CoreAVC is a H.264 decoder, which currently is much faster (at least ~30% faster) than the one in libavcodec (which is used by ffdshow, and therefore CCCP). If you have a slow computer that is having problems with H.264 playback, you can try using it.
Important Note: CoreAVC is not free. It's a commercial program and you have to buy it to use it. There are no free versions available (even the alpha that some people say is free), although a free 14-day trial is available. If you want to use CoreAVC, you will have to buy it from CoreCodec.
How to use CoreAVC instead of FFDShow
- Install CoreAVC. In the installer options, uncheck "Haali Media Splitter".
- Disable FFDShow's H.264 decoding by going to the CCCP settings manager (Start -> Programs -> Combined Community Codec Pack -> Settings) and ticking CoreAVC (unchecking H.264 in the process), and then pressing Next and then Apply. If you are using a separate FFDShow install, you need to go to its video decoder settings, click the Codecs entry in the list to the left, find the H.264 entry in the grid, and change it from "libavcodec" to "disabled".
CoreAVC will now get used instead of FFDShow for H.264 decoding, provided that no other filter on your system interferes.
If CoreAVC is so great, why not use in CCCP?
We'd like to, but simply put, we can't. The CoreAVC developers has repeatedly stated that CoreAVC will not be free for personal usage, nor open source. Since we really don't want to charge money for the CCCP, including it is not an option. There are no freely distributable versions available - anyone who tells you otherwise is incorrect!
Since one of the very core purposes of the CCCP is to make H.264 more widely accepted and useable, this is a serious problem, since CoreAVC's speed enables a much larger audience (the people with slow computers) to watch H.264 encoded video. We spoke to the libavcodec developers about this, and there is an ongoing optimization effort for the h264 decoder.
Why the alpha is illegal
It could be argued that the last free alpha version (0.0.0.4) that was originally distributed for testing purposes, should be free. However, this is not the case, mostly because the alpha contains an implementation of patented technology owned by the MPEG consortium and/or the Joint Video Team, and it is illegal to use such technology without paying the appropriate licensing fees (we (the CCCP team) were close to finding out the hard way since CoreCodec more or less threatened us with lawsuits unless the alpha version that used to reside here was removed). One could ask CoreCodec why they distributed the alpha freely at all when it was illegal in many countries in the first place, but it's unlikely that CoreCodec will answer (we did ask but got none). Most likely they just wanted lots of free alpha testing before going payware.