need software to edit/trim Video or MP3 files

[appledriver]

I want to convert a video file to MP3 file with cutting off the first half of the video.
I used Any Video Convertor free version. I trimed the video and the screen shows trimmed the start convert point and end convert point. However, when I click convert, the output file is not trimmed. it still a full length file.

Can anyone help me on this problem?

 

[ChCa]

MP3 is a kind of digital audio format. MPEG is for video.

Pinnacle, Avid can edit video files

 

[fmart.ca]

Cool Edit Pro可以任意切割和编辑音乐文件，源文件可以是Video文件，比如mpg。