A change observed...

[jcarrera]

In our house, we have two TVs, one connected directly to cable and one connected via a DVR box. In the past, I had noticed the the sound and picture on the TV connected to DVR was about (estimated) 3 seconds later than the TV directly on cable.

I attributed this to the delay due to tuner output being written to disk, then coming off the disk to the output. Yesterday, both sets happened to be on the same channel, and I thought I heard them in sync..so I went to listen carefully, and the DVR TV is only about 0.25 (estimated) seconds behind the directly connected TV.

Anybody confirm this change and what happened to cause it? It isn't a problem...is really better....just that changes intrigue me. And why does this post have extra blank lines at bottom?

 

[stevenl]

I doubt anything on the system changed, the delay comes from 2 sources,

1. The fact that the image arrives to your DVR digitally, then is converted to analog so your tv can view it,
2. Because the DVR starts recording every program as soon as you tune the channel,

when your analog tv gets the image it only just shows it. So no extra steps. It depends on how quickly the DVR process's the signal as to how long the delay is it could be a second it could be less. It also depends on the momment you tune the tv. If say you tune them at the same time the delay may be longer, but perhaps you tune the tv first then the dvr, they may get closer to sync.

 

[jcarrera]

I understand the reasons for the delay on the DVR system. The question is...why was it CONSISTENTLY/AWAYS about 3 seconds different and now is CONSISTENTLY/ALWAYS about 0.25 seconds.

It almost looks like before, the signal was written to disk, came off disk, was "analog-ized" , then sent to TV. And now is being sent to the analogizer in parallel with going onto the disk, rather than it all being a sequential process.

Why do my posts have blank lines at bottom?

 

[stevenl]

Who knows maybe your DVR is just working faster

 

[casper04]

I've seen it before, actually I've had many customers complain about the delay (especially after converting to digital 2 years ago). So what I did is reboot the box and when it comes on to the default channel it's in sync with the analog.
I've only been able to do it a couple times. It stays sync for a short period of time and when you change the channel on the box I think the delay comes back.

It's something really strange that I haven't been able to explain...