Prerequisites: LAME
MP3 is the audio codec most often used with Flash video, so you will need an MP3 encoder. FFmpeg doesn't include one, but it will use LAME, which creates good quality audio files, if you install it. Header files will be needed during the compile, so it is not enough to install a prebuilt binary using a package manager. Instead follow these directions to compile it from source:
Start by creating a working directory:
mkdir ~/lame
cd ~/lame
On a good day you can get the latest source code release of LAME from Sourceforge. The file you want will be named lame-3.97.tar.gz or something similar.
After downloading and unpacking the source or checking it out from CVS, change to the main directory and then enter the three commands which are typically used to build open source projects:
cd lame-3.97
./configure
make
sudo make install
First create a working directory:
mkdir ~/ffmpeg
cd ~/ffmpeg
The up-to-date version of FFmpeg generally compiles cleanly, and that is the version you usually will want:
svn checkout svn://svn.ffmpeg.org/ffmpeg/trunk ffmpeg
cd ffmpeg
Next, configure and make
./configure --enable-libmp3lame --enable-shared \
--disable-mmx --arch=x86_64
make
sudo make install
The --disable-mmx flag is not required on a PowerPC. If you leave it out on an Intel Mac, you will probably get a compile error, but it's worth trying since it will provide a speed boost.