我正在尝试同时从多个网络摄像头捕获图像，并使用 C++ 以最小的延迟自动保存它们。我还希望该程序能够在需要时更改网络摄像头的参数。我希望在 Platform SDK 上构建 Direct show 示例 (AMCap)，然后编辑代码以适合我的应用程序。但我不断收到错误。
我能够构建基类并将路径包含在“include”和“库文件”下。当我尝试构建 AMCap 时，出现以下错误。我正在使用 Visual Studio 2008 开发 XP。
Compiling...
amcap.cpp
d:\program files\microsoft sdks\windows\v6.1\samples\multimedia\directshow\capture\amcap\amcap.cpp(231) : error C2664: 'StringCchCatA' : cannot convert parameter 3 from 'WCHAR [260]' to 'STRSAFE_LPCSTR'
Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast
d:\program files\microsoft sdks\windows\v6.1\samples\multimedia\directshow\capture\amcap\amcap.cpp(327) : error C2664: 'GetProfileStringA' : cannot convert parameter 4 from 'WCHAR [260]' to 'LPSTR'
Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast
d:\program files\microsoft sdks\windows\v6.1\samples\multimedia\directshow\capture\amcap\amcap.cpp(2691) : error C2664: 'statusUpdateStatus' : cannot convert parameter 2 from 'WCHAR [120]' to 'LPCTSTR'
Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast
d:\program files\microsoft sdks\windows\v6.1\samples\multimedia\directshow\capture\amcap\amcap.cpp(2698) : error C2664: 'StringCchCopyNA' : cannot convert parameter 1 from 'WCHAR [1024]' to 'STRSAFE_LPSTR'
Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast
d:\program files\microsoft sdks\windows\v6.1\samples\multimedia\directshow\capture\amcap\amcap.cpp(2699) : error C2664: 'StringCchCopyNA' : cannot convert parameter 1 from 'WCHAR [1024]' to 'STRSAFE_LPSTR'
Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast
d:\program files\microsoft sdks\windows\v6.1\samples\multimedia\directshow\capture\amcap\amcap.cpp(2831) : error C2664: 'AppendMenuA' : cannot convert parameter 4 from 'BSTR' to 'LPCSTR'
Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast
d:\program files\microsoft sdks\windows\v6.1\samples\multimedia\directshow\capture\amcap\amcap.cpp(2887) : error C2664: 'AppendMenuA' : cannot convert parameter 4 from 'BSTR' to 'LPCSTR'
Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast
d:\program files\microsoft sdks\windows\v6.1\samples\multimedia\directshow\capture\amcap\amcap.cpp(3792) : error C2664: 'StringCchCopyA' : cannot convert parameter 3 from 'WCHAR [260]' to 'STRSAFE_LPCSTR'
Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast
d:\program files\microsoft sdks\windows\v6.1\samples\multimedia\directshow\capture\amcap\amcap.cpp(3838) : error C2664: 'OpenFileDialog' : cannot convert parameter 2 from 'WCHAR [260]' to 'LPTSTR'
Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast
d:\program files\microsoft sdks\windows\v6.1\samples\multimedia\directshow\capture\amcap\amcap.cpp(3844) : error C2664: 'GetFileAttributesA' : cannot convert parameter 1 from 'WCHAR [260]' to 'LPCSTR'
Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast
d:\program files\microsoft sdks\windows\v6.1\samples\multimedia\directshow\capture\amcap\amcap.cpp(3904) : error C2664: 'ICaptureGraphBuilder2::CopyCaptureFile' : cannot convert parameter 2 from 'TCHAR [260]' to 'LPOLESTR'
Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast
d:\program files\microsoft sdks\windows\v6.1\samples\multimedia\directshow\capture\amcap\amcap.cpp(4108) : error C2664: 'GetSize' : cannot convert parameter 1 from 'WCHAR [260]' to 'LPCTSTR'
Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast
d:\program files\microsoft sdks\windows\v6.1\samples\multimedia\directshow\capture\amcap\amcap.cpp(4112) : error C2664: 'GetFreeDiskSpaceInKB' : cannot convert parameter 1 from 'WCHAR [260]' to 'LPTSTR'
Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast
d:\program files\microsoft sdks\windows\v6.1\samples\multimedia\directshow\capture\amcap\amcap.cpp(4165) : error C2664: '_wtol' : cannot convert parameter 1 from 'TCHAR [21]' to 'const wchar_t *'
Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast
d:\program files\microsoft sdks\windows\v6.1\samples\multimedia\directshow\capture\amcap\amcap.cpp(4240) : error C2664: '_wtof' : cannot convert parameter 1 from 'TCHAR [32]' to 'const wchar_t *'
Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast
d:\program files\microsoft sdks\windows\v6.1\samples\multimedia\directshow\capture\amcap\amcap.cpp(4392) : error C2664: 'WriteProfileStringA' : cannot convert parameter 3 from 'WCHAR [260]' to 'LPCSTR'
Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast
d:\program files\microsoft sdks\windows\v6.1\samples\multimedia\directshow\capture\amcap\amcap.cpp(4403) : error C2664: 'StringCchCopyNA' : cannot convert parameter 3 from 'WCHAR *' to 'STRSAFE_LPCSTR'
Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast
d:\program files\microsoft sdks\windows\v6.1\samples\multimedia\directshow\capture\amcap\amcap.cpp(4421) : error C2664: 'StringCchCopyA' : cannot convert parameter 3 from 'WCHAR *' to 'STRSAFE_LPCSTR'
Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast
这些错误看起来像是字符串不匹配错误，因此尝试使用 unicode 字符集构建它们，并得到以下错误。
Compiling...
