A zone-aware compressor for watching films at home without waking the neighbours — and without the dull, lifeless sound that ordinary compression leaves behind when used on a sum signal.
It runs as a regular JACK client with a native GUI (Dear ImGui + GLFW), so it drops straight into Carla / Catia / qjackctl / PipeWire-JACK setups, but can equally be inserted into any PipeWire setup. It takes the full multichannel film sum (up to 7.1) and works on the whole mix at once.
I had been looking for a decent compressor that works on the sum of a 5.1/7.1 film, to keep the peace with my neighbours and still enjoy my home cinema. Modern cinema production tends to have extreme dynamics. Listening to that in a living-room cinema, I simply lose all the little sounds that make the atmosphere feel alive — because if I turn the volume up far enough to hear the birds chirping in the park-scene, the bomb suddenly going off shakes the walls. And behind those walls are neighbours. So I needed a different approach: proper dynamic compression that takes the characteristics of a film's final mix into account.
I tried various DAW plugins and found nothing suitable, so I wrote my own. Every compressor I tried struggled with the things that film soundtracks specifically bring with them.
Atmosphere / ambience. People, dogs, birds, traffic, the low hum of a spaceship. This mostly sits around -50 dB to -35 dB, depending on the type and age of the film.
Dialogue (including everyday sounds). Roughly -30/-20 dB up to about -10 dB.
The top end. Action sounds in action/horror movies, or generally the loud parts in other films where there are any, plus the music bed. Single events might still hit 0 dB.
Older films — even action films — tend to have a louder atmosphere stage and a quieter top end, so the perceived dynamic range is smaller, even though individual events still peak at 0 dB. Modern productions spread these zones much further apart.
To get transparent compression — compression you don't notice — you need something that changes its behaviour depending on which zone the signal is currently in. I tried cascading classic compressors; that was not transparent. cinecomp instead shapes a separate, smooth gain plateau for each zone (band-shaped weighting), with soft knees between them.
The goal: lift the atmosphere until it's nicely noticeable, lift dialogue a little less but keep it clearly audible, and tame gunshots and explosions so they still sound good but don't make me reach for the volume a dozen times per film.
I never liked the idea of compressing everything that "sticks out": used on a sum, that inevitably kills transients and becomes audible. So cinecomp uses upward compression for everything below the top-end threshold. Above it there is an optional duck stage — a classic downward compressor — for the rare true spikes, but it has very little to do, so we can run it at very gentle settings that still leave transients nicely intact.
A normal (downward) compressor reduces gain when the signal goes above a threshold: it pushes the loud parts down, then you add make-up gain to get back to a usable level. The net effect is that the peaks — the gunshot, the door slam, the orchestral hit — are exactly what gets attenuated. Transients lose their snap, make-up gain drags the noise floor up, and the whole mix ends up flatter and duller. That is the classic "compressed" sound.
Upward compression does the opposite. Everything above the threshold is left completely untouched — full original level, full transient shape. A gunshot stays a gunshot. What changes is that the quiet material underneath is raised toward the threshold, so you can lower your listening volume to a point where gunshots stay neighbour-friendly while atmosphere and dialogue remain perfectly audible.
Because the loud end is never reduced, there is no make-up gain pumping the hiss up and no transient "stomp". And because each zone's lift is a smooth, slowly-moving plateau (not a fast level-following squash), the micro-dynamics inside the atmosphere are preserved — it still breathes, it's just audible now. You raise the floor instead of crushing the ceiling: louder average level, intact transients, no dullness.
For the rare spikes that would be too much even at their original level (an explosion that still rattles the room), the optional duck stage acts only on the very top, with a soft knee and look-ahead, so it tames the wall-shaker without ever touching dialogue or atmosphere.
A compressor like this is internally a complex thing with dozens of parameters that all have to be right. Almost all of them are fixed to sensible values and are not meant to be touched in the UI — they are reachable through the init file if you really need them.
What you adjust per film is essentially two thresholds and two lifts (atmosphere and dialogue). In practice that's all it takes to fit the compression to any given film in seconds.
Dependencies (Linux):
# Debian/Ubuntu
sudo apt install build-essential pkg-config libjack-jackd2-dev libglfw3-dev libgl-dev
# Arch/Manjaro
sudo pacman -S base-devel pkgconf jack2 glfw mesa
# Fedora
sudo dnf install gcc-c++ make pkgconf jack-audio-connection-kit-devel glfw-devel mesa-libGL-develBuild:
makeOutput: a single self-contained ~900 KB ELF binary, cinecomp, in the
project root.
