Broadcaster identity
Read the code beside the programme
TG4 uses several subtitle codes in its listings. OS denotes English text displayed on screen; TS denotes selectable English subtitles; GS denotes selectable Irish subtitles. Combined codes describe a combination of onscreen and optional text. They describe the named programme transmission, so retain the code when choosing an edition rather than treating TG4 as having one permanent subtitle arrangement.
A useful first decision is whether you need a translation of Irish speech, text in Irish, or captions that also make relevant sound understandable. Those needs overlap, but the same text presentation need not satisfy all three. Someone following the story through English may prefer onscreen translation; someone studying the Irish dialogue needs the available Irish option.
An extra text layer can explain apparent duplication
An OS & TS listing can include an English translation already visible in the picture and an additional selectable English access layer. Before assuming duplicated text is a television fault, compare what changes when you toggle the optional subtitles during a short passage. Leave the programme playing long enough to include both dialogue and a pause with meaningful sound.
Write down what remains visible after the optional layer is off. This observation is more useful than changing screen size, colour settings or the television language. If text belongs to the programme image, the receiving device cannot remove it with a subtitle switch.
Compare the same episode across editions
TG4 documents different subtitle arrangements for Ros na Rún transmissions and Player catch-up. Use the current programme listing for your intended airing, rather than a remembered weekly time. A later repeat or omnibus may present text differently from an earlier transmission. The story can be familiar while the access arrangement changes.
For a household deciding between an appointment and replay, make a small comparison: programme date, episode, listing code, and text choices actually offered on the selected surface. Check a known line of dialogue in both versions. This avoids judging two different episodes or assuming that a Player option must exist on the linear channel.
Keep the selected version with the watchlist
Save the programme page or a brief note about the usable version. If the next episode offers different choices, repeat the item check instead of resetting the whole viewing setup. Older Player material can contain fixed subtitles, so one older recording is a poor test of the controls available on a newer episode.
Questions answered
Does GS mean the programme audio has changed?
No. It identifies an Irish subtitle option, not a different soundtrack.
Can the subtitle button remove all text on TG4?
Only optional text. Text contained in the video picture remains visible.
Sources & further reading
Official references for the subjects discussed. Service terms and device software can change.