63 replies to this topic

[Calico]

Hello,

I would like to know if some people have already got the same issue : with some programs, subtitles appears and disappears too fast comparing to what people are saying.

 

This behaviour seems to appear randomly because for some translations, it's OK. I can post a video if that could help.

 

I have this problem with DVB subtitles on French Canal+ channels, HD ones in general. With the official STB, it works fine but not with OpenPLi.

 

Do you know if this could be a provider thing or something in OpenPLi configuration ?

 

Thanks for your help !

[Erik Slagter]

They're broadcasting subtitles without timestamps.

[Calico]

OK that would be a great explanation indeed... In that case, do you have any idea how this could work correctly in their official STB ? Maybe a stream with encoded timestamps that the official STB can read and not OpenPLi ?

 

Erik, do you have ever heard other satellite providers that do the same thing ? broadcasting subtitles without any timestamp ?

 

May be we could include a new setting in subtitles configuration for this kind of behaviour ? Like "Keep displaying subtitles without timestamp" : x secs" ? Just a suggestion...

 

Thank you.

[pieterg]

OK that would be a great explanation indeed... In that case, do you have any idea how this could work correctly in their official STB ?

ok, it's very ugly, but because you're asking...
They adjusted the timing at which the subtitles are broadcast, to the buffer size of their official stbs.

[Erik Slagter]

And yes, more providers are doing this, unfortunately.

[Calico]

Thank you for your reply guys, it's an ugly way indeed..

A way to convince us using their STBs I suppose...

 

What do you think about *handling* this in OpenPLi if more and more providers are doing this ? It would be a great workaround

Edited by Calico, 27 September 2013 - 21:27.

[littlesat]

For us it is very hard to solve / work-a-round... as we cannot watch those French Canal+ channels....

Edited by littlesat, 27 September 2013 - 21:28.

[theparasol]

It would be indeed an ugly fix as for every single caid:srvid we have to research (try and error?) the max subtitle buffersize and implement it someway.

 

Or perhaps just add an user customizable subtitle buffersize that can be tweaked per channel by the user itself.

[Calico]

I don't know if I was clear in my first post, but subtitles appears for 100-200 ms - maybe less - and disappears directly until next subtitle. It's completely unusable.

 

Canal+ and Canalsat broadcast a lot of films and series in original version, it's a shame that they *cheat* like this.

If you tell me that this is happening more and more, I hope that OpenPLi developers could limit its impact with our suggestions.

 

@littlesat, I thought that Canal+ FR wasn't the only one to do this according to Erik's post, and that he had himself a subscription to a provider that has the same issue. Sorry for my misunderstanding.

Edited by Calico, 27 September 2013 - 23:46.

[Erik Slagter]

Other providers do something similar, not exactly the same.

 

From a subtitle having a timestamp it is perfectly clear when it should be shown. If a timestamp is lacking, it's completely up to the internal processing of audio and video inside the demux and decodes when it's shown. It's not down to a simple delay.

 

We have a setting "subtitle delay when timing lacks", you might want to enable that.

[dirocca]

hmm, as i already mentioned in dutch forum( http://openpli.org/f...ndpost&p=374068)

the option "subtitle delay when timing lacks" doesn´t seem to work.

 

grtz Philip

[Calico]

I tried what you advised me but it doesn't have any effect.

 

"Subtitle delay when timing lacks" is a setting for subtitles displaying too early or too lately when there is no timing, isn't it ?

 

Maybe I didn't explain myself clearly enough in the first post but in this case, there is no problem about that. There is no *sync* problem at all.

 

The only thing is that some subtitles don't appear long enough, randomly. This happens about on one subtitle for five during the show. 

[Erik Slagter]

hmm, as i already mentioned in dutch forum( http://openpli.org/f...ndpost&p=374068)

the option "subtitle delay when timing lacks" doesn´t seem to work.

Yes I guess we'll need to have a look at that, what particular channel, VTM iirc?

[Erik Slagter]

I tried what you advised me but it doesn't have any effect.

 

"Subtitle delay when timing lacks" is a setting for subtitles displaying too early or too lately when there is no timing, isn't it ?

 

Maybe I didn't explain myself clearly enough in the first post but in this case, there is no problem about that. There is no *sync* problem at all.

 

The only thing is that some subtitles don't appear long enough, randomly. This happens about on one subtitle for five during the show. 

Please believe me, under water it's the same problem.

[dirocca]

hmm, as i already mentioned in dutch forum( http://openpli.org/f...ndpost&p=374068)

the option "subtitle delay when timing lacks" doesn´t seem to work.

Yes I guess we'll need to have a look at that, what particular channel, VTM iirc?

VTM HD, één HD and Doglover had the same problem on KRO(http://openpli.org/f...ndpost&p=374257)

 

 

grtz Philip

[radar]

They adjusted the timing at which the subtitles are broadcast, to the buffer size of their official stbs.

Hello,

 

Can you please explain that? I cannot get it. These subs are well synced with the video but they disappear almost as soon as they appear. So, time to display them is correctly broadcasted but delay is not well broadcasted. Am I right? So, what's the link with the buffer, I cannot understand.

It is not possible to tell our boxes that it should display subs at least for x seconds?

[Erik Slagter]

Video frames are not displayed directly as they're received. As frames tend to have dependencies on each other (cf. "I", "P" and "B" frames) it is often necessary to receive and keep in memory several frames before all can be decoded. Besides that, they also have a time code, as do the audio frames, to be able to synchronise them.

 

To cut a long story short, video frames are shown with "some" delay after being received. The delay is dependent on various things, some of them depend on the design of the settopbox (both hardware and software) and are not predictable.

 

If all of the streams are accompanied with a proper timestamp (video/audio/subs) enigma and the hardware take care they are presented to the user at exactly the right time. If the subtitles have no timestamps, enigma has no other choice then to display them when they arrive (or with a fixed delay).

 

The reason you see the subs disappear so quickly is that subtitles have no "end time". They are started and then "overwritten" by an empty subtitle. If the original and the "empty" subtitle happen to arrive at almost the same time, and have no time stamps, you'll have the effect you see.

 

It's not the way it's supposed to work, without timestamps.

Edited by Erik Slagter, 28 September 2013 - 16:43.

[radar]

Thank you very much for your very clear explanation. The goal of the empty subs is only to overwrite the previous ones? I do not pretend to be smarter than you guys and I think that you'd have already thought about it, but you never know. What about doing something like this:

if delay_since_last_sub < 2 seconds && sub_empty:
  display_sub = false

Edited by radar, 28 September 2013 - 17:14.

[Erik Slagter]

Yes that were feasible if subs would never be shorter than 2 secs. But they are, especially when "live" subtitling.

 

The "delay when timing lacks" is the setting that should workaround around this problem, if it doesn't, it should have some care.

[malakudi]

I guess what is needed here is an option "minimum duration when timing lacks". Delay does something different.