CEA-608 as byte pairs.
Note that this format is not recommended since is does not specify to which field the caption comes from and therefore assumes it
comes from the first field (and that there is no information on the second field). Use GST_VIDEO_CAPTION_TYPE_CEA708_RAW if
you wish to store CEA-608 from two fields and prefix each byte pair with 0xFC for the first field and 0xFD for the second field.