Docs / How-to guides

Run ffmpeg on Remote Files

The mount is a path. ffmpeg does not know the file lives elsewhere.

Transcode a remote file

ffmpeg -i ~/KeibiDrop/Mount/raw/clip.mov -c:v libx264 -crf 20 out.mp4

ffmpeg reads the source sequentially; the mount streams it on demand with read-ahead, so the transcode runs at the link's pace without a full download first. Only the bytes ffmpeg reads cross the network.

Write results back

ffmpeg -i ~/KeibiDrop/Mount/raw/clip.mov -c copy ~/KeibiDrop/Mount/delivery/clip.mp4

Output written into the mount lands on the other machine as it is read there. The render-then-remux chain, one peer renders, the other remuxes cold through its own mount and the result propagates back, is part of KeibiDrop's test battery.

Probe and clip without fetching everything

ffprobe ~/KeibiDrop/Mount/raw/clip.mov
ffmpeg -ss 00:12:00 -i ~/KeibiDrop/Mount/raw/clip.mov -t 30 -c copy sample.mp4

A seek with -ss fetches the region it lands on, not the file up to it. Cutting a 30 second sample out of an hour-long remote recording moves roughly the sample, not the hour.

On slow links

• The first open of a large MP4 reads its index; on a high-latency link expect a short pause before frames flow.
• Leave prefetch off (the default). A transcode saturates the link by itself; prefetch on top starves seeks. See the configuration reference.
• Batch jobs script cleanly with kd.