ffplay/ffmpeg are unable to play back the Arte HD stream. Playing it
back with ffplay results stuttering audio/video (cpu usage not the
problem) and transcoding it with ffmpeg to anything you like gives a
file which has smooth audio but slowmotion video, so the audio ends way
before the video.

The ffmpeg based xine-lib plays the video part smoothly but only
produces a few audio samples once in a while. VLC and MPlayer work just
fine without any trouble. Even forcing mplayer to use ffmpeg as
demuxer, audio and video decoder doesn't cause any trouble. I've made
sure that both mplayer and my local ffmpeg installation have the svn
revision so mplayer obviously does more than just handing the data over
to ffmpeg's libs.

See ffmpeg Issue 788.