How to Use the FFmpeg Color Filter

The FFmpeg color filter is a virtual input source that allows you to generate a video stream consisting of a single, solid color. This article provides a quick guide on how to use this filter to create solid color backgrounds, define custom resolutions, set specific frame rates, and control duration for your video processing projects.

Basic Syntax of the Color Filter

The color filter is part of the lavfi (Libavfilter virtual input) format. The basic structure of the command requires you to specify the input format as lavfi and call the color filter with your desired parameters:

ffmpeg -f lavfi -i color=c=blue -t 5 output.mp4

In this basic example, FFmpeg generates a blue video with a default resolution (320x240) and frame rate (25 fps), and the -t 5 flag limits the output duration to 5 seconds.

Key Parameters for the Color Filter

To customize the generated video, you can pass several parameters inside the color filter, separated by colons (:):

• color (or c): Specifies the color of the video. You can use standard color names (e.g., black, red, white, aquamarine) or hex values (e.g., #FF5733 or 0x123456).
• size (or s): Defines the resolution of the output video. You can use standard abbreviations like hd1080 or write the dimensions explicitly (e.g., 1920x1080).
• rate (or r): Sets the frame rate (e.g., 30 or 60).
• duration (or d): Specifies how long the video should play (in seconds).

Practical Examples

1. Create a Full HD Black Video

To create a standard 10-second black video in 1080p at 30 frames per second:

ffmpeg -f lavfi -i color=c=black:s=1920x1080:r=30:d=10 output.mp4

2. Use Hex Color Codes

If you need a specific brand color, you can use a hex code. Note that you must escape the # symbol or wrap the filter chain in quotes:

ffmpeg -f lavfi -i color=c='#FF5733':s=1280x720:d=5 output.mp4

3. Create a Transparent Video Background

If you want to generate a transparent background (useful for overlays and complex compositing), you can use the color name transparent or set the color to none, which creates a channel with zero alpha value:

ffmpeg -f lavfi -i color=c=transparent:s=1920x1080:d=5 -c:v png output.mov

(Note: To retain transparency, you must export to a codec that supports alpha channels, such as ProRes or PNG).

Using the Color Filter in Complex Filtergraphs

You can also use the color filter inside a filter_complex graph as a background canvas for other assets, such as overlaying an image or a text watermark:

ffmpeg -f lavfi -i color=c=darkblue:s=1920x1080:d=5 -i logo.png -filter_complex "[0:v][1:v]overlay=main_w-overlay_w-10:main_h-overlay_h-10" output.mp4

This command generates a dark blue 1080p background and overlays logo.png in the bottom-right corner.