Convert GoPro Hero 2/3/4 MP4 to AVI for AviSynth

avconv -i GOPR0047.MP4 -acodec mp2 -b 100000k -ab 224000 GOPR0047.avi

if not found:

sudo apt-get install libavcodec-extra-53

in parallel:

find ./ -maxdepth 1 -name "*.MP4" -type f |  xargs -I@@ -P 8 -n 1 bash -c "filename=@@; avconv -i \$filename -acodec mp2 -b 100000k -ab 224000 \${filename/.MP4/}.avi"

For 120 fps video:

avconv -i GOPR0058.MP4 -acodec mp2 -vcodec ffv1 -b 100000k -ab 224000 GOPR0058.avi

in parallel:

find ./ -maxdepth 1 -name "*.MP4" -type f |  xargs -I@@ -P 8 -n 1 bash -c "filename=@@; avconv -i \$filename -acodec mp2 -vcodec ffv1 -b 100000k -ab 224000 \${filename/.MP4/}.avi"

The old way (causes audio issues on 1080p / 60fps video):

avconv -i GOPR0051.MP4 -acodec libmp3lame -ac 2 -ar 44800 -b 100000k -ab 100000 GOPR0051.avi