So you’re having problems with play back of various DVD’s, XviD/DivX/3ivX, MPEG-2, and other video formats on your system. What’s the issue? Well if you’re new to the world of audio and video on computers lets start with the basics. Pretty much all audio and video you’ll encounter will be compressed in some way. When you want to play an audio or video file on your system it passes through a codec (most commonly known as COmpression/DECompression, some shorten it to COder-DECoder, either way, same thing). The codec is what uncompresses the file so that your computer can process it further. It’s actually pretty complex and I won’t get into how it exactly works by drawing it out and providing an example using GraphEdit . As an example, even if a video you’re trying to play has a file extension of AVI it could require a codec that isn’t on your system. Despite another AVI file playing just fine.

Unfortunately Windows Media Player and Media Center don’t quite do a good job at reporting what codec you need to download to play a file. As a case in point see one of the best WMP FAQ’s out there. It’s made by a guy at Microsoft named Zach, it’s great resource for almost any WMP issue. Luckily, most file types are already handled but if you’re like many people around the planet downloading videos of the net then most likely you’ll need a couple that Microsoft doesn’t ship with built in. Many sites and sources realizing this have tried to solve the problem by creating codec packs. While most of them have good intentions, often times they do more harm than good. The reason being is that you may already have the required items to play back the media and either don’t realize it because it’s hidden or it’s not installed properly.

The most common issue I’ve seen is that a user has tried installing one of these codec packs on their system to play back a DivX video that was downloaded off of Kazaa, BitTorrent, WinMX, etc. Usually it’s quite easy to see the codec packs in the same search results as the video’s themselves making it all to easy to download and install something that won’t help your experience. Some common ones are the K-Lite, Nimo, and ACE codec packs. No matter what it’s called it’s probably got some stuff in their you don’t want and definitely don’t want. Uninstalling the codec packs doesn’t always work right either. Sometimes they’ll register a filter/codec on the system and won’t remove it correctly, leaving you with junk and videos unplayable.

The codec packs will also change your audio experience as well. Especially when it comes to AC3 (Dolby Digital) and other 5.1 content, like that found on DVD’s. Often times codec packs will install a decoder that takes priority over the one you want and should be using. Of course sometimes it might just be that you’ve not gone into the Audio Properties and set your speaker set up to 5.1  (Control Panel – Sounds and Audio Devices – Advanced under Speaker settings).

What do you do then? Well my personal advice is to stay far away from codec packs. Don’t install them, period. If you’ve downloaded a file and you can’t seem to play it your best bet is to check and see what type of codecs you’ll need to install to make it play. Once you’ve done that search for the name of the codec using Google or MSN Search, try and find the original creator of the codec and install that codec and that codec alone. Installing them one at a time make problems easier to track down and makes it easier to fix any issues it may cause.

Even then unless you’re really digging through the trenches chances are you won’t need more than 2 or 3 extra codecs to play most of the content out there.

Trying to determine what codec you should use? You can try out Marc Lion’s (MVP) Sherlock Codec Detector or use GSpot.

XviD, DivX, 3ivX? I recommend using Koepi’s “latest stable” decoder. There’s also ffdshow if you’re comfortable with something a bit more complex. Though if you go with ffdshow compatibility with MCE and some issues with WMP may come up now and again depending on usage and configuration.

DVD’s, DTS, AC3 content, ideally you’ll want to use either of the big 2. InterVideo WinDVD and CyberLink’s PowerDVD, or maybe the possible third… nVidia’s DVD solution whose name seems to change constantly, and whose status is up in the air. While it may work with players like Media Player Classic (not to be confused with Windows Media Player 6.4), ffdshow is also capable of playing back DVD’s but doesn’t work too well with WMP or MCE. Personally I’d recommend using WinDVD, it’ll work in WMP, MCE, it’ll convert your TV to WMV for syncing your Portable Media Center without issue. If you’re having issues playing back DVD’s or having issues with the sound not coming out of the speakers right most likely you’ve got something mixed up with multiple decoders. Microsoft has a tool that’ll help you determine what’s going on, the Windows XP Video Decoder Checkup Utility, is plain and simple. It’ll show you what you have installed, what’s preferred (setting preferred doesn’t always work), and whether it’s WMP, MCE, PMC compatible. If you have more than one decoder (not counting the one that is sometimes installed with Nero and the one that’s installed by Sonic) you should try and track down the extra’s and uninstall them. Also, those InterActual DVD’s, watch for those, often times they’ll install their own DVD decoder which makes things worse, I’d personally stay away from anything InterActual.

QuickTime, well, despite Apple’s best effort you don’t actually have to install it with iTunes (which does more than it should to your system, even if you don’t want or own an iPod). You can find the QuickTime stand-alone installer if you look carefully enough at their main download page. Just uncheck the two boxes and don’t bother with the email address when you click the button. Doing the Typical install for QuickTime usually doesn’t do any harm to the system. You might want to pay attention to the MIME types during setup. Making sure to uncheck playback for all but QuickTime’s own content. For a while I had issues where QuickTime would try and play back all my MIDI files on various websites. So keep an eye on that.

RealPlayer, ideally you wouldn’t install this . But if you do try and make sure you turn off any of the phone home features, all the extra content, etc. Otherwise you’ll get a player that tries to overstep it’s boundaries and push itself onto you.

OGG Vorbis, FLAC, a good codec source that seems to work pretty well for me is the illiminable ogg directshow codecs release.

So that realistically covers most file types you’ll find casually browsing various sites and P2P apps. Have a problem getting an audio or video file to play, not sure what codec you need, etc? Just ask in the comments, I’d be happy to answer any questions. Or take it to the microsoft.public.windows.mediacenter or microsoft.public.mediaplayer newsgroups where any number of users and MVP’s can answer your questions.