With all due respect to Yves, I would be very cautious about downloading
codec packs from the internet. A great many of these contain substandard
software and will cause you more trouble.
Codecs are available from reputable organizations, such as Microsoft. If you
are technically inclined, you can download the GSpot tool, which will
analyze the codecs in your content, so at least you'll know exactly what you
need.
The best thing to do is to contact the content provider, and ask them how to
obtain the necessary codecs for their content.
