The "libffmpeg-devel" package is required during the compilation, but it is not documented

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 - What steps will reproduce the problem?

I tried to compile the software with the following command:
python ./setup.py build

But I got an error message which says that the "libavutil/mathematics.h" file 
is missing.

After investigation, it appears that this file is in a "libffmpeg-devel" 
package. After installing it, it solved the problem.

 - What is the expected output? What do you see instead?

The list of requirements to compile the software should be written in a
"readme.txt" file given in the ".tar.gz" archive. Moreover, each one shall 
precise the version that can allow the compilation.

 - What version of the product are you using? On what operating system?

"Linux Mageia 1" 32 bits
"pyffmpeg-2.1beta.tar.gz"

 - Please provide any additional information below.

Original issue reported on code.google.com by 000JeanM...@gmail.com on 4 May 2012 at 2:17