It appears that libav, a fork of ffmpeg (see discussion here), is a more actively developed multimedia SDK and encoder. In order to install libav, instead of ffmpeg, on Ubuntu, I follow the wonderfulHOWTO on installing and using the latest FFMPEG and x264, with the following changes:
git clone git://git.libav.org/libav.git cd libav./configure --enable-gpl --enable-version3 --enable-nonfree \ --enable-postproc --enable-libfaac --enable-libmp3lame --enable-libopencore-amrnb \ --enable-libopencore-amrwb --enable-libtheora --enable-libvorbis --enable-libx264 \ --enable-libxvid --enable-x11grab --enable-libspeex --enable-libschroedinger \ --enable-libgsm --enable-libopenjpeg --enable-librtmp --enable-libdc1394 \ --enable-frei0r --enable-libdirac --enable-libvpx --enable-doc --enable-libpulse \ --enable-gnutls --enable-librtmp make sudo checkinstall --pkgname=libav --pkgversion="5:$(date +%Y%m%d%H%M)-git" \ --backup=no --deldoc=yes --fstrans=no --default hash x264 ffmpeg ffplay ffprobe
And that's it! Remember to replace the ffmpeg executable with avconv in your scripts!