There's a subtle library path problem building on OSX. The library path for x265 is empty, where all other libraries have their full path set. This causes a runtime error. So... David-Favor-iMac> which ffmpeg /david-favor-tools/osx-10.9/bin/ffmpeg David-Favor-iMac> ffmpeg -codecs | grep 26[45] dyld: Library not loaded: libx265.13.dylib Referenced from: /david-favor-tools/osx-10.9/bin/ffmpeg Reason: image not found David-Favor-iMac> otool -L /david-favor-tools/osx-10.9/bin/ffmpeg | grep x26[45] libx265.13.dylib (compatibility version 13.0.0, current version 0.8.0) /david-favor-tools/osx-10.9/lib/libx264.142.dylib (compatibility version 0.0.0, current version 0.0.0) Notice full path set for libx264 (and all other libraries), except libx265 which is empty. Temp workaround is to set a fallback library path to location of the libx265 library... David-Favor-iMac> export DYLD_FALLBACK_LIBRARY_PATH=/david-favor-tools/osx-10.9/lib David-Favor-iMac> /david-favor-tools/osx-10.9/bin/ffmpeg -codecs | grep x26[45] ffmpeg version 2.2-2014-04-02-62040-gcecb6d6 Copyright (c) 2000-2014 the FFmpeg developers built on Apr 2 2014 09:38:51 with gcc 4.8.2 (MacPots gcc48 4.8.2_0) configuration: --prefix=/david-favor-tools/osx-10.9 --enable-pic --enable-gpl --disable-indev=qtkit --disable-debug --extra-cflags='-I/david-favor-tools/osx-10.9/include -I/opt/local/include -I/usr/local/include -I/usr/include' --extra-ldflags='-Wl,-rpath,/david-favor-tools/osx-10.9/lib -Wl,-rpath,/opt/local/lib -Wl,-rpath,/usr/local/lib -Wl,-rpath,/usr/lib -L/david-favor-tools/osx-10.9/lib -L/opt/local/lib -L/usr/local/lib -L/usr/lib' --enable-version3 --enable-shared --disable-static --enable-ffplay --enable-ffprobe --enable-ffserver --enable-runtime-cpudetect --enable-nonfree --enable-zlib --enable-bzlib --enable-openssl --enable-libmp3lame --enable-libfaac --enable-libfdk_aac --enable-libvpx --enable-libtheora --enable-libvorbis --enable-libxvid --enable-libopus --enable-libopenjpeg --enable-libx264 --enable-libx265 --enable-postproc --enable-frei0r --enable-libopencore-amrnb --enable-libfreetype --enable-libmodplug --enable-libass --enable-openssl libavutil 52. 71.100 / 52. 71.100 libavcodec 55. 56.107 / 55. 56.107 libavformat 55. 36.100 / 55. 36.100 libavdevice 55. 11.100 / 55. 11.100 libavfilter 4. 3.100 / 4. 3.100 libswscale 2. 5.102 / 2. 5.102 libswresample 0. 18.100 / 0. 18.100 libpostproc 52. 3.100 / 52. 3.100 DEV.LS h264 H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10 (decoders: h264 h264_vda ) (encoders: libx264 libx264rgb ) DEV.L. hevc H.265 / HEVC (High Efficiency Video Coding) (encoders: libx265 )