Turn a square video into a vertical short
Take a 1:1 square video to a 9:16 vertical frame. The loss profile is completely different from a landscape source, which changes the right answer.
The decision that matters: Unlike 16:9, a square source cropped to 9:16 loses the sides but keeps roughly 56% of the frame - and padding costs only modest bars. Padding is usually the better trade here.
Step by step
- Check what you actually have
Read the dimensions, ratio, duration and size off the file before deciding anything. Most bad exports come from assuming the source rather than looking at it.
Inspect the file - Compare both options for a square source
Run 1080×1080 into a 1080×1920 canvas and see the bar thickness; then compare with the crop cost.
Letterbox calculator - Crop if you chose to fill the frame
Filling the vertical frame from a square source means cutting the left and right edges - place the box where the subject actually is.
Crop precisely
What this path cannot do
- Padding a square into 9:16 leaves visible bands; some feeds letterbox it further, doubling the effect.
- Cropping still discards the left and right edges, wherever you put the box.
Koldflux runs this whole sequence automatically from one source recording.
Automate this in Koldflux