我正在遵循此处的参考文献（http://developer.apple.com/iphone/library/qa/qa2010/qa1702.html）来从iPhone相机中获取视频。除了该页面上的代码外，这是一个全新的项目。我还将AVFoundation框架添加到了项目中。以下是我收到的链接错误：
Build my project of project my project with configuration Debug
CompileC "build/my project.build/Debug-iphoneos/my project.build/Objects-normal/armv6/MainViewController.o" /Users/mwilliamson/Projects/my_project/iphone/Classes/MainViewController.m normal armv6 objective-c com.apple.compilers.gcc.4_2
cd /Users/mwilliamson/Projects/my_project/iphone
setenv LANG en_US.US-ASCII
setenv PATH "/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin:/Developer/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/X11/bin:/opt/local/bin:/usr/local/git/bin"
/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/gcc-4.2 -x objective-c -arch armv6 -fmessage-length=0 -pipe -std=c99 -Wno-trigraphs -fpascal-strings -O0 -Wreturn-type -Wunused-variable -isysroot /Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS4.0.sdk -fvisibility=hidden -gdwarf-2 -mthumb -miphoneos-version-min=4.0 -iquote "/Users/mwilliamson/Projects/my_project/iphone/build/my project.build/Debug-iphoneos/my project.build/my project-generated-files.hmap" "-I/Users/mwilliamson/Projects/my_project/iphone/build/my project.build/Debug-iphoneos/my project.build/my project-own-target-headers.hmap" "-I/Users/mwilliamson/Projects/my_project/iphone/build/my project.build/Debug-iphoneos/my project.build/my project-all-target-headers.hmap" -iquote "/Users/mwilliamson/Projects/my_project/iphone/build/my project.build/Debug-iphoneos/my project.build/my project-project-headers.hmap" -F/Users/mwilliamson/Projects/my_project/iphone/build/Debug-iphoneos -I/Users/mwilliamson/Projects/my_project/iphone/build/Debug-iphoneos/include -I/Users/mwilliamson/Projects/my_project/iphone/opencv_device/include "-I/Users/mwilliamson/Projects/my_project/iphone/build/my project.build/Debug-iphoneos/my project.build/DerivedSources/armv6" "-I/Users/mwilliamson/Projects/my_project/iphone/build/my project.build/Debug-iphoneos/my project.build/DerivedSources" -include /var/folders/kW/kW6u6B7SGyGYu+nNumtIa++++TI/-Caches-/com.apple.Xcode.501/SharedPrecompiledHeaders/my_project_Prefix-alujyqxskcuyuogdsynmjyrkxbhh/my_project_Prefix.pch -c /Users/mwilliamson/Projects/my_project/iphone/Classes/MainViewController.m -o "/Users/mwilliamson/Projects/my_project/iphone/build/my project.build/Debug-iphoneos/my project.build/Objects-normal/armv6/MainViewController.o"
/Users/mwilliamson/Projects/my_project/iphone/Classes/MainViewController.m: In function '-[MainViewController captureOutput:didOutputSampleBuffer:fromConnection:]':
/Users/mwilliamson/Projects/my_project/iphone/Classes/MainViewController.m:126: warning: 'MainViewController' may not respond to '-imageFromSampleBuffer:'
/Users/mwilliamson/Projects/my_project/iphone/Classes/MainViewController.m:126: warning: (Messages without a matching method signature
/Users/mwilliamson/Projects/my_project/iphone/Classes/MainViewController.m:126: warning: will be assumed to return 'id' and accept
/Users/mwilliamson/Projects/my_project/iphone/Classes/MainViewController.m:126: warning: '...' as arguments.)
