Sparklux Help
What Sparklux does
It converts SDR video to HDR in real time. Nothing is converted to a new file — the processing happens as the picture is drawn. It also upscales the resolution.
HDR video (HDR10, HLG, Dolby Vision Profile 8) is shown exactly as it is, untouched.
Requirements
| macOS | 14 or later |
| HDR output | An HDR-capable display is required (built-in XDR display, a supported external display, …) |
| Formats | MP4 / MOV / M4V, HLS (.m3u8), direct links, network shares |
⚠️ On a display that cannot show HDR, the conversion does not run. The app says so at the top of the window.
Do this first — calibrate your display (⌘K)
This makes the brightness correct. Without it the app uses a conservative default.
- Press ⌘K
- Step 1 of 2 — press Enter when the white panel on the left and the patch on the right look equally bright. You have it right when the edge between them disappears
- Step 2 of 2 — raise the value and press Enter when it stops getting brighter
The measurement is remembered per display.
Presets (colour rendering)
Choose from the button at the right end of the control bar.
| No conversion | Show the source as it is |
| Subtle | Slightly brighter. Use when highlights clip |
| Cinema | Keeps midtones, lifts only the highlights |
| Natural | Natural brightness. The default; hard to break |
| Vivid | Keeps colour strong in bright areas |
| Real | Photographic tonality (uses a model) |
Use A/B to compare two presets.
Resolution (upscaling)
In the lower half of the same menu.
| No upscaling | Keep the source resolution |
| Sharper (MetalFX) | Default. Uses what is in the source; it does not invent edges |
| Sharper (Lanczos) | Classic upscaling |
| Sharper (strong) | Stronger |
⚠️ Upscaling does not run when the window is smaller than the source (there is nothing to gain). The status line says so. Go full screen or enlarge the window.
Keyboard
| Space | Play / Pause |
| ← / → | Back / forward 5 seconds |
| ⌥⌘← / ⌥⌘→ | Previous / next chapter |
| ↑ / ↓ | Volume |
| ⌘K | Calibrate the display |
| ⌘⌃F | Full screen |
| ⌘O | Open a file |
| ⌘⇧L | Open a URL |
Subtitles
- Embedded subtitles are read automatically
- External subtitles are picked up when they sit next to the video with the same name
(
movie.mp4→movie.srt). SRT and WebVTT; UTF-8, Shift_JIS, EUC and UTF-16 are handled
Audio
- 5.1 and 7.1 are passed through unchanged
- On a stereo output they are folded down so that dialogue is not lost
- Dolby Atmos titles play as the 5.1 or 7.1 bed underneath
Playing a URL
Press ⌘⇧L.
- A direct video link (
https://…/movie.mp4) - HLS (
https://…/index.m3u8) - A network share address
Streaming services (YouTube and similar)
⚠️ Sparklux cannot play these on its own. It can do so only if you have installed
yt-dlp yourself, in which case it invokes it.
brew install yt-dlp
- The app neither bundles nor installs yt-dlp
- Netflix, Prime Video and Disney+ cannot be played (they are protected)
- A VPN may cause the request to be refused (403). Turn it off and try again
- Services change their delivery from time to time. Update yt-dlp if playback stops working
Power saving
Choose it from the menu. On Automatic, when the machine gets hot or runs on battery, processing is paused in stages (model → sharpening → upscaling; the HDR conversion is kept until last). The status line says what was paused.
Pricing
One-time purchase. After a seven-day free trial, a single purchase lets you use the app forever on every Mac signed in to the same Apple ID. There is no monthly fee.
- On another Mac, choose “Restore Purchase” from the menu
- iCloud is used to manage the free trial (the start date only → Privacy Policy)
Troubleshooting
| Symptom | What to check |
|---|---|
| Colour does not change | Is the display HDR-capable (is there a warning at the top)? Is the preset set to “No conversion”? |
| Upscaling has no effect | Is the window smaller than the source? Check the status line. Full screen makes it work |
| Brightness looks wrong | Calibrate with ⌘K |
| A file will not open | In System Settings → Privacy & Security → Files and Folders, grant access, or reopen with ⌘O |
| A URL will not open | Check the URL and your connection. Streaming services have the limits described above |
| No sound | Is an audio track selected (menu → Audio Track)? |