Jim Burns - Are Some Blu Ray Players Better on HDMI HD Picture Quality? - Page 4 - AVS Forum
Forum Jump: 
 
Thread Tools
post #91 of 224 Old 03-03-2009, 09:15 AM
AVS Club Gold
 
Art Sonneborn's Avatar
 
Join Date: Jun 2000
Location: Battle Creek,MI USA
Posts: 22,305
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 13 Post(s)
Liked: 48
Quote:
Originally Posted by FrantzM View Post

So......What to conclude... PS3 is enough and provide the exact same results as any other player on the market.

Correct !

Art


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.



iRule rules my theater
 

"If she's amazing she won't be easy,if she's easy she won't be amazing"

 

Bob Marley

Art Sonneborn is offline  
Sponsored Links
Advertisement
 
post #92 of 224 Old 03-03-2009, 09:26 AM
AVS Addicted Member
 
Alimentall's Avatar
 
Join Date: Aug 2004
Location: Home by the sea
Posts: 14,157
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
The PS3 is the most capable piece of junk on the market. But it is a piece of junk ergonomically, usability, reliability wise, design wise, etc. We spend a significant amount of time running to people's homes to make them work again and again and again because they are hard for most people to use and update.

John
Alimentall is offline  
post #93 of 224 Old 03-03-2009, 09:29 AM
AVS Special Member
 
FrantzM's Avatar
 
Join Date: Feb 2003
Location: Southeast FL, USA
Posts: 2,071
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Art

Since you changed your avatar you, also have changed and gotten real mean!!

Frantz
FrantzM is offline  
post #94 of 224 Old 03-03-2009, 10:00 AM
AVS Club Gold
 
Art Sonneborn's Avatar
 
Join Date: Jun 2000
Location: Battle Creek,MI USA
Posts: 22,305
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 13 Post(s)
Liked: 48
Quote:
Originally Posted by FrantzM View Post

Art

Since you changed your avatar you, also have changed and gotten real mean!!

Sorry, I've been attacked on so many threads by folks with serious agendas etc that I've just taken a stance that is consistant but unfortunately increasingly more that way.

Art


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.



iRule rules my theater
 

"If she's amazing she won't be easy,if she's easy she won't be amazing"

 

Bob Marley

Art Sonneborn is offline  
post #95 of 224 Old 03-03-2009, 10:12 AM
AVS Special Member
 
FrantzM's Avatar
 
Join Date: Feb 2003
Location: Southeast FL, USA
Posts: 2,071
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by Art Sonneborn View Post

Sorry, I've been attacked on so many threads by folks with serious agendas etc that I've just taken a stance that is consistant but unfortunately increasingly more that way.

Art

I've edited my previous post... Seriously even with your PJ you have not been able to see any differences? Neither have I but as I stated earlier my experience with BD player is very limited and my PJ is far from the current SOTA...

Frantz
FrantzM is offline  
post #96 of 224 Old 03-03-2009, 10:54 AM
Advanced Member
 
mlang46's Avatar
 
Join Date: Aug 2006
Location: Boulder, Colorado
Posts: 906
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 11
Quote:
Originally Posted by twenty/twenty View Post

[QUOTE Either you get a complete skip or no degradation in the signal at all. That's the joy of digital.

What do you mean by complete skip?[/quote]

I mean the track has been skipped or a bit dropped.
mlang46 is offline  
post #97 of 224 Old 03-03-2009, 12:02 PM
AVS Club Gold
 
Art Sonneborn's Avatar
 
Join Date: Jun 2000
Location: Battle Creek,MI USA
Posts: 22,305
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 13 Post(s)
Liked: 48
Quote:
Originally Posted by FrantzM View Post

I've edited my previous post... Seriously even with your PJ you have not been able to see any differences? Neither have I but as I stated earlier my experience with BD player is very limited and my PJ is far from the current SOTA...

No difference in PQ with three different BD players.

Art


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.



iRule rules my theater
 

"If she's amazing she won't be easy,if she's easy she won't be amazing"

 

Bob Marley

Art Sonneborn is offline  
post #98 of 224 Old 03-03-2009, 12:11 PM - Thread Starter
AVS Addicted Member
 
Steve Bruzonsky's Avatar
 
Join Date: Jan 1999
Location: Gilbert, Arizona
Posts: 17,635
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 20 Post(s)
Liked: 21
No difference in picure quality for me in first using a Panasonic BD30K and more recently a Panasonic BD35K.

Interesting that the Pioneer Elite 09 and upcoming Denon Blu Ray playes have two HDMI outputs touted as one for video and one for audio. As though that will improve performance. I admit I am skeptical on that, because I would think all they are doing is splitting/amplifying one HDMI signal into two HDMI signals/outputs. Not like they can take the HDMI audio/video signal and separate it into separate HDMI audio and video components, dejitter, etc. Or can they?????

"Doug Winsor" used to troll at some AV Forums as "Steve Bruzonsky"! My home theater at:

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Steve Bruzonsky is online now  
post #99 of 224 Old 03-03-2009, 12:20 PM
AVS Special Member
 
FrantzM's Avatar
 
Join Date: Feb 2003
Location: Southeast FL, USA
Posts: 2,071
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Curious why did you acquire the 35K? Were you under the impression that it would be superior? What about sound quality?

