Global USE flags

Flag Description Packages
( 2
debug 3
headless Build headless components only 2
static-libs ... 3
systemd 3
test 8
truetype 2

Category USE flags

media-video

Flag Description Packages
X 2
examples 2

net-analyzer

Flag Description Packages
haproxy add plugin check_haproxy 2
hddtemp add plugin check_hddtemp.sh 2

sys-kernel

Flag Description Packages
hardened Use selection of hardening options recommended by Kernel Self Protection Project 2
initramfs Build initramfs along with the kernel. 2
savedconfig 2

Local USE flags

app-admin

fem-netbox-user-scripts

Flag Description
dokuwiki Install also DokuWiki scripts

app-emulation

grub-xen-host

Flag Description
pvh Build an additional grub bin for pvh.

app-pda

libplist

Flag Description
python

libusbmuxd

Flag Description
kernel_linux

dev-lang

php

Flag Description
${IUSE}
acl
apache2
bcmath Add support for libbcmath
berkdb
bzip2
calendar
cdb
cgi
cjk
cli Enable CLI SAPI
coverage Include gcov symbols for test coverage and lcov reports. Only useful for extension developers, and requires GCC.
crypt
ctype Enable ctype functions
curl
embed Enable embed SAPI
enchant Add supports Enchant spelling library.
exif
fileinfo Add fileinfo extension support
filter Add filter extension support
firebird
flatfile Add dbm support for flat files
fpm Enable the FastCGI Process Manager SAPI
ftp
gd Adds support for gd (bundled with PHP)
gdbm
gmp
hash Enable the hash extension
iconv
imap
inifile Add dbm support for .ini files
intl Enables the intl extension for extended internalization support
iodbc
ipv6
json Enable JSON support
kerberos
ldap
ldap-sasl Add SASL support for the PHP LDAP extension
libedit
mhash
mssql
mysql
mysqli
nls
oci8-instant-client
odbc
opcache Enables built-in opcode cache, replacing pecl-apc et al.
pcntl Add support for process creation functions
pdo Enable the bundled PDO extensions
phar Enables the phar extension to provide phar archive support
phpdbg Enable the PHP Debug Command Line SAPI (like gdb for php)
pos
posix
postgres
qdbm
readline
recode
selinux
session
session-mm Include <pkg>dev-libs/mm</pkg> support for session storage
sharedmem Add support for shared memory use
simplexml Support for SimpleXML
snmp
soap
sockets
spell
sqlite
ssl
sysvipc Support for System V-compatible inter-process communication
threads
tidy
tokenizer Add support for the PHP file parser
unicode
wddx Add support for Web Distributed Data eXchange
webp Enable webp support for GD in php-7.x
xml
xmlreader Enable XMLReader support
xmlrpc
xmlwriter Enable XMLWriter support
xpm
xslt Enable the XSL extension
zip
zlib

media-sound

aes67-linux-daemon

Flag Description
zeroconf

media-video

decklink-drivers

Flag Description
autostart Add DesktopVideoHelper to autostart
headers Install Decklink API headers.

