DVI exstenders

[litemover]

Is it just me or does anyone else think that we should be stepping into a new era bypassing all of the analogue RGB-HV and 15pin garbage, and go straight DVI to every source right out of the MAC?

It has gotten so cheap to do this and you can run signal now up to 6.15 miles, perfectly preserved.

This would abandon the need for the use of Image pros or other scan converters and would give you much higher resolutions as well as a much cleaner looking signal to source.

Any one interested in this should check out Gefen's line of DVI extender, DAs, and switchers. Gefen also makes a very inexpensive but high quality DVI to SDI converter with scaler and your choice of genlock or no genlock, each unit is under $1500.

Gefen's DVI extenders come in both fiber/Cat5/and copper DVI cable (Snagless). They range in price from $150 for the lowest end extender to $700 for Fiber, $500 for the new Fiber ST (4strand) extenders.

Thinklogical makes a single fiber ST extender with a DVI monitor output. They are on the expensive side though.

Currently most people are down-converting their DVI sources to analogue the up-converting to digital again using ImagePros or other scan converters. When you compare the difference of going straight DVI to a projector to going through 2 conversions the results are noticeable to say the least going straight DVI. The screen pops out at you and the clarity is unmatched.

Digital monitors are well under $200 ea now and I would encourage anyone who is wishing to upgrade their system to do this. Purelink makes matrix switchers for DVI up to 18x18 if you need backup. Everything is starting to sway towards DVi and away from SDI.

Any thoughts on this? I know it would put a lot of Imagepros out of business but you could convert one system per show by saving in ImagePro or other scan converter rentals. Some people charge as much as $1500/wk for an ImagePro HD, for this price you could buy 2 digital widescreen flat panels, a Matrox triplehead2go, a DVI DA 1x4, and a DVI fiber extender with fiber. It seems like a no brainer to me. With Dual link you could get resolutions up to 4k. This looks very realistic especially with the Christy line of digital cinema projectors. I've seen projections that I thought were actual doors and architecture with 4k DVI projection.

Let's hear it from the Imagepro owners....

Here are the links to the sites:
http://www.gefen.com
http://www.thinklogical.com

Christian Choi

[jasonrudolph]

Personally, I'm still on the fence on this one. I like using DVI when my signal runs are short, and when I need to do long runs I go SDI. A lot of the time, I actually like what the SDI (or HD-SDI) signal looks like a little more than a DVI signal. If you are using a good scaler/converter like an imagepro, I think it actually can clean up the look of the signal (doesn't look as "digital") I have even done shows where I was taking SD content and in order to send to the truck we converted to 1080I, and it honestly looked really good, I was shocked, no pixelation or artifacting at all. Also, SDI and HD-SDI cabling is MUCH more robust, and the gear is much more available, so when you get a bad unit, finding a replacement is easy.
Fiber gets really expensive really quickly, and the cabling is not nearly as robust. Even the military grade stuff can get damaged quite easily given the right circumstances, and finding replacements are not very easy all the time.
I still think for long runs sdi or HD-sdi is the way to go, but if you can keep the signal runs short, then go DVI.
Oddly enough, the place where I see the most benefit of staying DVI, is when usign LOW resolution devices, specifically the element labs stuff.
First off, their processors for the most part REQUIRE 1024x768, 60Hz DVI signal, they simply wotn take anything else.
But, more importantly, if you are trying to do ANY pixel-accurate stuff on things such as versatubes, or versatiles, or even Stealth for that matter, you HAVE to stay DVI the whole way. I was doing a show where even the elemnt labs' box added a row of pixels to the bottom of the stealth, we by-passed it and went direct DVI from a catalyst to the processor of the stealth, and this went away.

just my .02

Jason

[litemover]

Personally, I'm still on the fence on this one. I like using DVI when my signal runs are short, and when I need to do long runs I go SDI. A lot of the time, I actually like what the SDI (or HD-SDI) signal looks like a little more than a DVI signal. If you are using a good scaler/converter like an imagepro, I think it actually can clean up the look of the signal (doesn't look as "digital") I have even done shows where I was taking SD content and in order to send to the truck we converted to 1080I, and it honestly looked really good, I was shocked, no pixelation or artifacting at all. Also, SDI and HD-SDI cabling is MUCH more robust, and the gear is much more available, so when you get a bad unit, finding a replacement is easy.
Fiber gets really expensive really quickly, and the cabling is not nearly as robust. Even the military grade stuff can get damaged quite easily given the right circumstances, and finding replacements are not very easy all the time.
I still think for long runs sdi or HD-sdi is the way to go, but if you can keep the signal runs short, then go DVI.
Oddly enough, the place where I see the most benefit of staying DVI, is when usign LOW resolution devices, specifically the element labs stuff.
First off, their processors for the most part REQUIRE 1024x768, 60Hz DVI signal, they simply wotn take anything else.
But, more importantly, if you are trying to do ANY pixel-accurate stuff on things such as versatubes, or versatiles, or even Stealth for that matter, you HAVE to stay DVI the whole way. I was doing a show where even the elemnt labs' box added a row of pixels to the bottom of the stealth, we by-passed it and went direct DVI from a catalyst to the processor of the stealth, and this went away.

