Couple Of Questions

[dragon002]

jim & charper,

ergen is obviously mind melding with the tvs and his boxes to provide the audio. DVI carries no audio. PERIOD.

 

[Turd Fergeson]

SaltiDawg, I understand what you are saying. It sounds like the combination of the two in effect gives you a HDMI wire maybe I am wrong....so what if I am. The main reason I posted was to complement you on your last post, it was outstanding.

Anybody with that many posts must be right..... classic!!!!

 

[VIPERS-PIT]

My dvi cable carries audio. I taped a digital coax cable to it!!!!

 

[stevesmall]

Maybe the audio is added present at the DVI end of the cable but no protocol exists to allow it to be used by the DVI user? Or maybe E* manufactures their cables so that is is possible?

In any event, I'm sick and tired of people posting here that what is a fact is impossible.... simply because they don't understand how.

As I have said, my wife and many others go from their 942 STB to their TV using an HDMI to DVI cable married to a DVI to HDMI adapter (actually a 6" DVI to HDMI cable.) Like it or not.

you ask for advice and now you are sick of people answering CORRECTLY I MIGHT ADD. There is no WAY a dvi cable is passing an audio signal, you do not understand obviously and i apoligize to everyone else for the caps but this was deserved LOL

 

[stevesmall]

DVI has no audio pass-thru capabilities as yet. PERIOD.

As DVI and HDMI connections become more and more widely used, we are often asked: which is better, DVI (or HDMI) or component video? The answer, as it happens, is not cut-and-dried.

First, to clear away one element that can be confusing: DVI and HDMI are exactly the same as one another, image-quality-wise. The principal differences are that HDMI carries audio as well as video, and uses a different type of connector, but both use the same encoding scheme, and that's why a DVI source can be connected to an HDMI monitor, or vice versa, with a DVI/HDMI cable, with no intervening converter box.

The upshot of this article--in case you're not inclined to read all the details--is that it's very hard to predict whether a digital DVI or HDMI connection will produce a better or worse image than an analog component video connection. There will often be significant differences between the digital and the analog signals, but those differences are not inherent in the connection type and instead depend upon the characteristics of the source device (e.g., your DVD player) and the display device (e.g., your TV set). Why that is, however, requires a bit more discussion.

What are DVI, HDMI and Component Video?

DVI/HDMI and Component Video are all video standards which support a variety of resolutions, but which deliver the signal from the source to the display in very different ways. The principal important difference is that DVI/HDMI deliver the signal in a digital format, much the same way that a file is delivered from one computer to another along a network, while Component Video is an analog format, delivering the signal not as a bitstream, but as a set of continuously varying voltages representing (albeit indirectly, as we'll get to in a moment) the red, green and blue components of the signal.

Both DVI/HDMI and Component Video deliver signals as discrete red, green, and blue color components, together with sync information which allows the display to determine when a new line, or a new frame, begins. The DVI/HDMI standard delivers these along three data channels in a format called T.M.D.S., which stands for "Transmission Minimized Differential Signaling." Big words aside, the T.M.D.S. format basically involves a blue channel to which horizontal and vertical sync are added, and separate green and red channels.

Component Video is delivered, similarly, with the color information split up three ways. However, component video uses a "color-difference" type signal, which consists of Luminance (the "Y", or "green," channel, representing the total brightness of the image), Red Minus Luminance (the "Pr," or "Red," channel), and Blue Minus Luminance (the "Pb," or "Blue," channel). The sync pulses for both horizontal and vertical are delivered on the Y channel. The display calculates the values of red, green and blue from the Y, Pb, and Pr signals.

Both signal types, then, are fundamentally quite similar; they break up the image in similar ways, and deliver the same type of information to the display, albeit in different forms. How they differ, as we'll see, will depend to a great extent upon the particular characteristics of the source and display devices, and can depend upon cabling as well.

Isn't Digital Just Better?

It is often supposed by writers on this subject that "digital is better." Digital signal transfer, it is assumed, is error-free, while analog signals are always subject to some amount of degradation and information loss. There is an element of truth to this argument, but it tends to fly in the face of real-world considerations. First, there is no reason why any perceptible degradation of an analog component video signal should occur even over rather substantial distances; the maximum runs in home theater installations do not present a challenge for analog cabling built to professional standards. Second, it is a flawed assumption to suppose that digital signal handling is always error-free. DVI and HDMI signals aren't subject to error correction; once information is lost, it's lost for good. That is not a consideration with well-made cable over short distances, but can easily become a factor at distance.

