[linux-dvb] OSD (was: Re: Maximum number of PES filters - 8?)

[Carsten Koch <Carsten.Koch@icem.de>]

Ralph Metzler wrote:
....
> People want OSD during playback, I warn them that it might cause
> problems, they forget about that and then complain about the problems ...

that's not fair, Ralph!

If an API exists, I find it reasonable if people use it.
If that API has parameter limits that change from driver 
release to driver release, I find it reasonable if people
complain when code that use to work suddenly does not.
I also find it reasonable to expect that the API gives me
an error code when I, for example, try to create an OSD
window that is too large. Can you create a full-screen
OSD window with the current driver? If not, does the ioctl
return an error code or dies it simply not work? Or does
it work sometimes and crashes the firmware after prolonged use?



I think we all agree that the user needs some kind of
on-screen feedback.

I believe that my idea to (mis-)use teletext if we cannot
get OSD fast/large/reliable enough was a bad idea.
I apologize for pushing it. Of course, I was only searching
for alternatives that cause no more problems.

What are the alternatives? Is there a chance to get the
existing OSD fast/large/reliable enough soon? 
If not: should we dismiss it altogether and look for other ways?

Would people prefer an OSD that is fast/large/reliable, but
replaces (rather than overlays) the entire video picture while
it is active? Does the driver provide a suitable API that
allows us to display one still video frame from a bitmap
(symmetrical to VIDIOCMCAPTURE)?

Would it be a good idea to handle the OSD like the Sky digibox?
The Sky digibox provides two kinds of OSD:

1.  a small, non-transparent overlay window that displays
    the current and next program title, a little bit of
    on-screen help, the current channel name, the time, etc.
    It is similar in size and location to the window vdr
    displays when you press OK during playback. Outside
    this window, the normal video continues to be shown.

2.  a full-screen, non-transparent, non-overlay window that
    displays things that need more room, like the EPG, 
    the channel lists, the setup,lists of favorite channels, etc.
    Normal video is not shown and audio is muted when this
    window is visible.

I personally like the digibox OSD very much. It's EPG is
much easier to use than vdr's EPG, as it simply has more
room available, so it can show you a clear table with time
on the X axis and channels on the Y axis.

What do people think? Would that be useful?

Ralph, what do you say: If the OSD is limited to a small,
fixed, guaranteed size, would that make it fast and 
100% stable? Also, would it be easy (unless it's already
there) to provide the ioctl that is symmetrical to VIDIOCMCAPTURE?

Klaus, would you find that attractive?


Carsten.


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