Is There an Accessible Program to Edit MP4 Video Files on the Mac?

Hello, I’m Hyongsop Kim in Korea.
I have a question about editing mp4 files, cut specific section or paste.
I heard that quick time is accessible, so I tried to edit mp4 in quick time.
Even if it is possible to edit with trim function, editing detail is not possible, because moving slide is always jump to 5·10·15 and etc, in other words, I cannot move the slide to 17.2% or 73%.
One more problem is that quick time is not support save to mp4.
So my question is that is there any accessible program to edit mp4 with detailally such as start or end point set is possible with VoiceOver?
Please help me about this.
Thank you so much.