LiquidCast

Cast any video to Apple TV in 4K with 5.1 surround sound.

A compact macOS app that plays MKV, AVI, and other formats on your Apple TV via AirPlay — with quality you can't tell from the original.

Why LiquidCast?

Apple TV only plays certain formats (MP4, MOV). Got an MKV with 5.1 audio? AVI from years ago? LiquidCast handles it:

• Any format plays — MKV, AVI, WebM, MP4, MOV, whatever
• Original quality — 4K video + 5.1 surround audio preserved
• Instant start — Playback begins in seconds, not minutes
• Tiny footprint — Winamp-style 320×120 mini player

How It Works

LiquidCast automatically picks the fastest path to play your video:

Your File	What Happens	Wait Time
MP4/MOV (H.264 + AAC)	Plays directly	None
MKV (H.264 + AAC)	Quick repackage	~2 sec
MKV (H.264 + DTS/5.1)	Audio converted, video untouched	~3 sec
AVI/other formats	Full transcode via streaming	~5 sec

Videos stream while converting — no waiting for the whole file.

Download

Download LiquidCast v0.1.0 (949 KB)

First-time setup

1. Install FFmpeg (required for video conversion):

   /bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"
   brew install ffmpeg

2. Download and open the DMG
3. Drag LiquidCast to Applications
4. Right-click → Open (first launch only, to bypass Gatekeeper)

Requirements

• macOS 13.0+ (Ventura or later)
• FFmpeg — LiquidCast uses FFmpeg for transcoding. Without it, only MP4/MOV files will play.

Build from Source

1. Clone this repo
2. Open LiquidCast.xcodeproj in Xcode 15+
3. Build and run (Cmd+R)

Usage

1. Connect to AirPlay - Click the AirPlay icon and select your Apple TV
2. Open a video - Click + or drag a file onto the mini player
3. Control playback - Use the mini player or menu bar

Keyboard Shortcuts

Key	Action
Space	Play/Pause
←	Skip back 10s
→	Skip forward 30s
⌘O	Open file
⌘Q	Quit

Settings

Access from the menu bar:

• Ultra Quality — Maximum bitrates, 5.1 surround preserved
• Target Device — Apple TV (best) or Smart TV (compatible)
• Clear Cache — Delete converted files

Project Structure

LiquidCast/
├── Shared/
│   ├── LiquidCastApp.swift      # App entry + menu bar
│   ├── Models/AppState.swift    # Central state
│   ├── Transcoder/              # FFmpeg integration
│   ├── HTTPServer/              # HLS streaming server
│   └── Utils/                   # MediaAnalyzer, CacheManager
├── macOS/
│   ├── Views/MiniPlayerView.swift
│   └── Transcoder/              # FFmpeg process management
└── iOS/                         # iOS support (limited)

Under the Hood

• HLS Streaming — Start watching while the file converts
• Hardware encoding — Uses your Mac's VideoToolbox for speed
• Local server — Streams to Apple TV over your network
• Minimal dependencies — Just FFmpeg + Apple frameworks

License

MIT License