“_opus_multistream_encode”, referenced from: _libopus_decode_close in libavcodec.a(libopusdec.o) “_opus_multistream_decoder_destroy”, referenced from: _libopus_flush in libavcodec.a(libopusdec.o) “_opus_multistream_decoder_ctl”, referenced from: _libopus_decode_init in libavcodec.a(libopusdec.o) “_opus_multistream_decoder_create”, referenced from: “_opus_multistream_decode_float”, referenced from: _libopus_decode in libavcodec.a(libopusdec.o) “_opus_multistream_decode”, referenced from: Undefined symbols for architecture x86_64: If I want to build the 2.8 release build I will need to checkout that branch? One related question I assume this is the master branch I am building - which is the latest code. I get exactly the same error on a mac running mojave.