+home directory. The machine name is youtube regarding this usage.
+
+=item -f B<FMT>, --format=B<FMT>
+
+Specify the video format (quality) in which to download the video.
+
+For youtube.com, in particular, the meaning of the format codes is given as:
+
+=over
+
+=item WebM video at 480p: 43
+
+=item WebM video at 720p: 45
+
+=item H264 video in MP4 container at 480p: 18
+
+=item H264 video in MP4 container at 720p: 22
+
+=item H264 video in MP4 container at 1080p: 37
+
+=item H264 video in FLV container at 360p: 34
+
+=item H264 video in FLV container at 480p: 35
+
+=item H263 video at 240p: 5