Cutting the Cord - Follow Up

Cutting the Cord - Follow Up

February 4, 2013

As is always the case with content published on this site, the first version is certainly not the last. Through valued reader feedback, these articles are amended and updated over time. Chris MacKarell at Arri CSC Digital, whose feedback has routinely been beneficial to this site, raised some valid points on my post on Wireless HD-SDI that I'd like to include. The main concern is that for Wireless HD Video, because this digital signal has to be converted to analog for transmission and then converted back to digital upon reception, this resulting signal can never really be "identical" to a cable-bound one no matter how high quality it is.

How true! 

From Chris -

.. as far as wireless monitoring is concerned, here some questions you didn't touch on which certainly affect the quality of the image on the monitor:

At the Transmit end, precisely how is the deserializing and digital-to-analogue conversion of the original HDSDI signal performed?

How is the reverse, the analogue-to-digital conversion and serializing of the signal at the Receive end performed?

How high a fidelity are these DAC and ADC functions, what quantizing steps are taking place to perform them?

How are overly high peak-to-average power ratios in the modulated signal dealt with? - Note that this is usually done by clipping the transmitted sine wave.

How is intermodulation distortion i.e. non linearity in the signal chain handled?

If COFDM, how is this managed?

Of course, there are industry standards ( e.g. IEEE 802.20 ), but were they designed for the kind of critical application the DIT requires?

The key question is, can you trust what you see on your monitor at all times?

I suspect that for many, any questions at all around the image processing techniques applied and therefore the integrity of the subsequently transmitted image, are enough by themselves to mitigate against that signal's utility for serious critical imaging work.

And since all this processing will always be a necessary precursor of image transmission and reception, the wireless utility you seek for on set monitoring applications perhaps maynever be approached.

In short, whatever future technology developments occur, the underlying principles governing wireless transmission will not change. Wireless may therefore never yield the kind of critically accurate signal you require in your day-to-day work.

All of the above points will certainly affect image quality and is something to be aware of.  As Chris pointed out, "the underlying principles governing wireless transmission will not change," so no matter how good these systems are, just how cautious should we be in using them? Should we even be using them at all?

Unfortunately, we often don't have much choice in the matter and if the shot calls for wireless, then it has to be wireless. In my opinion, if you know the nuances of your wireless system and have spent some time testing and evaluating the image it produces, you can come to trust it. My favorite thing to say on the set when things become questionable is, "the scopes don't lie." Waveform and Vectorscope are probably the only thing on the entire set that are truly objective. They reveal problems now that will certainly be problems later and basically tell you everything you need to know about the video images you're working with. In the case of wireless video, the scopes can tell you just how well your system is putting that signal back together upon reception.

Here's a great way to test this - using scopes, compare the exact same image - one coming to you over the air and the other through a cable. Use one of the camera's HD-SDI outputs to feed the wireless Tx and then run a hardline to you from the camera's other output. Now switch between the two and study the waveform and vector. Are you seeing any shift in Chroma in the wireless image compared to the cable? What about contrast? Does the highlight and shadow information in the wireless waveform sit at the same place in the cabled image? What about midtones? Are they more compressed in the wireless image? 

Really if you're going to use this video signal for anything other than basic monitoring, any differences between the wireless and cabled image should be minimal. In the case of the Boxx Meridian, in my experience very little if any, shift in chroma or contrast is evident in the wireless image. As the signal degrades, the image becomes noisier and blockier but largely maintains its correct luma and chroma information. This is why we spend so much time testing gear. You're going to have to use it and often in very compromised situations. The more you know about its strengths and weaknesses, the more confident you can be in its operation. 

I encourage anyone who follows this site to contribute to the knowledge base and feel free to eviscerate anything I've written here with a fine-toothed comb. I'm a technician and not an academic so many of the topics I address here are much more focused on practical application or the "end-user experience" and not the hard science driving it. 

Cutting the Cord

Cutting the Cord

January 17, 2013

First post of 2013. I'm writing this on an overnight train. God bless free wifi. Here we go.

Someday we might look back at the time when we were forced to use masses of chaotic, unruly conduit with a certain nostalgia. But then likely be glad those days are long behind us.

Wireless HD = no cable between the camera and video monitoring. Instead we have a transmitter (Tx) on the camera coupled with a receiver (Rx) on the monitoring end that captures the 1920x1080 video signal out of the air and outputs it via HD-SDI to our on-set video system and/or monitors.

Wireless HD is finally here in a big way but with so many options now available, more on the way, and at so many different price points, which system is the right fit for your needs? This depends on many factors but among the current crop, don’t expect to find the perfect solution. At least not just yet.

Amazing breakthroughs have been made in this technology as the equipment is getting smaller, lighter, and capable of far greater range yet each product offering presents a specific set of advantages and disadvantages. At this time, the “perfect” wireless HD-SDI video system would have the following features:

Video output from Rx: 1920x1080, Uncompressed, 10 bit, 4:2:2, SMPTE 292M 1.485 Gbit/s HD video with embedded audio and timecode.

That is, a video carrier from the wireless system that is identical to which is delivered over standard 75ohm BNC cable -

“the transmission of uncompressed, unencrypted digital video signals (including timecode, audio, and metadata) within television systems”.

Really, 3G-SDI 444 SMPTE 424M 2.97 Gbit/s HD Video is preferred but this standard is not yet universal for on-set monitoring so 422 will suffice.