amcap.cpp
crossbar.cpp
SampleCGB.cpp
status.cpp
stdafx.cpp
Generating Code...
Compiling resources...
Microsoft (R) Windows (R) Resource Compiler Version 6.0.5724.0
Copyright (C) Microsoft Corporation. All rights reserved.
Linking...
amcap.obj : error LNK2019: unresolved external symbol "void __stdcall DbgAssert(unsigned short const *,unsigned short const *,int)" (?DbgAssert@@YGXPBG0H@Z) referenced in function "int __cdecl AppInit(struct HINSTANCE__ *,struct HINSTANCE__ *,int)" (?AppInit@@YAHPAUHINSTANCE__@@0H@Z)
crossbar.obj : error LNK2001: unresolved external symbol "void __stdcall DbgAssert(unsigned short const *,unsigned short const *,int)" (?DbgAssert@@YGXPBG0H@Z)
SampleCGB.obj : error LNK2001: unresolved external symbol "void __stdcall DbgAssert(unsigned short const *,unsigned short const *,int)" (?DbgAssert@@YGXPBG0H@Z)
amcap.obj : error LNK2001: unresolved external symbol _AM_KSCATEGORY_CAPTURE
amcap.obj : error LNK2001: unresolved external symbol _IID_IBaseFilter
crossbar.obj : error LNK2001: unresolved external symbol _IID_IBaseFilter
SampleCGB.obj : error LNK2019: unresolved external symbol _IID_IBaseFilter referenced in function "protected: long __thiscall ISampleCaptureGraphBuilder::GetMedium(struct IPin *,struct __MIDL___MIDL_itf_strmif_0000_0022_0003 &)" (?GetMedium@ISampleCaptureGraphBuilder@@IAEJPAUIPin@@AAU__MIDL___MIDL_itf_strmif_0000_0022_0003@@@Z)
amcap.obj : error LNK2019: unresolved external symbol __imp__timeGetTime@0 referenced in function "long __stdcall AppWndProc(struct HWND__ *,unsigned int,unsigned int,long)" (?AppWndProc@@YGJPAUHWND__@@IIJ@Z)
amcap.obj : error LNK2001: unresolved external symbol _CLSID_CaptureGraphBuilder2
amcap.obj : error LNK2001: unresolved external symbol _IID_ICaptureGraphBuilder2
amcap.obj : error LNK2001: unresolved external symbol _CLSID_FilterGraph
amcap.obj : error LNK2001: unresolved external symbol _IID_IGraphBuilder
amcap.obj : error LNK2001: unresolved external symbol _PIN_CATEGORY_CC
amcap.obj : error LNK2001: unresolved external symbol _PIN_CATEGORY_VBI
amcap.obj : error LNK2001: unresolved external symbol _MEDIATYPE_Audio
SampleCGB.obj : error LNK2001: unresolved external symbol _MEDIATYPE_Audio
amcap.obj : error LNK2001: unresolved external symbol _PIN_CATEGORY_ANALOGVIDEOIN
amcap.obj : error LNK2001: unresolved external symbol _AMPROPSETID_Pin
amcap.obj : error LNK2001: unresolved external symbol _IID_IKsPropertySet
amcap.obj : error LNK2001: unresolved external symbol _IID_IAMVfwCaptureDialogs
amcap.obj : error LNK2019: unresolved external symbol "void __stdcall DeleteMediaType(struct _AMMediaType *)" (?DeleteMediaType@@YGXPAU_AMMediaType@@@Z) referenced in function "int __cdecl InitCapFilters(void)" (?InitCapFilters@@YAHXZ)
SampleCGB.obj : error LNK2001: unresolved external symbol "void __stdcall DeleteMediaType(struct _AMMediaType *)" (?DeleteMediaType@@YGXPAU_AMMediaType@@@Z)
amcap.obj : error LNK2001: unresolved external symbol _FORMAT_VideoInfo
amcap.obj : error LNK2001: unresolved external symbol _IID_IAMStreamConfig
amcap.obj : error LNK2001: unresolved external symbol _MEDIATYPE_Video
SampleCGB.obj : error LNK2001: unresolved external symbol _MEDIATYPE_Video
