Quicktime Alternative

Very similar to Real Alternative, QuickTime Alternative is a trimmed down version of QuickTime that contains only the essential components needed for playing QuickTime content that is embedded in webpages.

Real Alternative

After having installed Combined Community Codec Pack on your fresh Windows System, you may stumple upon some real video files which don't play back (f.ex. Real Video 4.0 format isn't supported by ffdshow from that codec pack).

But there's still no reason to install the oficial Real Video package, which clutters your system with unnecessary stuff (that codec really sucks, go for x264 instead).


With Real Alternative you can play Real Media files without RealPlayer.
The pack can be used with any DirectShow-enabled media player, such as Media Player Classic, which is included as part of the package.
As you already will have installed the CCCP, you can just install the Lite version, which doesn't include Media Player Classic.

Combined Community Codec Pack

Combined Community Codec Pack is a DirectShow filter pack for Windows systems.

It covers a huge amount of video codecs and filters, and as far as I know the only one that officially is supporting the Matroska format (I like this one especially).

It is also unofficially endorsed by On2, the makers of the VP series of codecs (VP3, VP6, VP7) as a reliable codec pack to use for decoding video.

Also recommended by a large number of anime fansubbing groups, this filter pack is a must to install into a fresh Windows copy.

ffmpeg

ffmpeg is a very powerful video coding suite. It is a complete solution to record, convert and stream audio and video. It includes libavcodec, the leading audio/video codec library. ffmpeg is developed under Linux, but it can be compiled under most operating systems, including Windows.

How to enable mp3 support?

Because of license rights, ffmpeg doesn't include encoding support of mp3 by default.
So we have to recompile it or get a non-free version of ffmpeg.

Install from non-free repository

You can find an already compiled version of ffmpeg in the MediBuntu repository.
It contains a ffmpeg compiled with risky option.

Recompile by yourself

In Ubuntu this can be done quite simply.
Just follow these steps in a shell.

• Install necessary development packs:
  

  sudo apt-get install quilt libsdl1.2-dev libogg-dev libvorbis-dev liba52-dev
  libdts-dev libimlib2-dev texi2html libraw1394-dev libdc1394-13-dev
  libtheora-dev libgsm1-dev
  liblame-dev libxvidcore-dev libfaac-dev libfaad2-dev libx264-dev



• Download ffmpeg sources:
  

  cd /usr/local/src
  sudo apt-get source ffmpeg
  cd ffmpeg



• The most important step: enable support for mp3, x264, etc:
  

  export DEB_BUILD_OPTIONS=risky

  
  
• Build installable debian packages

  sudo dpkg-buildpackage
  cd ..



• Finally, install all generated debian packages:
  

  sudo dpkg -i ffmpeg_0.cvs20060823-3.1ubuntu4+medibuntu2_x86.deb libavcodec0d_0.cvs20060823-3.1ubuntu4+medibuntu2_x86.deb libavcodec-dev_0.cvs20060823-3.1ubuntu4+medibuntu2_x86.deb ... 

  
  Essentially, you have to list all generated debian packages here.
  
  Maybe you could do something like this:
  

  sudo dpkg -i `ls *.deb`

Test the non-free version

That's it. Now we can test the installation:

 ffmpeg -i some_of_your_movies.avi -ar 44100 test.flv

This should convert one of your AVI movies into a Flash Video.
ffmpeg shouldn't claim any longer about unknown codec for output stream 0.1 (the audio one).