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Legend
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Discussion Starter · #1 ·
In these forums I have often seen the question "did you have the same problem watching live as when watching the recording?". But surely when watching "Live" TV you are really watching is the buffer from the HDD. So a signal is received, the DVR records it to the buffer and then reads it back and plays it. Therefore you are always watching a recording and so the question is irrelevant.

Or am I wrong and either there is a split in the signal so it is not actually read from the buffer before being output when live or there is a different mechanism involved in processing the temporary buffer compared with a real recording?
 

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Godfather
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Andrew_J_M said:
In these forums I have often seen the question "did you have the same problem watching live as when watching the recording?". But surely when watching "Live" TV you are really watching is the buffer from the HDD. So a signal is received, the DVR records it to the buffer and then reads it back and plays it. Therefore you are always watching a recording and so the question is irrelevant.

Or am I wrong and either there is a split in the signal so it is not actually read from the buffer before being output when live or there is a different mechanism involved in processing the temporary buffer compared with a real recording?
I have an HR20 in the living room and an H20 in the bedroom. I have the H20 going through a rf modulator to another TV in the kitchen. Yesterday I had the HR20 an H20 on the same channel and th living room TV and kitchen TV were both in sync. So unless the H20 also has a buffer it has to be live on the HR20.

Edit: I take that back. I remember the HR20 was about 1/2 a second behind. There was a slight reverb between the two. So maybe it is buffered before you actually watch it. Sorry about the confusion.
 

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DBSTalk Club Member
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It is buffered. All DVR's buffer what you are watching "live". That is why you can
pause it or rewind it.

If you want to really explore what you are watching live, just think how long the
transmission to your house takes from the football field and then add the DVR buffering.

Now realize that the next play already started and you haven't finished watching
the current "live" play...........AAAAACCCCKKKKKKKKKKK time warp. :D
 

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Legend
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It's a few seconds behind "live." If you have a regular receiver with no DVR, you will see things happen on the other receiver a few seconds ahead of the DVR.
 

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Beer Aficionado
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All D* is more than a few seconds behind live. I USED to watch Badger games and listen to the radio because tv announcers are so horrible. But when the games are on D* (ESPN, etc) vs OTA I can't do that because on the radio the play was half over before they snapped the ball on tv.
 

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Legend
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Yes, any satellite program will be behind live because of the uplink and downlink time. Your closest to live will be an analog OTA broadcast.
 

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Legend
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While watching the Steeler game last weekend, my sister called and as we were talking, I said, "The Steelers are goingt o pick this ball off". My friends were amazed at my prediction, but meanwhile, my sister told me it happened.
The plays were about 3 seconds behind. I am in New Mexico and she is in Pittsburgh, watching OTA. Figuring about 1/2 - 3/4 second per satellite 'hop' there is still some lag. Seems like the HR10-200 didn't lag as much, I'll have to check how close the HR10 and HR20 are this weekend. (But both buffer anyway)
 

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Last Mon nights game was a good 10 secs behind the live action! My son was listening to the game on radio in his room, and came out to watch some plays well before the ball was snapped!
 

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Lifetime Achiever
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Live? What is live?

If one is watching a game OTA via a network feed, you've already have at least two sat. up/downs: 1) from the camera truck to the network and 2) from the network to your local station.. Possibly three if it has to go to a regional uplink center before hitting the network distribution center.

Then if you're watching on directv, you'll have another one or two up/downs as they take the local OTA (analogue or digital) and send it to their transmission center and then right back to you.

I'm reminded of a definition I got of real-time data from a military electronics eng. For him real-time was capturing the data from a nuclear underground test when the electronics package was mounted 1m from the bomb and going to be completely annihilated within milliseconds after the blast. Anything less than that was not even close to real time. :)

Cheers,
Tom
 

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Hall Of Fame
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Of course, since the signal travels at over 186,000 miles per second, it is not the distance travelled that causes the delay, but the processing that it goes through.
 

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Hall Of Fame
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paulman182 said:
Of course, since the signal travels at over 186,000 miles per second, it is not the distance travelled that causes the delay, but the processing that it goes through.
The distance doesn't cause the whole delay, but it certainly does contribute to it. An up/down satellite hop by itself adds a quarter of a second delay, without including any processing done on either end.
 

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Hall Of Fame
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I don't know about the HR20, but a few of us have speculated that on the R15 live is really live when you're completely caught up. I do realize this is contrary to how most other DVRs work. See my post (which the following link should anchor to) and the one following it:

http://www.dbstalk.com/showthread.php?p=662626&highlight=buffer#post662626

The only reason you'd really need to use the buffer for the output stage when completely caught up is to help make it seamless when the user chose to trickplay. I honestly haven't played around with live TV on the R15 enough to say whether it is or isn't seamless.

I do know last night I tried to pause something I was watching live and it refused all trickplay ops. I could change the channel, but couldn't trickplay the live buffer (almost as though it wasn't buffering and was just sending the tuner output to the MPEG decoder directly).
 

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Hall Of Fame
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There is also a difference if the DVR is a D* or Tivo
 

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I think the issue is not so much the delay of getting the signal from source to destination, but what happens to it at that point.

From my experience, every DVR box out there - whether it's hooked to satellite or cable will delay the signal a little more than coming through a non-dvr box. And that's probably due to the buffer as has been pointed out.

I had the R15 in one room and a regular non-DVR box in another, they were not in sync. My friend had a DVR and nonDVR box in his apartment, source comast. Same effect.
 

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cbearnm said:
Seems like the HR10-200 didn't lag as much, I'll have to check how close the HR10 and HR20 are this weekend. (But both buffer anyway)
In a previous HT setup, I had a Mits SR5 HD receiver in the family room and a SAT-T60 DirecTiVo in the master bedroom. If you were standing in the right place on the stairway, you could hear both and obviously the DirecTiVo was behind because of the buffering. Fast forward a couple of years and I had a HR10 in the family room and the same DirecTiVo in the master bedroom. The HR10 was behind the DirecTiVo. Now I've both both a HR10 and a HR20 in the family room and in switching between the two the HR20 is behind with a much more noticeable lag. So, is it "live or is it buffered"? It's now buffered quite a bit with the HR20.
 

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Legend
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paulman182 said:
Of course, since the signal travels at over 186,000 miles per second, it is not the distance travelled that causes the delay, but the processing that it goes through.
Apparently that's correct. From what I have read, it only takes about .25 seconds to go up and come back down.

Interesting link where you can track all the satellites... I didn't realize there were so many!!!

http://science.nasa.gov/Realtime/JTrack/3D/JTrack3D.html
 
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