Delays between Receivers
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hector @ 1st Nov 11:04PM:
Delays between Receivers

Why is there a 2-3 delay with my two receivers?

I have the main DVR/receiver in the living room and non-dvr receiver in the bed room and if the same channel is viewed, the living room receiver is 2-3 secs behind the bed room receiver.

Why is that happening?

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djrobx @ 1st Nov 11:32PM:
Re: Delays between Receivers

The DVR is buffering shows to disk, which can add some delay. Although I found my non-DVR was usually behind the DVR, for whatever reason.

It's pretty common for digital TV services to not sync up when tuned to the same channel, even without a DVR.
--
AT&T U-Hearse
Your funeral. Delivered.

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texasguy37 @ 2nd Nov 12:47AM:
Re: Delays between Receivers

I noticed the same behavior with my DVR's when I had Dish Network.
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hector @ 2nd Nov 03:07AM:
Re: Delays between Receivers

I see. It was particularly annoying today because of the World Series! My wife watching in the bed room is a philly fan and I'm a Yanks fan. Doing some home work and watching in the living room, I knew 2-3 seconds ahead of time what happen with a batter because of her clapping, screaming, yelling and moaning! The delay was killing the suspense! :)
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texasguy37 @ 2nd Nov 04:21AM:
Re: Delays between Receivers

Tell your wife to control herself!
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ozzy6900 @ 2nd Nov 11:40AM:
Re: Delays between Receivers

said by hector :

I see. It was particularly annoying today because of the World Series! My wife watching in the bed room is a philly fan and I'm a Yanks fan. Doing some home work and watching in the living room, I knew 2-3 seconds ahead of time what happen with a batter because of her clapping, screaming, yelling and moaning! The delay was killing the suspense! :)
Or you could use this delay to continue to work, then when you hear something from the other room, it's time to watch the game! :D
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rpeAMP @ 2nd Nov 05:45PM:
Re: Delays between Receivers

Interestingly enough, when 2 out of my 3 receivers are tuned to the same channel, I have the time delay issue. But, when all 3 are on the same channel, they are synchronized.
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aturner733 @ 2nd Nov 07:02PM:
Re: Delays between Receivers

I've noticed the same thing but as djrobx stated mine is the non-dvr unit behind the dvr unit. I thought maybe this had something to due with the (hopefully) soon phase 3 upgrade. it would make since that if the stb could be paused it would have to be looped through the dvr, which could cause it to be delayed more.

just wishfull thinking.
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Tel @ 2nd Nov 07:36PM:
Re: Delays between Receivers

There has always been a delay on any setup I've seen where one box is on HD and the other is on SD. Even when I had Charter cable, the HD signal was delayed several seconds behind the SD signal no matter which box was tuned to HD.
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ILpt4U @ 2nd Nov 08:11PM:
Re: Delays between Receivers

The delay I had was always the First TV to join a stream, be it the DVR or other STBes, is about 2 seconds behind all additional TVs that join that same stream.

All Subsequent boxes though are perfectly synced joining that stream.

What I always thought, was the IPTV streams are unicast at first -- so when the first STB "Tunes"/begins a stream, it unicasts it. Then it joins the multicast stream -- that is how you get the instant channel changes. However, the unicast & multicast streams aren't synced perfect, so that stream is just slightly behind live time

All subsequent boxes join that already existing stream, so they have no unicast/multicast handoff, and therefore are all synced together.