Build a .deb (in a throwaway debian:12 container, so the host
needs no dev packages and the binary stays glibc-portable — glibc 2.36
runs on bookworm and every newer Debian/Ubuntu):
bash build-deb.sh # → dist/cinecomp_<version>_amd64.deb
DOCKER_IMAGE=… bash build-deb.sh # override base image
BUILD_NATIVE=1 bash build-deb.sh # build on the host instead of Docker./cinecomp # defaults
./cinecomp --name comp2 --osc 14042 # second instance
./cinecomp --state /path/to/preset.ini # custom preset file| Flag | Default | Purpose |
|---|---|---|
--name <s> |
cinecomp |
JACK client name |
--osc <port> |
14041 |
OSC server port (UDP) |
--state <path> |
$XDG_CONFIG_HOME/cinecomp/state.ini |
persistence |
Settings auto-save: ~1 s debounce on slider changes, plus a final save on exit. The standalone build processes by default (bypass off) — you install it to use it. The Bypass toggle (top header row) switches to delay-matched pass-through.
cinecomp uses a single topology: zonal v2 — band-shaped gain plateaus per zone, an asymmetric upward envelope, and a soft-knee duck on top. That is the whole product; there is nothing to pick.
Two earlier prototypes — Classic (one upward stage + duck) and
Zonal v1 (summed atmo + dialogue stages + duck) — are retired. They
are no longer reachable from the GUI; the engine still accepts the old
/cinecomp/architecture OSC value only so that legacy state files keep
loading.
The v2 plateau topology is verified on hard cinema test scenes (the John Wick double-shot, the A-Quiet-Place alarm-clock and tinkering scenes, Das Boot on the open sea). It doesn't pump, it leaves transients untouched, and it lifts atmosphere transparently by up to +24 dB.
8 inputs / 8 outputs, 7.1 convention:
in_L in_R in_C in_LFE in_LS in_RS in_RBL in_RBR
out_L out_R out_C out_LFE out_LS out_RS out_RBL out_RBR
No per-layout configuration. cinecomp is layout-agnostic via smooth
per-channel weights: silent ports are automatically kept out of the
detection, so the same settings work unchanged from plain 2.0 stereo
through 5.1 right up to 7.1 — you never tell it which layout you have.
Just wire the channels you actually use (for stereo only in_L/in_R
and out_L/out_R) and leave the rest open; the active channels are
detected and the unused ones ignored.
cinecomp ships six built-in stock presets — two era families, three intensities each:
90ies Low 90ies Mid 90ies Hi
Modern Low Modern Mid Modern Hi
The era lives in the zone map: 90ies mixes have a louder, hotter atmosphere and dialogue with a smaller dynamic spread; modern mixes push the zones much further apart. The intensity (Low → Mid → Hi) raises the atmosphere and dialogue lift and brings in the duck. Pick the era that fits the film, then how hard you want it.
One dropdown lists the six stock presets plus any of your own. Type a name + Save to store the current settings under that name; pick an entry to load it; Del removes the active named one. Selection and values persist across restarts in the state file, and a preset you save under a stock name overrides that built-in one.
Full UDP OSC API (same paths as the Aroio embedded-device variant of this engine). Main controls:
/cinecomp/bypass i — 0/1
/cinecomp/detector i — 0=RMS, 1=Peak (Dual retired)
/cinecomp/architecture i — legacy/compat only; engine runs v2
# Zonal stages (the live topology)
/cinecomp/atmo/threshold f /cinecomp/atmo/max_gain f /cinecomp/atmo/knee f
/cinecomp/dialog/threshold f /cinecomp/dialog/max_gain f /cinecomp/dialog/knee f
/cinecomp/upward/attack_ms f /cinecomp/upward/release_ms f
/cinecomp/duck/attack_ms f /cinecomp/duck/release_ms f
# Legacy classic-stage paths — still accepted, but ignored under v2
/cinecomp/threshold f /cinecomp/ratio f /cinecomp/max_gain f
# Fixed internal guards — accepted for compat, not user-facing
/cinecomp/noise/floor f /cinecomp/noise/knee f
# Presets — the six stock presets are NAMED presets
/cinecomp/named/apply s — load a stock or user preset by name
/cinecomp/named/save s /cinecomp/named/delete s
# Legacy internal slots (not shown in the GUI, kept for compat)
/cinecomp/preset/select i — 0=LOW, 1=MID, 2=HIGH
/cinecomp/preset/save i /cinecomp/preset/reset i
# Meter subscribe
/cinecomp/subscribe — enable UDP meter broadcast
/cinecomp/unsubscribe
/cinecomp/get
Full list: see the doc comment at the top of src/audio_engine.c.
Cinema-tuned, zonal v2 plateau topology:
Architecture: zonal v2 Detector: Peak Bypass: OFF
Atmo: thr -35 / lift +24 / knee 20
Dialog: thr -10.5 / lift +10 / knee 13.5
Up-Env: attack 451 ms / release 20 ms (asymmetric: slow rise / fast fall)
Duck: thr -14 / ratio 1.8 / knee 16.5 / attack 9 / release 51 (LOW: off)
Fixed internal guards (not in GUI):
noise floor -80 / knee 10.5 · SC-HPF 20 Hz · lookahead 20 ms
Legacy classic-stage params (ignored — architecture is fixed v2):
thr -10 / ratio 4 / max_gain 10 / makeup 0
On first start (no state file) these built-in defaults are active and
the six stock presets are seeded into the dropdown; pick one (e.g.
Modern Mid) or just tweak — later changes persist to the state file.
MIT — see LICENSE.
Bundled third-party components:
- Dear ImGui: MIT —
vendor/imgui/LICENSE.txt - GLFW: zlib/libpng — distribution package