download srpms and rebuild package with other options

[Ambrogio]

Hi all,

I would like to understand well it in general, but I have a little
problem.

I would like to use ffmpeg to convert amr files into wav or other.

I installed via yum from freshrpms all ffmpeg (and all related
dependencies) but when I trie to convert my file with the command

ffmpeg -i Reg.amr Reg.wav I receive this output

FFmpeg version CVS, Copyright (c) 2000-2004 Fabrice Bellard
  configuration:  --prefix=/usr --libdir=/usr/lib64
--mandir=/usr/share/man --incdir=/usr/include/ffmpeg
--extra-cflags=-fPIC --enable-mp3lame --enable-libogg --enable-vorbis
--enable-theora --enable-faad --enable-faac --enable-libgsm
--enable-xvid --enable-x264 --enable-a52 --enable-a52bin --enable-dts
--enable-pp --enable-shared --enable-pthreads --enable-gpl
--disable-opts --disable-strip

I think that I have to download the source package and rebuild with
--enable-amr_nb --enable-amr_wb --enable-mp3lame

I don't know how to make it via rpm.

Can someone explain me all the steps?

Tnx
 Ambrogio