To fix the first TV: After other TVs have joined the stream, change the channel on TV 1, and change it back to the original channel, now forcing that first TV to leave, and then rejoin the multi-steam in progress, syncing it with the other STBes

If any of this is confusing, I'll try to word it another way...
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Tel @ 2nd Nov 09:07PM:
Re: Delays between Receivers

I always thought it was normal. My Charter cable HD was 2-3 seconds behind SD. My Uverse and my daughters Uverse has the same delay between HD and SD and oddly enough, my brother who has Comcast has a delay between HD and SD.
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ILpt4U @ 2nd Nov 09:12PM:
Re: Delays between Receivers

HD vs SD will be a little different

I was talking if multiple receivers are watching the same stream, either an HD or SD stream

An SDTV can watch an HD stream -- the box downconverts it to SD to output to the SDTV
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walta @ 3rd Nov 10:21AM:
Re: Delays between Receivers

I found this delay annoying enough to run a wire from to the DVRs video out to the second TVs video input. Plus you can monitor the DVR in sync. That would be a cool software feature to allow a second box monitor in sync with the DVR

When you could watch both digital and analog over the air TV a stations signals were out of sync.

Walta
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hector @ 3rd Nov 01:15PM:
Re: Delays between Receivers

Ok, I think it is HD vs SD related.

Just tested it now (1:11pm EST)

With Law and Order on SD (ch 124) in the non-DVR receiver, and L&O on SD (ch 124) in the DVR recever, I hear about 1 sec delay in the non-DVR receiver. When I switch the DVR receiver to HD (ch 1124), it is delayed now by 1-2 seconds.

Let me try the reverse....

Ok, with NON-DVR receiver on HD and DVR receiver on SD, its is nearly in sync.

Woohoo!! Now I don't have to tell the wife to SHUT UP!! :)
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hector @ 3rd Nov 01:27PM:
Re: Delays between Receivers

said by ozzy6900 :

Or you could use this delay to continue to work, then when you hear something from the other room, it's time to watch the game! :D
Right, which is how it went most of the game. I used her as a notification alert that something good (yes!!) or bad (groans) happen or about to happen! :)

But I see now that if I put the non-dvr receiver on HD channel and the dvr receiver on a SD channel then the viewing is in sync now.

Interesting...
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joako @ 3rd Nov 06:35PM:
Re: Delays between Receivers

Let me pose this question:

I have I have 6 receivers can I tune them all to the same channel at the same time and watch the same thing on 6 televisions, or only up to 4?
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PRescott7-2097
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ILpt4U @ 3rd Nov 06:45PM:
Re: Delays between Receivers

If all 6 receivers are watching the same "steam"/channel, that is only 1 Stream, and absolutely you can watch it on all 6 STBes/TVs

If you are using HD & SD versions of that stream, you are using 2 Streams, but again that is still completely fine.

You always have 4 streams among X number of STBes, where X is a number at least 1 and no greater than 8
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txdust @ 3rd Nov 10:19PM:
Re: Delays between Receivers

I use to be a tech support for Uverse and would get called on this daily. The issue is you have a number of streams all independent from each other. When you turn on a receiver box that box in essence raises its hand to grab a stream. When a second box is turned on even on the same channel that box takes claim to a different stream. If your watching the game in the living room, and your son is watching the game in his room, think of the 2 TV's to be working on separate service. Which mean they travel from the AT&T center all the way to your V-rad box, than to your house. The greater the distance between you and the AT&t service center the great chance for these signals to unsync and be on an independent time line signal wise. This is not like your co-ax cable which is split at your house to separate rooms, where the unsync is too small to notice. This is caused by miles of traffic and unseen interference.
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txdust @ 3rd Nov 10:30PM:
Re: Delays between Receivers

What you experienced is the trial and error method to sync them. By switching the streams on and off you can by pure luck sync them up. That is the only fix for this problem that I know of. I worked for 2-wire/AT&T for some time and as long as the TV was digital this problem would continue. Hope for your sake you can sync the shows for your wife with little trial and error.
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ILpt4U @ 3rd Nov 10:46PM:
Re: Delays between Receivers

txdust-

I am able to sync multiple receivers, repeatedly, and at multiple locations.

The Unicast/Multicast stream setup makes sense to both explain the problem, and also provide a solution.

