Yes, it seems that Quicktime and QTKit APIs are now deprecated in Sierra, so the error you get is normal.
A workaround is to use the macOS 10.11 SDK, that you can download here.
Place the “MacOSX10.11.sdk” folder in /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs
And set the Base SDK to “OS X 10.11” for the again target in the Xcode project settings.