These are the packages that would be merged, in order:

Calculating dependencies ... done!
Dependency resolution took 1.60 s (backtrack: 0/20).

[ebuild  N     ] media-libs/giflib-6.1.3:0/7::gentoo  USE="-doc -static-libs" 460 KiB
[ebuild  N     ] dev-libs/libunibreak-8.0:0/8::gentoo  USE="-doc -man -static-libs -test" 1063 KiB
[ebuild  N     ] media-libs/alsa-topology-conf-1.2.5.1-r1::gentoo  USE="-verify-sig" 12 KiB
[ebuild  N     ] media-libs/alsa-ucm-conf-1.2.16.1::gentoo  USE="-verify-sig" 83 KiB
[ebuild  N     ] dev-lang/duktape-2.7.0-r3:0/2.7.0::gentoo  1003 KiB
[ebuild  N     ] media-libs/alsa-lib-1.2.16.1::gentoo  USE="python -debug -doc -verify-sig" PYTHON_SINGLE_TARGET="python3_14 -python3_12 -python3_13 (-python3_15)" 1104 KiB
[ebuild  N     ] acct-group/rtkit-0-r3::gentoo  0 KiB
[ebuild  N     ] media-libs/opus-1.6.1::gentoo  USE="-custom-modes -debug -deep-plc -doc -dred -hardened -osce -static-libs -test" CPU_FLAGS_X86="sse" 10228 KiB
[ebuild  N     ] dev-lang/yasm-1.3.0-r2::gentoo  USE="nls" 1458 KiB
[ebuild  N     ] media-libs/dav1d-1.5.4:0/7::gentoo  USE="8bit 10bit asm -test -xxhash" 1015 KiB
[ebuild  N     ] media-libs/x264-0.0.20240513-r1:0/164::gentoo  USE="interlaced -opencl -static-libs" 822 KiB
[ebuild  N     ] media-libs/x265-4.3:0/217::gentoo  USE="10bit 12bit cet -numa -test -vmaf" 2005 KiB
[ebuild  N     ] media-libs/xvid-1.3.7-r2::gentoo  USE="-examples" 683 KiB
[ebuild  N     ] acct-group/polkitd-0-r3::gentoo  0 KiB
[ebuild  N     ] dev-libs/double-conversion-3.4.0:0/3::gentoo  USE="-test" 6871 KiB
[ebuild  N     ] dev-libs/md4c-0.6.0::gentoo  USE="md2html -test" 263 KiB
[ebuild  N     ] sys-libs/mtdev-1.1.7::gentoo  295 KiB
[ebuild  N     ] x11-misc/xkeyboard-config-2.48::gentoo  USE="-test" 931 KiB
[ebuild  N     ] x11-libs/xcb-util-renderutil-0.3.10::gentoo  256 KiB
[ebuild  N     ] dev-db/sqlcipher-4.6.1::gentoo  USE="readline -debug -libedit -tcl -test" 18667 KiB
[ebuild  N     ] media-gfx/qrencode-4.1.1-r1:0/4::gentoo  USE="png -test" 451 KiB
[ebuild  N     ] media-libs/libexif-0.6.26::gentoo  USE="nls -doc -verify-sig" 1305 KiB
[ebuild  N     ] x11-libs/libXScrnSaver-1.2.5::gentoo  USE="-doc" 266 KiB
[ebuild  N     ] media-libs/libvpx-1.16.0:0/12::gentoo  USE="highbitdepth -doc -postproc -static-libs -test" 5504 KiB
[ebuild  N     ] x11-libs/libXv-1.0.13::gentoo  USE="-doc" 275 KiB
[ebuild  N     ] media-libs/libass-0.17.5-r1:0/9::gentoo  USE="fontconfig libunibreak -test -verify-sig" 450 KiB
[ebuild  N     ] net-libs/libssh-0.12.2:0/4::gentoo  USE="sftp zlib -debug -examples -fido2 -gssapi -mbedtls -pcap -server -static-libs -test -verify-sig" 742 KiB
[ebuild  N     ] media-libs/libwebp-1.6.0:0/7::gentoo  USE="gif jpeg opengl png tiff -static-libs -swap-16bit-csp" CPU_FLAGS_X86="avx2 sse2 sse4_1" 4196 KiB
[ebuild  N     ] acct-user/rtkit-0-r3::gentoo  0 KiB
[ebuild  N     ] acct-user/polkitd-0-r3::gentoo  0 KiB
[ebuild  N     ] x11-libs/libxkbcommon-1.13.2::gentoo  USE="X -doc -static-libs -test -tools -wayland" 1215 KiB
[ebuild  N     ] x11-libs/xcb-util-wm-0.4.2::gentoo  279 KiB
