Do you have microstutters?

[ZeitGeist]

Ok, you guys are going to love this. I'm sitting around talking to my wife this afternoon while i'm waiting for the Indy to restart. Somehow we start talking about TV - OK, I start talking TV electronics and my wife pretends to be interested for awhile. Anyway, to show her how I'm not obsessed with HD and PQ and TV electronics, I tell her she's got it good, some people are so obsessed with their equipment they can't it. They spend all their time trying to find flaws. "Well, that's what you do," she says. To prove how I'm different, I tell her about this thread - how there are people that actually think there is an almost imperceptible split-second stutter on all the Voom channels. I'm sitting there with a smug "see I'm not totally obsessed HD PQ person like you think" look on my face when my wife says, "Yeah, I see that". I'm dumbfounded for a second and then I explain to her in my best "I'm not trying to be condescending to you, Dear, but this is about the TV and there is no way you could possibly really understand what they are talking about so I'm actually being condescending to you voice" what she's probably talking about is pixelation. "No, you've shown me that. I know what that is. No, this is almost like a person is one position and in the blink of an eye they have moved just a tiny bit but the move wasn't smooth." I don't even know what to say at first so I try to reexplain how she can't possibly be seeing what she thinks she's seeing. "No, I see it. It happens about every 30 seconds are so. Just real small. You gotta kinda look for it but sometimes it's a lot more noticeable."
So, in an attempt to be honest to all participating in the thread I've decided to be forthcoming and admit that the "microstutter" issue is even disputed in my own household. I don't even know what to say, this is from the woman who I catch watching the SD feed of HD shows half the time because she can't tell the difference or, even worse, doesn't really care - "The shows already on here. I'm watching it. What's the point in changing?" So, I don't see it but my wife does and everything she says agrees with what you guys are saying. Furthermore, I can guarantee she hasn't been reading this forum so it's not a matter of suggestion.

dave

 

[Scubasoul]

Ok, you guys are going to love this. I'm sitting around talking to my wife this afternoon while i'm waiting for the Indy to restart. Somehow we start talking about TV - OK, I start talking TV electronics and my wife pretends to be interested for awhile. Anyway, to show her how I'm not obsessed with HD and PQ and TV electronics I tell her she's got it good, that there are some people so obsessed with their equipment that they can't actually just sit and enjoy the picture they are always trying to find flaws. For example, I tell her that there are people that actually think there is a problem on all the Voom channels with the picture were there is an almost imperceptible split-second stutter. I'm sitting there with a smug "see I'm not totally obsessed HD PQ person" look on my face when my wife actually perks up and says, "Oh yeah, I see that". I'm dumbfounded for a second and then I explain to her in my best "I'm not trying to be condescending to you, Dear, but this is about the TV and there is no way you could possibly really understand what they are talking about so I'm actually being condescending" that she's probably talking about pixelation. "No, you've shown me that. I know what that is. No this is almost like a person is one position and in the blink of an eye they have moved just a tiny bit but the move wasn't smooth." I don't even know what to say at first so I try to reexplain how she can't possibly be seeing what she thinks she's seeing. "No, I see it. It happens about every 30 seconds are so. Just real small. You gotta kinda look for it but sometimes it's a lot more noticeable."
So, in an attempt to be honest to all participating in the thread I've decided to be forthcoming and admit that the "microstutter" issue is even disputed in my own household. I don't even know what to say, this is from the woman who I catch watching the SD feed of HD shows half the time because she can't tell the difference or, even worse, doesn't really care - "The shows already on here. I'm watching it. What's the point in changing?" So, I don't see it but my wife does and everything she says agrees with what you guys are saying. Furthermore, I can guarantee she hasn't been reading this forum so it's not a matter of suggestion.

dave

Better trust your wife, she's right

 

[Ilya]

Did you say APRIL?????

Yes. Why? It was on April 19, that's when I posted on this subject here in this forum as well. But I wouldn't expect this to be fixed very quickly. Fortunately this a very small problem, not even noticeable to many.

Interesting, he actually confirms that they are aware of the problem and are trying to fix it.

At a very least they were aware of the postings made by GeneWildershair and others. The real question is whether they were able to track it down to a specific technical problem in the STB. That remains to be seen.

 

[ChetK]

I am not the kind of person that says, "I told you so". So, I'm not going to do that.

