kenner

A command-line tool for applying the Ken Burns pan/zoom effect to still images, producing video output via ffmpeg.

Features

• Smooth zoom + pan animation on any still image
• Handles landscape, portrait, and wide panoramic images automatically
• Crops to output aspect ratio without letterboxing or empty space
• Configurable focal point, pan direction, zoom level, duration, and resolution
• Random focal point and direction when not specified

Requirements

• Go 1.16+
• ffmpeg (with ffprobe)

Build

go build -o kenner .

Usage

./kenner -input <image> [options]

Options

Flag	Default	Description
-input	(required)	Input image path
-output	<input>_kenburns.mp4	Output video path
-duration	10	Video length in seconds
-fps	25	Frames per second
-width	1920	Output width in pixels
-height	0 (auto 16:9)	Output height in pixels
-focal-x	random	Focal point X coordinate
-focal-y	random	Focal point Y coordinate
-direction	random	Pan direction
-zoom	1.3	End zoom level (e.g. 1.3 = 30% zoom)
-scale-up	auto	Internal upscale factor

Directions

north, south, east, west, northeast, northwest, southeast, southwest

Examples

Basic usage (random focal point and direction)

./kenner -input photo.jpg

Produces photo_kenburns.mp4 — a 10-second, 1920x1080 video with a random pan/zoom.

Specify direction and duration

./kenner -input landscape.jpg -duration 15 -direction southeast

15-second video panning southeast with a gradual 1.3x zoom.

Portrait image, panning north

./kenner -input portrait.jpg -direction north -zoom 1.5

Automatically crops to 16:9, zooms to 1.5x while panning upward.

Custom focal point and output size

./kenner -input photo.jpg -focal-x 960 -focal-y 540 -width 1280 -height 720 -duration 8

Zooms into the center of a 1920x1080 image, outputting 1280x720 at 8 seconds.

Wide panoramic banner

./kenner -input banner.png -direction east -width 1280 -zoom 1.4

Crops the wide image to 16:9 and pans eastward.

How It Works

1. Detects input image dimensions via ffprobe
2. Crops to the target output aspect ratio, centering on the focal point
3. Scales up the cropped image to provide room for zooming
4. Constructs an ffmpeg zoompan filter with computed expressions for smooth linear interpolation of zoom level and pan position
5. Encodes to H.264 MP4

License

GPL-2.0