Frantz
FrantzM is offline  
post #100 of 224 Old 03-03-2009, 12:26 PM - Thread Starter
AVS Addicted Member
 
Steve Bruzonsky's Avatar
 
Join Date: Jan 1999
Location: Gilbert, Arizona
Posts: 17,635
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 20 Post(s)
Liked: 21
Quote:
Originally Posted by FrantzM View Post

Curious why did you acquire the 35K? Were you under the impression that it would be superior? What about sound quality?

Gotta real good price and moved the 30K to another system in my home. Also the 35K is BD Live 2.0, too! Didn't get it expecting any better or different audio or video.

"Doug Winsor" used to troll at some AV Forums as "Steve Bruzonsky"! My home theater at:

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Steve Bruzonsky is online now  
post #101 of 224 Old 03-03-2009, 12:41 PM
AVS Addicted Member
 
amirm's Avatar
 
Join Date: Jan 2002
Location: Washington State
Posts: 18,083
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 755 Post(s)
Liked: 434
Quote:
Originally Posted by Steve Bruzonsky View Post

Not like they can take the HDMI audio/video signal and separate it into separate HDMI audio and video components, dejitter, etc. Or can they?????

They can. To the extent one of the transmitters doesn't have video fed to it, then it can certainly help the audio. Keep in mind that audio and video are seperate as they come from the decoder. So steering one into one transceiver and the other into another, is pretty easy.

I have not dug into HDMI spec enough to know if it can run without video. But even if it cannot, they can always send out pure black video as to not have it change constantly.

Now, which AVR or processor can merge two HDMI ports into one and not back out any improvement in above?

Amir
Founder,
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

"Insist on Quality Engineering"

amirm is offline  
post #102 of 224 Old 03-03-2009, 12:41 PM
 
faberryman's Avatar
 
Join Date: Oct 2001
Posts: 546
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by Steve Bruzonsky View Post

Not like they can take the HDMI audio/video signal and separate it into separate HDMI audio and video components, dejitter, etc. Or can they?????

Meridian yes, Denon doubtful.
faberryman is offline  
post #103 of 224 Old 03-03-2009, 12:44 PM
AVS Addicted Member
 
thebland's Avatar
 
Join Date: Jan 2001
Location: Detroit, Michigan USA
Posts: 23,834
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 200 Post(s)
Liked: 133
Quote:
Originally Posted by amirm View Post


I have not dug into HDMI spec enough to know if it can run without video. But even if it cannot, they can always send out pure black video as to not have it change constantly.

I think it requires some sort of video stream.. Lumagen, when sending audio only via one of the 2 HDMI outputs, also sends 'blank video' at 1080i.. I think it was discussed in the Lumagen beta forum and that Jim said a video signal must accompany an audio one... Not 100% though..


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


There are more than a handful of [op amps] that sound so good that most designers want to be using them as opposed to discreet transistors. Dave Reich, Theta 2009
thebland is online now  
post #104 of 224 Old 03-03-2009, 12:59 PM
 
faberryman's Avatar
 
Join Date: Oct 2001
Posts: 546
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by thebland View Post

I think it requires some sort of video stream.. Lumagen, when sending audio only via one of the 2 HDMI outputs, also sends 'blank video' at 1080i.. I think it was discussed in the Lumagen beta forum and that Jim said a video signal must accompany an audio one... Not 100% though..

The audio piggybacks on the video so you need to either have your display on or have an HDMI sink link the Radiance to get audio over HDMI.
faberryman is offline  
post #105 of 224 Old 03-03-2009, 01:11 PM
AVS Addicted Member
 
Michael Grant's Avatar
 
Join Date: Apr 2001
Location: Austin, TX
Posts: 10,239
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 22
Quote:


I have not dug into HDMI spec enough to know if it can run without video. But even if it cannot, they can always send out pure black video as to not have it change constantly.

Yeah, audio is sent over the video blanking interval.

Not only do you have to send a video signal of some sort, the video resolution determines the available audio bandwidth. For high-res multichannel you actually have to send an HD video stream, I believe.

For synchronization purposes I can't see it being practical to use a different resolution than it was originally tied to. I mean, a design that splits, say, a 1080p24 video signal and the 7.1 LPCM audio data, re-attaches the audio to a 720p24 video stream seems prone to design error. So in all likelihood the video format selected for the "pure audio" stream is going to be exactly the same as it was before the split. I could be wrong about this though.

Furthermore, from an analog signal transmission standpoint, blanking out that video signal doesn't help as much as you might think. That's because the HDMI signal spec scrambles the video data to ensure that there aren't long strings of 1s or 0s in a row, and there will be plenty of nonzero packet header and ECC bits left.

As far as I can tell, without more information to justify it, this notion that splitting the audio from the video seems just a bit more marketing hogwash. You can get the same bang from your buck with a simple 1x2 repeater.

