[mythtv-users] The Race to Change the Channel

schachte at csse.unimelb.edu.au schachte at csse.unimelb.edu.au
Tue Oct 18 22:41:43 EDT 2005


On Tue, Oct 18, 2005 at 03:32:41PM +0800, W.Kenworthy wrote:

> The alternative view: in Australia (Perth) the program info is lousy,
> missing  or plain wrong.

I'm in Melbourne, and I find the ninemsn scraper (from
http://immir.com/tv_grab_au) is pretty good.  My only complaint is
that it doesn't know movies from regular programs.  But the ninemsn
web page doesn't seem to have that info, either.

> Channel surfing is where its at (we only have a small handful of
> channels - not counting the dups), and the delays are a real pain

My family hasn't yet gotten beyond channel surfing, and they find the
delay annoying.  In fact, most of the time they just switch to
watching the TV directly (using the TV's tuner).  Maybe that will
change eventually, but it would still be nice to fix the slow channel
change problem, for WAF reasons.

I assume much of the slow channel change problem is due to the need to
buffer a few seconds of programming before it can start to be shown.
I don't think it takes 4 or 5 seconds for my DVB card to lock a
channel.  One thing that would probably help a little, at least
psychologically, would be to grab a frame as soon as the tuner locks
the station and display that until the buffer has enough program to
start showing is normally.

A better solution, if it's possible, would be to start showing frames
as they're being written to the ring buffer, but employ the time
stretching code to slow things down a bit (without distorting the
voices), until the buffer has gotten far enough ahead to show the
program normally.  If the program is slowed by 20%, the buffer should
get 4 seconds ahead in around 20 seconds, at which point the program
could go to normal speed.  This would be a bit annoying, but less so
than a 4 or 5 second delay on channel changes.

-- 
Peter Schachte              Free trade is the weapon of the strong,
schachte at cs.mu.OZ.AU        protectionism is the shield of the weak.
www.cs.mu.oz.au/~schachte/      -- William Kaiser 
Phone: +61 3 8344 1338      


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