So What Does Determine Image Quality?

Video doesn't just translate directly from source material to displays, for a variety of reasons. Very few displays operate at the native resolutions of common source material, so when you're viewing material in 480p, 720p, or 1080i, there is, of necessity, some scaling going on. Meanwhile, the signals representing colors have to be accurately rendered, which is dependent on black level and "delta," the relationship between signal level and actual as-rendered color level. Original signal formats don't correspond well to display hardware; for example, DVD recordings have 480 lines, but non-square pixels. What all of this means is that there is signal processing to go on along the signal chain.

The argument often made for the DVI or HDMI signal formats is the "pure digital" argument--that by taking a digital recording, such as a DVD or a digital satellite signal, and rendering it straight into digital form as a DVI or HDMI signal, and then delivering that digital signal straight to the display, there is a sort of a perfect no-loss-and-no-alteration-of-information signal chain. If the display itself is a native digital display (e.g. an LCD or Plasma display), the argument goes, the signal never has to undergo digital-to-analog conversion and therefore is less altered along the way.

That might be true, were it not for the fact that digital signals are encoded in different ways and have to be converted, and that these signals have to be scaled and processed to be displayed. Consequently, there are always conversions going on, and these conversions aren't always easy going. "Digital to digital" conversion is no more a guarantee of signal quality than "digital to analog," and in practice may be substantially worse. Whether it's better or worse will depend upon the circuitry involved--and that is something which isn't usually practical to figure out. As a general rule, with consumer equipment, one simply doesn't know how signals are processed, and one doesn't know how that processing varies by input. Analog and digital inputs must either be scaled through separate circuits, or one must be converted to the other to use the same scaler. How is that done? In general, you won't find an answer to that anywhere in your instruction manual, and even if you did, it'd be hard to judge which is the better scaler without viewing the actual video output. It's fair to say, in general, that even in very high-end consumer gear, the quality of circuits for signal processing and scaling is quite variable.

Additionally, it's not uncommon to find that the display characteristics of different inputs have been set up differently. Black level, for example, may vary considerably from the digital to the analog inputs, and depending on how sophisticated your setup options on your display are, that may not be an easy thing to recalibrate.

The Role of Cable and Connection Quality

Cable quality, in general, should not be a significant factor in the DVI/HDMI versus Component Video comparison, as long as the cables in question are of high quality. There are, however, ways in which cable quality issues can come into play.

Analog component video is an extremely robust signal type; we have had our customers run analog component, without any need for boosters, relays or other special equipment, up to 200 feet without any signal quality issues at all. However, at long lengths, cable quality can be a consideration--in particular, impedance needs to be strictly controlled to a tight tolerance (ideally, 75 +/- 1.5 ohms) to prevent problems with signal reflection which can cause ghosting or ringing.

DVI and HDMI, unfortunately, are not so robust. The problem here is the same as the virtue of analog component: tight control over impedance. When the professional video industry went to digital signals, it settled upon a standard--SDI, serial digital video--which was designed to be run in coaxial cables, where impedance can be controlled very tightly, and consequently, uncompressed, full-blown HD signals can be run hundreds of feet with no loss of information in SDI. For reasons known only to the designers of the DVI and HDMI standards, this very sound design principle was ignored; instead of coaxial cable, the DVI and HDMI signals are run balanced, through twisted-pair cable. The best twisted pair cables control impedance to about +/- 10%. When a digital signal is run through a cable, the edges of the bits (represented by sudden transitions in voltage) round off, and the rounding increases dramatically with distance. Meanwhile, poor control over impedance results in signal reflections--portions of the signal bounce off of the display end of the line, propagate back down the cable, and return, interfering with later information in the same bitstream. At some point, the data become unrecoverable, and with no error correction available, there's no way to restore the lost information.

