#Combine into montage 4 videos
avconv -i octopus_resize.mp4 -i jellyfish_nosound_resize.mp4 -i monkeytool.mp4 -i celegans_resize.mp4 -filter_complex \
'[0:v]pad=iw*2:ih*2:0:0[int2];[int2][1:v]overlay=0:H/2[int3];[int3][2:v]overlay=W/2:0[int4];[int4][3:v]overlay=W/2:H/2[out]' \
-map [out] -an -c:v libx264 -crf 23 -preset veryfast nervous_noaudio.mp4