Seconds 1 to 4
job_293d57ea89b7473eThe correct form, with the rebase.
ffmpeg -i https://cdn.rendobar.com/assets/examples/sample.mp4 -vf "trim=start=1:end=4,setpts=PTS-STARTPTS" -t 5 out.mp4container filter
The FFmpeg trim filter
Selects a time range from a stream inside the filter graph.
3 of 3 variants measured Measured 2026-08-20
The part that catches people
trim leaves the original timestamps intact, so the output starts at whatever time you trimmed from and most players show a gap. setpts=PTS-STARTPTS after it is what actually rebases the clip to zero, and it is required, not optional.
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 |
|---|---|---|---|
| Seconds 1 to 4 | 714 ms | 363.1 KB · 1280x720 | $0.0022 |
| Duration form | 725 ms | 363.1 KB · 1280x720 | $0.0021 |
| Without the rebase | 667 ms | 363.1 KB · 1280x720 | $0.0021 |
The fastest variant here is not the smallest. Without the rebase finished the encode in 667 ms, while Seconds 1 to 4 produced the smallest file at 363.1 KB. Which one matters depends on whether you are paying for compute or for storage.
The exact commands
Duration form
job_aa1f03cb64984016Same window expressed as a length.
ffmpeg -i https://cdn.rendobar.com/assets/examples/sample.mp4 -vf "trim=start=1:duration=3,setpts=PTS-STARTPTS" -t 5 out.mp4Without the rebase
job_0d3587d28fa34efcIncluded to show the timestamps problem, not as a recommendation.
ffmpeg -i https://cdn.rendobar.com/assets/examples/sample.mp4 -vf "trim=start=1:end=4" -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 trim filter do?
Selects a time range from a stream inside the filter graph.
What is the most common mistake with trim?
trim leaves the original timestamps intact, so the output starts at whatever time you trimmed from and most players show a gap. setpts=PTS-STARTPTS after it is what actually rebases the clip to zero, and it is required, not optional.
How long does trim take to run?
On a 1280x720 five-second H.264 source, the fastest variant on this page (Without the rebase) spent 667 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 trim?
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. crop Cuts a rectangle out of each frame, positioned from the top-left corner. 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.
Run trim without installing FFmpeg
Every command on this page ran through the API against a URL. No binary, no server.