just my .02

Jason

DVI as far as a signal is far superior than an SDI signal both in the way it is transmitted as well as the amount of GBs transferred, TMDS (Transition Minimized Differential Signaling) used to transfer DVI is impervious to hum and electromagnetic interference and replicates the original digital signal perfectly and without differential from the source. SDI is a scrambled signal sent to a decoder that uses 10 1s and 1 0s to unscramble the interface line by line in a frame, DVI constantly reproduces the entire frame instead of scans it, it sends unencrypted, un-packeted data using TDMS which also allows for much high transfer rates.

SDI depends on 4 different and expensive protocols to reach digital 1080p signals, while DVI-D only uses 2, DVI and DVI dual link to reach 4K signals. Here are some comparisons:

SD-SDI = 270 Mbit/s, 360 Mbit/s, 143 Mbit/s, and 177 Mbit/s Max resolution = 480i, 576i

DVI-D= Is pixel sensitive and transmits the luminance and 24 bits of color per pixel up to 6.15 miles with resolutions of up to 2112x1214 pixels at a stunning rate of 161mhz.

HD-SDI transmits the exact same way as SD-SDI except that it uses 20 0z and 20 1s and can achieve resolutions of uo to 1920x1080 I=Interlaced

Dual link -DVI shatters that barrier at a very low cost transmitting 3840 × 2400 (4k) at 70mhz.Max.

The standards for the extremely expensive equipment that is used to transmit a Dual Link SDI signals needs 2 SDI cables and maxes out at 1080P, with Dual link SDI CRC (error correction) is required as well as packet timing synchronization, this is why the gear to make it happen is so much more expensive than DVI, it has lot more to process and decode as well as time each packet that comes in. DVI doesn't send packets, it send one frame continuously and seamlessly.

The only competition for the clarity of video signal to DVI currently is HDMI which allows for copy protection and encryption.

This year at CES all video standards will have been voided out by a completely new standard called UDI, United display interface, combining the features of both DVI dual link and HDMI, still using TDMS instead of serial data packetization that SDI uses. The big difference is that you will be able to send Rights managed content through it at 36bits per pixel and an alarming 4 times the amount of transfer rate (16gbs compared to 4gbs HDMI and DVI use), it also has clock sync included so i expect this to be the best possible standard for computer based media servers.

Regarding Cabling, Copper DVI cable is just as robust as SDI cabling, I agree that it is not as easily found yet but as with all new standards it takes time for everyone to get on the same page. FiberST is very strong and practical for multiple installations, it was made rugged and furthermore it is very thin as well as totally impervious and unaffected by electromagnetic interference as SDI and RGB-HV is.

When you are using a computer as your video source and Catalyst, you don't need a scaler. This is one of the biggest areas of confusion between Video operators and Catalyst operators, the video operators want to scale everything to fit the raster when it's much better for the Catalyst operator to scale and fit the display to the Raster as he/she needs it. I've had scaling wars between me and the video operator. The biggest advantage is that I have a globally updating palette should the raster start drifting as it usually does so I can update the scale and position of my image within the raster as I need it and without the use of external scalers. The other thing I hate about ImagePros and scalers is that the video techs tend to try to squeeze the entire raster into whatever sized area so that any NTSC or PAL standard ccir 601 data can be played through it without any problems. I HATE it when my content that I build to fit certain resolutions is squeezed into an unrecognizable vertically or horizontally thin area. I plan on certain resolutions and I use many different ones to fit certain screens instead of just one or two. Some people may find this to be complex, trying to fit 18 submixes per cue into each screen, it can be done in 2 seconds with a flick of the wrist if you number all of your comps in the same order every-time and they relate to the screens. You just need to use Fan start when you grab all you video source layers in sequence or ina group and fan them into place. It's that simple. People have made it harder and that is why some video operators I know squeeze everything into an area that any standard 720x486 piece can be played in. This has always bugged me.

To some things up, standard are always changing, DVI, in my humble opinion is both a superior signal for clarity than SDI and is less susceptible to hum.

UDI should be what the real future thinkers are thinking about.

