Closed caption data is definitely not teletext.
Since it contains a EIA-608 compatibility stream,
the EIA_608 codec ID is at least not completely wrong.
Fixes subtitle playback in MPlayer with the sample in
trac ticket #1482.
To fix the ticket itself I expect FFmpeg will need
a closed-caption to SRT decoder first.
Signed-off-by: Reimar Döffinger <Reimar.Doeffinger@gmx.de>