Poor quality on listening radios or seen videos on internet

[fred_m]

Hy for all,

I have installed on my machine Fedor Core 4 64 bits, Firefox 1.5, realplayer 10, mplayer and skype.

I get poor quality of radios on internet, videos on internet and voip calls using skype. When a seen videos on mplayer, the audio and video is ok.

If i use same programs on windows, the quality is very good, so my internet link is ok.

I think that is missing any codec on my linux.

How i solve this problem ??

Tanks.