The solution I mentioned earlier I have been able to reproduce results to sync the same stream on multiple STBes.
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ILpt4U @ 3rd Nov 10:55PM:
Re: Delays between Receivers

I was about to go into a long, detailed post of how Switched Digital Video & Multicast works, and then using that to explain why the TVs are not synced, but then decided that info is already out there to be found, and once you understand Multicast vs Unicast, then the sync issue is more clear
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ILpt4U @ 3rd Nov 11:01PM:
Re: Delays between Receivers

said by txdust :

I use to be a tech support for Uverse and would get called on this daily. The issue is you have a number of streams all independent from each other. When you turn on a receiver box that box in essence raises its hand to grab a stream. When a second box is turned on even on the same channel that box takes claim to a different stream. If your watching the game in the living room, and your son is watching the game in his room, think of the 2 TV's to be working on separate service. Which mean they travel from the AT&T center all the way to your V-rad box, than to your house. The greater the distance between you and the AT&t service center the great chance for these signals to unsync and be on an independent time line signal wise. This is not like your co-ax cable which is split at your house to separate rooms, where the unsync is too small to notice. This is caused by miles of traffic and unseen interference.
The scenario as it is described here is just not true. If 2 TVs in one house are watching the same channel, it is one stream being MultiCast to multiple boxes.

The reason the first TV is slower, is because it began the stream as UniCast -- It takes some measure of time (though pretty quick) for the STB to request to join the Multicast, be it at the VRAD, CO, or higher level, so to achieve instant channel changes, the streams always start Unicast, and is handed off to Multicast

The Second TV doesn't have to ask for the Multicast, because it is already present on the LAN, and it is able to join an in-progress Multicast stream that is already there. Same with a 3rd, 4th, 5th, etc. So those additional TVs don't have that slight delay where the buffer is on the 1st TV from the Unicast-to-Multicast handoff.
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rpeAMP @ 3rd Nov 11:10PM:
Re: Delays between Receivers

said by ILpt4U :

said by txdust :

I use to be a tech support for Uverse and would get called on this daily. The issue is you have a number of streams all independent from each other. When you turn on a receiver box that box in essence raises its hand to grab a stream. When a second box is turned on even on the same channel that box takes claim to a different stream. If your watching the game in the living room, and your son is watching the game in his room, think of the 2 TV's to be working on separate service. Which mean they travel from the AT&T center all the way to your V-rad box, than to your house. The greater the distance between you and the AT&t service center the great chance for these signals to unsync and be on an independent time line signal wise. This is not like your co-ax cable which is split at your house to separate rooms, where the unsync is too small to notice. This is caused by miles of traffic and unseen interference.
The scenario as it is described here is just not true. If 2 TVs in one house are watching the same channel, it is one stream being MultiCast to multiple boxes.

The reason the first TV is slower, is because it began the stream as UniCast -- It takes some measure of time (though pretty quick) for the STB to request to join the Multicast, be it at the VRAD, CO, or higher level, so to achieve instant channel changes, the streams always start Unicast, and is handed off to Multicast

The Second TV doesn't have to ask for the Multicast, because it is already present on the LAN, and it is able to join an in-progress Multicast stream that is already there. Same with a 3rd, 4th, 5th, etc. So those additional TVs don't have that slight delay where the buffer is on the 1st TV from the Unicast-to-Multicast handoff.
This explanation is correct. That's the beauty of IP multicast technology.
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ssj4android @ 4th Nov 10:08PM:
Re: Delays between Receivers

Isn't the point of the unicast to fill in the gap until an I-Frame in the multicast stream? Wouldn't it have to unicast until the new STB gets to an I-Frame in the multicast?
How does it do that, anyway?
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ILpt4U @ 4th Nov 11:56PM:
Re: Delays between Receivers

The "How" I have no idea -- and don't even know who to ask...

I do know a new stream request begins Unicast, and then joins the Multicast very shortly thereafter

But once that Multicast stream is already on your LAN, if another STB requests that same stream, it just immediately joins the multicast
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