Visual c ++ programming for camera video capture and storage

Http://www.mscto.com/vc/2009022674609.htmlanother Use the sample grabber filter to capture images


Visual c ++ programming video capture by cameras released at: 09:16:49 Source: Author: Click: 798 Preface

DirectShow is a set of development kits provided by Microsoft for streaming media processing on the Windows platform and released together with the DirectX Development Kit. DirectShow provides powerful support for capturing and playback of Multimedia Streams. Using DirectShow to develop applications, we can easily capture data from the acquisition card that supports the WDM driver model, and perform corresponding post-processing and even storage into files.

DirectShow is based on COM. To compile DirectShow applications, you need to understand the basic knowledge of COM Client programming. DirectShow provides a large number of interfaces, but it is not easy to find in programming. If you can build a video capture class to encapsulate some common actions, it is more convenient.

　　Programming Logic

To create a video capture application more easily, DirectShow provides an object called capture graph builder. Capture graph Builder provides the icapturegraphbuilder2 interface, which can be used to create and control capture.
Graph.

To create a video capturing program, you must first obtain and initialize the icapturegraphbuilder2 interface, and then select an appropriate video capturing device. After the device is selected, create a capture filter for the device and call addfilter
Add filter to filter graph.

If you only want to use a camera for real-time monitoring, you only need to call icapturegraphbuilder2: renderstream on the basis of the above:

Icapturegraphbuilder2 * pbuild; // capture graph Builder // Some initialization code is omitted Ibasefilter * pcap; // video capture filter. // The initialization and addition of filter graph code are omitted. Pbuild-> renderstream (& pin_category_preview, & mediatype_video, pcap, null, null );

DirectShow provides a method to capture static images: Use the sample grabber filter. Follow these three steps:

Step 1: Define a class to implement the callback interface isamplegrabbercb for sample grabber:

Class csamplegrabbercb: Public isamplegrabbercb { // Complete it in the class provided later } Csamplegrabbercb MCB;

Step 2: Call renderstream to connect still pin, sample grabber, and default Renderer Filter.

Step 3: Configure sample grabber to capture data.