BUT I do want to honestly say that I can't believe my theory was correct!!! I mean, this is something really technical and it was just a thought that I had. I want to say THANKS to those who took my theory and ran with it to narrow down the truth (timing of the stutter vs. the theory = fact). This has got to be the most gratifying thread I have ever participated in on the internet (and I have participated in many). I'll be especially happy if they fix this problem after many of their customers have reported this "problem/issue."

Props go to the SatelliteGuys.US for creating this free forum for us to collaborate as consumers. Yay SatelliteGuys!!!

 

[eschu97611]

I am not the kind of person that says, "I told you so". So, I'm not going to do that.

BUT I do want to honestly say that I can't believe my theory was correct!!! I mean, this is something really technical and it was just a thought that I had. I want to say THANKS to those who took my theory and ran with it to narrow down the truth (timing of the stutter vs. the theory = fact). This has got to be the most gratifying thread I have ever participated in on the internet (and I have participated in many). I'll be especially happy if they fix this problem after many of their customers have reported this "problem/issue."

Props go to the SatelliteGuys.US for creating this free forum for us to collaborate as consumers. Yay SatelliteGuys!!!

Congrats if you have indeed "nailed it"


The question now is, "Will Voom Fix it?" And "When?"

 

[Scubasoul]

I am not the kind of person that says, "I told you so". So, I'm not going to do that.

BUT I do want to honestly say that I can't believe my theory was correct!!! I mean, this is something really technical and it was just a thought that I had. I want to say THANKS to those who took my theory and ran with it to narrow down the truth (timing of the stutter vs. the theory = fact). This has got to be the most gratifying thread I have ever participated in on the internet (and I have participated in many). I'll be especially happy if they fix this problem after many of their customers have reported this "problem/issue."

Props go to the SatelliteGuys.US for creating this free forum for us to collaborate as consumers. Yay SatelliteGuys!!!

I hope you were right, and kudos to you and Ilya. Without your input I would have never taken a damn stop watch and measured the thing.

I hope that they fix the problem eventually, that's what it's all about.

 

[deeann]

...and then I explain to her in my best "I'm not trying to be condescending to you, Dear, but this is about the TV and there is no way you could possibly really understand what they are talking about. ........

(snip)

"No, I see it. It happens about every 30 seconds are so. Just real small. You gotta kinda look for it but sometimes it's a lot more noticeable."

Oh man, this makes me laugh....to quote from the Simpsons-

"HA-HA"



But seriously- I'm glad you posted this. Scubasoul has good advice.

Scubasoul, I'm glad you posted that 'drop-frame' means time-code frame reference only w/no physical frames being dropped (as it's as confusing/misleading term) - I was going to do that earlier but didin't have the time.

Not to confuse the issue, but for anyone who happened to read my older posts on the subject, is that while noticable,the Voom microstutter doesn't seem nearly as severe as the problem with SureWest digital cable I was having. With SW, the working theory the headend tech at the time (before he quict the company) and I had (after ruling out pulldown settings, frequency-mismatch, etc.) was that when a malfuntioning encoder they were using spit out a bad frame after choking on a glitch from the the HITS (Headend in the Sky) feed, the ECC (Error Correction Circuitry) on the Philips STB they were using would hold over the last good frame (for at least half of a second) which was *really* super-distracting (more like "macro" stutters ).

But back to Voom:
Until I looked really close today I only noticed some larger skips around every 8-10 minutes (didn't time it), but today I looked really close and could see a minor skip every 30 seconds or so. And yep- it is a problem- not the showstopper 'cancel my service' problem I had with SW, but it's there nonetheless.

From Illya:

So, this might be fixed it in the future. I hope this is just a configuration parameter that can be set through the software (to use 59.94Hz frequency instead of 60Hz).

Me too. I hope it's a 'simple' enough fix.

 

[Ilya]

Props go to the SatelliteGuys.US for creating this free forum for us to collaborate as consumers. Yay SatelliteGuys!!!

Exactly right! Problems like this one require collective effort of many. Thanks to this forum!

As for how soon this problem can be fixed, I don't know yet if this will make it to the next release, but I am pretty optimistic that it can be fixed via software update. I think a frequency divider (for some clock generating chip in the STB) needs to be adjusted - just a guess

 

[ChetK]

clock generating chip

In the business, they call them "time base correctors" and they are usually on the programming providers end BEFORE sending the signal to the customers house.

