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What is DVI, and how will it benefit me?


Also, I know what 1394 is, but what will it do for me on a TV?


I am about to buy a Hitachi tomorrow. The one on sale at Sears, and I just want to know if I should do that, or the Mits with the upgrade policy. .


Thx!


B
 

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DVI (with HDCP copy protection) may be used for copy protection purposes on future programming. it has been rumored that at some time in the future only sets with a DVI input will be able to resolve the full HD image of a broadcast. all other outputs from a digital cable box or satellite receiver (component, etc.) will be downrezzed to some lower resolution (possibly 480p.) there is no guarantee that DVI will be the standard but it is leading the pack at the moment...and going forward i personally wouldn't buy a set that lacked a DVI input.


as for 1394 (aka firewire) it has bi-directional capability so basically it can be used to let different AV components talk with one another. it probably won't be the standard for copy protection purposes.
 

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DVI is a wideband digital video interface--wideband enough to carry digital HDTV signals after decompression. It is emerging as the favored interface for connecting digital video sources to displays. IEEE-1394 is a lower-bandwidth but bidirectional interface that can be used to carry compressed diigtal video, as well as audio and control information. On a TV set, DVI is likely to be more useful to you than 1394.
 

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"If DVI becomes the standard, will Mitsu give an upgrade option to replace the Firewire input with a DVI input?"


Mits actually has a statement that describes their upgrade policy and it includes a list of features, DVI is not on the list. I think Mits runs a significant risk, in that salesmen at retail stores are telling customers that Mits will offer upgrades to all future technology. Anyone that has a clue about technology, knows that it's virtually impossible to be able to upgrade a consumer item cost effectively for unknown future technology.


However, when you read the actual Mits language, it is clear that the upgrade is not open ended. Then there is the question of how much these upgrades will cost. By the time you need it and do a cost analysis, you may conclude that you might as well get a new set.
 

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Zeus, in a word, no. You would not replace Firewire with DVI, because Firewire is a network to bring compressed data to the MPEG-2 decompression system in Firewire-equipped TVs. That decompressor in turn handles decoding HDTV signals that a built-in HDTV tuner receives. So it would amount to gutting multiple features of the TV.


If anything, you may want to inquire of Mits whether they will have an option to _add_ DVI, not replace Firewire.
 

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At Cedia... or on the way back I got stuck at the airport with the TI connectivity group... and we had a 3 hour debate about 1394 and firewire...


Here are the pros and cons in a nutshell


DVI


Pros


1) Uncompressed video, theoretically a better picture since it is post MPEG-2 decompression..


2) capable of HDMI encryption the rumored hollywood favorite for encryption of HDTV and other signals


Cons


1) limited distance... max length is about 50'


2) large connector, making prewire inside new construction more of a pain


3) expensive cables, and not easy to share this signal with multiple devices


4)To share or increase the length of the signal, one may have to use fiber or other proprietary repeaters that are costly..



1394


Pros


1) small cheap cable....


2) capable of being shared throughout your entire house via cat5e...


3) capable of obtaining an GUID (network ip adress) allowing for networking of multiple components throughout your home


4) capable of sharing HDTV and digital audio


5) 300ft is the limiting distance without needing to bounce off of something (PRO OR CON)


6) Also capable for encryption to rival HDMI.. (Theoretically may be easier to hack... which is why it seems hollywood has gone the other way...)


CONS


1) Proprietary to TI


2) Compressed video... depending upon source... A DVD for example could be uncompressed by the player, recompressed again the 1394, then sent out again to be uncompressed... Hence possible picture degredation... Although I take these statements with a grain of salt... (Anyone who has used a DV cam to download video to a computer for editing cant tell me that there is more artifacting than the old analog captures... granted this is probably more of an analog to digital issue.. but the quality is still pretty high...


3) Very good bus for recording HDTV or Digital material on DVHS...


Anyone else feel free to add to this list... as needed.... I am sure there is a ton of stuff that I can't pull off the top of my head without going back to the white papers... :rolleyes: :confused:
 

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A Firewire-equipped DVD player would not decompress and recompress the MPEG-2 data on the disc, it would simply put the data on the network for a Firewire-equipped TV to read and decompress. That's how Firewire-equipped DV cams and ATSC receivers communicate now.
 

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Another benefit of 1394 is you only need one input on the TV. 1394 can be connected in a daisy chain of up to 63 devices. You can even use a 1394 hub as a center terminal instead of daisy chaining. This eliminates any worry over lack of HD inputs on a set. DVI cannot do this.
 

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Quote:
Originally posted by briley1
What is DVI, and how will it benefit me?
DVI is being pushed as a standard for one reason only: To deny consumers the ability to record programs in HD. Uncompressed HDTV video is too large a datastream to be recorded with current technology. Hollywood likes this. However, it provides no "benefit" to the consumer other than ensuring that your TV is "future-proofed" in the event Hollywood gets its way.
 

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DVI has value as future-proofing, quite apart from Hollywood's interest. It can also provide a very high quality image from an HD source without requiring a conversion to analog for transmission over other types of connections, and without decompression hardware in the TV. So it has benefits for quality vs cost tradeoffs. It is unfortunate that it is being used as a pawn in copyright control wrangling.
 

