> > dyld: Symbol not found: _kVTCompressionPropertyKey_H264EntropyMode What system? kVTCompressionPropertyKey_H264EntropyMode is available since macOS 10.9 and iOS 10.8. If targeting older system, we have to define it's value like kVTVideoDecoderSpecification_RequireHardwareAcceleratedVideoDecoder in videotoolbox.c