DVI and HDMI connections, for this reason, are subject to the "digital cliff" phenomenon. Up to some length, a DVI or HDMI cable will perform just fine; the rounding and reflections will not compromise the ability of the display device to reconstruct the original bitstream, and no information will be lost. As we make the cable longer and longer, the difficulty of reconstructing the bitstream increases. At some point, unrecoverable bit errors start to occur; these are colloquially described in the home theater community as "sparklies," because the bit errors manifest themselves as pixel dropouts which make the image sparkle. If we make the cable just a bit longer, so much information is lost that the display becomes unable to reconstitute enough information to even render an image; the bitstream has fallen off the digital cliff, so called because of the abruptness of the failure. A cable design that works perfectly at 20 feet may get "sparkly" at 25, and stop working entirely at 30.

In practice, it's very hard to say when a DVI or HDMI signal will fail. We have found well-made DVI cables to be quite reliable up to 50 feet, but HDMI cable, with its smaller profile, is a bit more of a puzzle. Because the ability to reconstitute the bitstream varies depending on the quality of the circuitry in the source and display devices, it's not uncommon for a cable to work fine at 30, 40, or 50 feet on one source/display combination, and not work at all on another.

The Upshot: It Depends

So, which is better, DVI or component? HDMI or component? The answer--unsatisfying, perhaps, but true--is that it depends. It depends upon your source and display devices, and there's no good way, in principle, to say in advance whether the digital or the analog connection will render a better picture. You may even find, say, that your DVD player looks better through its DVI or HDMI output, while your satellite or cable box looks better through its component output, on the same display. In this case, there's no real substitute for simply plugging it in and giving it a try both ways.

http://www.pcmag.com/encyclopedia_term/0,2542,t=HDMI&i=44161,00.asp

http://www.ramelectronics.net/html/howto-dvi-hdmi.html (scroll down)

http://www.ept.ca/docs/index.php?PageName=article&ArticleID=18462&ShowMode=long

YEAH what he said

 

[SaltiDawg]

you ask for advice and now you are sick of people answering CORRECTLY I MIGHT ADD. There is no WAY a dvi cable is passing an audio signal, you do not understand obviously and i apoligize to everyone else for the caps but this was deserved LOL

I never asked for advice. I stated the fact that my wife's cable setup carried the stereo sound from her STB to her TV. I also posted two links where this very subject was discussed, to include multiple posts by folks documenting that fact. If you can't accept that - well that's your loss. As you gain more knowledge and experience maybe you'll become a contributor here.

I love reading "late night" posts such as yours.

 

[SaltiDawg]

charper1,

He obviously has a digital coax or some other connection going to the audio receiver, Seeing his wife uses it and he doesn't, maybe he should verify how it is getting there from his wife

Jimbo,

I did the setup. There is only the cabling I described going from the 942 to the TV. Before you post sarcasm you should go read the posts at the links I posted and you'll see that numerous people are saying that this is so. You do a disservice to those of us trying to learn by belittling factual information that is posted - particularly when you have no knowledge/experience with the equipments involved.

Also, I don't understand how you concluded that I "don't use it." You seem to just be all about assumptions.

I do not know if this is correct, but in another threads we we discussing this very issue and in response to my speculating as to how this was so, CABill replied:

"There aren't any "extra" wires in the cable. The audio is carried on the very same data lines that the video is carried on. DVI has no provision during initial negotiation for audio but HDMI protocol does. The HDMI source reads what the sink (TV, A/V receiver, ...) is capable of (both audio and video) and decides what to send for both. The digital audio is nothing more than bits mixed with the video on the data lines."

Again, I do not know if this is the correct explanation, but the fact of the matter with the setup I described the audio is present. PERIOD

 

[Dog6869]

Maybe the audio is added present at the DVI end of the cable but no protocol exists to allow it to be used by the DVI user? Or maybe E* manufactures their cables so that is is possible?

In any event, I'm sick and tired of people posting here that what is a fact is impossible.... simply because they don't understand how.

As I have said, my wife and many others go from their 942 STB to their TV using an HDMI to DVI cable married to a DVI to HDMI adapter (actually a 6" DVI to HDMI cable.) Like it or not.

DVI stands for Digital Visual Interface, and is a new signal input that many newer LCD monitors now offer. DVI offers a completely digital connection from your computer's graphics card to the monitor, and often results in an improved image display with more accurate color representation and sharper overall image quality.