Implementation of ccapturevideo for video capturing

// Ccapturevideo video capture Class header file //////////////////////////////////////// ///////////////////////////// # If! Defined (afx_capturevideo_h1_f5345aa4 _ a3arrayf_4b07_b843_3d87c4287aa0 _ included _) # Define afx_capturevideo_h1_f5345aa4 _ a3arrayf_4b07_b843_3d87c4287aa0 _ included _ //////////////////////////////////////// ///////////////////////////// // Capturevideo. h: header file //////////////////////////////////////// ///////////////////////////// # If _ msc_ver> 1000 # Pragma once # Endif // _ msc_ver> 1000 # Include <atlbase. h> # Include <windows. h> # Include <dshow. h> # Ifndef safe_release # Define safe_release (x )\ If (null! = X )\ {\ X-> release ();\ X = NULL ;\ } # Endif Class csamplegrabbercb; Class ccapturevideo: Public cwnd { Friend class csamplegrabbercb; Public: Void graboneframe (bool bgrab ); Hresult Init (INT ideviceid, hwnd ); Int enumdevices (hwnd hlist ); Ccapturevideo (); Virtual ~ Ccapturevideo (); PRIVATE: Hwnd m_hwnd; Igraphbuilder * m_pgb; Icapturegraphbuilder2 * m_pcapture; Ibasefilter * m_pbf; Imediacontrol * m_pmc; Ivideowindow * m_pvw; Ccomptr <isamplegrabber> m_pgrabber; Protected: Void freemediatype (am_media_type & mt ); Bool bindfilter (INT DeviceID, ibasefilter ** pfilter ); Void resizevideowindow (); Hresult setupvideowindow (); Hresult initcapturegraphbuilder (); }; # Endif //! Defined (afx_capturevideo_h1_f5345aa4 _ a3arrayf_4b07_b843_3d87c4287aa0 _ included _) //------------------------------------------------------------------- // The implementation file capturevideo. cpp of the ccapturevideo video capture class //------------------------------------------------------------------- // Capturevideo. cpp: Implementation of the ccapturevideo class. // //////////////////////////////////////// ///////////////////////////// # Include "stdafx. H" # Include "capturevideo. H" # Ifdef _ debug # UNDEF this_file Static char this_file [] =__ file __; # Define new debug_new # Endif Bool boneshot = false; // global variable Class csamplegrabbercb: Public isamplegrabbercb { Public: Long lwidth; Long lheight; Tchar m_szfilename [max_path]; // bitmap file name Csamplegrabbercb (){ Strcpy (m_szfilename, "C :\\ donaldo.bmp "); } Stdmethodimp _ (ulong) addref () {return 2 ;} Stdmethodimp _ (ulong) release () {return 1 ;} Stdmethodimp QueryInterface (refiid riid, void ** GMM ){ If (riid = iid_isamplegrabbercb | riid = iid_iunknown ){ * GMM = (void *) static_cast <isamplegrabbercb *> (this ); Return noerror; } Return e_nointerface; } Stdmethodimp samplecb (double sampletime, imediasample * psample ){ Return 0; } Stdmethodimp buffercb (double dblsampletime, byte * pbuffer, long lbuffersize ){ If (! Boneshot) return 0; 　 If (! Pbuffer) return e_pointer; Savebitmap (pbuffer, lbuffersize ); Boneshot = false; Return 0; } // Create a bitmap file Bool savebitmap (byte * pbuffer, long lbuffersize) { Handle HF = createfile ( M_szfilename, generic_write, file_assist_read, null, Create_always, null, null ); If (HF = invalid_handle_value) return 0; // Write the file header Bitmapfileheader BFH; Memset (& BFH, 0, sizeof (BFH )); BFH. bftype = 'mb '; BFH. bfsize = sizeof (BFH) + lbuffersize + sizeof (bitmapinfoheader ); BFH. bfoffbits = sizeof (bitmapinfoheader) + sizeof (bitmapfileheader ); DWORD dwwritten = 0; Writefile (HF, & BFH, sizeof (BFH), & dwwritten, null ); // Write bitmap format Bitmapinfoheader BiH; Memset (& BiH, 0, sizeof (BiH )); BiH. bisize = sizeof (BiH ); BiH. biwidth = lwidth; BiH. biheight = lheight; BiH. biplanes = 1; BiH. bibitcount = 24; Writefile (HF, & BiH, sizeof (BiH), & dwwritten, null ); // Write bitmap data Writefile (HF, pbuffer, lbuffersize, & dwwritten, null ); Closehandle (HF ); Return 0; } }; Csamplegrabbercb MCB; //////////////////////////////////////// ////////////////////////////// // Construction/destruction //////////////////////////////////////// ////////////////////////////// Ccapturevideo: ccapturevideo () { // Com library intialization If (failed (coinitialize (null)/*, coinit_apartmentthreaded )))*/ { Afxmessagebox ("coinitialize failed! \ R \ n "); Return; } M_hwnd = NULL; M_pvw = NULL; M_pmc = NULL; M_pgb = NULL; M_pcapture = NULL; } Ccapturevideo ::~ Ccapturevideo () { // Stop media playback If (m_pmc) m_pmc-> stop (); If (m_pvw ){ M_pvw-> put_visible (oafalse ); M_pvw-> put_owner (null ); } Safe_release (m_pcapture ); Safe_release (m_pmc ); Safe_release (m_pgb ); Safe_release (m_pbf ); Couninitialize (); } Int ccapturevideo: enumdevices (hwnd hlist) { If (! Hlist) Return-1; Int id = 0; // Enumerate video capturing devices Icreatedevenum * pcreatedevenum; Hresult hR = cocreateinstance (clsid_systemdeviceenum, null, clsctx_inproc_server, iid_icreatedevenum, (void **) & pcreatedevenum ); If (HR! = Noerror) Return-1; Ccomptr <ienummoniker> PEM; HR = pcreatedevenum-> createclassenumerator (clsid_videoinputdevicecategory, & PEM, 0 ); If (HR! = Noerror) Return-1; PEM-> Reset (); Ulong cfetched; Imoniker * PM; While (hR = PEM-> next (1, & PM, & cfetched), HR = s_ OK) { Ipropertybag * pbag; HR = PM-> bindtostorage (0, 0, iid_ipropertybag, (void **) & pbag ); If (succeeded (HR )) { Variant var; Var. Vt = vt_bstr; HR = pbag-> Read (L "friendlyname", & var, null ); If (hR = noerror) { Tchar STR [2048]; Id ++; Widechartomultibyte (cp_acp, 0, var. bstrval,-1, STR, 2048, null, null ); : Sendmessage (hlist, cb_addstring, 0, (lparam) Str ); Sysfreestring (var. bstrval ); } Pbag-> release (); } PM-> release (); } Return ID; } Hresult ccapturevideo: Init (INT ideviceid, hwnd) { Hresult hr; HR = initcapturegraphbuilder (); If (failed (HR )){ Afxmessagebox ("failed to get video interfaces! "); Return hr; } // Bind device filter. We know the device because the ID was passed in If (! Bindfilter (ideviceid, & m_pbf) return s_false; HR = m_pgb-> addfilter (m_pbf, l "capture filter "); // HR = m_pcapture-> renderstream (& pin_category_preview, & mediatype_video, // M_pbf, null, null ); // Create a sample Grabber HR = m_pgrabber.cocreateinstance (clsid_samplegrabber ); If (! M_pgrabber ){ Afxmessagebox ("fail to create samplegrabber, maybe qedit. dll is not registered? "); Return hr; } Ccomqiptr <ibasefilter, & iid_ibasefilter> pgrabbase (m_pgrabber ); // Set the video format Am_media_type MT; Zeromemory (& mt, sizeof (am_media_type )); Mt. majortype = mediatype_video; Mt. Subtype = mediasubtype_rgb24; HR = m_pgrabber-> setmediatype (& mt ); If (failed (HR )){ Afxmessagebox ("fail to set media type! "); Return hr; } HR = m_pgb-> addfilter (pgrabbase, l "Grabber "); If (failed (HR )){ Afxmessagebox ("fail to put sample grabber in graph "); Return hr; } // Try to render preview/capture pin HR = m_pcapture-> renderstream (& pin_category_preview, & mediatype_video, m_pbf, pgrabbase, null ); If (failed (HR )) HR = m_pcapture-> renderstream (& pin_category_capture, & mediatype_video, m_pbf, pgrabbase, null ); If (failed (HR )){ Afxmessagebox ("can't build the graph "); Return hr; } 　 HR = m_pgrabber-> getconnectedmediatype (& mt ); If (failed (HR )){ Afxmessagebox ("failt to read the connected media type "); Return hr; } Videoinfoheader * VIH = (videoinfoheader *) Mt. pbformat; McB. lwidth = VIH-> bmiheader. biwidth; McB. lheight = VIH-> bmiheader. biheight; Freemediatype (MT ); HR = m_pgrabber-> setbuffersamples (false ); HR = m_pgrabber-> setoneshot (false ); HR = m_pgrabber-> setcallback (& McB, 1 ); // Set the video capture window M_hwnd = hwnd; Setupvideowindow (); HR = m_pmc-> Run (); // start video capture If (failed (HR) {afxmessagebox ("couldn't run the graph! "); Return hr ;} Return s_ OK; } Bool ccapturevideo: bindfilter (INT DeviceID, ibasefilter ** pfilter) { If (DeviceID <0) Return false; // Enumerate all Video Capture Devices Ccomptr <icreatedevenum> pcreatedevenum; Hresult hR = cocreateinstance (clsid_systemdeviceenum, null, clsctx_inproc_server, Iid_icreatedevenum, (void **) & pcreatedevenum ); If (HR! = Noerror) { Return false; } Ccomptr <ienummoniker> PEM; HR = pcreatedevenum-> createclassenumerator (clsid_videoinputdevicecategory, & PEM, 0 ); If (HR! = Noerror) { Return false; } PEM-> Reset (); Ulong cfetched; Imoniker * PM; Int Index = 0; While (hR = PEM-> next (1, & PM, & cfetched), HR = s_ OK, index <= DeviceID) { Ipropertybag * pbag; HR = PM-> bindtostorage (0, 0, iid_ipropertybag, (void **) & pbag ); If (succeeded (HR )) { Variant var; Var. Vt = vt_bstr; HR = pbag-> Read (L "friendlyname", & var, null ); If (hR = noerror) { If (Index = DeviceID) { PM-> bindtoobject (0, 0, iid_ibasefilter, (void **) pfilter ); } Sysfreestring (var. bstrval ); } Pbag-> release (); } PM-> release (); Index ++; } Return true; } Hresult ccapturevideo: initcapturegraphbuilder () { Hresult hr; // Create the igraphbuilder Interface HR = cocreateinstance (clsid_filtergraph, null, clsctx_inproc_server, iid_igraphbuilder, (void **) & m_pgb ); // Create icapturegraphbuilder2 Interface HR = cocreateinstance (clsid_capturegraphbuilder2, null, clsctx_inproc, Iid_icapturegraphbuilder2, (void **) & m_pcapture ); If (failed (HR) return hr; M_pcapture-> setfiltergraph (m_pgb ); HR = m_pgb-> QueryInterface (iid_imediacontrol, (void **) & m_pmc ); If (failed (HR) return hr; HR = m_pgb-> QueryInterface (iid_ivideowindow, (lpvoid *) & m_pvw ); If (failed (HR) return hr; Return hr; } Hresult ccapturevideo: setupvideowindow () { Hresult hr; HR = m_pvw-> put_owner (oahwnd) m_hwnd ); If (failed (HR) return hr; HR = m_pvw-> put_windowstyle (ws_child | ws_clipchildren ); If (failed (HR) return hr; Resizevideowindow (); HR = m_pvw-> put_visible (oatrue ); Return hr; } Void ccapturevideo: resizevideowindow () { If (m_pvw ){ // Fill the image with the entire window Crect RC; : Getclientrect (m_hwnd, & rc ); M_pvw-> setwindowposition (0, 0, RC. Right, RC. Bottom ); } } Void ccapturevideo: graboneframe (bool bgrab) { Boneshot = bgrab; } Void ccapturevideo: freemediatype (am_media_type & mt) { If (mt. cbformat! = 0 ){ Cotaskmemfree (pvoid) Mt. pbformat ); // Strictly unnecessary but tidier Mt. cbformat = 0; Mt. pbformat = NULL; } If (mt. Punk! = NULL ){ Mt. Punk-> release (); Mt. Punk = NULL; } }