63 replies to this topic

[diedie]

No problem, many thanks!

[Erik Slagter]

I'm afraid I will have to announce that without support of someone who is very technical knowledgeable about DVB subtitles, I won't be able to solve this problem. The matter is just too complex, the subs are sent encapsulated in three layers, the data is compressed bitmaps and metadata, so it's very hard to determine whether a sub is "empty" or not. Also, as I stated before, DVB subs do not come with a timeout, they're simply overwritten at some time.

[Calico]

Hello,

Do you have some news about this since your last post Erik ?

 

I was thinking about something : if I follow you correctly, we should have the same behaviour if we use a Common Inteface card on a TV with DVB-S(2) tuner ?

[Erik Slagter]

I'd love to resolve this issue, but DVB subs are really complex (and also the implementation in enigma2). This being contrary to text subs, which are quite easy to implement. What we need is someone that is familiar with all the ins and outs of DVB subs. The specifications leave too much space for questions. An nice example: DVB subs have a timeout. You'd expect this value to be used for removing the subtitle from the screen when it's done, but that's not the case. It's a fallback to prevent subs being displayed for hours if the removal of the sub has been "missed" (due to fast forwarding). With these channels you can see the timeout is always seven seconds, even though some subtitles are removed almost immediately. Subs can be removed by various means, the sub itself can be set to "empty" or even spaces, but the sub can also be removed from the "page" and the "page" can be redrawn. Or even the complete page can be flushed. It's not so clear what method is used. One big problem is that subs are bitmap encoded, so you add logging to see what's happening, but you'll never know what subtitle it's about, or of it's even a blank subtitle (removal).