Michael
Michael Grant is offline  
post #106 of 224 Old 03-03-2009, 01:20 PM
AVS Special Member
 
robena's Avatar
 
Join Date: Aug 2000
Posts: 1,682
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 12
Quote:
Originally Posted by Michael Grant View Post

ee it being practical to use a different resolution than it was originally tied to. I mean, a design that splits, say, a 1080p24 video signal and the 7.1 LPCM audio data, re-attaches the audio to a 720p24 video stream seems prone to design error. So in all likelihood the video format selected for the "pure audio" stream is going to be exactly the same as it was before the split. I could be wrong about this though.

I have an Edge processor that does exactly that (from what I read), feeding my ML40 a 720p signal.

I have been using various HDMI splitters before, and I always had audio drops. With the Edge, audio drops have disappeared.

Robert
robena is online now  
post #107 of 224 Old 03-03-2009, 01:25 PM
AVS Addicted Member
 
amirm's Avatar
 
Join Date: Jan 2002
Location: Washington State
Posts: 18,083
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 755 Post(s)
Liked: 434
Quote:
Originally Posted by Michael Grant View Post

For synchronization purposes I can't see it being practical to use a different resolution than it was originally tied to. I mean, a design that splits, say, a 1080p24 video signal and the 7.1 LPCM audio data, re-attaches the audio to a 720p24 video stream seems prone to design error. So in all likelihood the video format selected for the "pure audio" stream is going to be exactly the same as it was before the split. I could be wrong about this though.

From sync point of view, it would not only have to be the same resolution but driven from the same video clock. Otherwise, you lose AV sync over time.

Quote:


Furthermore, from an analog signal transmission standpoint, blanking out that video signal doesn't help as much as you might think. That's because the HDMI signal spec scrambles the video data to ensure that there aren't long strings of 1s or 0s in a row, and there will be plenty of nonzero packet header and ECC bits left.

What happens post HDMI transmitter is an issue in the receiver. To the extent the HDMI transceiver is not having a high frequency video signal constantly changing, one can imagine it results in a more stable situation assuming whoever designed it, didn't screw up other things.

You are right that the the receiver still sees a dynamic signal. However, if that signal is constant (i.e. doesn't change from frame to frame) then your ear is less likely to be bothered by it.

Quote:


As far as I can tell, without more information to justify it, this notion that splitting the audio from the video seems just a bit more marketing hogwash. You can get the same bang from your buck with a simple 1x2 repeater.

I agree that a lot has to be done right for this to be a real benefit. Until then it does remain a marketing thing...

Amir
Founder,
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

"Insist on Quality Engineering"

amirm is offline  
post #108 of 224 Old 03-03-2009, 01:32 PM
LJG
AVS Special Member
 
LJG's Avatar
 
Join Date: Jun 2000
Location: Brookville, NY
Posts: 3,995
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 12 Post(s)
Liked: 16
Quote:
Originally Posted by Jim Burns View Post

Haven't read the entire post yet but wanted to answer because "little Steve" (you some times learn too much form AVS forum) thought I would not. I will read the rest and answer later tomorrow this is quality time with the girl friend.

Those that know me are expecting me to recommend something off the shelf, not this time. I think a HTPC is the way to go here. I still do not know of a regular player that stands out above the rest. Does not mean it does not exist but I have not found it.

Finding an above average off the shelf player has been an issue for me too.


Would like to hear more about " I think a HTPC is the way to go here "
LJG is offline  
post #109 of 224 Old 03-03-2009, 01:35 PM
AVS Special Member
 
robena's Avatar
 
Join Date: Aug 2000
Posts: 1,682
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 12
Quote:
Originally Posted by amirm View Post

From sync point of view, it would not only have to be the same resolution but driven from the same video clock. Otherwise, you lose AV sync over time.

That seems logical, but the DVDO site gives this information about the Edge:

Quote:


4. What signals can the EDGE output?

EDGE has one HDMI 1.3 output that outputs both audio and video. The second HDMI output only carries audio, with blank 720p video, which is intended to carry audio to a connected Audio/Video Receiver.

And as I posted before, no audio problems at all.

Robert
robena is online now  
post #110 of 224 Old 03-03-2009, 04:11 PM
AVS Special Member
 
Glimmie's Avatar
 
Join Date: Sep 2000
Location: Los Angeles, CA
Posts: 7,952
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 149 Post(s)
Liked: 215
Quote:
Originally Posted by amirm View Post

From sync point of view, it would not only have to be the same resolution but driven from the same video clock. Otherwise, you lose AV sync over time.


What happens post HDMI transmitter is an issue in the receiver. To the extent the HDMI transceiver is not having a high frequency video signal constantly changing, one can imagine it results in a more stable situation assuming whoever designed it, didn't screw up other things.

You are right that the the receiver still sees a dynamic signal. However, if that signal is constant (i.e. doesn't change from frame to frame) then your ear is less likely to be bothered by it.


I agree that a lot has to be done right for this to be a real benefit. Until then it does remain a marketing thing...

The data stream is a fixed format. You don't just drop the video away. And furthermore it makes no difference if you send balck video or a busy picture. As stated above the data is scrambled anyway for HDCP. HDMI AFAIK does not do a polynomial scrambling as it has a dedicated clock pair. But HDSDI and SDI do in fact scramble for the sole purpose of clock recovery - nothing to do with copy protection.

