I'm already trying to compile a list of modules that you cannot do without, but I know for a fact that I'm missing some. Mainly because I can never get the seeking function of MP4 video's working (MP4 mod) unless I install dozens of (unnecessary) modules. I'd appreciate it if someone could give me the name of the right module perhaps

So to start of with, I'd recommend:
- VLC
- Mplayer
- FMPEG
- FFMPEG-PHP
I'll expand the list further once I get back home and/or see the replies in this topic