It is great that you have a wife that is smarter than you and you can say that in a public blog room.....

 

[SaltiDawg]

...

It is great that you have a wife that is smarter than you and you can say that in a public blog room.....

She is smarter than I.

From the User Manual for The 942, Page 114:

"Connecting To The Nearby TV (TV1)"

"HDTV Digital/Audio/Video Connections"

"The HDTV Digital/Audio connection provides high-quality audio and video to your HDTV or HD Monitor in one cable."

"1 Connect an HDTV Digital Audio/Video cable between the HDTV Digital/Audio connection on the receiver and HDTV set or monitor. You may need to use the adapter provided with your receiver."

Steps 2-4 verifies that the video is being displayed correctly.

"5 Turn up the volumn on your HDTV and confirm you have sound. If you don't have sound your system may require you to connect audio (red and white) RCA-type cables between the receiver Audio Outputs and audio input connections."

In step five we do have stereo sound on the TV speakers via the HDMI to DVI cable and the DVI to HDMI adapter , which is the norm and did not have to resort to the backup audio configurations.

http://www.dishnetwork.com/downloads/pdf/technology/ViP622_DVR/Chapter12.pdf

I think it is great that you would publish your lack of knowledge here in a "a public blog room."

 

[dragon002]

She is smarter than I.

From the User Manual for The 942, Page 114:

"Connecting To The Nearby TV (TV1)"

"HDTV Digital/Audio/Video Connections"

"The HDTV Digital/Audio connection provides high-quality audio and video to your HDTV or HD Monitor in one cable."

"1 Connect an HDTV Digital Audio/Video cable between the HDTV Digital/Audio connection on the receiver and HDTV set or monitor. You may need to use the adapter provided with your receiver."

Steps 2-4 verifies that the video is being displayed correctly.

"5 Turn up the volumn on your HDTV and confirm you have sound. If you don't have sound your system may require you to connect audio (red and white) RCA-type cables between the receiver Audio Outputs and audio input connections."

In step five we do have stereo sound on the TV speakers via the HDMI to DVI cable and the DVI to HDMI adapter , which is the norm and did not have to resort to the backup audio configurations.

http://www.dishnetwork.com/downloads/pdf/technology/ViP622_DVR/Chapter12.pdf

I think it is great that you would publish your lack of knowledge here in a "a public blog room."

if you have dishnowork, why is this thread in the DIRECTV hd section??

 

[SaltiDawg]

if you have dishnowork, why is this thread in the DIRECTV hd section??

The discussion is about HDMI to DVI To HDMI capabilities. Dish is only an example and serves to document a capability - nothing do do with Dish per se.

I notice that you were OK with this when earlier in this thread you incorrectly said, "DVI carries no audio. PERIOD." Now when confronted with a User Manual and two different threads populated with persons that routinely do this you save face by questioning why the thread is here?

Good face save. lol

I suspect this thread will now fall surprisingly silent, as opposed to numerous "Thanks for that find."

 

[charper1]

I am confused as hell now, now I know you have a 942 but; on pg 24 of the DVR921 (aka DP921) user guide "DVI Output - this digital connection will give you the highest quality video, both in SD and HD. Use a DVI cable to make this connection to your HDTV or HD monitor. If you use this output for video, you must still connect the audio with the AUDIO OUTPUTS or the DIGITAL AUDIO OUTPUT."

This is repeated on pg 31. So even their own user guide is saying the DVI out has no audio to send to the TV.


Yet on the user guide part you posted I can't find one mention of a DVI connection being used, just HDMI/HDMI; I may be blind so a pg# would be nice.


Is this the quote you are referencing for this thread? http://www.satelliteguys.us/showthread.php?t=56423&highlight=942+HDMI+DVI+audio

Just to confirm that the HDMI port on the 942 works. I am using the HDMI port on the 942 connected to the HDMI to DVI cable that is provided with the 942 which connects to the DVI to HDMI adapter (also included) which connects to the HDMI port on my TV. It sends audio and video and I have used this for over 2 months now with no problems at all. I have never had a drop with audio or video the entire time. My TV is a Toshiba made in 2005.

