Channel Changing Lag

[sticky]

Eventually I will be controlling a Scientific Atlanta 2100 cable box with this (meaning pvr 250 and sage tv) and actysis.

What sort of channel lag is there using this type of setup. Channel lag meaning the time it takes to switch between channels.

Thanks.

Al

[dkardatzke]

It's a couple seconds. Once you tell SageTV to change the channels, it then has to send the commands to your receiver. Then since SageTV is a few seconds behind Live TV b/c it's always recording you end up with a few seconds delay.

This is the same for a TiVo ReplayTV. Actually my old TiVo was notorious for only making about 50% of the channel changes where SageTV makes 99.9%. Of course I'm biased

[sticky]

Much quicker with the standard cable feed obviously.

Cool..

THanks for the reply.

[Mike Young]

Is it possible to adjust the lag ? I never tried Tivo, but my replay was no more than 1 second behind realtime, the channel changing lag was quick enough to not be noticeable at all.
Obviously this is not a huge problem, but it would be nice.

mike/

[Mike Young]

Update...I have noticed that when I first start SageTV, my Remote works pretty quickly, with maybe a 1-2 second delay, but after viewing livetv for a while if I press a button on the remote it might take significantly more time to process. Pressing menu for instance, caused the screen to freeze for about 8 to 10 seconds before the SageTV menu appeared, this seems to be consistant with the lag-time between the feed and Sage. I am asuming that Sage waited to display the menu until it had played everything in the buffer.
I had noticed before that the delay seemed to grow, but had not realized that there could be any other ill effects because of this.
what exactly is the cause of this delay, is it the time it takes to write to the HD ? if so then optimizing for disk io would help. Are there any processes that would benifit from increased priority ?

mike/

[mlbdude]

There should be 0 delay to get an OSD or menu displayed. The only thing in the buffer is the MPEG2 video (though this might change with the 350 in 2.0).

Can you tell me about your remote and how it is hooked up or point me to a thread where you already did?

[Mike Young]

I am using an ATI remote wonder with the X10 plugin (not the ATI drivers) and girder. I agree, it makes little sense why the menu would be delayed. I would expect there to be some overhead with girder processing the sendmessage to Sage, but not 8 or 10 seconds worth. I have only noticed the delay when viewing livetv, though admitedly, I have not preformed exhaustive testing - I have only a small window to experiment each evening. Since this PC is completely dedicated to SageTV, I am trying to optimize it specificaly for Sage and related apps.
It seems to me that the combination of the Hardware (Athlon XP 2500, PVR-250, 512mb) and the SageTV software should be far superior to my 3 year old ReplayTV unit, and capable of even better results once I learn to tune it properly!

mike/

[mlbdude]

I will guess that you are right that the problem is outside of Sage or at least not directly reated to Sage. What does it take to fix the problem (putting Sage to sleep etc.)?

[Mike Young]

Yes, once I get the menu, or guide or whatever, then its fine. Im not sure if its linear or not, just that I have noticed it is sure to happen if Ive been watching livetv for 15-20 minutes or so. I may have incorrectly associated it with the issue of the increasing delay time between the feed signal and Sage LiveTV.
I can try a faster disk for capture tonight and see if that makes a difference.