ffmpeg mp4 concat on diff size inputs

#ffmpeg concat when inputs of DIFF sizes the FAQ docs for concat do not work for me
# INPUT yuv420p, 500x868
# INPUT yuv420p, 1222x780
# prep audio
./ffmpeg  -i _seg1.mp4  -vn -f u16le -acodec pcm_s16le -ac 1 -ar 44100 - > temp1.a < /dev/null
./ffmpeg  -i _seg2.mp4  -vn -f u16le -acodec pcm_s16le -ac 1 -ar 44100 - > temp2.a < /dev/null
cat temp1.a temp2.a  > all.a
# drop audio and create streams (mp2) that can input to /cat/, balance the size using crop/pad
./ffmpeg -i _seg1.mp4 -r:v 10 -c:v libx264 -bsf:v h264_mp4toannexb -an out1.h264
./ffmpeg -i clipperDemo_p2-4-6-2012.mp4 -r:v 10 -c:v libx264 -bsf:v h264_mp4toannexb -vf crop=500:780 -an out2.h264
./ffmpeg -i out2.h264  -c:v copy  -vf pad=1220:780:360:0:violet -an out3.h264
#mp2 to mp4
cat out1.h264 out3.h264 | ./ffmpeg -i pipe:0 -vcodec copy -an  out_all.mp4
#mux audio cat & vid
./ffmpeg -f u16le -acodec pcm_s16le -ac 1 -ar 44100 -i all.a  -i out_all.mp4 -vcodec copy final.mp4