* Found these USE flags for media-video/ffmpeg-0.8.6:
 U I
 - - 3dnow            : Adds support for 3dnow multimedia processor instructions
 - - 3dnowext         :  Enable manually-optimised routines using the AMD 3DNow!Ex SIMD instruction set, present in modern AMD CPUs. (Check for 3dnowext in /proc/cpuinfo to know whether your CPU supports it).
 - - X                : Adds support for X11
 - - aac              : Enables support for MPEG-4 AAC Audio
 - - aacplus          : AAC+ encoding via media-libs/libaacplus.
 - - alsa             : Adds support for media-libs/alsa-lib (Advanced Linux Sound Architecture)
 - - amr              : Enables Adaptive Multi-Rate Audio support
 - - avx              : Adds support for Advanced Vector Extensions instructions (Intel Sandy Bridge, AMD Bulldozer and later chips)
 - - bindist          : Flag to enable or disable options for prebuilt (GRP)  packages (eg. due to licensing issues)
 - - bzip2            : Use the bzlib compression library
 - - cpudetection     : Enables runtime CPU detection (useful for bindist, compatibility on other CPUs)
 - - debug            : Enable extra debug codepaths, like asserts and extra output. If you want to get meaningful backtraces see http://www.gentoo.org/proj/en/qa/backtraces.xml
 - - dirac            : Enable Dirac video support (an advanced royalty-free video compression format) via the reference library: dirac.
 - - doc              : Adds extra documentation (API, Javadoc, etc). It is recommended to enable per package instead of globally
 + - encode           : Adds support for encoding of audio or video files
 - - faac             : Use external faac library for AAC encoding
 - - frei0r           : Enable frei0r wrapping in libavfilter
 - - gsm              : Adds support for the gsm lossy speech compression codec
 - - hardcoded-tables : Use pre-calculated tables rather than calculating them on the fly.
 - - ieee1394         : Enable FireWire/iLink IEEE1394 support (dv, camera, ...)
 - - jack             : Adds support for the JACK Audio Connection Kit
 - - jpeg2k           : Support for JPEG 2000, a wavelet-based image compression format
 - - mmx              : Adds support for optimizations for Pentium MMX and Athlon class processors
 - - mmxext           : Enables mmx2 support
 + - mp3              : Add support for reading mp3 files
 - - network          : Enables network streaming support
 - - oss              : Adds support for OSS (Open Sound System)
 - - pic              : Force shared libraries to be built as PIC (this is slower)
 - - qt-faststart     : Build and install qt-faststart application
 - - rtmp             : Enable Real Time Messaging Protocol using librtmp
 - - schroedinger     : Enable Dirac video support (an advanced royalty-free video compression format) via libschroedinger (high-speed implementation in C of the Dirac codec).
 - - sdl              : Adds support for Simple Direct Layer (media library)
 - - speex            : Adds support for the speex audio codec (used for speech)
 - - ssse3            : faster floating point optimization for SSSE3 capable chips (Intel Core 2 and later chips)
 - - static-libs      : Build static libraries
 - - test             : Workaround to pull in packages needed to run with FEATURES=test. Portage-2.1.2 handles this internally, so don't set it in make.conf/package.use anymore
 - - theora           : Adds support for the Theora Video Compression Codec
 - - threads          : Adds threads support for various packages. Usually pthreads
 - - truetype         : Adds support for FreeType and/or FreeType2 fonts
 - - v4l              : Enable support for video4linux (using linux-headers or userspace libv4l libraries)
 - - vaapi            : Enables VAAPI (Video Acceleration API) for hardware decoding
 - - vdpau            : Enables VDPAU decoders (requires nVidia video cards to offload CPU processing to video card
 - - vorbis           : Adds support for the OggVorbis audio codec
 - - vpx              : Enables vp8 codec support using libvpx: Decoding vp8 does not require this to be enabled but libvpx can also be used for decoding; encoding vp8 requires this useflag to be enabled though.
 - - x264             : Enable h264 encoding using x264
 - - xvid             : Adds support for xvid.org's open-source mpeg-4 codec
 - - zlib             : Adds support for zlib (de)compression