ffmpeg

Flag Description
amf Enables support for AMD's Advanced Media Framework (AMF)
amr Enables Adaptive Multi-Rate Audio support
amrenc Enables Adaptive Multi-Rate Audio encoding support with <pkg>media-libs/vo-amrwbenc</pkg>.
appkit Enables Apple AppKit framework
bluray Enable playback of Blu-ray filesystems
bs2b Enables <pkg>media-libs/libbs2b</pkg> based Bauer stereo-to-binaural filter.
cdio Enables audio CD grabbing with <pkg>dev-libs/libcdio</pkg>.
chromaprint Enables audio fingerprinting support with <pkg>media-libs/chromaprint</pkg>.
chromium Builds libffmpeg.so to enable media playback in Chromium-based browsers like Opera and Vivaldi.
codec2 Enables codec2 low bit rate speech codec support via <pkg>media-libs/codec2</pkg>.
cpudetection Enables runtime CPU detection (useful for bindist, compatibility on other CPUs)
cuda Enables CUDA-based acceleration. Mostly used for specific filters.
dav1d Enables AV1 decoding via <pkg>media-libs/dav1d</pkg>.
decklink Enable support for Blackmagic Design capture devices (Decklink)
drm Enable use of <pkg>x11-libs/libdrm</pkg> for various hardware accelerated functions and Kernel Mode Setting screen capture
fdk Use external fdk-aac library for AAC encoding
flite Adds a text-to-speech filter based on <pkg>app-accessibility/flite</pkg>.
frei0r Enable frei0r wrapping in libavfilter
fribidi Enables fribidi support in the drawtext filter.
gcrypt Enables gcrypt support: Needed for rtmp(t)e support if openssl, librtmp or gmp is not used.
glslang Use <pkg>dev-util/glslang</pkg> to compile GLSL
gme Enables support for <pkg>media-libs/game-music-emu</pkg> for playing various video game music formats.
gpl Build GPL code. Should be enabled unless you require LGPL binaries.
hardcoded-tables Use pre-calculated tables rather than calculating them on the fly.
iec61883 Support for FireWire DV/HDV input device using <pkg>media-libs/libiec61883</pkg>.
jpegxl Enable JPEG XL de/encoding via <pkg>media-libs/libjxl</pkg>.
kvazaar Enables <pkg>media-libs/kvazaar</pkg> based HEVC encoder.
libaom Enables <pkg>media-libs/libaom</pkg> based AV1 codec support.
libaribb24 Enables ARIB text and caption decoding via <pkg>media-libs/aribb24</pkg>.
libdrm Enables <pkg>x11-libs/libdrm</pkg> support for better screen grabbing and hardware accelerated codecs.
libilbc Enables iLBC de/encoding via <pkg>media-libs/libilbc</pkg>.
liblc3 Enable Low Complexity Communication Codec de/encoding support via <pkg>media-sound/liblc3</pkg>
libndi_newtek Enable support for Newtek NDI
libplacebo Adds flexible GPU-accelerated processing filter based on <pkg>media-libs/libplacebo</pkg>.
librtmp Enables Real Time Messaging Protocol using librtmp (<pkg>media-video/rtmpdump</pkg>) in addition to FFmpeg's native implementation.
libsoxr Enables audio resampling through <pkg>media-libs/soxr</pkg>.
libtesseract Enables the OCR filter via <pkg>app-text/tesseract</pkg>.
libv4l Uses <pkg>media-libs/libv4l</pkg> for video4linux instead of direct calls. Adds support for more devices via the userspace library.
libxml2 Uses <pkg>dev-libs/libxml2</pkg> to enable dash demuxing support.
lv2 Enables lv2 audio filter wrapper.
mipsdspr1 Enables MIPS DSP ASE R1 optimizations.
mipsdspr2 Enables MIPS DSP ASE R2 optimizations.
mipsfpu Enables floating point MIPS optimizations.
network Enables network streaming support
nvenc
ocr Enable Optical Character Recognition (OCR) filter support via <pkg>app-text/tesseract</pkg>
opencl Enable OpenCL support
openh264 Enables H.264 encoding suppoprt via <pkg>media-libs/openh264</pkg>.
openmpt Enable MPTM tracked music files decoding support via <pkg>media-libs/libopenmpt</pkg>
openssl Enables <pkg>dev-libs/openssl</pkg> support. Adds support for encrypted network protocols (TLS/HTTPS).
pic Force shared libraries to be built as PIC (this is slower)
postproc Build and install libpostproc.
qrcode Enable QR encode generation support via <pkg>media-gfx/qrencode</pkg>
qsv Enable Intel Quick Sync Video via <pkg>media-libs/intel-mediasdk</pkg> (ffmpeg versions older than, and including, 5.1) or <pkg>media-libs/libvpl</pkg> (ffmpeg version newer than 5.1).
quirc Enable QR decoding support via <pkg>media-libs/quirc</pkg>
rabbitmq Enable AMQP stream support via <pkg>net-libs/rabbitmq-c</pkg>
rav1e Enables AV1 encoding support via <pkg>media-video/rav1e</pkg>.
rubberband Adds time-stretching and pitch-shifting audio filter based on <pkg>media-libs/rubberband</pkg>.
shaderc Use <pkg>media-libs/shaderc</pkg> to compile GLSL
snappy Enable <pkg>app-arch/snappy</pkg> support. Required for e.g. Vidvox Hap encoder.
sndio Enable support for the <pkg>media-sound/sndio</pkg> backend
soc Apply additional patches for efficient playback on some SoCs (e.g. ARM, RISC-V).
srt Enable support for Secure Reliable Transport (SRT) via <pkg>net-libs/srt</pkg>
ssh Enable SSH/sftp support via <pkg>net-libs/libssh</pkg>.
svt-av1 Enables AV1 encoding support via <pkg>media-libs/svt-av1</pkg>.
twolame Enables MP2 encoding via <pkg>media-sound/twolame</pkg> as an alternative to the internal encoder.
vidstab Enables video stabilization filter using vid.stab library (<pkg>media-libs/vidstab</pkg>).
vmaf Enables Netflix's perceptual video quality assessment filter using the library (<pkg>media-libs/libvmaf</pkg>).
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.
vulkan Enables support for the vulkan API for GPU offload.
x265 Enables HEVC encoding with <pkg>media-libs/x265</pkg>.
zeromq Enables <pkg>net-libs/zeromq</pkg> support with the zmq/azmq filters.
zimg Enables <pkg>media-libs/zimg</pkg> based scale filter.
zvbi Enables <pkg>media-libs/zvbi</pkg> based teletext decoder.

ndi-sdk

Flag Description
doc
tools Install additional NDI tools

voctomix

Flag Description
gui Voctomix GTK+ application

net-analyzer

fem-nagios-plugins

Flag Description
bandwidth add plugin check_bindwidth checks switch SNMP
cgiirc add plugin check_cgiirc
gentoo-portage add plugin check_gentoo_portage
lvm add plugins check_vg_size check_lvm_cache
mailqueue-exim add plugin check_mailqueue_exim
net_traffic add plugin check_net_traffic
nfs add plugin check_nfs
nrpe_wrapper add plugin check_nrpe_wrapper
openvpn_clients add plugin check_openvpn_clients
raid add plugin check_raid
ram add plugin check_ram
sensors add plugin check_sensors
smart_sectors add plugin check_smart_sectors
temp_sensor add plugin check_sensor
uptime add plugin check_uptime checks switch SNMP
xen add plugin check_xen_cpu
xml-rpc add plugin check_xml-rpc

nagios-plugins-extended

Flag Description
apache Install Apache plugin
corosync Install Corosync plugins
megaraid Install LSI Megaraid plugin
nginx Install Nginx plugin
portage Install Portage plugins
portageagewarn Patch Portage plugin to report age from critical to warn state
suid Set SUID-Flag for several plugins
tcptraffic Install TCP-Traffic plugin
temp Install Temperature-sensor plugin
timestamp Install Timestamp-Check plugin

sys-kernel

femkvm-kernel

Flag Description
experimental Apply experimental patches; for more information, see "https://wiki.gentoo.org/wiki/Project:Kernel/Experimental".