The signal is changing at the rate of the clock signal. It doesn't matter if the is no picture or sound or video and audio of a full symphony.

I realize some people here want to see an "audiophile" grade HDMI port. Sorry it doesn't work that way. It either meets the HDMI spec or it doesn't. Jitter in video streams is corrected by FIFO's so any jitter is reclocked to the limits of the receiver PLL.

Glimmie's HT Page
Being redone - comming soon!

Glimmie is offline  
post #111 of 224 Old 03-03-2009, 04:38 PM
AVS Special Member
 
Glimmie's Avatar
 
Join Date: Sep 2000
Location: Los Angeles, CA
Posts: 7,952
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 149 Post(s)
Liked: 215
Quote:
Originally Posted by amirm View Post

That is not the reason they would impact fidelity. The reason there may be a difference for audio, is due to power consumption of those servos. Imagine a scenario where the disc resonates every time you excite the chassis with 200 Hz. That resonance causes the pit to go in and out of focus. The servo as you correctly state, will track, however it will also draw power and in doing so, causes noise on the power supply line. That noise then potentially impacts the clock oscillators for the DAC or HDMI output, causing jitter to either increase or change spectrum. Since the distortion is correlated with what is playing, it tends to be much more noticeable than if it were constant.

The issue for this thread is that even with the above, it is hard to think of what damage it can do to video. If we had an analog CRT as the display, the jitter may manifest itself as pixels moving but for a digital device, that would not be the case.

Sorry but I have to disagree with this theory as well. Specifically the power supply part. These power supplies are well regulated. In addition the PLL in a high quality design will have a dedicated regulator or at least be activily filtered to ensure pure DC to the circuit. Even a cheap player probably has at least a simple RC or LC filter in the PLL power rails.

I would be far more convinced the mechanical vibration could stress the focus servo beyond it's correction bandwidth than cause any issue with the units power busses.

There will always be those who think placing their BluRAy player on expensive cones or other elevation devices will make it look and sound better but just as in CD players, this has no scientific merits.

Now an analog turntable - thats another story!

Glimmie's HT Page
Being redone - comming soon!

Glimmie is offline  
post #112 of 224 Old 03-03-2009, 04:55 PM
AVS Addicted Member
 
Michael Grant's Avatar
 
Join Date: Apr 2001
Location: Austin, TX
Posts: 10,239
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 22
Quote:


I have been using various HDMI splitters before, and I always had audio drops. With the Edge, audio drops have disappeared.

Well there you go... that's important and useful info. Certainly, if you can drop down to 720p, you're reducing the bandwidth required to carry the audio, and that is in theory a more robust result. I just figured (wrongly) that it would be too much of a pain to do.

Michael
Michael Grant is offline  
post #113 of 224 Old 03-03-2009, 05:03 PM
AVS Addicted Member
 
amirm's Avatar
 
Join Date: Jan 2002
Location: Washington State
Posts: 18,083
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 755 Post(s)
Liked: 434
Quote:
Originally Posted by Glimmie View Post

The data stream is a fixed format.

I don't understand what point are you making with this.

Quote:


And furthermore it makes no difference if you send balck video or a busy picture.

I tend to disagree . Let me explain it this way. In an ideal situation, the receiver would only get audio and nothing else. Any other signal, especially a high frequency video signal, is going to, through cross-talk, leak into the DAC (through its clock). We are trying to lower the chances of that.

Quote:


As stated above the data is scrambled anyway for HDCP. HDMI AFAIK does not do a polynomial scrambling as it has a dedicated clock pair. But HDSDI and SDI do in fact scramble for the sole purpose of clock recovery.

We wouldn't necessarily need HDCP for the audio channel although that would limit us to 16-bits.

Quote:


The signal is changing at the rate of the clock signal. It doesn't matter if the is no picture or sound or video and audio of a full symphony.

It might matter at macro level.

Quote:


I realize some people here want to see an "audiophile" grade HDMI port. Sorry it doesn't work that way. It either meets the HDMI spec or it doesn't. Jitter in video streams is corrected by FIFO's so any jitter is reclocked to the limits of the receiver PLL.

I see where the issue is. You are focusing at the cable ends, we are looking at the big picture. .

The PLL does track the HDMI clock. But at some point, we generate another clock driven from it for audio. Assuming that clock is immune to HDMI cable jitter (which is not a good assumption but let's go with it), the audio clock can get impacted by other activity in the system.

To the extent I have a totally seperate audio subsystem in a high-end processor, lack of video samples changing every pixel is helpful in reducing distortion. I guarantee you that I can measure their impact on power supply rails no matter how much you decouple the circuit or filter it. The pulses can also leak in other ways. This is why processors have modes to turn off video data paths or even front panel displays for better audio. Everything is interconnected even if it seems that it is not.

Yes, having black doesn't mean the circuits are quiet. They are still counting pixels, etc. But the level of activity is far less than real video coming at it.

