Fade in 1s
job_172a0e7cac4a4dc0From black, starting at zero.
ffmpeg -i https://cdn.rendobar.com/assets/examples/sample.mp4 -vf "fade=t=in:st=0:d=1" -t 5 out.mp4transition filter
The FFmpeg fade filter
Fades video in from or out to a solid colour over a number of seconds.
3 of 3 variants measured Measured 2026-08-20
The part that catches people
fade takes its start position in seconds with st= but in FRAMES with s=, and the two are easy to confuse. A fade-out also needs you to know the duration in advance, because st is absolute, not measured from the end.
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 |
|---|---|---|---|
| Fade in 1s | 976 ms | 508.4 KB · 1280x720 | $0.0050 |
| Fade out at 4s | 1557 ms | 520.1 KB · 1280x720 | $0.0030 |
| Both ends | 995 ms | 516.4 KB · 1280x720 | $0.0025 |
The exact commands
Fade out at 4s
job_f74ad71863a647c2Absolute start. Change the source length and this is wrong.
ffmpeg -i https://cdn.rendobar.com/assets/examples/sample.mp4 -vf "fade=t=out:st=4:d=1" -t 5 out.mp4Both ends
job_1a3ca4c87d9a4d2cChained, which is the only way to do both.
ffmpeg -i https://cdn.rendobar.com/assets/examples/sample.mp4 -vf "fade=t=in:st=0:d=1,fade=t=out:st=4:d=1" -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 fade filter do?
Fades video in from or out to a solid colour over a number of seconds.
What is the most common mistake with fade?
fade takes its start position in seconds with st= but in FRAMES with s=, and the two are easy to confuse. A fade-out also needs you to know the duration in advance, because st is absolute, not measured from the end.
How long does fade take to run?
On a 1280x720 five-second H.264 source, the fastest variant on this page (Fade in 1s) spent 976 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 fade?
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 fade without installing FFmpeg
Every command on this page ran through the API against a URL. No binary, no server.