Centre square
job_f72fdda6f8c749d3x and y omitted, so FFmpeg centres the rectangle.
ffmpeg -i https://cdn.rendobar.com/assets/examples/sample.mp4 -vf "crop=720:720" -t 5 out.mp4video filter
The FFmpeg crop filter
Cuts a rectangle out of each frame, positioned from the top-left corner.
3 of 3 variants measured Measured 2026-08-20
The part that catches people
crop runs before scale in a filter chain unless you order it otherwise, and its x and y default to centring, not to zero. Writing crop=w:h and expecting a top-left crop is the usual surprise.
Measured, not described
Every row below is a real job. The same 1280x720 five-second H.264 source went through each variant, so the numbers are comparable to each other and to every other filter page on this site. Encode time is the FFmpeg step on its own, separated from the download and the upload.
| Variant | Encode | Output | Cost |
|---|---|---|---|
| Centre square | 710 ms | 316.2 KB · 720x720 | $0.0025 |
| Explicit top-left | 783 ms | 242.8 KB · 720x720 | $0.0023 |
| Vertical 9:16 | 592 ms | 210.0 KB · 404x720 | $0.0020 |
The exact commands
Explicit top-left
job_5466089c4f3d47ebThe same size anchored at the origin, which is what most people meant.
ffmpeg -i https://cdn.rendobar.com/assets/examples/sample.mp4 -vf "crop=720:720:0:0" -t 5 out.mp4Vertical 9:16
job_52697434610e45cfExpression form, using input height to derive a social-video crop.
ffmpeg -i https://cdn.rendobar.com/assets/examples/sample.mp4 -vf "crop=ih*9/16:ih" -t 5 out.mp4How these numbers were produced
Each variant was submitted to the Rendobar API as an ffmpeg job against the same public source file, and the response was recorded verbatim. Encode time is the API's own per-step timing for the FFmpeg step. Output size is the byte count of the file the job produced. Cost is what the job was actually billed.
Nothing here was estimated, and the whole set is re-runnable, so if a figure looks wrong it can be checked rather than argued about. The 72 variants behind this filter reference cost $0.193082 in total to measure.
Frequently asked questions
What does the FFmpeg crop filter do?
Cuts a rectangle out of each frame, positioned from the top-left corner.
What is the most common mistake with crop?
crop runs before scale in a filter chain unless you order it otherwise, and its x and y default to centring, not to zero. Writing crop=w:h and expecting a top-left crop is the usual surprise.
How long does crop take to run?
On a 1280x720 five-second H.264 source, the fastest variant on this page (Vertical 9:16) spent 592 ms inside FFmpeg. That figure is the encode step alone, measured separately from the download and the upload, so it is the filter's own cost rather than the round trip.
Do I need FFmpeg installed to use crop?
Not with Rendobar. Every command on this page ran through the Rendobar API against a URL, with no local FFmpeg install and no server. The job id next to each row is the real job that produced the numbers.
Other filters, measured the same way
scale Resizes video to a target width and height, with optional aspect-preserving arithmetic. fps Resamples video to a constant frame rate by duplicating or dropping frames. transpose Rotates video by 90 degree steps, optionally flipping as it goes. pad Adds bars around the frame to reach a target size without cropping the picture. overlay Composites one video or image on top of another at a chosen position.
Run crop without installing FFmpeg
Every command on this page ran through the API against a URL. No binary, no server.