Of course, in the world of mass market products the above doesn't matter. But if you are talking about spending a ton of money for the last bit of quality, then it is fair consideration. In theory at least .

But sure, the interface has many faults. No one here is trying to defend HDMI. Just saying that if something can be done about its faults, it should be looked at. If after someone builds it, we measure it and listen to it and makes no difference, then fine.

Amir
Founder,
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

"Insist on Quality Engineering"

amirm is offline  
post #114 of 224 Old 03-03-2009, 05:20 PM
AVS Special Member
 
Glimmie's Avatar
 
Join Date: Sep 2000
Location: Los Angeles, CA
Posts: 7,952
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 149 Post(s)
Liked: 215
Quote:
Originally Posted by amirm View Post

I don't understand what point are you making with this.


I tend to disagree . Let me explain it this way. In an ideal situation, the receiver would only get audio and nothing else. Any other signal, especially a high frequency video signal, is going to, through cross-talk, leak into the DAC (through its clock). We are trying to lower the chances of that.


We wouldn't necessarily need HDCP for the audio channel although that would limit us to 16-bits.


It might matter at macro level.


I see where the issue is. You are focusing at the cable ends, we are looking at the big picture. .

The PLL does track the HDMI clock. But at some point, we generate another clock driven from it for audio. Assuming that clock is immune to HDMI cable jitter (which is not a good assumption but let's go with it), the audio clock can get impacted by other activity in the system.

To the extent I have a totally seperate audio subsystem in a high-end processor, lack of video samples changing every pixel is helpful in reducing distortion. I guarantee you that I can measure their impact on power supply rails no matter how much you decouple the circuit or filter it. The pulses can also leak in other ways. This is why processors have modes to turn off video data paths or even front panel displays for better audio. Everything is interconnected even if it seems that it is not.

Yes, having black doesn't mean the circuits are quiet. They are still counting pixels, etc. But the level of activity is far less than real video coming at it.

Of course, in the world of mass market products the above doesn't matter. But if you are talking about spending a ton of money for the last bit of quality, then it is fair consideration. In theory at least .

But sure, the interface has many faults. No one here is trying to defend HDMI. Just saying that if something can be done about its faults, it should be looked at. If after someone builds it, we measure it and listen to it and makes no difference, then fine.


Are you trying to say digital hash gets into the analog circuits. Well yes it does and is difficult to filter out. A really good design would encapsulate the analog circuitry in a shielded enclosure with a dedicated power supply feeding it. In fact doesn't the Poineer 09 do just this?

But be assured enough digital hash is coupled into he audio circuit from other sources. So much so that the video data noise is probably not significant. What about the control processor? This is much lower in frequency with much stronger harmonics in the audio band.

Your video data distortion theory sounds plausible however in the real world it is insignificant in relation to the other problems of mixed signal design.

Glimmie's HT Page
Being redone - comming soon!

Glimmie is offline  
post #115 of 224 Old 03-03-2009, 05:32 PM
AVS Special Member
 
Glimmie's Avatar
 
Join Date: Sep 2000
Location: Los Angeles, CA
Posts: 7,952
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 149 Post(s)
Liked: 215
Quote:
Originally Posted by Michael Grant View Post

Well there you go... that's important and useful info. Certainly, if you can drop down to 720p, you're reducing the bandwidth required to carry the audio, and that is in theory a more robust result. I just figured (wrongly) that it would be too much of a pain to do.

Well you need to buffer the audio packets enough to ride out the delta difference in the data rates. But in a mass produced consumer ASIC, not a big deal.

My take on these HDMI audio problems is crappy implementation or HDCP issues in the audio device. There is no reason you should need to kill the video to get error free audio. The processor manufactures are just doing this because the audio component folks can't get HDMI right.

Seems funny that HDMI audio works just fine in a Costco Visio TV but not in some high end audio gear.

Glimmie's HT Page
Being redone - comming soon!

Glimmie is offline  
post #116 of 224 Old 03-04-2009, 05:53 PM
AVS Addicted Member
 
amirm's Avatar
 
Join Date: Jan 2002
Location: Washington State
Posts: 18,083
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 755 Post(s)
Liked: 434
Quote:
Originally Posted by Glimmie View Post

Are you trying to say digital hash gets into the analog circuits. Well yes it does and is difficult to filter out. A really good design would encapsulate the analog circuitry in a shielded enclosure with a dedicated power supply feeding it.

The issue is not the analog stage but digital. We are trying to deal with nanosecond jitter on a 44.1Khz audio clock. If that clock jumps left or right depending on whether I have a blue pixel or red, then I have an issue. Yes, if you step back it all looks like "hash." But we are not concerned about what it looks like with a slow scan on the scope but what it does from sample to sample.

Quote:


In fact doesn't the Poineer 09 do just this?

How would it do anything like what we are talking about if its HDMI receiver is handling both audio and video?

Quote:


But be assured enough digital hash is coupled into he audio circuit from other sources. So much so that the video data noise is probably not significant.

That is a big leap of faith. How do we know the relative impact of each? I have clear data that turning video helps with audio fidelity. By your notion, that is impossible. Yet there it is. Besides, a good designer can deal with the other sources. But he is stuck with whatever HDMI hands to it.