amcap.obj : error LNK2001: unresolved external symbol _PIN_CATEGORY_CAPTURE
amcap.obj : error LNK2001: unresolved external symbol _MEDIATYPE_Interleaved
amcap.obj : error LNK2001: unresolved external symbol _IID_IAMVideoCompression
amcap.obj : error LNK2001: unresolved external symbol _IID_IMediaEventEx
amcap.obj : error LNK2001: unresolved external symbol _IID_IVideoWindow
amcap.obj : error LNK2001: unresolved external symbol _MEDIATYPE_Stream
SampleCGB.obj : error LNK2001: unresolved external symbol _MEDIATYPE_Stream
amcap.obj : error LNK2001: unresolved external symbol _PIN_CATEGORY_PREVIEW
amcap.obj : error LNK2001: unresolved external symbol _IID_IConfigAviMux
amcap.obj : error LNK2001: unresolved external symbol _MEDIASUBTYPE_Avi
amcap.obj : error LNK2001: unresolved external symbol _IID_IBasicVideo
amcap.obj : error LNK2001: unresolved external symbol _FORMAT_DvInfo
amcap.obj : error LNK2001: unresolved external symbol _IID_IMediaControl
amcap.obj : error LNK2001: unresolved external symbol _IID_IAMDroppedFrames
amcap.obj : error LNK2001: unresolved external symbol _IID_IAMTVAudio
amcap.obj : error LNK2001: unresolved external symbol _IID_IAMTVTuner
amcap.obj : error LNK2001: unresolved external symbol _LOOK_UPSTREAM_ONLY
amcap.obj : error LNK2001: unresolved external symbol _IID_IAMCrossbar
crossbar.obj : error LNK2001: unresolved external symbol _IID_IAMCrossbar
amcap.obj : error LNK2001: unresolved external symbol _CLSID_AudioInputDeviceCategory
amcap.obj : error LNK2001: unresolved external symbol _CLSID_VideoInputDeviceCategory
amcap.obj : error LNK2001: unresolved external symbol _CLSID_SystemDeviceEnum
SampleCGB.obj : error LNK2001: unresolved external symbol _CLSID_SystemDeviceEnum
amcap.obj : error LNK2001: unresolved external symbol _IID_ICreateDevEnum
SampleCGB.obj : error LNK2001: unresolved external symbol _IID_ICreateDevEnum
amcap.obj : error LNK2019: unresolved external symbol _acmFormatChooseW@4 referenced in function "void __cdecl ChooseAudioFormat(void)" (?ChooseAudioFormat@@YAXXZ)
amcap.obj : error LNK2019: unresolved external symbol _acmMetrics@12 referenced in function "void __cdecl ChooseAudioFormat(void)" (?ChooseAudioFormat@@YAXXZ)
amcap.obj : error LNK2001: unresolved external symbol _IID_IAMCopyCaptureFileProgress
crossbar.obj : error LNK2019: unresolved external symbol "void __cdecl DbgLogInfo(unsigned long,unsigned long,unsigned short const *,...)" (?DbgLogInfo@@YAXKKPBGZZ) referenced in function "public: __thiscall CCrossbar::CCrossbar(struct IPin *,long *)" (??0CCrossbar@@QAE@PAUIPin@@PAJ@Z)
crossbar.obj : error LNK2019: unresolved external symbol "public: __thiscall CBaseList::~CBaseList(void)" (??1CBaseList@@QAE@XZ) referenced in function "public: __thiscall CGenericList::~CGenericList(void)" (??1?$CGenericList@VCRouting@@@@QAE@XZ)
crossbar.obj : error LNK2019: unresolved external symbol "public: __thiscall CBaseList::CBaseList(unsigned short const *,int)" (??0CBaseList@@QAE@PBGH@Z) referenced in function "public: __thiscall CGenericList::CGenericList(unsigned short const *,int,int,int)" (??0?$CGenericList@VCRouting@@@@QAE@PBGHHH@Z)
