CEA-608 rendering broken

Created by: TobbeEdgeware

The rendering of Closed Captioning CEA_608 is broken (since 2.2.1, it seems). The mixed samples included in the reference player renders both TTML and CEA-608 at the same time. The URL is http://vm2.dashif.org/dash/vod/testpic_2s/cea608_and_segs.mpd

The plain CEA-608 sample (http://vm2.dashif.org/dash/vod/testpic_2s/cea608.mpd) is working better, but the rendered size is too small and does not scale when going to full screen.

I hope to fix this for 2.4, but if I don't manage it may be better to include the plain samples instead of the mixed cases.