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Discussion Starter · #1 ·
I have a ReplayTV 5504. I'm using the serial port connected to my DirecTV RCA 420 receiver. When I change the channels there is a slight pause for a sec or 2. Is there anyting I can do to speed that up? Since I'm using the serial port I'd think it'd be pretty seemless (not like an IR blaster). Is there any tips you guys have for me to speed it up? Much appreciated. :)
 

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A whole second or two? That's actually pretty quick.


I don't think there are any ways to improve that speed. However, rather than channel surf, try surfing the channel guide instead.


If you really insist on channel surfing and you have a couple different inputs to the TV, connect the DirecTV receiver straight to the TV using another input and surf that way. You'll pretty much lose any functionality of the Replay (ie, recording, pausing live TV, ect), but it will speed up your channel surfing.
 

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Quote:
Originally posted by yanksno1
I have a ReplayTV 5504. I'm using the serial port connected to my DirecTV RCA 420 receiver. When I change the channels there is a slight pause for a sec or 2. Is there anyting I can do to speed that up? Since I'm using the serial port I'd think it'd be pretty seemless (not like an IR blaster). Is there any tips you guys have for me to speed it up? Much appreciated. :)
No, that's how a DVR works. The delay is largely a result of the need to do buffering to permit all of the nifty pausing/rewinding/etc. with "live" TV. As Ace987 notes, 1-2 seconds is fast for a DVR.
 

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Discussion Starter · #4 ·
I should actually say it does seem longer then a sec or 2. I definetly notice it. Whats strange is I did have a Tivo Series 2 unit (no longer though b/c I had 2 units crash on me) and when it was connected to the serial cable it didn't seem to have the pause that the Replay does (or at least I don't remember it having that). I don't really channel surf, but I do hit the previous (go back) button on my remote when switching between channels, so the pause is sorta annoying. Bummer you can't really do anything to change it to make it quicker.
 

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This problem could be solved by design on PVRs (maybe even in software)


All that would be required is to delay the buffering for 5 seconds when surfing channels. Then you could surf as in the past, but if you stay on a channel for more than 5 seconds, the buffer would be there for the PVR features (Pause, Rewind, etc.).


The hardware (or software) would do the buffering in the background and then seamlessly synchronize it with the unbuffered live feed and you would then be watching the buffered video after 5 seconds.


Of course many people stop surfing after a few weeks of getting a PVR.

But why must I give up a TV feature when aquiring a PVR. [Demand/Economics & Marketing ... yes I know.]


I don't see why future models of any PVR could not add this as a feature or switchable option. I'm not holding my breath (especially for RTV) since most PVR user interface design is rather limited anyway IMO.
 

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The hardware (or software) would do the buffering in the background and then seamlessly synchronize it with the unbuffered live feed and you would then be watching the buffered video after 5 seconds.
I'm no expert, but I think this would be impossible as long as the source is a live feed. Think about it - you cannot buffer data that has not been received yet. Having 5 seconds (or 5 minutes) of buffer for a live feed necessarily means that what you are watching is 5 seconds (or 5 minutes) behind that live feed. There are only two ways of accomplishing this for a live feed that I know of. One is what is currently being done - delaying the signal for a few seconds, which leads to the delay in changing channels. The second is to travel in time into the future for the required buffer period.


What you described would be possible if changing channels on a digital feed streamed the data to your cable or satellite box at a rate faster than the bit rate of the video source. I don't know much about the technical details of digital cable or satellite, so I guess that it is possible that this is the way it works (but I don't think so). In other words when you change the channel your cable or satellite box starts buffering content for that channel at a rate faster than the displayed bit rate. If this is so, then a PVR that can get the source as it comes into the box (e.g. Cable PVR's), and not the output source can be made to have this functionality. But PVR's that only take the feed from the output signal of the box can never have this functionality.
 

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Originally posted by oldyellow
I'm no expert, but I think this would be impossible as long as the source is a live feed. Think about it - you cannot buffer data that has not been received yet.
I agree. What Brin described--i.e.seamless merging of live viewing to buffered viewing after X seconds--cannot work without time travel (or a delay, which is what already happens). However, it should be possible to display live video while simultaneously buffering that live video. Upon the first time the user pressed Pause/Stop/Rewind/Instant Replay, the video would would switch to the buffer. For this to work, the buffer needs to be caught up to the point in the live feed where the user entered trick play. Assume the buffer is 2 seconds behind live TV, this means a two second delay would have to be introduced for the *first* use of a trick play function after each channel change. (For everything to work properly, the delay needs to be made constant somehow).


For example, the software would have to enforce a mandatory 2-second minimum for the first Pause/Stop event after each channel change. Likewise, the software would have to impose a 2-second delay between the time the first time the user hits rewind and the time rewinding actually commences. Instant Replay could be, well, instant--provided that it jumps back at least 4 (or so) seconds, which isn't a problem since it currently does 7 seconds. After the first trick play function--regardless of what it is-- the user is stuck in the buffer and is 2 seconds behind live TV for the duration of viewing that channel.


I think the above could work well. It would involve some tricky video timing/positioning issues to make everything seamless, but I think it is possible. No matter what, there has to be a delay somewhere--well, at least until MPEG-2 encoding can be done instantaneously. The above method just shifts the delay from the beginning of the channel change, which channel surfers hate, to the first use of a trick play function, which most people would likely find more tolerable.
 

