[FFmpeg-user] Fragmented mp4

[Er errechydy]

Hi thanks for the great work, i hope you guys fine,
I have a question related to fragmented mp4 that works on media source extension, i tried this code :
" ffmpeg -i bunny.mp4 -movflags frag_keyframe+empty_moov+default_base_moof fragmented.mp4 "
but when i try to play the video using media source extension and append other videos buffer ( made with the same command above ) it didn't work.
My second question is what is the difference between 
" -f segment -segment_time 30 v%01d.mp4 "
and 
" -ss 0 -t 30 v1.mp4 "
they don't produce the same video , because when i use mp4fragment from Bento4 to turn the final video to fragmented mp4 , it worked with the second command but it didn't work for the first one, that means videos produced with " -f segment -segment_time 30 v%01d.mp4 " are different than from " -ss 0 -t 30 v1.mp4 ".
thanks