Teletext subtitles (1 Viewer)

[misterd]

Except for subtitles what exactly is the problem with the current teletext implementation? (must admit i havent read all of this thread, so this might be a stupid question).

There are several problems with the current implementation. First of all the stuttering. I have fixed this in my private version and did some enhancements to the renderer but this fix is really only a workaround and it could be that it doesn't work for everyone. The reason is that the stuttering is something like a timing problem of rendering the received bytes and rendering the image by the core.
Also mantis bug 930 is a timing problem, but this is really hard to fix with the current implementation. Especially for TVE2, because the filter solution doesn't work there.
And last but not least the rotation time. With TVE3 the client has to request the page and somewhere there is a bug, because the rotation time is always set to 15 seconds. This is really annoying, because you always to have wait this time for an update. In TVE2 an event is raised when a new page arrives and the page gets automatically updated. Of course you can add an event to TVE3 and the problem is solved, but regarding to all other problems I don't prefer this solution.
From my point of view I think it's the best to write one filter that can handle the whole teletext stuff. Also other applications that use TVE3 doesn't need to write their own teletext mechanism and can use this filter. My main problem is that I have no idea how the windows teletext mode in MP can be done with a filter, but this is that I will think about next month.

 

[vuego]

My solution would be to store the whole teletext data in the ts files and write a special directshow filter that display the teletxt page with VMR9.

Does this mean that it will not work with Vistas EVR?

 

[misterd]

Does this mean that it will not work with Vistas EVR?

Since I don't have Vista installed, I can't evaluate this. I only had a small look into the documentation and found out that mixing is also available in EVR, but it's different from VMR9. So it should be possible.
The reason for this approach is very simple. With VMR9 the mixing of the video and the teletext or subtitles is done by VMR9 automatically. You could also use this function for another nice feature too, which was requested very often in the forum. But I don't tell you what it is, because it isn't easy to implement and people will always ask when it is implemented

@all
I completed the patch today and will do some testing tomorrow (need new SVN build). When it will work, I will post it on sourceforge. For the patch I ported the modifications back to TVE2.

I still don't have much time and so I can't work a lot on the filter approach at the moment.

MisterD

 

[tourettes]

Does this mean that it will not work with Vistas EVR?

Since I don't have Vista installed, I can't evaluate this. I only had a small look into the documentation and found out that mixing is also available in EVR, but it's different from VMR9. So it should be possible.
The reason for this approach is very simple. With VMR9 the mixing of the video and the teletext or subtitles is done by VMR9 automatically. You could also use this function for another nice feature too, which was requested very often in the forum. But I don't tell you what it is, because it isn't easy to implement and people will always ask when it is implemented

@all
I completed the patch today and will do some testing tomorrow (need new SVN build). When it will work, I will post it on sourceforge. For the patch I ported the modifications back to TVE2.

I still don't have much time and so I can't work a lot on the filter approach at the moment.

MisterD

With the filter design, please contact Ziphnor as he has been already working with it But as I quick note, is not possible to use VMR9 mixing as YUV is used in MP / VMR9. Have a look on the DVB subtitle implementation (currently work in progress. There is a SubtitleRenderer.cs inside the MP handling all the drawing and communication to the directshow subtitle filter.

 

[ziphnor]

tourettes:

I believe misterd's patch goes beyond teletext subtitles, ie a complete teletext filter. If this is the case, we have to be careful not to replicate code too much, but on the other hand i still believe that subtitles should be supported separately, users dont want to think about what the source of subtitles is, they just want them to show up.

misterd:
I believe it would be a really good idea to let MP render the teletext as tourettes mentions. This would make it work with both VMR9 and EVR, and it wouldnt confuse the auto-cropper plug-in which captures the final VMR9 frame, in order to determine black bars.

 

[misterd]

First of all the patch which fixes the stuttering and some other things is now on sourceforge. Patch 1754269
This patch is for TVE3 and TVE2, because it's to complicated to change only TVE3. Since I don't have many shows with subtitles in Germany, I could not test it, but I think that you will get better results with TVE2. The reason is that MP should update the page every time it receives a new page.


Now to the filter topic:
My intention is a filter for handling the teletext at all as ziphnor already mentioned, but I think that it can be used for handling teletext and the teletext subtitles. Here a small draft of my plan:
1.) Extend TsWriter to store the teletext data, and configure TSFileSource for reading them (small modification in MP only)
2.) Write a small filter, which transmit every received packet to MP like TsWriter it already with the server. This would create a similar handling like it is in TVE2.
3.) Extend MPWriter to store the teletext data.
4.) Extend the filter and implementation of step 2 to detect the subtitle pages and add them to the available subtitles etc.
5.) Remove the old implementation in the server and TsWriter.
6.) See if it can be done with VMR9/EVR and move the code from MP to the filter
Any ideas, suggestions, help is really appreciated.

MisterD

 

[misterd]

Small update:
Frodo added my patch yesterday to svn. So it should be available now. I hope you all enjoy it.

Thanks Frodo for adding it to svn.

MisterD

 

[tourettes]

6.) See if it can be done with VMR9/EVR and move the code from MP to the filter

You would need to create a transform filter -> not possible to use HW acceleration anymore.

 

[Throt]

Hi MisterD

Thanks for the patch, haven't tried the compiled SVN one, but added your patch directly to the source 2 days ago (TVE2).

Just some first impressions, stuttering is down considerably (if you have the hardware for it ?!?). On my "gaming pc" c2d 2.4ghz, nvidia 7950gx2 yada yada it flows beautifully, but on the htpc, an amd64 and nvdidia 6150 it slows down to 3-4 fps 2-3 times per minute. But that can very well be something with my system ...

I got double subtitle fields (4 rows) now and then (on both systems) and if the broadcast goes from 2 lines to 1 line of subs the last sub is still displaying on the upper row.

Subtitles aren't "cleaned up", they are left until the next text come.

If displayed above 800x600 they are "cropped".

Greets
Throt

 

[misterd]

Hi Throt,
the problem with the stuttering could be some kind of a synchronization problem.
The patch starts a background thread for the rendering the images of the teletext pages. In TVE2 also the page update event updates these images. So it could be that this is the problem. Perhaps it could be solved, if you disable the dvb-epg grabbing.
I'm using and AMD Athlon XP 3000+ with a Geforce 6200 and TVE3 and I don't get any stuttering when using teletext.

Regarding to the not cleaned up or cropped subtitles, could you please provide some screenshots, so I can reconstruct the issues. I will look at this problem, but I can't promise anything, because I don't have any idea what's going wrong there.

Regards,
MisterD