Opening a .mp4 file with notepad++

Solution 1:

Any file on the drive is just a series of 0 and 1. Some groups of them in some locations have special meaning (like the "magic bytes" that would indicate that "this is a mp4 file", etc)

When you open the mp4 file with notepad++, notepad++ ignored the "magic bytes" that say "hey this is a mp4 file!" because it simply doesn't know any better and instead assumed the file was just a badly written text file and read it into memory as such, and assumed the 0 and 1 were plain ASCII text characters and displayed the result to you.

There are all sorts of non-printable characters when something like that happens, and some include calls to the PC speaker system (system beep), etc. so you can get really weird results if you simply cat the file too... although some files on some systems - a simple WAV file on a Linux system for example - can be made sense of by sending it directly to the sound hardware cat /path/to/foo.wav > /dev/dsp