ModsFinder

AetherFlow (Letterbox Mod)

by Kiwisaki

AetherFlow draws cinematic black bars across the top and bottom of the screen when a player sneaks, and the bars fade out when the player stops.

FabricClient-side onlyMIT LicenseOpen source1.21.4

What it does

Holding Shift activates a letterbox effect in which smooth black bars slide in and out with an ease-in, ease-out motion. The bars sit behind the hotbar and other HUD elements, so the interface stays readable while the frame narrows. The effect triggers on its own once the mod is active, and no key is needed beyond the sneak control.

AetherFlow is a client-side only mod, so only the player's client needs it and servers run without it. It is released under the MIT License and is open source, with source code published publicly. The Fabric build targets 1.21.4 and is the only loader offered. Installing it requires Fabric Loader and Fabric API, after which the game is launched and the configuration is adjusted if needed. The author credits beltrancruz and the FabricMC community.

The mod is small in scope, and its authors note minimal performance impact. It suits players who want a film-like view during adventure play or while filming screenshots, without changing gameplay or world content.

Key features

  1. Sneak-triggered letterbox

    Sneaking shows black bars at the top and bottom of the screen, creating a cinematic frame.

  2. Smooth fade animation

    The bars fade in and out with an ease-in, ease-out curve rather than snapping into place.

  3. HUD layering

    The bars render behind the hotbar and other HUD elements so the interface remains visible.

  4. Automatic activation

    Once installed and configured, the effect runs without a separate toggle, tied to sneaking.

Compatibility

Latest build for each game version and loader.

1.21.41.0.0
ReleaseBetaAlphaNot available

Only full game releases are shown. This mod publishes no snapshot builds.

How it compares

Full comparison

Ji AFK Cinematic is also client-side only and covers 1.21 – 26.3 on Fabric, but it uses a custom license and is not open source. Cinematic Respawn is client-side only, offered for Fabric, Forge and NeoForge across 1.7.10 – 26.2, and is under All rights reserved, so it is not open source. AetherFlow is open source under the MIT License and targets only 1.21.4 on Fabric.

ModLoadersGame versionsEnvironmentUpdated
AetherFlow (Letterbox Mod)Fabric1.21.4Client-side only2025-07-25
Ji AFK CinematicFabric1.21 – 26.3Client-side only2026-09-21
Cinematic RespawnFabric, Forge and NeoForge1.7.10 – 26.2Client-side only2026-09-22

Questions

Does AetherFlow need Fabric API?

Yes. Fabric Loader and Fabric API must both be installed before AetherFlow is launched.

Does AetherFlow have to be installed on the server?

No. It is installed on the player's side alone, so servers need nothing.

Which game versions does AetherFlow support?

The only game version listed is 1.21.4, and the latest Fabric file is 1.0.0 for 1.21.4, published 2025-07-25.

In the catalog

AetherFlow (Letterbox Mod) is one of 19,031 Adventure mods on ModsFinder, and one of 10,052 Adventure mods for Fabric. 17,979 mods support Minecraft 1.21.4.

Adventure mods19,031Fabric modsMods for 1.21.417,979

Similar mods

Sound Physics Remastered1.19 – 26.3Advancement Plaques1.12.2 – 26.3JourneyMap1.7.10 – 26.3Boat Item View1.16.5 – 26.3Shoulder Surfing Reloaded1.7.10 – 26.3Dynamic Lights1.17 – 26.2

What the author says

No configuration needed. The mod activates the effect automatically when sneaking. Developed by @beltrancruz Special thanks to FabricMC and the Minecraft modding community.
Kiwisaki, on the Modrinth page

Official listing

Owner
Kiwisaki
Published
2025-07-25
Updated on Modrinth
2025-07-25
Facts verified
2026-10-15

Tags

AdventureUtility
Open on ModrinthCompare