LinuxQuestions.org - Loop ends unexpectedly after one run!

Hey!

I'm trying to make my life a whole lot easier by making a bash-script, who reads a directory and greps the files that ends on mpg and mpeg, defined in a pattern.temp written by the script.
The script was designed for converting musicvideos into compliant DVD-files.

When reading (a lot of) files, the script runs smoothly the first time, but when trying to run the commands on the second file, ffmpeg somehow enforces the script to quit.
I've tried to comment out the ffmpeg line, and then the script runs just fine (even though it is useless without the ffmpeg command).

Could it be an issue with the way ffmpeg interprets the syntax's?
Hope some of you can help me, because it is starting to drive me crazy :P

Best regards
trex_dk

Code:

#!/bin/sh



if [ "$1" = "" ]; then

        echo "Specify directory containing mpegs"

else

        if [ ! -d $1 ]; then

                echo "Directory does not exist!"

                exit 0

        fi



        if [ -e patterns.temp ]; then

                rm patterns.temp

        fi

        touch patterns.temp

        echo ".mpg" > patterns.temp

        echo ".mpeg" >> patterns.temp



        numVideos=`ls $1 | grep -f patterns.temp | wc -l`



        i=1

        ls $1 | grep -f patterns.temp | while read file; do

                if [ -f "$1/$file" ]; then

                        echo "-- $file ($i / $numVideos) --"

                        echo "> Processing audio"

                        ffmpeg -i "$1/$file" -ab 256 -ar 48000 -ac 2 -acodec ac3 -y "$1/$file.ac3"

                        echo "> Processing video"

                        mpegdemux -d -s 0xe0 "$1/$file" "$1/$file.m2v"

                        echo "> Multiplexing"

                        mplex -f 8 -o "$1/final_$file" "$1/$file.m2v" "$1/$file.ac3"

                        rm -f "$1/$file.ac3" "$1/$file.m2v"

                        echo "> DONE!"

                        i=`expr $i + 1`

                fi

        done



        rm patterns.temp

fi



exit 0