TalkingSoft.com Forums: Newbie needs some help understanding Codecs - TalkingSoft.com Forums

In spite of all the reading I've done, I don't feel the concepts are cemented in my mind yet. I understand that Codecs are small programs that encode & decode audio/video with a specific format. But where are these programs stored and how do software audio/video players use them.

Windows media player seems to know how to play an MP3 but not a DVD (mpeg-2). Presumably I need to install an mpeg-2 codec but what one to install? Are some of my choices YMPEG, Stinkys MPEG2 Codec, NVIDA PureVideo Decoder, ffdshow (or is this just a filter) ? At the same I have Cyberlink DVD player installed which does play DVDs natively. Is the codec built-in to Cyberlink? It doesn't seem to get it's codec from the same place as Windows Media Player. Can you make Cyberlink play mpeg-4 files if the codec is installed, and if so will Windows Media Player also be able to work on mpeg-4, or do different players look in different places for their codec?

When I installed Virtualdub, I had to install AC3 ACM decompressor so that Virtualdub could understand AC3. Now that AC3 ACM is installed can Windows Media Player or Cyberlink DVD player make use of it as a decompressor if they can't natively understand AC3? What is the difference between AC3 ACM and AC3 Filter?

What is DirectShow?

How does a Filter function differently from a Decoder, since they both seem to function as decompressors?


Thanks in advance for your time.

Filter IS a codec, many codecs are directshow comaptable, the acm codecs are recognized by certain appslike you saw, vdub isone. The specific diff. I actually forgot, but suffice tosay.... the codecs are use to decode the media files. First a splitter is used to split the audio from the video, then the proper, hopefulyy, codec is called to jandle the decoding.
For a nice overview it would be easiest for you to google Graphedit, then drop a file on it and tell it to render. The resulting graph will show you how the codecs are used. The priority settings are what win uses to choose which codec to use. It tries them in order until it hits on a combo that works. If you load alot of codecs on your system you'll find it takes longer for win to start playing files, it has to hunt through them to find the right combo. The higher the pririty the sooner it gets tried.

Graphedit will show you what is meant by 'filter chains' and all that jazz.

Have fun!

topcat139