Quote:


What about the control processor? This is much lower in frequency with much stronger harmonics in the audio band.

The DSP is not producing harmonic in audio band. Any DSP would be running in Mhz and not Khz. But your point is correct that its digital interactions can also cause jitter. However, we can do something about it as we design the processor. For example, I can make sure that the load on the DSP stays constant so that we don't jump from ideal to full on all the time, causing corrolated jitter on the clock.

Quote:


Your video data distortion theory sounds plausible however in the real world it is insignificant in relation to the other problems of mixed signal design.

For high-end reproduction of audio, if it is plausible, that is all we need to work on . I can't sit here and tell you how bad the HDMI audio situation is because when I went searching for equipment to measure it, I couldn't find any. Until there is real measurements telliing that I don't start with huge jitter before I get to later stages, I think it is fair to keep some hope that we can do better than we are right now.

Amir
Founder,
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

"Insist on Quality Engineering"

amirm is offline  
post #117 of 224 Old 03-04-2009, 06:07 PM
AVS Special Member
 
Glimmie's Avatar
 
Join Date: Sep 2000
Location: Los Angeles, CA
Posts: 7,952
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 149 Post(s)
Liked: 215
Quote:
Originally Posted by amirm View Post

The issue is not the analog stage but digital. We are trying to deal with nanosecond jitter on a 44.1Khz audio clock. If that clock jumps left or right depending on whether I have a blue pixel or red, then I have an issue. Yes, if you step back it all looks like "hash." But we are not concerned about what it looks like with a slow scan on the scope but what it does from sample to sample.

The DSP is not producing harmonic in audio band. Any DSP would be running in Mhz and not Khz. But your point is correct that its digital interactions can also cause jitter. However, we can do something about it as we design the processor. For example, I can make sure that the load on the DSP stays constant so that we don't jump from ideal to full on all the time, causing corrolated jitter on the clock.

I have clear data that turning video helps with audio fidelity. By your notion, that is impossible. Yet there it is. Besides, a good designer can deal with the other sources. But he is stuck with whatever HDMI hands to it.

1) DVD and BluRay are not 44.1khz but are 48khz. This is due to the required clock lock to video rates. The clock phase is not going to jump based on different video data combinations. The 48K clock is divided down from the pixel clock - it has to be as the data is synchronous to it. The only video format that used 44.1 was laser disk. But there the digital audio stream was on a dedicated FM carrier with no relationship to the video FM carrier or the base audio FM carriers either. In a multeplexed stream such as HDMI, the data packets must all be clock locked.

2) The "control processor" I am talking about is the internal computer that controls the device. Like sliding the disk carriage in and out. These do run in the KHZ range. Sure their master clock may be tens of mhz but the actual SPI and Ic2 control busses run in the KHZ range.

3) I explained that in the other post. It seems to me based on the reports in this forum that most audio only HDMI implementations are not designed properly. So yes, in this case blanking the video may help. But that's not the fault of the HDMI standard.

SDi and HDSDI both can carry embedded AES audio. As SDI and HDSDI are single wire transport protocols, the data is inhierently jittery. The clock is extracted from the data stream and relies on the scrambling of the bits to minimize excessive blocks of ones or zeros. Based on your logic that jitter in the stream affects the audio qualiy, then how does emebedded audio in SDI work? I'll tell you how as I design broadcast systems and products for a living. The reclocking arrests the jitter. As long as you can recover the data crossings, you can recover the data with full accuracy. This has been done for years with SDI. Yes we worry a lot about jitter but not as it upsets subjective picture and sound quality. Because it doesn't. Excessive transport stream jitter means complete data loss plain and simple. FWEIW, HDMI should be far superior to HDSDI in this respect as it has a dedicated clock line. So the residual jitter to the receiver should be very low.

Digital audio packaged with video is a different animal than that of plain CD. The clocks are derived from the pixel clock. DVD and Bluray don't have these jitter issues due to the strict timing requirments of the video processing chain. If I understnd you right you are claiming that changes in other portions of the multiplexed data stream effect the decoded audio quality. I just don't buy it other than hash bleeding into the analog circuits as I outlined above. Now of course if your demultiplexer is not framing the packets properly, you will have a lot of signal distortion across all the signals being carried. But that is teh typical digital cliff effect and quite obvious.

Your theory will receive rave reviews in stereo and home video magazines as most readers love to hear about all the perceived problems with their equipment. They can't come around to the idea that some things previously at fault in analog systems make no difference in performance with digital technologies.

Glimmie's HT Page
Being redone - comming soon!

Glimmie is offline  
post #118 of 224 Old 03-04-2009, 07:58 PM
AVS Addicted Member
 
amirm's Avatar
 
Join Date: Jan 2002
Location: Washington State
Posts: 18,083
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 755 Post(s)
Liked: 434
Quote:
Originally Posted by Glimmie View Post

1) DVD and BluRay are not 44.1khz but ar 48khz. This is due to the required clock lock to video rates.

