Performance Improvement A few weeks ago, when looking up how to extract video from a specified time frame using ffmpeg, I encountered an option that greatly improves the performance on using ffmpeg. What used to take a few minutes now takes a few seconds if not shorter. if you have already downloaded chansplit all add -c copy -copyts to the ffmpeg lines Code: if [ $extractFront = "yes" ];then date +"%Y-%M-%d %H:%M:%S - Starting front channel " >> chanSplitAll.log.txt chan="-front" newName=$(echo $outDir/$fname_NoExt$chan.$ext|sed 's/--front/-front/g') rm $newName ffmpeg -i $f $sound -map v:0 -async 1 -c copy -copyts $newName fi if [ $extractRear = "yes" ];then date +"%Y-%M-%d %H:%M:%S - Starting rear channel " >> chanSplitAll.log.txt chan="-rear" newName=$(echo $outDir/$fname_NoExt$chan.$ext|sed 's/--rear/-rear/g') rm $newName ffmpeg -i $f $sound -map v:1 -async 1 -c copy -copyts $newName fi My google drive and box accounts have version 10. The chansplit script files can be acquired from Google drive and box.net https://drive.google.com/folderview?id=0B-YpHDCsVqFENDd3OWl0em9fNzA&usp=sharing https://app.box.com/s/dlpz1rud480phgcca5htwp8l1s7fsz2a It appears you may need a recent version of ffmpeg. I needed to update my version I had on Windows to get "-c copy -copyts" to work This is the first work I did in over a year on chansplit all as my rear channel camera died on my two channel system and I have bought a few single channel systems since then.