How to limit output filesize of ffmpeg input stream to 10 megabytes

Question

I am subscribing to an input stream from tvheadend using ffmpeg and I am writing that stream to disk continuously . I'd like to limit this output stream so that there are 10 megabytes of data stored at maximum at any time.

I already looked into sponge from moreutils and the linux buffer command to build some kind of a pipe . Though, I could not find a working solution yet. Who can point me into the right direction?

Answer 1

You need just -fs key. It sets output filesize limit in bytes.

You can type ffmpeg -i input -fs 10M -c copy output, where input is your input address, output - filename you want your file to have. M specifies that you want size in megabytes (also k for kilobytes is allowed).

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For overwriting you can use a small sript like this

#!/bin/bash

t=1
while :
do
 ffmpeg -i input -fs 10M -c copy output$t
 t=`expr $t + 1`
done

I think this is more elegant than trying to do everything using ffmpeg only.