[ebuild  N     ] dev-libs/libevdev-1.13.7::gentoo  USE="-doc -test" 462 KiB
[ebuild  N     ] x11-libs/xcb-util-0.4.1::gentoo  262 KiB
[ebuild  N     ] x11-libs/xcb-util-image-0.4.1::gentoo  283 KiB
[ebuild  N     ] media-video/ffmpeg-8.1.3:0/60.62.62::gentoo  USE="X alsa bzip2 cairo dav1d drm fontconfig gmp gnutls gpl jpeg2k libass opengl openssl ssh truetype webp x264 x265 xml xvid zlib -amf -amr -amrenc (-appkit) -bluray -bs2b -cdio -chromaprint -chromium -codec2 -cuda-clang -doc -dvd -fdk -flite -frei0r -fribidi -gcrypt -gme -gsm -iec61883 -ieee1394 -jack -jpegxl -kvazaar -ladspa -lame -lcms -libaom -libaribb24 -libcaca -libilbc -liblc3 -libplacebo -librtmp -libsoxr -lv2 -lzma -modplug -nvenc -ocr -openal -opencl -opencolorio -openh264 -openmpt -opus -pulseaudio -qrcode -qsv -quirc -rabbitmq -rav1e -rist -rubberband -samba -sdl -snappy -sndio -soc -sofa -speex -srt -svg -svt-av1 -theora -twolame -v4l -vaapi -vdpau -verify-sig -vidstab -vmaf -vorbis -vpx -vulkan -zeromq -zimg -zvbi" 11458 KiB
[ebuild  N     ] net-libs/tox-0.2.23:0/0.2::gentoo  USE="av ipv6 log-error -daemon -debug -dht-node -experimental -key-utils -log-debug -log-info -log-trace -log-warn -test" 989 KiB
[ebuild  N     ] sys-auth/polkit-126-r3::gentoo  USE="nls pam -elogind -examples -gtk -introspection -kde (-selinux) (-systemd) -test" 446 KiB
[ebuild  N     ] dev-libs/libinput-1.32.0:0/10::gentoo  USE="-doc -lua -test" INPUT_DEVICES="-wacom" LUA_SINGLE_TARGET="lua5-4" 944 KiB
[ebuild  N     ] sys-auth/rtkit-0.14::gentoo  USE="(-selinux) (-systemd)" 41 KiB
[ebuild  N     ] x11-libs/xcb-util-cursor-0.1.6::gentoo  267 KiB
[ebuild  N     ] media-libs/openal-1.25.2::gentoo  USE="alsa dbus (-coreaudio) -debug -gui -jack -oss -pipewire -portaudio -pulseaudio -sdl -sndio" CPU_FLAGS_X86="sse sse2 sse4_1" 1107 KiB
[ebuild  N     ] dev-qt/qtbase-6.11.2-r2:6/6.11.2::gentoo  USE="X concurrent dbus gui libinput network nls opengl sql sqlite ssl udev widgets xml (zstd) -accessibility -brotli -cups -custom-cflags -eglfs -evdev -gles2-only -gssapi -gtk -icu -io-uring (-journald) -libproxy -mysql -oci8 -odbc -postgres -renderdoc -sctp -syslog -test -tslib -vulkan -wayland" 49398 KiB
[ebuild  N     ] dev-qt/qttools-6.11.2:6/6.11.2::gentoo  USE="assistant linguist opengl qdbus widgets (zstd) -custom-cflags -designer -distancefieldgenerator -gles2-only -kmap2qmap -pixeltool -qdoc -qml -qmlls -qtattributionsscanner -qtdiag -qtplugininfo -vulkan" LLVM_SLOT="22 -17 -18 -19 -20 -21" 9992 KiB
[ebuild  N     ] dev-qt/qttranslations-6.11.2:6/6.11.2::gentoo  USE="-custom-cflags" 1652 KiB
[ebuild  N     ] dev-qt/qtsvg-6.11.2:6/6.11.2::gentoo  USE="-custom-cflags -test" 2287 KiB
[ebuild  N     ] net-im/qtox-1.18.4::gentoo  USE="X -spellcheck" 5274 KiB

Total: 47 packages (47 new), Size of downloads: 146743 KiB

The following USE changes are necessary to proceed:
 (see "package.use" in the portage(5) man page for more details)
# required by net-im/qtox-1.18.4::gentoo
# required by =net-im/qtox-1.18.4 (argument)
>=media-video/ffmpeg-8.1.3 webp