Here is script you can use to split vids un Ubuntu/Debian. It's not fast, it starts a new read for each part.
1)
sudo apt-get install libav-tools
2)
Then make a script file with contents (towebm.sh):
#################################
#!/bin/bash
doconvert()
{
i=0
while (($i < $MAXTIME)); do
MINS=$(bc <<< "scale=0; $i/60")
SECS=$(bc <<< "scale=0; $i - ($MINS * 60)")
MINS=$(printf "%02d" $MINS)
SECS=$(printf "%02d" $SECS)
OUTFN="$OUTFNPR$MINS-$SECS.webm"
if [[ ! -f "$OUTFN" ]]; then
echo "Converting $MINS:$SECS ($i)..."
avconv -i "$INFN" -sn -y -acodec libvorbis -aq 5 -ac 2 -qmin 0 -qmax 63 -crf 10 -b:v 1000K -ss 00:$MINS:$SECS -t 00:00:55 "$OUTFN"
else
echo "skipping $OUTFN"
fi
i=$(( i + 55 ))
done
}
if [[ -z "$1" ]] || [[ -z "$2" ]] || [[ -z "$3" ]] || [[ -z "$4" ]]; then
echo "Usage: ./towebm.sh [infile] [outfile-prefix] [vid-length-minutes] [vid-length-seconds]"
exit 1;
fi
INFN="$1"
OUTFNPR="$2"
MAXTIME=$(( $3*60 + $4 ))
doconvert
echo "Done"
#################################
3)
chmod +x towebm.sh
4)
./towebm.sh "/home/user/AylaDirtyPissCunt01.avi" "/home/user/AylaDirtyPissCunt01-" 1 27