Re: Thoughts on VDR evolution - my 2 cent

["Ralph Metzler <" <rjkm@netcologne.de>]

Klaus Schmidinger writes:
 > When I voted against sending the teletext info as a still frame
 > I wasn't really thinking about re-insertion. As far as I understand
 > this, re-insertion means generating the same "vertical blank" information
 > as in analog videotext. If we send the teletext through this bottleneck,
 > I'm afraid we will lose a lot of the possibilities digital teletext
 > offers. The VDR PC could chache all of the pages sent and have them
 > ready instantaneously. But with re-insertion the information would
 > have to be sequentially sent through the video signal's vertical
 > blank, and it would be as slow as in the old analog days.
 > Maybe I'm not understanding this correctly, so if re-insertion
 > actually means something else, please enlighten me.

The digitial teletext which comes in PES packets is not faster than
analog teletext. You get exactly the same informtion at the same
speed. The only difference is the caching of many pages in the PC.

While it is not possible to switch on re-insertion and get the PES
packet at the same time you could still get the VBI data from the
SAA7146.
But I would see that as a last resort if you really want re-insertion 
to use it on TV and all the pages on your PC.


 > > Here is an idea: maybe we could get rid of the OSD junk
 > > altogether, simply by leaving the TV set in teletext mode
 > > and generating teletext pages for the On-screen-displays
 > > as well?

Not possible. See my last mail.


 > What I would really like to have is a faster OSD.
 > Since the driver doesn't do very much here, it must be the
 > firmware that slows things down - or is this done in hardware
 > and thus can't be improved? 

I think the main problem is the way OSD commands and data are
transferred to the ARM.
Itīs e.g. not designed to work concurrently with playback. But I warned
everybody here on the list when I enabled it that there could be
problems with that.
I think the whole OSD part needs to be rewrittten.


 > Ralph, any comments on this? I heard that convergence has presented
 > a settop box on the IBC - was that based on the Siemens DVB card?
 > Does it use the OSD? If so, with anything a little more complex
 > than the VDR menus (and I guess a commercial product would present
 > some fancy graphical interface?!) I'd say this must be veeeerrrrryyyy
 > ssssssllllooooooooooooooooowwwwww.... On the other hand, maybe I'm
 > using the OSD the wrong way in VDR, and it could be much faster if
 > accessed correctly. Any hints here would be greatly appreciated.

No, it is not using the OSD of the card. 
It uses the PCs video card for display and transparent windows for
OSD. But thatīs different in this case since the box has itīs own
TV out.


Ralph