So we are down to nitpicking I see . In that case, I will turn the tables and tell you that sample rates up to 96 Khz are required in Blu-ray players. It all depends on what the content is encoded at. I simply picked one example.
Quote:


The clock phase is not going to jump based on different video data combinations. The 48K clock is divided down from the pixel clock - it has to be as the data is synchronous to it.

Yup and it will suffer from jitter just the same. The synchronous nature only applies to ability to extract the data, but not its absolute timing. Here is a good link to read more: http://www.tnt-audio.com/clinica/jitter1_e.html. It is an old article but explains nicely in clear language how you can wind up with jitter even when you drive the clock as you state and use a PLL as you explain below.
Quote:


2) The "control processor" I am talking about is the internal computer that controls the device. Like sliding the disk carriage in and out. These do run in the KHZ range. Sure their master clock may be tens of mhz but the actual SPI and Ic2 control busses run in the KHZ range.

You are way behind the times my friend . The type of processors used in BD players are far more powerful. Gone are the days of the little micro lighting up the front panel on a CD player and controlling the drive. Indeed, there are a number of processors in a Blu-ray decoder, all running at hundreds of MHz. Here is an example processor from Sigma Designs which powers a number of Blu-ray players: http://www.sigmadesigns.com/public/P...SMP8640_br.pdf

* 333 Mhz Audio DSPs (3 of them!)
* 667 Mhz MIPS
* 333 Mhz MIPS CPU

Here is the Broadcom part used in Samsung and some other BD players:http://www.broadcom.com/collateral/pb/7440-PB02-R.pdf

They don't give you the CPU speed directly but you can deduce it is not in Khz range by:

* Dual 333/400-MHz 32-bit DDR2 interface

You are not going to find any low-end micro like you are envisioning. BD-J requires a ton of horsepower as do decoding of all the advanced audio formats in multi-channel. Even the front-end runs in MHz region given the fact that the Blu-ray drive spins at > 48 Mbit/sec.
Quote:


SDi and HDSDI both can carry emebdded AES audio. As SDI and HDSDI are single wire transport protocols, the data is inhierently jittery. The clock is extracted from the data stream and relies on the scrambling of the bits to minimize excessive blocks of ones or zeros. Based on your logic that jitter in the stream affects the audio qualiy, then how does emebedded audio in SDI work?

You mean when they don't use house clock to sync everything together? If so, then yes, they also suffer from jitter if they attempt to convert the samples to audio as opposed to moving them from device A to device B. Keep in mind that we do not have house sync in consumer players.
Quote:


I'll tell you how as I design broadcast systems and products for a living.

Ah, time to recite our resumes, eh? So here is a bit of mine. I used to be VP engineering at two broadcast video companies (Abekas and Pinnacle Systems). While I didn't do hands on design there, I am very familiar with the space and standards used. Two of the products I managed won technical Emmy awards. So you could say we share a common experience in that front.
Quote:


The reclocking arrests the jitter. As long as you can recover the data crossings, you can recover the data with full accuracy.

Again, we are talking past each other. We are not talking about whether you can recover samples correctly. We are talking about whether the timing of the output clock is impacted or not. Read the above article and see the example where RF noise on a S/PDIF cable causes jitter!
Quote:


This has been done for years with SDI. Yes we worry a lot about jitter but not as it upsets subjective picture and sound quality. Because it doesn't. Excessive transport stream jitter means complete data loss plain and simple.

We are not talking about excess jitter. Nor are we talking about jitter in a communication channel. We are talking about audio samples not being converted to analog at precise time that were captured. If you ever so slightly change their positions, you make the system non-linear and create harmonic distortion. Perfect clock does not exist in real world. No PLL cleans up all jitter. But you can take steps to reduce jitter.
Quote:


I think you have read too many stereo magazine articals about jitter in CD players. Most of those articals are wrong from an electrical engineering perspective and furthermore DVD and Bluray don't have those issues due to the strict timing requirments of the video processing chain.

Please, ask me who I am before you make assumptions about me . I am an electrical engineer and have been in audio, video, computer, network, etc. field for 40+ years. I have also been lucky to have had jobs which allowed me to have the best toys in the world to play with such things and gain real world experience in addition to my own engineering know-how. In my last job at Microsoft, I helped drive the specs for HD optical formats and technology from my group ships in every Blu-ray player. So I don't just read a magazine and come and post here.

The bottom line is that there is a completely different science and approach to high-end audio and video. Anyone can build something that puts out audio and video. But it takes a lot more knowledge to know if they are both right. Joe Kane would be out of a job if people knew even simple concepts of what color space to use. You wouldn't believe what we went through with Toshiba to make sure their HD DVD players programmed the HDMI transceivers to not do conversion to faulty 4:4:4, blow levels, not produce proper 24p, etc. Yup the device put out an image that impressed many but it still wasn't right until later firmware fixes.

And there is absolutely nothing in Blu-ray spec that makes the format perform any better than DVD. It reads the data like one did from DVD and sends it out. So I don't know what you mean by strict timing requirements.

Anyway, I hope you keep an open mind as you read all of this. The whole world of high-end audio/video is not made up of lunatics who hallucinate these things. There is science involved. And people who know what they are doing.

