Color & filter adjustments

Color correction is the difference between footage that looks like it came from a professional shoot and footage that looks like a home video. Cameras routinely produce clips that are slightly too dark (underexposed), washed out (low contrast), or color-shifted (the auto white balance picked the wrong tone). These are quick fixes when you have the right controls.

The three main adjustments cover most correction needs. Brightness corrects exposure. Contrast controls the separation between dark and light areas. Saturation controls how vivid or muted the colors are. Most footage needs a small adjustment to all three rather than a large adjustment to one.

The color adjustments are applied using FFmpeg's eq (equalization) filter with three parameters: eq=brightness=B:contrast=C:saturation=S. Brightness ranges from -1 to 1 in FFmpeg's scale. Contrast ranges from 0 to 2 (1.0 is no change, 2.0 doubles contrast). Saturation ranges from 0 to 3 (1.0 is no change, 0 produces grayscale, 3 is maximum saturation). The tool passes the values with three decimal places of precision using .toFixed(3).

The output is re-encoded with libx264 at the ultrafast preset and CRF 23, with AAC audio and +faststart. The eq filter applies mathematically to every pixel in every frame, so the processing time scales directly with video length and resolution.

For footage shot in shade or overcast, start with brightness +0.05 to +0.10 and contrast 1.10 to 1.20. Most phone cameras in low light produce soft, slightly gray results that these values correct. Avoid pushing brightness above +0.2 without increasing contrast: boosting brightness without contrast makes the image look hazy.

Saturation of 1.3 to 1.5 is the standard range for social media color grading: it makes colors pop without looking unnatural. Saturation above 2.0 typically looks artificial. For a desaturated or cinematic look, values between 0.5 and 0.8 produce a muted, filmic palette.

DaVinci Resolve and Premiere have primary color correction tools with the same three controls plus many more. For a quick correction before sharing, opening a color grading application is more than the task requires. Mobile apps apply color adjustments to photos but not to video. This tool applies the same eq filter that professional FFmpeg workflows use, locally in the browser.