crossbar.obj : error LNK2019: unresolved external symbol "protected: void * __thiscall CBaseList::GetNextI(struct __POSITION * &)const " (?GetNextI@CBaseList@@IBEPAXAAPAU__POSITION@@@Z) referenced in function "public: class CRouting * __thiscall CGenericList::GetNext(struct __POSITION * &)const " (?GetNext@?$CGenericList@VCRouting@@@@QBEPAVCRouting@@AAPAU__POSITION@@@Z)
crossbar.obj : error LNK2019: unresolved external symbol "protected: void * __thiscall CBaseList::RemoveHeadI(void)" (?RemoveHeadI@CBaseList@@IAEPAXXZ) referenced in function "public: class CRouting * __thiscall CGenericList::RemoveHead(void)" (?RemoveHead@?$CGenericList@VCRouting@@@@QAEPAVCRouting@@XZ)
crossbar.obj : error LNK2019: unresolved external symbol "protected: struct __POSITION * __thiscall CBaseList::AddTailI(void *)" (?AddTailI@CBaseList@@IAEPAU__POSITION@@PAX@Z) referenced in function "public: struct __POSITION * __thiscall CGenericList::AddTail(class CRouting *)" (?AddTail@?$CGenericList@VCRouting@@@@QAEPAU__POSITION@@PAVCRouting@@@Z)
crossbar.obj : error LNK2019: unresolved external symbol "protected: void * __thiscall CBaseList::GetI(struct __POSITION *)const " (?GetI@CBaseList@@IBEPAXPAU__POSITION@@@Z) referenced in function "public: class CRouting * __thiscall CGenericList::Get(struct __POSITION *)const " (?Get@?$CGenericList@VCRouting@@@@QBEPAVCRouting@@PAU__POSITION@@@Z)
SampleCGB.obj : error LNK2001: unresolved external symbol _MEDIASUBTYPE_MPEG2_PROGRAM
SampleCGB.obj : error LNK2001: unresolved external symbol _MEDIASUBTYPE_MPEG2_VIDEO
SampleCGB.obj : error LNK2001: unresolved external symbol _CLSID_FilterMapper2
SampleCGB.obj : error LNK2001: unresolved external symbol _IID_IFilterMapper2
SampleCGB.obj : error LNK2001: unresolved external symbol _IID_IKsPin
SampleCGB.obj : error LNK2001: unresolved external symbol _CLSID_MPEG2Demultiplexer
SampleCGB.obj : error LNK2001: unresolved external symbol _FORMAT_MPEG2Video
SampleCGB.obj : error LNK2001: unresolved external symbol _FORMAT_WaveFormatEx
SampleCGB.obj : error LNK2001: unresolved external symbol _MEDIASUBTYPE_MPEG2_AUDIO
SampleCGB.obj : error LNK2001: unresolved external symbol _IID_IMpeg2Demultiplexer
D:\Documents and Settings\Chris Salthouse\My Documents\Visual Studio 2008\Projects\AMCap\Debug\AMCap.exe : fatal error LNK1120:60 unresolved externals
我应该使用 Unicode 还是多字节？我不明白是什么导致了这个问题。任何帮助或建议表示赞赏。非常感谢您抽出时间！
您的库目录中是否包含 BaseClasses？您需要让链接器找到 Strmbase.lib（发布）或 Strmbasd.lib（调试）。
编辑：我正在使用带有 PSDK 6.0 的 vs2005，它对我来说工作得很好。
您可以使用多字节或unicode，只要您在基类项目和amcap项目中具有相同的设置即可。检查 unicode 与多字节，并检查运行时（静态或 dll）wchar_t 的设置是/否、调用约定等。确保所有这些匹配。
1>Build FAILED.
1>
1>main.obj : error LNK2001: unresolved external symbol _IID_IBaseFilter
1>main.obj : error LNK2001: unresolved external symbol _IID_IGraphBuilder
1>main.obj : error LNK2001: unresolved external symbol _IID_IMediaControl
1>main.obj : error LNK2001: unresolved external symbol _IID_IMediaEventEx
1>main.obj : error LNK2001: unresolved external symbol _IID_IVideoWindow
1>main.obj : error LNK2001: unresolved external symbol _CLSID_FilterGraph
1>D:\flexlm\Jangra\Debug\DirectShowLib-2010.dll : fatal error LNK1120: 6 unresolved externals
1> 0 Warning(s)
1> 7 Error(s)
1>
1>Time Elapsed 00:00:00.84
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========