Amir
Founder,
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

"Insist on Quality Engineering"

amirm is offline  
post #119 of 224 Old 03-04-2009, 08:12 PM
AVS Special Member
 
Glimmie's Avatar
 
Join Date: Sep 2000
Location: Los Angeles, CA
Posts: 7,952
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 149 Post(s)
Liked: 215
Quote:
Originally Posted by amirm View Post


Ah, time to recite our resumes, eh? So here is a bit of mine. I used to be VP engineering at two broadcast video companies (Abekas and Pinnacle Systems). While I didn't do hands on design there, I am very familiar with the space and standards used. Two of the products I managed won technical Emmy awards. So you could say we share a common experience in that front.

So you are possibly Phil Bennet? You worked for Juniad Sheik? Along side with Lance Kelson, Ian Craven.

Do you want me to go back to prior Ampex days where they all came from?

I'm not just some AV wannabe either. I was Fred's VP of engineering and CTO for 15 years and hold a Drexel BSEE myself! That should be enough info to figure it out.

On second though you can't be any of the folks I named above. They all understood digital video processing to the nth degree. You must be from the Scitex days when these companies went down hill. Scitex turned Abekas into a consumer level company. Pinnicle - didn't you guys put out the Cinewave card. TALK ABOUT JITTER! Nothing could clean that up. And the response form the engineering group, that would be your group, claimed it was not designed to feed a router, only directly into an HDCAM! Huh? Thank god AJA came along with a competative product that complied with industry specs. And as far as the Pinnicle San Jose shop products, I know first hand DirecTV in Marina Del rey had big problems with the early HD servers and bad HDSDI compliance.

Quote:


You mean when they don’t use house clock to sync everything together?

See it's the subtle comments. "house clock" is not video facility terminology and would not used by the names listed either. It's "house sync" or "genlock" Surely anyone involved in video equipment design to the extent you claim would have that burned into their vocabulary. House clock is a recording studio term and proble used in other industries as well. Now you have a background in audio design, that is apparent. But don't BS me when it comes to broadcast video.

P.S. that artical you posted is all baout strict audio only circuits. In none of the block diagrams do I see a FIFO to iron out data jitter. Almost all video based designes I have ever seen on that level of detail uses timing FIFOs to fix that. This is a commen technique since the vaccum days of video but the audio industry didn't need to deal with this issue until digital came along.

Glimmie's HT Page
Being redone - comming soon!

Glimmie is offline  
post #120 of 224 Old 03-04-2009, 09:04 PM
AVS Addicted Member
 
amirm's Avatar
 
Join Date: Jan 2002
Location: Washington State
Posts: 18,083
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 755 Post(s)
Liked: 434
Quote:
Originally Posted by Glimmie View Post

So you are possibly Phil Bennet? You worked for Juniad Sheik? Along side with Lance Kelson, Ian Craven.

No, I am not any of them. My real name is part of my alias.

Quote:


Do you want me to go back to prior Ampex days where they all came from?

I prefer that we talk about the topic at hand and not each other .

Quote:


On second though you can't be any of the folks I named above. They all understood digital video processing to the nth degree.

They were experts in digital video. No doubt. But I wouldn't hire any of them design a high-end audio system. There is a difference between them and someone like Bob Stuart (Meridian founder). They are all great at what they do, but the fields are different.

Quote:


You must be from the Scitex days when these companies went down hill. Scitex turned Abekas into a consumer level company.

No I am not. I left Scitex as soon as they purchased the company.

Quote:


Pinnicle - didn't you guys put out the Cinewave card. TALK ABOUT JITTER! Nothing could clean that up. And the response form the engineering group, that would be your group, claimed it was not designed to feed a router, only directly into an HDCAM! Huh? Thank god AJA came along with a competative product that complied with industry specs. And as far as the Pinnicle San Jose shop products, I know first hand DirecTV in Marina Del rey had big problems with the early HD servers and bad HDSDI compliance.

You spelled Pinnacle wrong . And I am not familiar with any of those products as I left the company many years ago. But so you know, when I arrived at Abekas, the engineers there were struggling with SDI I/O cards just the same. And got you know what for it from the networks until multiple redesigns later. And I saw the same thing at Pinnacle. The Sony silicon was a pain to use then as was the third-parties who designed the same.

Quote:


P.S. that artical you posted is all baout strict audio only circuits. In none of the block diagrams do I see a FIFO to iron out data jitter. Almost all video based designes I have ever seen on that level of detail uses timing FIFOs to fix that. This is a commen technique since the vaccum days of video but the audio industry didn't need to deal with this issue until digital came along.

You can have all the FIFOs you want but it won't solve anything. The DAC has a clock that is running at the audio sampling rate *post FIFO stage*. That clock, cannot and will not be perfect. Any variations in that clock causes the audio samples to be converted to analog at the wrong time. If you like to point me to an article which shows how a DAC can have 100% accurate clock with zero jitter, I would be happy to read it and comment on it.

Amir
Founder,
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

"Insist on Quality Engineering"

amirm is offline  
Closed Thread Ultra Hi-End HT Gear ($20,000+)

User Tag List

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off