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?

Solution

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).

---

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.

Comments

[Jabb]

thanx. the -fs option will stop ffmpeg. I'd like to overwrite the segment continuosly. I think I found a good solution that is quite close to what I need. -f ssegment -segment_time 60 -segment_wrap 2 tmp/out%03d.ts

[Ngoral]

Please, see the edit I made: there's a small script that can help you.

[Jabb]

Thanks. I disagree though. It is more elegant to use a native ffmpeg function instead of implementing sth. external. But since your solution is more exact I will accept it as an answer.

[Qin Heyang]

Can I also use G as the unit for Gigabyte?

[Ngoral]

@QinHeyang I can't tell right away from looking at a documentation. I guess you can simply try. I thinm it'll fail if G is not a right option