[mythtv-users] I'm in....

[Chris Delis]

On Fri, 14 Nov 2003, Boyd II, Willy wrote:
> 
> >-----Original Message-----
> >From: Torsten Schenkel [mailto:torsten.schenkel at web.de] 
> >Sent: Friday, November 14, 2003 9:07 AM
> >To: Discussion about mythtv
> >Subject: Re: [mythtv-users] I'm in....
> >
> >
> >On Fri, 2003-11-14 at 15:50, bpierce815 at charter.net wrote:
> >> On Fri, 14 Nov 2003 06:27:01 -0800 (PST)
> >>   Peter Greis <peter_greis at yahoo.com> wrote:
> >> >Greetings All,
> >> 
> >> Greetings
> >> 
> >> >One observation is that it takes an eternity (4-5
> >> >seconds) to change channels. Is anyone else seeing
> >> >this ?
> >> 
> >> I also see that it takes a long time to change channels, I
> >> was attributing mine to the slow cpu(C3 Nemiah).  But I am 
> >> not sure that this is correct. 
> >
> >No, the channel change can't be instantaneous. What you are 
> >watching is a stream that's been recorded to disk and is 
> >played from there. You are usually 3-4 seconds behind, so 
> >it'll take this time to change channels. There might be a 
> >possibility with playing the first minute a bit slower to 
> >accumulate the 4 second buffer, but I don't think I'd like that.
> >
> >Hint: Use the browse mode! 
> 
> One thing I'm still trying to figure out is how this 3,4-second buffer is
> determined.  Is it variable, and depending mainly on speed of hardware?  I
> know a buffer must exist, not disputing that.  Just wondering about how the
> size of the buffer is determined.  Is it simply a matter of the player will

You can determine the size of the ringbuffer during setup.

Also, I _think_ part of the delay is caused by deleting the old ringbuffer
and creating a new one. 


> play as soon as it sees data, and 3-4 seconds is the best we can do?  Or is
> it stored in some variable in the code, and 3-4 seconds worth of data seemed
> reasonable for most systems?  (And I'm actually one that promised to look
> through the code and figure this out :-D  I have to admit I haven't gotten
> beyond a few basics timing tests in my spare time, so not trying to be a
> hypocrite)  Does anyone with a Tivo or ReplayTV see a 3-4 second delay?  For
> a hardware encoder, and therefore just a simple player off of /dev/video0,
> with modern hardware, I'm surprised that 3-4 seconds is the smaller buffer
> that will play reliably.  For software encoding I realize that's a different
> story...  but if the buffer is designed around a catch-all solution, maybe
> it can be shortened for hardware encoder systems?  
> 
> - Willy
> 
> >
> >> I am also seeing video and
> >> audio get a little jumpy when the OSD comes up.  Are you 
> >> seeing this as well? What hardware are you running?
> >
> >This is due to the slow hardware. ME6000 on this side. Got 
> >lots better with the pvr350 though.
> >
> >Torsten
> >-- 
> >Config files for pvr350 tv-out and framebuffer: 
> >http://www-isl.mach.uni-karlsruhe.de/>~hi93/ivtv-pvr-350-conf.tgz
> >
> >
> 
>