OMP — Opportun Media Player

A local media player built on Avalonia and FFmpeg. Its headline feature: route different audio tracks from the same file to different audio output devices simultaneously — for example, main audio to your speakers and a commentary track to a headset, playing at the same time.

opportunv.github.io/OpportunMediaPlayer

Source-available, not OSI open source: free for any noncommercial use, but not under a license like MIT/GPL. See License below.

Screenshots

Features

• Multi-output audio routing — assign any audio track to any output device; the same track can be sent to multiple devices at once, each with independent volume.
• Per-output and master volume, 0–200%, composed multiplicatively (each slider's feel stays independent of the other). A quick per-output volume popup sits right on the main toolbar, next to the full routing/delay controls in Options.
• Playback speed control — 0.5x–2x, YouTube-style presets, pitch-preserving (speeding up or slowing down doesn't change pitch).
• Subtitles with positionable zones — assign subtitle tracks to on-screen zones you define and style. Load an external subtitle file onto an already-open video from Options, on top of whatever the file/URL itself provides.
• Open URL playback via yt-dlp — paste a page URL (File → Open URL...) and OMP resolves and streams it. When a video exposes multiple audio dubs or caption tracks, they show up as ordinary routable audio/subtitle tracks, same as a local file's — including auto-generated captions, in the original language and (when different) the app's own UI language.
• Light / dark / system theme, applied consistently across the main window, popups, and dialogs.
• In-app keyboard shortcut reference (Help → Keyboard Shortcuts).

Keyboard shortcuts

Keys	Action
Space	Play / pause
Left Arrow	Step back
Right Arrow	Step forward
Up Arrow	Increase volume
Down Arrow	Decrease volume
M	Toggle mute
F	Toggle fullscreen
C	Toggle subtitles
Esc	Exit fullscreen
Shift + ,	Decrease playback speed
Shift + .	Increase playback speed

Double-clicking the video also toggles fullscreen. The same shortcut list is available from Help → Keyboard Shortcuts inside the app.

Platform support

• Windows x64 — fully supported, native FFmpeg libraries bundled.
• Linux x64 — native FFmpeg libraries bundled and CI builds/tests pass, but real-world testing so far has only been on a single Ubuntu 22.04/24.04 VirtualBox VM — broader distro and desktop environment coverage is unverified. If you try it on something else, a report via Issues is welcome either way.
• macOS (Apple Silicon and Intel) — confirmed working on one Apple Silicon Mac so far — Intel and broader macOS version coverage is still unverified. Unlike Windows/Linux, FFmpeg isn't bundled; install it yourself first via Homebrew: brew install ffmpeg@7. Try it and report back via Issues, good or bad.
• Ships self-contained (bundles its own .NET 10 runtime) — no separate .NET install needed.
• URL playback is optional and needs yt-dlp installed separately (winget install yt-dlp.yt-dlp / brew install yt-dlp / pip install -U yt-dlp) — OMP looks for it on your PATH by default, or you can point it at a specific executable from Options. Not required for local files.

Limitations

These are current, code-level limits, not artificial restrictions — worth knowing before you rely on OMP for a given file:

Video

• Only the first video track in a file is used; files with multiple video tracks (e.g. multi-angle) can't switch between them.
• Decoding is software-only — no GPU-accelerated decode. Playback of very high-resolution or high-bitrate video is limited by CPU decode speed.
• All video is converted to 8-bit BGRA for display regardless of source bit depth — no HDR or 10-bit-aware rendering.
• Frame buffers are sized once when a file opens; a stream that changes resolution mid-playback is not handled.

Audio

• Every audio track is downmixed/converted to 16-bit stereo before playback — no surround-sound passthrough and no output above 16-bit, regardless of the source format.
• A given output device can only be assigned to one route at a time (you can't send two different tracks to the same speaker simultaneously), but the same track can fan out to multiple devices.

Subtitles

• Only text-based subtitle formats are supported: SRT, ASS, SSA, WebVTT, and MOV_TEXT. Bitmap-based subtitles (PGS, VobSub/DVD, DVB, XSUB) are detected and listed, but can't be routed or rendered.
• Of ASS/SSA styling, only bold, italic, and line breaks are applied. Color, custom fonts, position/movement, karaoke, and animation override tags are ignored. Embedded container fonts are not used.

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