Building FFMPEG on Mac OSX Snow Leopard

FFMPEG is an amazing set of video and audio conversion tools, accessible via the command-line. It's rather fiddly to use, but being a command-line program it can be easily integrated into your server-side tools. The sequence of steps below worked perfectly for me on Snow Leopard with XCode 3.2.4 installed.

cd ~
# checkout the latest version of the source
svn checkout svn://svn.ffmpeg.org/ffmpeg/trunk ffmpeg
cd ffmpeg

# enable mp3 support (you need to install lame first. omit --enable-libmp3lame to build without it)
./configure --enable-libmp3lame --enable-shared  --disable-mmx --arch=x86_64

# compile
make

# install
sudo make install

Example Commands

Here are some of the commands I've run so far..

Rotate a video 90 degrees clockwise (good for films shot in portrait

ffmpeg -vf "transpose=1" -i input.mp4 output.mp4

Note that there are many tutorials on the web that suggest you should use --vfilter "rotate=90" to rotate a video. This no longer works, as vfilters has been renamed vf, and the rotate option has been removed. As of Dec 2010, the above command does work.

Convert a mp3 to a flv audio file

ffmpeg -y -i myfile.mp3 -f flv -acodec libmp3lame -ab 64 -ac 1 myfile.flv

I'm using this command as part of a project I'm working on, flv is better than mp3 as you can stream (using flowplayer) an flv in such a way that user can jump around to any point of the audio without needing to download it all to that point. However, this is quite fiddly, a future blog post will explain how I did this!

find command - search ignoring svn folders

find . -not \( -name .svn -prune \) -name 'search-pattern'

Very handy.

Syncing web servers with rsync

rsync is an amazing useful file tree synchronisation command-line tool. It's included by default on mac OS X.
Essentially you point it at a remote source directory and a local directory and it'll make the local directory reflect the remote one exactly in an amazingly fast manner. It is able to do this by only sending the changes to files across, and even then it compresses those changes so downloads are super-quick.

This means it's an excellent tool for updating the contents of remote web servers.

Now in a standard linux way, rsync is incredibly flexible and Google searches give you tons of seriously complicated stuff on it, most of which can be ignored if you just want to sync folders. For instance most tutorials include how to set up the rsync deamon, and how to make that secure.
In fact you don't need to do this at all (though I'm sure it's really useful in some circumstances), you can simply run rsync directly. It'll log in using ssh, so make sure you have a ssh user set up.

The best way to use rsync is to perform a PULL from your remote server..

eg

• ssh to your remote server


• run rsync pointing it at the machine holding the data to sync

Example Command

Log into the remote machine (e.g. the web server) and type:

rsync -avz --exclude '.svn/*' -v --delete user@example.com:path-on-example-server/ /path-on-this-server/

This command connects to example.com as the user 'user' and will sync the folder path-on-this-server with the path-on-example server on example.com. --delete means delete any files on this server that are not on the one we're syncing with. --exclude '.svn/*' will ensure that any svn folders are not copied. This is really handy.