How can i use mp4box to automatically importing mp4 and m4a files

[chpiter]

(Please forgive me for my poor English)
for example:
mp4box -add 4.21.f137.mp4 -add 4.21.f140.m4a 4.21.mp4
info:
IsoMedia import - track ID 1 - Video (size 1920 x 1080)
IsoMedia import - track ID 1 - Audio (SR 44100 - 2 channels)
Saving to 4.21.mp4: 0.500 secs Interleaving

[cnbeining]

For MP4Box:

e.g.:
MP4Box -fps 23.976 -add video1.h264 -add audio2.aac video.mp4

For myself I prefer to use ffmpeg. They would do the same job, it 's just my preference :)
e.g.:
ffmpeg -i video.m4v -i audio.m4a -c:a copy -c:v copy output.mp4

Hope this will help.

[jaimeMF]

Closing since this is not a problem with youtube-dl.