Installing libavfilter with ffmpeg
The ffmpeg in the current repositories comes without most filters, such as overlay and movie. Those are needed if you want to watermark videos or add a logo to a video. To enable them, you'll have to install ffmpeg from SVN and configure it with --enable-filter=movie --enable-avfilter-lavf
1. Install libavfilter from SVN
svn co svn://svn.ffmpeg.org/soc/libavfilter ./checkout.sh
2. Configure and make:
./configure --enable-filter=movie --enable-avfilter-lavf make
The new ffmpeg binary will in the the 'ffmpeg' folder.
Example for watermarking a video with ffmpeg:
ffmpeg -i video.avi -vf "movie=0:png:logo.png [wm];[in][wm] overlay=X:Y:1 [out]" out.avi
You'll have to replace X and Y with the actual offset in the video.