[vdr] Re: Questions about the subtitles-plugin

[ÿso-8859-1?B?SORt5GzkaW5lbiBKb3Jp?ÿjori.hamalainen@teliasonera.com>]

> Ahh, hmm, thanks. I can't say I understood you too well, but 
> I'll experiment when I get home. You'd improve your UI if you 
> 'grayed out' the delay setting when the "sync=yes".
> And if the UI also said what the delay is and what '10' 
> means, it'd start to be understandable..

Should I try again:

Sync option means that should the plugin try to sync to DVB timestamps
(== PTS, presentation time stamp, DVB video&audio frames have them).

On "yes" setting it tries, but there are some problems and
you can see what they are by searching "getstc" on mailing lists.

On "no" plugin doesn't sync to DVB-video, it generates timing
(how long should subtitle be on screen) based on operating system clock.
Delay is after how long plugin should 'delay' the subtitle before
presenting it. Without delay plugin would show it at once subtitle
is received to buffer (seconds too early compared to audio/video).

subtitle comes at (wall clock): 15:20:00.00
subtitle start pts (dvb timestamp) = 123.00s
subtitle stop pts = 124.50s

So subtitle should be shown 1.5 seconds according the DVB-stream.
Now we have this delay variable, I don't know if it is 
# of frames  or 1/10second or 1/100second but I guess it is 1/10 second.
And based on my guessing "delay = 20" means delay of 2 seconds.

Subtitles plugin will put subtitle on screen (wall clock): 15:20:02.00
And remove from screen (wall clock): 15:20:03.50

Pekka Virtanen, the osd-subtitles author, can clarify more & correct 
my (miss-)believes :-).

I hope you now have a view to the ideology behind the plugin?

And.. You are right about graying out and using units on configuration values.

> >>How are subtitles recorded?
> > 
> > Subtitles are recorded like they are coming from tuner/demux.
> > Plugin sets additional DVB-filters to receive subtitles stream and 
> > tells VDR to capture it when recording.
> > 
> > If you are thinking about DVD you need to convert them.
> 
> OK, they don't get written permanently on the video stream on 
> disk, so I can 'undisplay' them later..

yes on Yle channels (just to make sure, MTV&Nelonen has them on
video stream).

> Some things that would be nice are
> - Ability to position subtitles lower on the screen

That's the "offset" -option. :-) Also it should have an unit (pixels?)

> - An anti-aliased font, the current one looks annoyingly sharp-edged

The subtitles come in DVB stream as a bitmap (like in DVD).
So the 'font' is not rendered by subtitles -plugin.

I think the bitmaps are originally antialiased (?) but they appear 
crappy because of OSD color limitations (no free 'colors' to show 
antialiased colors properly => lack of different shades of gray). But I
might be wrong.

BR, Jori


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