How to brighten a video in VLC

Both sliders make the picture lighter, but they do it in very different ways. VLC’s image adjust filter is open source, so you can see exactly what each one does.

• Brightness adds the same amount to every pixel’s lightness. Its value runs from 0 to 2 with 1 meaning no change. Because black is raised as much as everything else, a strong setting turns the darkest parts grey and the clip looks hazy.
• Gamma bends the tone curve instead. It runs from 0.01 to 10, again with 1 as no change, and values above 1 lift the midtones while pure black and pure white stay where they are. That is why it usually looks more natural on dark footage.
• Contrast stretches the tones apart around the middle. After raising Gamma, a little extra contrast brings back some punch.
• Saturation runs from 0 to 3. Brightened video often looks pale, and a small increase helps; 0 gives black and white.
• Hue rotates all colours around the colour wheel. Leave it at the centre unless you are correcting a strong tint.

Leave Brightness Threshold unticked. It turns every pixel pure black or pure white based on the brightness setting, which is a special effect rather than a correction.

The sliders only affect what VLC draws on screen. To get a brighter file, VLC has to decode the video, run it through the same filter and encode it again. On Windows and Linux you can do that from the Convert dialog.

1. Set Image adjust the way you want it in Adjustments and Effects, then click Save so the values are stored in VLC’s preferences.
2. Choose Media → Convert / Save... (Ctrl+R), click Add..., pick your video and click Convert / Save.
3. Under Profile, choose one such as Video - H.264 + MP3 (MP4), then click the spanner button (Edit selected profile).
4. On the Video codec tab, make sure Video is ticked and Keep original video track is not; a filter can only work when the video is re-encoded.
5. Open the Filters sub-tab, tick Image properties filter and click Save.
6. Click Browse next to Destination file, give the copy a new name, and click Start. VLC shows progress in the seek bar while it converts.

The Image properties filter in the profile has no sliders of its own. Going by VLC’s source code, it reads the Brightness, Gamma and other values from the settings you saved in step 1, so if those are left at their defaults the copy comes out unchanged. Convert a short test clip first and compare it with the original.

Afterwards, untick Image adjust and click Save again, or every video will keep playing brighter. You may also want to untick the filter in the profile, or set up a separate one with Create a new profile, so later conversions don’t pick it up.

VLC for Mac uses its own interface. Choose Window → Video Effects..., open the Basic tab and tick Image Adjust. You get Hue, Contrast, Brightness, Saturation and Gamma sliders, plus a Reset button. The effect behaves the same way as on Windows: it changes playback, not the file.

The Mac window can store settings as named profiles (Duplicate current profile..., Organize profiles...) and has an Apply profile at next launch option. Saving a brightened copy is the gap. In VLC 3.0 for Mac, File → Convert / Stream... lets you choose a profile and Customize... the codecs, but it offers no list of video filters. On a Mac, use Photos or iMovie for the saved file; brightening a video on a Mac walks through both.

• Sliders do nothing: check that Image adjust is ticked. The sliders are greyed out until it is.
• Every video is now too bright: the settings apply to all playback, not one file. Untick Image adjust, and click Save if you saved them earlier.
• The converted file is as dark as before: the filter wasn’t ticked in the profile, Keep original video track was on, or the slider values weren’t saved before converting.
• The copy is blocky or much smaller: the profile’s bitrate is lower than the original’s. Adjust it under Encoding parameters on the Video codec tab.
• The picture is grainy: dark footage carries sensor noise, and any brightening lifts it. Use less Gamma, or a tool with noise reduction aimed at dark areas.

If the clip is mostly a night scene, night video enhancement explains how far it can realistically go before the grain takes over.

VLC is excellent for brighter playback, but saving a copy takes a profile edit, a saved setting and a conversion you can’t preview. brighten.video shows the result live and exports in one pass, entirely in your browser. The video is never uploaded, and there is no account or watermark.

• Click Select video, then press Auto brighten or choose Night video, Dim room, Backlit or Slightly dark, and set Strength.
• Drag the Before and after divider across a dark scene. More options has Exposure, Midtones (gamma), Shadows, Blacks, Contrast and Noise reduction, each with its own reset.
• Click Export video, choose Format, Size and Quality under Export settings, then Download video when “Your video is ready” appears.

Like a VLC conversion, the export is re-encoded, and detail that was recorded as pure black can’t be brought back. For keeping the loss small, see brightening a video without losing quality.