Conversion to .avi of some problematic .flv files

Recently I ve found in the net some .flv files that does not play in mplayer nor vlc (under Ubuntu intrepid), both complaining with a message:

[flv @ 0x8837aa8]Unsupported video codec (7)

These files comes encoded with the H.264 codec, and for a reason I ignore, mplayer and vlc refuses to play them, despite they support such a encoding. ffmpeg, however does, but not certainly the version shipped with Ubuntu. So the trick is to compile the latest sources of ffmpeg, which you can find via svn at:

svn checkout svn://svn.ffmpeg.org/ffmpeg/trunk ffmpeg

As the idea is to compile and use a new version of ffmpeg without touching the Ubuntu's version, you can compile it statically and install it in a directory of your own:

./configure --prefix=/path/to/your/dir --enable-static
make
make install

It is not necessary to do this under root (in fact the idea is avoid being root). Once compiled, you can use your new ffmpeg to convert the annoying file:

/path/to/your/dir/bin/ffmpeg -i your_annoying_file.flv -vcodec copy your_new_file.avi

And voilà! (at last it worked for me!)