And in this thread http://www.dbstalk.com/showthread.php?t=48027&highlight=hdmi+audio

There is debate of it working or not, with little details other than what cable to try and using an adapter and that if it does work it only for 2.0 sound. As to you smart-assed comments earlier; true my post count has nothing to do with anything and I never said it did (even though you were attracted to comment on it) BUT the cases of all the devices I have installed and wired via DVI, component and HDMI do matter and I have never seen one case where DVI would pass audio to the TV (in its current incarnation). Both the Dish and DirecTV user manuals attest to that very fact; as to the spec for DVI itself; as were the C&P reading I posted. The bottom line is you TV works and great for that.

 

[shugo77]

My DVI cable provides power to my TV, and it also hooks up to my DSL modem for internet.

LOL

*NOTE* The above statement is provided "as is" with no warranty or guarantee of any kind. It is intended as sarcasm, and only provided as a humorous anecdote. I cannot be held responsible if anyone is offended by it.

 

[charper1]

At this point it doesn't matter I tested 2 receivers with this audio setup and no sound. So HIS works and thats great.

 

[SaltiDawg]

At this point it doesn't matter I tested 2 receivers with this audio setup and no sound. So HIS works and thats great.

You are being abtuse, I assume. Nobody has suggested audio is available by DVI. The setup described is HDMI => DVI => DVI => HDMI

I earlier posted:

"I do not know if this is correct, but in another threads we we discussing this very issue and in response to my speculating as to how this was so, CABill replied:

"There aren't any "extra" wires in the cable. The audio is carried on the very same data lines that the video is carried on. DVI has no provision during initial negotiation for audio but HDMI protocol does. The HDMI source reads what the sink (TV, A/V receiver, ...) is capable of (both audio and video) and decides what to send for both. The digital audio is nothing more than bits mixed with the video on the data lines."

Again, I do not know if this is the correct explanation, but the fact of the matter with the setup I described the audio is present. PERIOD "

 

[dragon002]

My DVI cable provides power to my TV, and it also hooks up to my DSL modem for internet.

LOL

*NOTE* The above statement is provided "as is" with no warranty or guarantee of any kind. It is intended as sarcasm, and only provided as a humorous anecdote. I cannot be held responsible if anyone is offended by it.

wow.......internet too!

i just use mine for long distance and fueling my bar-b-que grill.

and shugo, i love the disclaimer!!!!

 

[SaltiDawg]

At this point it doesn't matter I tested 2 receivers with this audio setup and no sound. So HIS works and thats great.

You tested it with an HDMI out of a STB via a HDMI to DVI cable in turn plugged into a DVI to HDMI adapter or cable in turn plugged into a TV?

 

[rockaway1836]

SaltiDawg, I think I understand what your saying here. You are saying that by using the DVI to HDMI adapter you are in essence making a HDMI cable. Is that correct? I also have a DVI to HDMI cable as well as the DVI to HDMI adapter. Trouble is I have 2 TV's with DVI inputs and none with HDMI. So I can't check it out yet.

 

[SaltiDawg]

...

Yet on the user guide part you posted I can't find one mention of a DVI connection being used, just HDMI/HDMI; I may be blind so a pg# would be nice.
...

And in this thread http://www.dbstalk.com/showthread.php?t=48027&highlight=hdmi+audio

There is debate of it working or not, with little details other than what cable to try and using an adapter and that if it does work it only for 2.0 sound. ...

The 942 reciever comes with both an HDMI to DVI Cable and also a 6" DVI to HDMI cable/adapter. This allows any purchaser to mate up with the output of the receiver to either his DVI or HDMI on the rear of their TV. The other receiver you posted, the 921 comes only with a DVI cable and sound, as we know, is not supported by protocol in DVI.

There is no debate in that thread about stereo audio being received via the HDCP to DVI to HDCP, except one lone poster (who continued to be wrong in taking a shot at me above in this thread PERIOD. lol ) He was quickly corrected in the other thread. Read the entire thread.

It is my understanding that 5.1 stereo is not supported by the current HDMI protocol but will be in some future revision - allowing single cable connection of both digital video and digital sound via one cable.

In the case being discussed, we run the cable to a TV set so there is no need for 5.1 with our two speaker TV.