Pad adds borders to fit; crop fills the frame but trims edges.

What is force_original_aspect_ratio?

An ffmpeg scale option to preserve aspect while scaling.

Commands copy audio stream without re-encoding.

Consider `-crf 18 -preset veryslow` for best quality (H.264).

Aspect Ratio Converter

Compute crop/pad and get ffmpeg commands.

Tip: Your data stays in your browser.

Source width

Source height

Target ratio

Target resolution example: 608×1080 (scaled)

ffmpeg commands

ffmpeg -i input.mp4 -vf "scale=608:1080:force_original_aspect_ratio=decrease,pad=608:1080:(ow-iw)/2:(oh-ih)/2:black" -c:a copy output_pad_608x1080.mp4

ffmpeg -i input.mp4 -vf "scale=608:1080:force_original_aspect_ratio=increase,crop=608:1080" -c:a copy output_crop_608x1080.mp4

FAQs

Pad or crop?
Pad adds borders to fit; crop fills the frame but trims edges.
What is force_original_aspect_ratio?
An ffmpeg scale option to preserve aspect while scaling.
Audio changed?
Commands copy audio stream without re-encoding.
Any quality tips?
Consider `-crf 18 -preset veryslow` for best quality (H.264).

Guides

YouTube Thumbnail Size and Ratio (2025)

Exact sizes and aspect ratios for YouTube, Shorts, and Instagram thumbnails — with quick presets.

Read →

Convert 16:9 to 9:16 Without Cropping (ffmpeg)

Pad to vertical or crop intelligently. Copy-ready ffmpeg commands and when to use each.

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