graph. The imediacontrol interface provides the flow of data in the filer graph. <br/> ccomqiptr <imediacontrol, & iid_imediacontrol> pcontrol = m_pcapturegraph; <br/> hR = pcontrol-> Run (); </P> <p> If (failed (HR )) <br/>{< br/> error (text ("cocould not run graph"); <br/> return hr; <br/>}</P> <p>}

 

It is best to add it to the ccameradlg: oninitdialog () function.

Coinitializeex (null, coinit_apartmentthreaded); // initialize the com environment <br/> zeromemory (m_rgpmvideomenu, sizeof (m_rgpmvideomenu); <br/> getallcapdevices (); <br/> initandstartpreview ();

In this way, you can easily display the data.