DVB : Audio selection

[StephaneM]

Hello all,

I see some great improvments with DVB-T : SageTV is scanning properly the French channels (provided I populate the frequency for "France" first in the PredefinedScan.frq. Does SageTV dev. team want this frequencies by the way ?) and correctly parse EPG data.

What's better is I do this only on my test machine with an indoor antenna with a very poor reception and SageTV is currently the only DVB program that renders a smooth video with such a poor reception (in comparison with Fusion HDTV software, GBPVR, MyTheatre). I'm very impressed with what SageTV dev. team has done here !

However, for all channels that have more than one audio streams. I can't seem to select the sound track in SageTV. When I do choose an audio stream with the option menu, nothings change (wether it is for switching from French to German, or from Stereo to AC3)

Has anyone got some success with this feature?

Also will it be possible to have Teletext subtitles and DVB subtitles at some point in the future? This would be the very last thing to have in SageTV for a feature complete DVB solution.

Regards,
Stéphane.

[Madcoder]

Originally Posted by StephaneM

Also will it be possible to have Teletext subtitles and DVB subtitles at some point in the future? This would be the very last thing to have in SageTV for a feature complete DVB solution.

I second the request for this. It would be SO nice to have since in Finland subtitles are broadcast on various teletext pages. There are some other European countries doing this too if I recall correctly.

[StephaneM]

Well, the selection of the Audio stream in Live TV (for DVB / ATSC streams) this will be fixed in a upcoming beta (so it is currently not working with 6.0.12).

However, I heard nothing about subtitles

So, I thinked about it. If you choose to save the show as a transport stream with SageTV, the recordings does include all PIDs according to the PMT (in English that means that all streams intended for a program are to be found in the file saved by SageTV : Video / Audio / Teletext etc...)

Then why not having a little utility like ShowAnlayzer, that will analyze the transport stream in real time and extract the subtitle to a file (preferabily in SRT format) and then have a STV / STVi doing the job for displaying the subtitles if they are written to disk by the previous utility.

I already verified that "ProjectX" is able to load a SageTV transport stream and create a valid SRT file with the teletext subtitle (though they were obviously not in sync with the video, but at least it's doable).

Obviously with this we cannot have the subtitle in real time, but a in near real time : I guess pausing the video for two / three seconds should be largely enough to have the subtitles available.

PS: I do not have the knowledge (yet) to do this, basically what is needed is knowledge of Transport Streams (kinda easy), knowledge of subtitles format : Teletext / DVB (don't know anything about it), knowledge of Java / Studio API (I'm lost here).

So if anyone has more knowledge than I do... you're welcome to give your thoughts about this.

Regards,
Stéphane.

[Narflex]

Stephane,

I actually wrote an STV a few years ago that did this with the CC from NTSC recordings made w/ the PVR350 (the one that'll insert CC in the user_data field of the MPEG2 video header). It was just a test out of curiosity, but it worked.

Basically, I wrote a java class which analyzed an MPEG2 file and extracted all of the CC information out of it along with the corresponding timestamps. Then I wrote a wrapper for that which would give me the CC text based on a given time in the media file. Then I added a text widget in the OSD for SageTV that made a call into that wrapper and got the CC text and then displayed it. It was actually a fairly easy project if you know how to parse the MPEG data.

[StephaneM]

Originally Posted by Narflex

Then I added a text widget in the OSD for SageTV that made a call into that wrapper and got the CC text and then displayed it. It was actually a fairly easy project if you know how to parse the MPEG data.

I also seen a couple of STV that does handle SMI files. So It's doable.

I really saw this as a two part project:

1) The stream analyzer: it does analyze the video in real time and produce a SMI / SRT file with the subtitle(s).

2) An addition to a STV that handle the selection of the SMI file (basically: OFF / Language 1 / Language 2) and displays the subtitle over the video.

The first part I may be able to do it. However for the second part: I'm not so confortable with Java and Sage API / Studio. So I looked a little and I think a text widget with a suitable animation property is the base of this but the inspiration is not coming for now (and I'm already busy on a Streamzap utility right now)

[Madcoder]

I'll donate...lets see this feature in action!!!

[StephaneM]

Originally Posted by Madcoder

I'll donate...lets see this feature in action!!!

Don't get this excited I was just throwing some ideas (and actually evaluate if it's doable or not).

And I'm now depressed : DVB subtitles are just like DVD subtitles, those are bitmaps. So Teletext subtitle should be easy, but DVB subtitle : no idea, but you get the point (extracting the sub, then have the STV read the produced file and create bitmaps in memory to render them...uh)

[Narflex]

Originally Posted by StephaneM

Don't get this excited I was just throwing some ideas (and actually evaluate if it's doable or not).

And I'm now depressed : DVB subtitles are just like DVD subtitles, those are bitmaps. So Teletext subtitle should be easy, but DVB subtitle : no idea, but you get the point (extracting the sub, then have the STV read the produced file and create bitmaps in memory to render them...uh)

I wouldn't recommend trying to do bitmap subtitles using the technique I describe. That's better dealt with in the media player.

[fleetwood]

Any updates on this subject? I'm still missing those subtitles...

[Joni]

FYI:

Here's the DVB-SUB specification: ETSI EN 300 743, available from ETSI web site

And here's a paper on how to implement it.

I think Project X has an DVB subtitles Java implementation, but it's probably GPL'd.


Cheers, Joni

(Missing out on Monday night Fellini movies on YLE Teema :-)