Teletext subtitles (2 Viewers)

[misterd]

The computing power isn't the only reason. I think that the main reason is the handling of the rendering in MP itself.
I will try to explain it.
Before my patch the rendering of the pages was done in one of the main threads of MP. Since the creation of the images needs a lot of cpu time, it blocked the rendering of the video.
Now the images were created in separated thread with lowest priority and only every 300 milliseconds. But there is an exclusion: All page updates (e.g. subtitles) are rendered in a third thread to get it sync.
So we have to differ between two scenarios. If you only get stuttering when the pages are updated, than I could transfer the image creation to my separated thread. But if you even get stuttering when you enter the teletext page number than we have to find another solution (e.g. filter solution).

MisterD

 

[vuego]

I'm trying out teletext subtitles in TVE3 (SVN15504). Only some subtitles are shown and when they do they stay on too long. Perhaps this is a known issue?

I was wondering if there's a possibility to scale the subtitles? On my projector the subtitles are more than 2 meters wide I would like to bring it down to 30% or so. What about an option to change size of the whole teletext "window" instead of it going fullscreen?

Thanks for your work on this

 

[Throt]

Hi

Thanks for the info, it's interesting to learn more how things work.

I haven't seen any stuttering if I only open for example P100 (except when P100 is shown) and leave it at that. There is also no stuttering when entering pagenumbers.

But if I activate the subtitles there is stuttering on and off regardless if there is any actual subtitling. Perhaps the page updates comes even if there is no text to be shown? Anyway, I think your idea about transferering imagecreation should do the trick as all things point to the update scenario.

Now when I've done some more testing, I can see some delays of the text sometimes, but the tricky thing is to know whether it's MP or the actual broadcast (I suspect the latter), TT subtitling usually isn't that in sync/good anyway.

Rgds
Throt

 

[misterd]

I'm trying out teletext subtitles in TVE3 (SVN15504). Only some subtitles are shown and when they do they stay on too long. Perhaps this is a known issue?

I was wondering if there's a possibility to scale the subtitles? On my projector the subtitles are more than 2 meters wide I would like to bring it down to 30% or so. What about an option to change size of the whole teletext "window" instead of it going fullscreen?

Thanks for your work on this

In TVE3 the update interval is almost 15s. The reason is that in TVE3 the client don't recognize automatically if a page is updated or not, since this is handled by the server.

Your idea about changing the size of the teletext is really interesting. But since there are still some major issues with it, I don't think that it's a good idea to integrate it until all major issues are gone and their is a real support for teletext subtitles.

Anyway, I think your idea about transferering imagecreation should do the trick as all things point to the update scenario.

OK. I have attached a test version for you which does the update in the background thread. The disadvantage of this that an update could take up to 300 msec, because the background thread is sleeping.

Regards,
MisterD

 

[Throt]

Hi

I've quicktested the background version. Unfortunately the stuttering is still there, or now more of a slowdown when the subtitles update, fps drops for a longer period (approx 1s). But I'll do some more testing tonight.

Rgds
Throt

 

[misterd]

Hi,
this is really strange and I have no idea how I can improve it again. If you think the update in the background thread is the better solution, than I will include it in the next patch.

Regards,
MisterD

 

[Throt]

Hi,

As with the last patch, adding some extra "cpu-horsepower" did the trick. If I run it on my other machine there is no stuttering. Which of the solutions that is better I can't really say as the both work similarly. But if the background solution is a "cleaner" one for you then you should absolutely use it.
I hope any of you other people viewing this thread can do tests on their setups so we can find where the minimum spec is. I've so far tested on a AMD 3200+ and a C2D 2,13Ghz and I get stutter on the 3200+

Anyway, great work MisterD !

Rgds
Throt

 

[Strong73]

Hi,

I am very interested in TELETEXT SUBTITLE option. Because at this moment, I have about 14 channels with (without) teletext subtitles. So if I updated latest SVN, reconfigure keyboard shortcuts... It is that all I have to do to test subtitles? So I don`t need zip file?

My system: TVE3 + 3 client PC.

-Strong-

 

[misterd]

Hi all,
today I tried to find the reason for the cropping problem and I found the bug. In the attached zip file you find a modified version for TVE2 including the vanished pages fix. I also fixed a bug in the update process, so perhaps the stuttering is gone now. In the attached version page updates are handled directly and not within the background thread. I updated TVE2 again, because testing is much easier and gives better results than TVE3.

If you want to test teletext subtitles in TVE3 than you can you a recent SVN, but since there is a problem in the update process it isn't usable at all. Currently I'm trying to eliminate all bug in the page renderer, before I continue with the next step.

Regards,
MisterD

 

[Throt]

Hi

Stuttering is down considerably on the slower rig, I still get them when subs are showed, but the stuttering is shorter, mostly more of a twitch . One thing that has come up with this version is that in SDTV resolution, the letter "M" is cropped. It loses it's left vertical line, perhaps a step down in fontsize would fix this?

Rgds
Throt