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I agree about the live feed time travel problem.


j.m. explained it better than I. Basically the idea is for the delay to be incorporated into some normal delay function like stop or pause which are usually more than 2 seconds. Stop woudl be easy, but pause would introduce the delay. As was mentioned you can't pause the live video that has not been buffered yet.... ow, this is bending my neurons...thinking... with...a...delay.


Maybe the live feed could drop a couple live frames each second and be matched to the buffer in under a minute. The frames would still be recorded in the buffer but the live feed would get time compressed for a short while. Or did I break another law of physics ;)
 

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Quote:
Originally posted by Brin
Maybe the live feed could drop a couple live frames each second and be matched to the buffer in under a minute. The frames would still be recorded in the buffer but the live feed would get time compressed for a short while. Or did I break another law of physics ;)
You're breaking the laws of physics there. The live buffer would be just that, live. Since there is no instantaneous encoder/decoder, the live signal would just be whatever is coming from the output of the cable/receiver/other-worldly source. There is no way of just slowing it down.


At best, you could have 2 signals, 1 live and 1 from being encoded. The encoded signal is going to be a few seconds behind the live feed. You could watch the whole show live without a pause, but the second you do a pause or an IR, you'd switch from the live signal to the encoded signal.


This could work, but I doubt you'll ever see this on anything branded ReplayTV anytime in the near future.
 

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Too slow to fix the laws of typing about the laws of physics.


Well I realized my last post broke the laws of physic about 10 minutes after I wrote it. But by then I was on the highway, wondering if I would make it home to edit the post before someone pointed out the obvious (for the second time) -- I can't drop frames that have not yet been recorded.


But one could jump back 2 seconds at the first commercial fade out, repeating it by the delay amount. Of course that would involve ShowNav CA (CB?) and who want's to see a commercial restarting even if it does synchronize to the buffer. I agree that this will never happen with RTV.
 

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In radio there's a delay device that delays the audio by up to 7 seconds so that if a caller or guest uses profanity, you can hit a "dump" button and the profanity won't make it on the air. In recent years these have worked to build up to the 7 seconds when first put in line or after a dump. I don't know how the circuit works, but I think this is what Brin suggested with the programming going through a ReplayTV, that the buffering would go from none and build up to a small buffer. Early electronic audio delay devices worked much like the ReplayTV, when first put on line there'd be a gap in the audio where it switched from live to delayed and after hitting dump, there'd be a gap where it went from delayed to live and back to delayed.


I know with audio and video in a device like a ReplayTV this would not be a simple task. Just trying to use an analogy to illustrate what I think he was alluding to.
 

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...and in addition to all of that which oldyellow just said - one must ask :


WHY BOTHER?!?!?? Trying that hard to get rid of the buffering delay is pointless and futile...


Is there _actually_ someone out there that is so completely, pathetically addicted to TV that they just can't cope with a 3 to 5 second delay and just can't manage to adapt - therefore causing them to suffer a Marjory traumatic emotional event - that leaves them scarred for the remainder of their life? It's soooo nice that Dr. Darwin's hypothesis and associated theory happens to apply to ****-Sapiens too...
 

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Quote:
Originally posted by rm -rf *.*
...and in addition to all of that which oldyellow just said - one must ask :


WHY BOTHER?!?!?? Trying that hard to get rid of the buffering delay is pointless and futile...


Is there _actually_ someone out there that is so completely, pathetically addicted to TV that they just can't cope with a 3 to 5 second delay and just can't manage to adapt - therefore causing them to suffer a Marjory traumatic emotional event - that leaves them scarred for the remainder of their life? It's soooo nice that Dr. Darwin's hypothesis and associated theory happens to apply to ****-Sapiens too...


Actually I would say that a significant number of people are addicted to TV and other consumer products in ways that cause them to make purchases that make it easier for them rather than more difficult. Of course they can adapt, but many would choose a competing product if it were easier to use. That is all this is about, making products easier to use and not forcing people to adapt to the limitations of the equipment.


Most people purchasing electronic equipment don't care one bit about how the equipment works. But they do notice things that reduce their enjoyment of the equipment, and if a competitor makes a product that works faster with similar features and price point, they will buy it. TV manufacturers have made their tuners faster so there is a minimal delay when switching channels, and this is promoted as a feature.


Not everyone cares about such things, but telling customers they have to live with the design limitations and adapt is not a selling point. As usual the marketplace will decide the success or failure of competing products.
 

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Quote:
Originally posted by FarmBubba
One solution is to have 3 tuners and have the extra tuners "caching" the next channels. This would only work on cable or OTA though.
The tuners would have to be telepathic. How else would they know what channel I'm going to next? Though I realize you have Ch+/Ch- channel surfing in mind with your solution, the annoying (to some) delay isn't limited to that. Channel surfing is an easy habit to break. Where the delay really causes problems IMO is for sports freaks who are continuously flipping between 5 games on 5 different channels. The delay makes doing so pretty frustrating. The solution, of course, is to watch the games by bypassing the ReplayTV. However, then you can't rewind to catch that bad call/great play etc.


I really think the solution I posted above is a good one that is very doable and cost effective.
 
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