Composites one video or image on top of another at a chosen position.
Without shortest=1 the output runs as long as the LONGEST input, so overlaying a small logo on a long video is fine, but overlaying a long loop on a short clip silently extends the clip. The other trap is format: overlaying a transparent PNG onto yuv420p can lose the alpha unless the chain converts.
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 |
|---|---|---|---|
| Top-left, 10px inset | 2077 ms | 563.0 KB · 1280x720 | $0.0036 |
| Bottom-right | 1115 ms | 533.0 KB · 1280x720 | $0.0027 |
| Centred | 3968 ms | 596.8 KB · 1280x720 | $0.0056 |
Explicit stream labels. A two-input overlay needs them, and -vf cannot express it.
ffmpeg -i https://cdn.rendobar.com/assets/examples/sample.mp4 -i https://cdn.rendobar.com/assets/brand/web-app-manifest-192x192.png -filter_complex "[0:v][1:v]overlay=10:10" -t 5 out.mp4Capitals are the base, lowercase the overlay. This is the expression people look up.
ffmpeg -i https://cdn.rendobar.com/assets/examples/sample.mp4 -i https://cdn.rendobar.com/assets/brand/web-app-manifest-192x192.png -filter_complex "[0:v][1:v]overlay=W-w-10:H-h-10" -t 5 out.mp4Same convention, centred.
ffmpeg -i https://cdn.rendobar.com/assets/examples/sample.mp4 -i https://cdn.rendobar.com/assets/brand/web-app-manifest-192x192.png -filter_complex "[0:v][1:v]overlay=(W-w)/2:(H-h)/2" -t 5 out.mp4Each 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.
Composites one video or image on top of another at a chosen position.
Without shortest=1 the output runs as long as the LONGEST input, so overlaying a small logo on a long video is fine, but overlaying a long loop on a short clip silently extends the clip. The other trap is format: overlaying a transparent PNG onto yuv420p can lose the alpha unless the chain converts.
On a 1280x720 five-second H.264 source, the fastest variant on this page (Bottom-right) spent 1115 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.
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.
Every command on this page ran through the API against a URL. No binary, no server.