Since SDI has been as video standard for so long, it's always difficult to sway standards, look at Catalyst for example,Profile and EVS are still the standards in large productions but Catalyst has so many more features at a much lower price.

I see the industry divided, there are protocols and equipment that are both technologically and visually superior most importantly a fraction of the cost and there are the current standards that are less superior and cost a fortune still so everyone can pay off their gear. I tend to want to go with the technologically superior and higher clarity products that are cheaper than the one's that are less superior and exponentially more expensive.

Time will tell where things are headed. All ImagePro HDs already have DVI ports on them and have had for years. They recognize that DVI is a hugely growing standard.

To sum things up, I recently did a job in NY and they used some mpeg video server that used nothing but DVI-D and Thinklogical extenders. The screen was the clearest and most color accurate projection I have seen in years. Furthermore they used a scrim in front of the screen and made a 3d logo all with DVI-D and it looked like it was literally popping out at you. It was so clear, everyone was impressed. There was no banding, it looked very clear, there wasn't any digital artifacting - it was 3 blended projectors blended within the software and it looked way better than anything I've seen. That one experience really made me think "Why are we downconverting to analogue and then upconverting to SDI when we already have DVI-D available to us straight out of the mac, then I started looking at prices of DVI equipment and knew right then that it was both a much cleaner signal and much more affordable way to go direct to both projectors and element labs/barco LED processors that only take DVI-D.

Everything is headed digital anyway. It's hard to even find an analogue monitor these days.

This isn't directed to you, Jason, I don't mean to be argumentative ust informative, but anyone on the ImagePro bandwagon needs to protect their interest, after all they paid a fortune for each one and need to get them paid off before technology passes them up, guess what guys, it already has. So when I hear, SDI and Image pros are better than DVI, I just shake my head in disbelief that someone actually believes that.

All catalyst owners can upgrade their systems to DVI output including cabling and extenders for the cost of an imagepro Rental. If you don't wish to use fiber, you can use copper DVI cable up to 300 meters 600ft with no problem.

Christian Choi

[jasonrudolph]

This isn't directed to you, Jason, I don't mean to be argumentative ust informative, but anyone on the ImagePro bandwagon needs to protect their interest, after all they paid a fortune for each one and need to get them paid off before technology passes them up, guess what guys, it already has. So when I hear, SDI and Image pros are better than DVI, I just shake my head in disbelief that someone actually believes that.
Christian Choi

Christian,

No worries, I wasn't meaning to be argumentative either, and the whole point of discussion forums, in my opinion, is to offer differing points of view, and ways to do things differently, that why I enjoy reading them. While I mostly agree with you, I have simply found that the condition of DVI gear is not normally very good in the rental market, most of this stuff is built to sit in a computer rack and never move, and becuase of this, I have run in to many more problems with DVI based gear on shows.
There are also other resaons for imagepros in the system. I like them as a troubleshooting tool, its nice to have a dedicated generator, and the ability to black out the screen while I am working so everyone doesnt see what I am doing on the big screens is noce as well.
DVI is definitely the wave of the future, it has already come a long way in the past year, and given another year or so, I'm sure it will be seen much more on shows, but I think the robustness of the gear still needs to come a bit further. Also, like I said, finding this gear is not always so easy, especially in quantity, and if you are routing through a truck which is converting to SDI anyways, what does it matter if you go DVI or not?
There are definitely some very good uses for DVI distribution, but its not the end-all solution just yet.

[litemover]

Jason,

You really should take a look at all the new DVI products out there. They are meant for non-permanent installations. Gefen is very durable and anything that uses Fiber ST or copper DVI long length cable is just as durable as any other option.

You must be doing a lot of shows to be seeing that much DVi gear, if you're seeing a lot of DVI gear on your shows doesn't that say something?

DVI delivers the clearest and more accurate representation of the original source available. If you would've seen upfront and how clear the screen looked without the use of Imagepros you would agree. Ask Ian, he was there. The DVI fed 3 projector based screen was breath taking, ask Mike Karsch how he felt about the clarity of the screen. These guys only use DVI and have s[pent a considerable amount of money on Thinklogical extenders to make DVI their standard and they were total pros.

You keep saying you are doing a lot of shows with DVI on it. It would seem to me that this indicates that people like the look and clarity of DVI better than anything else because it is better.

Before you make a final judgment on the durability, read some of the specs on the boxes.

The Gefen super booster are so small and compact, not much to them you can literally throw them around and it wouldn't effect them. Same with the Thinklogical Vis-23s

ImagePros constantly overheat, you can't stack them without them overheating, and they get just as damaged so the point could be made that Imagepros aren't meant to be mobile out of their racks either.