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Quote:
Originally posted by d4lions
At Cedia... or on the way back I got stuck at the airport with the TI connectivity group... and we had a 3 hour debate about 1394 and firewire...


Here are the pros and cons in a nutshell


...

1394


...


CONS


1) Proprietary to TI

Huh? Doesn't Apple hold the 1394 patent?

Quote:


2) Compressed video... depending upon source... A DVD for example could be uncompressed by the player, recompressed again the 1394, then sent out again to be uncompressed... Hence possible picture degredation...

Of course, if DVD players sent their compressed video out directly, this wouldn't be a problem.
 

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Additional 1394 CON:


A "unit" wishing to "overlay" something on a picture received & forwarded via 1394 will have to decompress (a fairly accurate, non-error prone process), overlay the image, then finally recompress (a potentially very error-prone/costly process).


A feature could be added to the standard which would allow an "overlay video stream" which the "unit" I describe above could simply encode that overlay image in MPEG-2. Low quality overlay would probably be okay as this would likely be used for things like menus, etc... Perhaps the standard thought of this already and I'm just dense :)
 

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Leaving aside what Hollywood might prefer, the technical choice between DVI and Firewire depends on where in the signal path the MPEG decoder function is located. Firewire is for compressed signals which have not yet been decoded; DVI is for uncompressed signals which are the output of an MPEG decoder. DVI is an ideal input interface for a HDTV-ready display; an integrated HDTV could (theoretically) support both DVI and Firewire inputs plus Firewire output to a recording device.
 

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Quote:
Originally posted by edmc
Additional 1394 CON:


A "unit" wishing to "overlay" something on a picture received & forwarded via 1394 will have to decompress (a fairly accurate, non-error prone process), overlay the image, then finally recompress (a potentially very error-prone/costly process).


A feature could be added to the standard which would allow an "overlay video stream" which the "unit" I describe above could simply encode that overlay image in MPEG-2. Low quality overlay would probably be okay as this would likely be used for things like menus, etc... Perhaps the standard thought of this already and I'm just dense :)
This crap is so far from the truth, its hurts. There are several protocols that allows overlay information to be transmitted on Firewire without ever touching the MPEG2 data stream. So there is no need to decompress MPEG2 until it reaches the display. One of these protocols is HAVi ( www.havi.org ). And there are a couple of IEEE standards supported by most manufactures that include integated OTA DTV turners.


IEEE1394 Firewire is the perfer consumer digital interface. It makes systems easy to connect and control. There is no need to have all of these wire-bundles behind our Home Theater Systems when using Firewire.


By 2007 all HDTV sets, VCRs, and DVD-recorders will have OTA DTV turners. Since all HDTV Sets will have OTA DTV turners and MPEG2 decorders there is no need to place MPEG2 decoders in VCRs and DVD-recorders.
 

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Will the DVI inputs on these tvs accept DVI-I inputs, or only DVI-D? If I am not mistaken, DVI-I is analog, while DVI-D is digital.
 

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Correction, DVI-A is analog, DVI-D is digital, and DVI-I is a combination allowing for DVI-D to DVI-D or DVI-A to DVI-A. Are all TVs made with DVI-D inputs?
 

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Quote:
A Firewire-equipped DVD player would not decompress and recompress the MPEG-2 data on the disc, it would simply put the data on the network for a Firewire-equipped TV to read and decompress. That's how Firewire-equipped DV cams and ATSC receivers communicate now.
Theoretically this is true... depending where in the datastreat that firewire takes the signal... it usually is always before the decoding of mpeg 2... all firewire equipped dv cams record in mpeg-2 and spit out the compressed video to the computer who then decodes..


Slim- is absolutely correct... I guess i wrote it wrong in haste...


I would tend to agree that Firewire is a better bus... and that DVI although it may add PQ... is really chosen for the fact that it is difficult to record the uncompressed data


-A-
 

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Quote:
Originally posted by d4lions
Theoretically this is true... depending where in the datastreat that firewire takes the signal... it usually is always before the decoding of mpeg 2... all firewire equipped dv cams record in mpeg-2 and spit out the compressed video to the computer who then decodes..
Minor quibble: Although the video recorded by consumer digital video cameras is compressed, it's not via MPEG2. If it were, there would be no need to "render" it when creating DVDs from it. The compression mechanism used on DV cams requires 13-18GB per hour of recorded material, nearly an order of magnitude in excess of what MPEG2 requires for the same duration.


That said, there are a few new cameras from Sony that use MPEG4 encoding to Micro-MV format tape. This, unfortunately, makes them incompatible with most 3rd party editing and rendering software.


--

- Jeff
 

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Someone like Mitsubishi or Hitachi could create an entire suite of Firewire products that would be a fabulous home entertainment network (HEN), and have a somewhat proprietary, somewhat HAVi-based solution that lets you treat a PVR as a video server for the whole family, and share peripherals like DVD and D-VHS decks, and... and... Coulda shoulda woulda, I'm afraid.


They may be waiting to see if HD-DVD goes with MPEG-2 before commiting to a Firewire HEN.


I'd like to see TiVo or SonicBlue jump into the fray with a Firewire PVR/HEN server and create a Firewire-based solution that would work for Hit, Mits and Sony TVs.


(I'm clenching my beak in anticipation of eggregious puns like 'which comes first, the HEN or the egg'.)
 
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