Nageru is a live video mixer, based around the standard M/E workflow.


  • High performance on modest hardware (720p60 with two input streams on my Thinkpad X240 [1]); almost all pixel processing is done on the GPU.

  • High output quality; Lanczos3 scaling, subpixel precision everywhere, white balance adjustment, mix of 16- and 32-bit floating point for intermediate calculations, dithered output, optional 10-bit input and output support.

  • Proper sound support: Syncing of multiple unrelated sources through high-quality resampling, multichannel mixing with separate effects per-bus, cue out for headphones, dynamic range compression, three-band graphical EQ (pluss a fixed low-cut), level meters conforming to EBU R128, automation via MIDI controllers.

  • Theme engine encapsulating the design demands of each individual event; Lua code is responsible for setting up the pixel processing pipelines, running transitions etc., so that the visual look is consistent between operators.

  • Comprehensive monitoring through Prometheus metrics.


The preferred way of getting Nageru is usually from your Linux distribution of choice, but you can of course also compile it yourself (which will also usually give you a newer version). It currently need:

  • Movit, my GPU-based video filter library ( You will need at least version 1.5.2.

  • Qt 5.5 or newer for the GUI.

  • QCustomPlot for the histogram display in the frame analyzer (no longer needed from Nageru 2.2.0).

  • libmicrohttpd for the embedded web server.

  • x264 for encoding high-quality video suitable for streaming to end users.

  • FFmpeg for muxing, and for encoding audio. You will need at least version 5.0.

  • Working OpenGL; Movit works with almost any modern OpenGL implementation. Nageru has been tested with Intel on Mesa), and with NVIDIA’s proprietary drivers. The status of AMD’s proprietary drivers is currently unknown.

  • libzita-resampler, for resampling sound sources so that they are in sync between sources, and also for oversampling for the peak meter.

  • LuaJIT, for driving the theme engine. You will need at least version 2.1.

  • libjpeg, for encoding MJPEG streams when VA-API JPEG support is not available.

  • Protocol Buffers (protobuf), for storing various forms of settings and state.

  • Meson, for building.

  • Optional: CEF (Chromium Embedded Framework), for HTML graphics. If you build without CEF, the HTMLInput class will not be available from the theme. You can get binary downloads of CEF from

    Download the right build for your platform (the “minimal” build is fine) and add -Dcef_dir=<path>/cef_binary_X.XXXX.XXXX.XXXXXXXX_linux64 on the meson command line (substituting X with the real version as required).

  • Optional: libsrt, for SRT inputs (by default, Nageru will listen on port 9710, although you can change this port on the command line, turn it off with –srt-port -1, or turn it off live in the UI). SRT can also be used for output in addition to listening for HTTP (see –srt-destination). If you build with libsrt, make sure it is not linked to OpenSSL, for license reasons.

  • Optional: SVT-AV1, for encoding high-quality video suitable for streaming to end users (higher quality than using x264, but not nearly as mature). You will need at least version 1.5.0.

Futatabi also needs:

  • A fast GPU with OpenGL 4.5 support (GTX 1080 or similar recommended for best quality at HD resolutions, although 950 should work).

  • SQLite, for storing state.

If on Debian bullseye or something similar, you can install everything you need with:

apt install qtbase5-dev libqt5opengl5-dev qt5-default

pkg-config libmicrohttpd-dev libusb-1.0-0-dev libluajit-5.1-dev libzita-resampler-dev libva-dev libavcodec-dev libavformat-dev libswscale-dev libavresample-dev libmovit-dev libegl1-mesa-dev libasound2-dev libx264-dev libbmusb-dev protobuf-compiler libprotobuf-dev libsqlite3-dev meson libjpeg-dev libsrt-gnutls-dev

Exceptions as of September 2023:

  • Debian does not carry CEF (but it is optional). You can get experimental (and not security-supported) CEF Debian packages built for unstable at, and then configure Nageru with

    meson obj -Dcef_dir=/usr/lib/x86_64-linux-gnu/cef -Dcef_build_type=system -Dcef_no_icudtl=true

The patches/ directory contains a patch that helps zita-resampler performance. It is meant for upstream, but was not in at the time Nageru was released. It is taken to be by Steinar H. Gunderson <> (ie., my ex-work email), and under the same license as zita-resampler itself.

Nageru and Futatabi use Meson to build. For a default build, type

meson obj && cd obj && ninja

To start it, hook up your equipment, and then type “./nageru”.