Christian

[jasonrudolph]

I am doing quite a bit of shows, and there is a lot of DVI gear on it, but it is alwyas a mix. Like I said before, there are places where I feel DVI is a better route to go, and there are others where I still prefer to go SDI. I have yet to be on a show where one thing is the solution for everything. I have simply been trying to point this out.
While the gefen gear can be good, I feel there are still improvements to be made on it before Id want to start using it for all my stuff. Their support sucks, and finding replacement gear is not always easy.
Yes, imagepros have their issues, but those issues (such as overheating) are known by people who use them, and you design around those issues,.(i.e. dont stack them without ventilation)
I have not made a final judgement on the gear yet, but any judgements I have made thus far have been based solely on actual use of the gear, not based on specs.

I still cant go DVI if I need to send a feed to a video truck which can only take SDI, which happens all the time.
Its still easier for me to get SDI gear than DVI over fiber stuff, more shops have this gear in quantity.
Imagepros still give me more flexibility in troubleshooting systems.
I still cant go DVI inot most seamless switchers.

I am not saying I am against using DVI gear, just that it has its places in my opinion, as does SDI gear, and that I think some of the gear still needs to come a bit further. I'm sure in a few years, it will be more readily available, but SDI is not going away any time soon, and in an industry where we have to work with amny different types of gear, it is still something we need to plan on using.

Its just like lighting. You use different tools for different jobs.

Jason

[Mr_P]

Some interesting views.
I agree with both opinions. Mainly because I've used both scenarios. DVI fibre distribution and the image-pro to SDI/HDSDI

Its a good discussion point - but the is NO definitive answer.
WHY?
Because it depends upon the requirements of the production.

I mulled over the question of what to include in a new catalyst rack for quite a time - one answer I arrived at was just to install 2 x DVI DA's - then Ive you the choice of adding either image-Pro or DVI-fibre distribution in a small rack on top, depending upon the production requirements.

Every job I do, the distribution requirements change.

One thing to note though, that I didn't see mentioned above, is processing delay. Image-Pros (and other scan converters) will inherently add a few frames delay to the signal. If you then add in the OB truck and LED screen processor - you wont want to be putting a live closeup of your singer on the screen for too long! Delay in live performance and TV work is a key consideration.

So - Im going to join jason on the fence too - but my feet are on the DVI-fibre distribution side when possible...

Simon

[SourceChild]

Hey Christian,
What models are you using?

[IanH]

Permit me to reply,
Our client purchased a Thinklogical DCS fiber switcher with the Vis 23 Transmitters and recievers.

The TX and Rx boxs can be joined by a ST fiber and work independently

but we wanted the system to work via a matrix... it worked out of the box in Vegas for the Latin Grammys and image quality was stunning.

the Txs all have a monitor loopthrough and store the EDID data-- they can also power via DVI

The Rx have two DVI outputs - perfect for hot backup projectors and have Multi voltage Powersupplys --- very usefull in USA with 208v projectors.

Control is ONLY via IP ----one slight down side is a lack of a confidence display on the DCS.... but i am talking to the tech team at Think Logical currently.

Currently its just sitting on the desk, but hopefully next week it will be intergrated into a rack with the Raid array and some other toys.

We use standard orange patch fibers for local runs (cheap) and purchased 300ft Mil spec 4 cores for the projector feeds ---shame they are Black ---look just like a dmx cable.

One thing i would add is that even though we could use a Cat - DCS -Screen path we will still have a whole pile of Image Pros in the system doing SDI feeds to Plasmas and OB trucks --- AND providing a confidence monitor.

blessed is the Image Pro and all who sail/fly with one

My collegue FOH (JR) has a SDI to DVI device that we were hoping to test on this show as a return back from the OB truck but play time is over... its show time..

Regards

IanH ---- as normal sitting round the back in the dark

PS ----RB is a God---

Miracle One ---Screen warping ---- september tour, 2 hours to show -- we need a screen --got screen and projector, rigged both after doors projector at least 25 degrees off access and over shooting ---catalyst warped image in perfectly in seconds and that included the phone call for advice on how.
oh we used an image pro on SDI input of cat to mix clients DVD and TXT computer
Miracle two. ---- Blending -- with over 30years experiance of wide screen i was a catalyst blending sceptic, Encore yes, Spyder yes.. But for the LGs we used dual outputs of 1920 with blending for a forty foot screen - well chuffed with the blend ---(the dust stayed on the blendpro box) --

feel free to ask if you need more info,

[SourceChild]

Ian,

I have more questions. Email me when you get the chance.

SourceChild AT Runbox DOT com

Todd