Resize a video (1080p, 720p, 480p)
Lowering the resolution is the most effective way to make a video smaller: going from 4K to 1080p, or from 1080p to 720p, cuts the file size without the difference being visible on a phone. The width is calculated automatically to keep the proportions.
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The lower the number, the better the picture and the larger the file.
How to use it
- Install ffmpeg if you haven't already.
- Open a terminal in the folder containing your file.
- Copy the generated command, adjust the file names if needed, then run it.
- Open the resulting file to check the result.
Which resolution should you choose?
1080p suits big screens and YouTube, 720p suits messaging apps and phones, and 480p suits very small uploads. Combined with a CRF of 23, a one-minute 720p video usually weighs between 5 and 15 MB depending on the amount of motion.
The audio
The audio is copied unchanged: only the picture is recalculated. If ffmpeg reports an audio-related error, replace "-c:a copy" with "-c:a aac -b:a 160k".
Frequently asked questions
Why "-2" for the width?
The value -2 tells ffmpeg to calculate the width that keeps the proportions, rounded to an even number: the H.264 format requires even dimensions.
Does upscaling a video improve its quality?
No: upscaling adds interpolated pixels, not detail. The file gets larger without getting sharper. That's why the default option never upscales.
What about a vertical video?
The target height applies to the vertical side: a 1080 × 1920 phone video reduced to "720p" will come out at 405 × 720. To target the width instead, replace "scale=-2:720" with "scale=720:-2".