Ld "build/my project.build/Debug-iphoneos/my project.build/Objects-normal/armv6/my project" normal armv6
cd /Users/mwilliamson/Projects/my_project/iphone
setenv IPHONEOS_DEPLOYMENT_TARGET 4.0
setenv PATH "/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin:/Developer/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/X11/bin:/opt/local/bin:/usr/local/git/bin"
/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/gcc-4.2 -arch armv6 -isysroot /Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS4.0.sdk -L/Users/mwilliamson/Projects/my_project/iphone/build/Debug-iphoneos -F/Users/mwilliamson/Projects/my_project/iphone/build/Debug-iphoneos -filelist "/Users/mwilliamson/Projects/my_project/iphone/build/my project.build/Debug-iphoneos/my project.build/Objects-normal/armv6/my project.LinkFileList" -dead_strip -lz -lstdc++ /Users/mwilliamson/Projects/my_project/iphone/opencv_device/lib/libcxcore.a /Users/mwilliamson/Projects/my_project/iphone/opencv_device/lib/libcv.a -miphoneos-version-min=4.0 -framework Foundation -framework UIKit -framework CoreGraphics -framework AVFoundation -o "/Users/mwilliamson/Projects/my_project/iphone/build/my project.build/Debug-iphoneos/my project.build/Objects-normal/armv6/my project"
Undefined symbols:
"_CVPixelBufferGetBaseAddress", referenced from:
-[MainViewController imageFromSampleBuffer:] in MainViewController.o
"_CVPixelBufferUnlockBaseAddress", referenced from:
-[MainViewController imageFromSampleBuffer:] in MainViewController.o
"_CVPixelBufferLockBaseAddress", referenced from:
-[MainViewController imageFromSampleBuffer:] in MainViewController.o
"_CMSampleBufferGetImageBuffer", referenced from:
-[MainViewController imageFromSampleBuffer:] in MainViewController.o
"_CVPixelBufferGetHeight", referenced from:
-[MainViewController imageFromSampleBuffer:] in MainViewController.o
"_kCVPixelBufferPixelFormatTypeKey", referenced from:
_kCVPixelBufferPixelFormatTypeKey$non_lazy_ptr in MainViewController.o
(maybe you meant: _kCVPixelBufferPixelFormatTypeKey$non_lazy_ptr)
"_CVPixelBufferGetWidth", referenced from:
-[MainViewController imageFromSampleBuffer:] in MainViewController.o
"_CVPixelBufferGetBytesPerRow", referenced from:
-[MainViewController imageFromSampleBuffer:] in MainViewController.o
"_CMTimeMake", referenced from:
-[MainViewController setupCaptureSession] in MainViewController.o
"_CVPixelBufferGetDataSize", referenced from:
-[MainViewController imageFromSampleBuffer:] in MainViewController.o
ld: symbol(s) not found
collect2: ld returned 1 exit status
CompileC "build/my project.build/Debug-iphoneos/my project.build/Objects-normal/armv7/MainViewController.o" /Users/mwilliamson/Projects/my_project/iphone/Classes/MainViewController.m normal armv7 objective-c com.apple.compilers.gcc.4_2
cd /Users/mwilliamson/Projects/my_project/iphone
setenv LANG en_US.US-ASCII
setenv PATH "/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin:/Developer/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/X11/bin:/opt/local/bin:/usr/local/git/bin"
/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/gcc-4.2 -x objective-c -arch armv7 -fmessage-length=0 -pipe -std=c99 -Wno-trigraphs -fpascal-strings -O0 -Wreturn-type -Wunused-variable -isysroot /Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS4.0.sdk -fvisibility=hidden -gdwarf-2 -mthumb -miphoneos-version-min=4.0 -iquote "/Users/mwilliamson/Projects/my_project/iphone/build/my project.build/Debug-iphoneos/my project.build/my project-generated-files.hmap" "-I/Users/mwilliamson/Projects/my_project/iphone/build/my project.build/Debug-iphoneos/my project.build/my project-own-target-headers.hmap" "-I/Users/mwilliamson/Projects/my_project/iphone/build/my project.build/Debug-iphoneos/my project.build/my project-all-target-headers.hmap" -iquote "/Users/mwilliamson/Projects/my_project/iphone/build/my project.build/Debug-iphoneos/my project.build/my project-project-headers.hmap" -F/Users/mwilliamson/Projects/my_project/iphone/build/Debug-iphoneos -I/Users/mwilliamson/Projects/my_project/iphone/build/Debug-iphoneos/include -I/Users/mwilliamson/Projects/my_project/iphone/opencv_device/include "-I/Users/mwilliamson/Projects/my_project/iphone/build/my project.build/Debug-iphoneos/my project.build/DerivedSources/armv7" "-I/Users/mwilliamson/Projects/my_project/iphone/build/my project.build/Debug-iphoneos/my project.build/DerivedSources" -include /var/folders/kW/kW6u6B7SGyGYu+nNumtIa++++TI/-Caches-/com.apple.Xcode.501/SharedPrecompiledHeaders/my_project_Prefix-gtrotaxhqdjhgqbqbsnyeqjkaxdt/my_project_Prefix.pch -c /Users/mwilliamson/Projects/my_project/iphone/Classes/MainViewController.m -o "/Users/mwilliamson/Projects/my_project/iphone/build/my project.build/Debug-iphoneos/my project.build/Objects-normal/armv7/MainViewController.o"
/Users/mwilliamson/Projects/my_project/iphone/Classes/MainViewController.m: In function '-[MainViewController captureOutput:didOutputSampleBuffer:fromConnection:]':
/Users/mwilliamson/Projects/my_project/iphone/Classes/MainViewController.m:126: warning: 'MainViewController' may not respond to '-imageFromSampleBuffer:'
/Users/mwilliamson/Projects/my_project/iphone/Classes/MainViewController.m:126: warning: (Messages without a matching method signature
/Users/mwilliamson/Projects/my_project/iphone/Classes/MainViewController.m:126: warning: will be assumed to return 'id' and accept
/Users/mwilliamson/Projects/my_project/iphone/Classes/MainViewController.m:126: warning: '...' as arguments.)
Ld "build/my project.build/Debug-iphoneos/my project.build/Objects-normal/armv7/my project" normal armv7
cd /Users/mwilliamson/Projects/my_project/iphone
setenv IPHONEOS_DEPLOYMENT_TARGET 4.0
setenv PATH "/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin:/Developer/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/X11/bin:/opt/local/bin:/usr/local/git/bin"
/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/gcc-4.2 -arch armv7 -isysroot /Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS4.0.sdk -L/Users/mwilliamson/Projects/my_project/iphone/build/Debug-iphoneos -F/Users/mwilliamson/Projects/my_project/iphone/build/Debug-iphoneos -filelist "/Users/mwilliamson/Projects/my_project/iphone/build/my project.build/Debug-iphoneos/my project.build/Objects-normal/armv7/my project.LinkFileList" -dead_strip -lz -lstdc++ /Users/mwilliamson/Projects/my_project/iphone/opencv_device/lib/libcxcore.a /Users/mwilliamson/Projects/my_project/iphone/opencv_device/lib/libcv.a -miphoneos-version-min=4.0 -framework Foundation -framework UIKit -framework CoreGraphics -framework AVFoundation -o "/Users/mwilliamson/Projects/my_project/iphone/build/my project.build/Debug-iphoneos/my project.build/Objects-normal/armv7/my project"
Undefined symbols:
"_CVPixelBufferGetBaseAddress", referenced from:
-[MainViewController imageFromSampleBuffer:] in MainViewController.o
"_CVPixelBufferUnlockBaseAddress", referenced from:
-[MainViewController imageFromSampleBuffer:] in MainViewController.o
"_CVPixelBufferLockBaseAddress", referenced from:
-[MainViewController imageFromSampleBuffer:] in MainViewController.o
"_CMSampleBufferGetImageBuffer", referenced from:
-[MainViewController imageFromSampleBuffer:] in MainViewController.o
"_CVPixelBufferGetHeight", referenced from:
-[MainViewController imageFromSampleBuffer:] in MainViewController.o
"_kCVPixelBufferPixelFormatTypeKey", referenced from:
_kCVPixelBufferPixelFormatTypeKey$non_lazy_ptr in MainViewController.o
(maybe you meant: _kCVPixelBufferPixelFormatTypeKey$non_lazy_ptr)
"_CVPixelBufferGetWidth", referenced from:
-[MainViewController imageFromSampleBuffer:] in MainViewController.o
"_CVPixelBufferGetBytesPerRow", referenced from:
-[MainViewController imageFromSampleBuffer:] in MainViewController.o
"_CMTimeMake", referenced from:
-[MainViewController setupCaptureSession] in MainViewController.o
"_CVPixelBufferGetDataSize", referenced from:
-[MainViewController imageFromSampleBuffer:] in MainViewController.o
ld: symbol(s) not found
collect2: ld returned 1 exit status