Prime Video on an ultrawide monitor, without the black bars
Watching a series or a film on Prime Video on a 21:9 or 32:9 monitor often means a picture framed by black on every side. Here is why that happens and how to fill the screen in Chrome, including the parts that work differently on protected video.
Where the bars come from
Films and series come in different shapes. Cinema releases are often around 2.39:1, many modern series use 2.00:1, and documentaries are usually 16:9. Streaming services typically deliver all of them as a 16:9 video, painting black bars into the picture when the content is wider. Those bars are part of the video, so the player cannot remove them.
On a 21:9 monitor the player fits that 16:9 video to the screen height and leaves black at the sides too. The result is a window inside a window: on 3440×1440 a 2.39 film covers only about 55% of the screen, and on a 32:9 monitor about 37%.
| What you watch | 21:9 (3440×1440) | 32:9 (5120×1440) |
|---|---|---|
| 2.39 film inside a 16:9 stream | 44.6% black | 62.8% black |
| 2.00 series inside a 16:9 stream | 33.9% black | 55.6% black |
| 16:9 documentary | 25.6% black | 50% black |
The black bar calculator shows the same for any monitor size.
How to fill the screen
- Add UltraFill to Google Chrome on Windows or macOS and pin the icon to the toolbar.
- Open a title on Prime Video and go full screen.
- Hover over the top of the video and click UltraFill, or press Alt + U (Option + U on a Mac).
- In the Screen tab, choose the format of what you are watching. Start with 2.39 for films and 2.00 or 2.20 for series. If thin bars remain, try the neighbouring format; if the picture looks cut off, go one step narrower.
- Click Fill the screen or press Alt + Z.
- Hold Alt + C to check against the original.
On a 21:9 monitor a 2.39 film then fills the screen with practically nothing cut. A 2.00 series loses a thin strip at the top and bottom with crop, which is rarely noticeable. If a close-up feels tight, drag the frame in the panel preview or use Alt + Shift + arrow keys.
Choosing the format once
Prime Video protects its streams with DRM, so the browser does not let any extension look at the frames. That is why UltraFill cannot measure the bars automatically there, and you set the format yourself. With PRO the title profile remembers your choice for each film or series, so the next episode opens filled the way you left it. Auto-fill in full screen (PRO) can then apply it the moment you go full screen.
Not sure which format a title uses? The guide to black bars on 21:9 lists the common formats and what each one looks like on an ultrawide.
Crop, stretch or elastic on 32:9
On a 32:9 monitor even a perfectly chosen format leaves black at the sides, because no common film format is that wide. You can crop (free) and lose about a third of the height of a 2.39 film, stretch (free) and keep everything at the cost of wider shapes, or use elastic stretch (PRO), which keeps the center natural. On protected players like Prime Video elastic uses a gentler, simpler stretch. The 32:9 guide covers super ultrawide settings in detail.
Sound and other limits on protected video
- Sound tools (clear dialog, night mode, volume leveling, the 5-band equalizer, volume above 100%) work after one extra step: click the UltraFill icon in the toolbar or press Alt + Shift + U (Option + Shift + U on a Mac). Chrome shows a small sharing badge on the tab while it is on, which is normal.
- Effects that read the frames, such as denoise, ambient glow, the split before and after view and frame snapshots, only work on unprotected video.
- Framing, zoom, rotate, flip and the color and light sliders work as usual.
Night mode and clear dialog are especially handy for action films watched late, where explosions are loud and voices quiet. The sound presets (PRO) set this up in one click.
Questions
Why does Prime Video have black bars on my ultrawide?
Wide films and series are usually delivered inside a 16:9 video with bars baked in, and a 21:9 or 32:9 monitor adds its own bars at the sides.
Why can't UltraFill find the format automatically on Prime Video?
Prime Video uses DRM, so Chrome blocks extensions from reading the frames. You choose the format by hand, and with PRO the title profile remembers it.
Which format should I choose?
Try 2.39 for most cinema films and 2.00 or 2.20 for many series. If bars remain, pick a wider format; if the picture looks cut, pick a narrower one.
Do the sound tools work on Prime Video?
Yes. Click the UltraFill icon or press Alt + Shift + U (Option + Shift + U on a Mac) once on the tab.
Does UltraFill work in other browsers?
UltraFill is made for Google Chrome on Windows and macOS.
UltraFill is an independent extension and is not affiliated with Prime Video, Amazon or any other streaming service mentioned on this page. Service names are used only to describe compatibility.