KSKPix — Open-Source Licenses & Source Offer

Last updated: July 26, 2026

KSKPix is built on outstanding open-source software. This page lists every open-source component bundled in the KSKPix apps, per platform, along with its license — and, for the copyleft (LGPL) components, the exact buildable source and scripts so those libraries can be rebuilt and relinked as their licenses provide.

KSKPix ships as three builds from two codebases, and they do not bundle the same media stack, so the platform each component applies to is called out throughout:

• Apple TV (tvOS) — native SwiftUI app
• iPhone & iPad (iOS) — Flutter app
• Android phones & tablets — Flutter app
• Android TV & Fire TV — native Jetpack Compose app

Copyleft components (LGPL)

These carry source-availability obligations, which the links below satisfy.

AetherEngine — LGPL v3, with an App Store exception (Apple TV)

The primary playback engine on Apple TV is AetherEngine by Vincent Herbst, used under the GNU LGPL v3 together with that project's App Store / DRM exception. We build it from the published sources with a small number of local patches of our own.

• Upstream source, version 5.23.7: superuser404notfound/AetherEngine
• Our modifications: aether-5.23.7-kskpix.patch
• The build script that produces the framework we ship: build-aether.sh

FFmpeg — LGPL v2.1 or later (all platforms)

KSKPix uses libraries from the FFmpeg project under the GNU LGPL v2.1. Every FFmpeg build we ship is LGPL-only — configured without any GPL component. FFmpeg is a trademark of Fabrice Bellard, originator of the FFmpeg project. There are three distinct FFmpeg builds across the apps:

• iPhone & iPad — our own static build (FFmpeg 7.1.5), used by the MediaBridge playback path. Source tarball (sha-256 pins in checksums.txt), our pinned build script build-ffmpeg.sh, our complete modifications ffmpeg-7.1.5-mediabridge.patch and one added bitstream filter dovi_convert_bsf.c. The script produces the exact FFmpegBridge.xcframework the app ships; because it is linked statically, relinking a modified FFmpeg means rebuilding with this script and replacing the framework in the app project.
• Apple TV — the dynamic frameworks from FFmpegBuild 2.2.0, which arrive with AetherEngine. Unmodified upstream binaries; that project's build.sh is the recipe. As dynamic frameworks these can be replaced in the app bundle directly.
• Android — the FFmpeg inside libmpv, via media_kit (below). Unmodified upstream binaries.

libVLC / TVVLCKit — LGPL v2.1 or later (Apple TV)

The alternate playback engine on Apple TV uses TVVLCKit from the VideoLAN project. We use unmodified official binaries (CocoaPods TVVLCKit); source is available from VideoLAN at the link above.

mpv / media_kit — LGPL v2.1 or later (iPhone, iPad, Android)

The alternate playback engine in the mobile app uses libmpv via media_kit. We use unmodified official media_kit binaries; their build recipes are published at libmpv-darwin-build and libmpv-android-build.

libzvbi — LGPL v2.0 or later (Apple TV)

Teletext decoding, arriving with AetherEngine's FFmpeg build and conveyed under LGPL v2.1; its ure.c is MIT. Its three GPL-licensed source files are removed before the library is built, so no GPL code is compiled into the app — that modification is published in FFmpegBuild's build.sh. Source: zapping.sourceforge.net/ZVBI.

FriBidi — LGPL v2.1 or later (iPhone, iPad)

Bidirectional text for subtitle rendering, built by the same script as our FFmpeg build above.

Permissive components

Media & playback

• AndroidX Media3 / ExoPlayer — Apache 2.0 (Android TV, Fire TV, Android phones). The mobile app ships a small fork of the video_player_android plugin, which reads its buffer and track-language preferences natively; the fork is Apache 2.0 like its upstream.
• dav1d (AV1 decoding) — BSD 2-Clause, VideoLAN (Apple TV, iPhone, iPad)
• libdovi (dolby_vision crate, Dolby Vision RPU processing) — MIT, quietvoid/dovi_tool (Apple TV, iPhone, iPad)
• zimg (colour-space conversion) — WTFPL, sekrit-twc/zimg (Apple TV)
• libass — ISC · FreeType — FTL · HarfBuzz — MIT (subtitle rendering, built by the same script as our FFmpeg build) (iPhone, iPad)

App frameworks & libraries

• Flutter — BSD 3-Clause · Dart — BSD 3-Clause (iPhone, iPad, Android phones)
• Kotlin, Kotlin Multiplatform runtime, kotlinx (coroutines, serialization, datetime) — Apache 2.0 (all platforms; the shared data layer)
• Jetpack Compose, AndroidX (incl. TV Material, Lifecycle, WorkManager) — Apache 2.0 (Android TV, Fire TV, Android phones)
• SQLDelight — Apache 2.0 · sqflite — MIT · SQLite — public domain (all platforms)
• Ktor client — Apache 2.0 · OkHttp — Apache 2.0 · Dio — MIT (networking)
• Coil — Apache 2.0 (Android TV, Fire TV) · cached_network_image / flutter_cache_manager — MIT (mobile)
• Riverpod, go_router, flutter_svg, share_plus, url_launcher, path_provider, shared_preferences, package_info_plus, device_info_plus, connectivity_plus, wakelock_plus — BSD 3-Clause / MIT (mobile)
• flutter_secure_storage — BSD 3-Clause · encrypt — BSD 3-Clause · crypto — BSD 3-Clause (credential storage and encrypted backups)
• ZXing — Apache 2.0 (Android TV, Fire TV) · qr_flutter / qr — BSD 3-Clause · mobile_scanner — BSD 3-Clause (device-to-device transfer QR codes)
• SMBClient — MIT (Apple TV)
• Firebase SDKs (crash reporting & anonymous analytics, opt-out in Settings) — Apache 2.0 · CrashKiOS — Apache 2.0 (all platforms)
• JetBrains Mono (basis of the KSK Term brand font) — SIL OFL 1.1 · Google Fonts package — Apache 2.0

Written offer

License texts for all of the above are available at the linked projects. If you would like any of this source material on physical media, or object code suitable for relinking a modified LGPL library into the app, ask us through the support page and we will provide it.