[vdr] Estimate free disc

[Usenet-372112@zocki.toppoint.de (Rainer Zocholl)]

In commands.conf i have a line

Freier Speicherplatz   : df -h | grep '/video' 
| awk '{ print "ca."(int(($4*1024/(0.5*60))))"min (" 100 - $5 "% = "$4") frei"; }'

giving the output

"ca.218min (14% = 6.2G) frei"

this is based under the assumption that the 
"typical" stream(?) will result in 0,5Mbyte/sec = 30MB/min or 1,8GB/h

Is that assumption OK/realistic?

What is the relation to the 22000/27500 (?) data rate from Satellite?