However, this could be a costly upgrade to fix for Voom. The IBP formatting of Mpeg2 is a difficult format to tap into the pipeline with additional equipment. This is further complicated by the fact that time based correctors aren't cheap and I'm sure they are even more expensive for an HD signal. Also, I'm not sure if you would need a time based corrector for each channel or if there is a solution for multiple channels.

HD is fairly new. Especially to Voom. I have no doubt that it will be fixed, but I would look for a quick solution to this problem. It may go away once they upgrade to WM9. I haven't done enough studies on Mpeg-4 to know if it uses the same kind of 15 GOP IBP structure that Mpeg-2 uses.

 

[vurbano]

well, the first step in solving a problem is to define the problem and accumulate data. Isnt that right Eschu?. - LMAO

 

[eschu97611]

well, the first step in solving a problem is to define the problem and accumulate data. Isnt that right Eschu?. - LMAO

You got it V, data, give me data-btw who are the "we"? Still waiting for that "data"-LMAO

 

[Ilya]

In the business, they call them "time base correctors" and they are usually on the programming providers end BEFORE sending the signal to the customers house.

I don't think this problem is on the transmitting end. If this was the case you wouldn't see any stutter on OTA channels. I think the problem is in the STB: output frequency is different from the input frequency. IMO, the STB itself is loosing frames.

 

[deeann]

In the business, they call them "time base correctors" and they are usually on the programming providers end BEFORE sending the signal to the customers house.

That's interesting! I didn't think TBC's were needed at all once the video was within the digital realm (for digital to digital transmission). I thought they were only needed for analog to digital conversion or analog to analog (for cleanup, colorburst removal, etc).

 

[oddwunn]

I agree that the problem is at the decoding end, not the encoding.

How close did the first appearance of stutters coincide with the release of firmware 5.68? And was the stuttering there before the update?

 

[Ilya]

How close did the first appearance of stutters coincide with the release of firmware 5.68? And was the stuttering there before the update?

The microstutter problem was reported by Gr8Reb8, GeneWildershair and others long before the very first software update. For example, see this thread: stutter problem...

 

[digitald]

stutter

I have had my system almost a week now & I definitely notice a slight stutter or glitch very subtle but it is there.

 

[Ilya]

Well, I did some measurements with a stop-watch timer trying to time the stutter frequency. As suggested by Scubasoul, I used the CNN ticker, which indeed seems to be the easiest way to reproduce this problem. Excellent tip, by the way! I registered 30 skipped frames over a period of 10 minutes with a one second precision. This translates into 33 1/3 seconds per skipped frame with a good accuracy!

I also checked an OTA channel. It was showing a weather warning ticker. Not only it had the same stutter frequency, but it was even in phase(!) with the stutter on the CNN channel. I think this pretty much proves that the problem is at the decoding end.

I think we nailed it! Thanks everyone! It's been fun... :up

Ilya.

 

[ZeitGeist]

Well, if y'all are right then I hope that Wilt or someone will give you feedback to let you know that you were right and I hope it is firmware and not hardware related - if it does actually exist.

david

 

[Scubasoul]

Well, I did some measurements with a stop-watch timer trying to time the stutter frequency. As suggested by Scubasoul, I used the CNN ticker, which indeed seems to be the easiest way to reproduce this problem. Excellent tip, by the way! I registered 30 skipped frames over a period of 10 minutes with a one second precision. This translates into 33 1/3 seconds per skipped frame with a good accuracy!

I also checked an OTA channel. It was showing a weather warning ticker. Not only it had the same stutter frequency, but it was even in phase(!) with the stutter on the CNN channel. I think this pretty much proves that the problem is at the decoding end.

I think we nailed it! Thanks everyone! It's been fun... :up

Ilya.

Yes Ilya, I also think we nailed it. The timing of ~34 sec. is indeed a strong indication that it has something to do w/ 29.97fps vs. 30 fps. Hopefully we get some more info from Wilt.

 

[Scubasoul]

Well, if y'all are right then I hope that Wilt or someone will give you feedback to let you know that you were right and I hope it is firmware and not hardware related - if it does actually exist.

david

Still saying "...if it does actually exist", although your wife told you she sees it?

Not much trust there, heh