Zero Latency (no delay). As we’re almost always in a double system production environment, meaning picture and sound are recorded separately. For the purpose of on-set monitoring as far as video village is concerned, video and sound need to be in perfect sync. In a wireless system with latency, that is one with frame delay, picture will lag behind sound so presents a problem for those evaluating actor performance, etc. at video village. Our perfect wireless video system is one without a single frame of delay.

Small physical footprint. Ideally the Tx is small, light, unobtrusive, and can be easily powered from the camera without drawing excessively. It should be mountable in several ways and shouldn’t get in the way of the assistants or operator. This goes for the Rx as well. It should be small as it will often need to be hidden so as not to be seen by the camera(s). It needs to be mobile, easy to set up, easy to power, and most importantly – mountable to a stand as its position will change constantly in search of the best connection with the Tx.

Ease of operation. No overly complicated menus please.

Signal quality. The ideal wireless system would output a signal of no different quality than what comes through a video cable. Unfortunately, the technology isn’t quite there yet but several of these systems are very good. The wireless signal needs be very high quality and at great distances. The longer, the better. Again, this is something that is improving but in general, the range one gets with all these systems is never quite  what you need and the greater the distance, the more degraded the signal. In a perfect world, the range would be so good that the Rx could live on the DIT or Video Assist Operator’s cart and never have to be moved. Unfortunately, this is not the case at all. The Rx will likely need to be mounted to a stand, positioned high in the air, and placed within a clean line of sight of the Tx to create an acceptable video link.

This point of signal quality proves to be the most problematic if we’re hoping to use the wireless signal for engineering purposes, that is – image evaluation, quality control, real time camera painting, and the creation of useful color correction data to be put into the post production pipeline. In order to do this we require a very robust signal. In my experience, you can accomplish certain engineering tasks wirelessly but it’s less than ideal as trying to create a wireless image of high enough quality can be a time consuming and occassionally futile process.

Not one of these existing wireless solutions can claim to satisfy all these points perfectly but several of them do a good enough job under the right circumstances.

The ultimate goal of wireless HD video technology is to replace the physical video cable between the camera and monitoring with a wireless alternative of equal quality. We’re getting closer all the time. Let’s explore some of the current options.

FIRST - WHY GO WIRELESS?

So many reasons.. But here are a few in no particular order.

I know the cables in my rack work. I know the cables feeding my monitoring and looping through my hardware work. I know this because I routinely test and remove faulty cables. Because I know my stuff works, if there are video system errors, 9 times out of 10 it’s because of a rental house cable tied into the camera. Or a bad BNC barrel. Or a failing cable harness. In other words, the problem is likely at or near the camera and intermittent signal indicates a defective cable somewhere in the chain. Quickly identifying where though can be problematic. If I have only one short cable feeding my Tx directly from the camera’s HD-SDI port, the chances of cable related signal problems have effectively been eliminated.

Going wireless saves enormous amounts of time and energy. Cabling multi-cam can be a challenging task requiring a lot of cable and lots of hands on deck. As cable runs get longer, barrels are introduced which are notorious for failure. Additionally, any run longer than a few hundred feet will require a repeater. Setting all this up and trouble shooting inevitable problems takes time, time that should be, but is rarely available on set. All that cable is heavy, takes up a lot of room on carts, and requires a person(s) tasked with safely and efficiently running it out and pulling it back for every setup. Ideally a dedicated Utility person would do this but having that crucial extra set of hands is unfortunately not always available to the camera department. You can thank diminishing production budgets for this. The beauty of wireless is that as long as the cameras are powered up, they are always transmitting. And as soon as DIT is ready to go, there’s an image to start working with. In practice, wireless is a godsend to an understaffed camera department.

Video cables are a filthy occupational hazard to our job, especially here in New York City. I’m sure many readers can attest to how often they’ve been on location in the middle of the night pulling up hundreds of feet of cable from toxic Manhattan gutters covered in dog by-product, antifreeze and motor oil, garbage juice, and god only knows what else. I don’t wish this task on anyone and regardless of work gloves, regardless if cabling is “someone else’s job”, it’s extremely dirty work and a wireless set is a more sanitary set. Granted, because of the current limitations of the wireless equipment, cables still must be run to the Rx. However, these runs are typically far shorter and usually involve a single cable so this practice is definitely more efficient.

CURRENTLY AVAILABLE WIRELESS HD VIDEO SYSTEMS:

I’ve used most of these products fairly extensively so can speak to the nuances of their operation - where they excel and where they fall flat. I’ll also disclose now that I am a Boxx Meridian owner/operator so do have a vested interest in these though I’ll be the first to admit they can be frustratingly finicky. The point that I’ll make again is that wireless HD video is an emerging technology and is far from perfect. There are major shortcomings preventing any of these systems from being the perfect solution for what I’ve proposed. The wireless set CAN be accomplished but be aware that for now, ditching the video cable just trades one set of problems for another. 

BOXX MERIDIAN 

“Boxx provides Digital Microwave Transmissions at a fraction of the cost of traditional COFDM systems.”

The science behind this technology is fascinating and something that I’ve been learning about though osmosis but not one that I’m particularly well versed in. For the purposes of this blog post, it’s relevant but not impactful enough to warrant the time it would take to really get into this. But here's some info if you're interested.  

An explanation of Coded Orthogonal Frequency-Division Multiplexing (COFDM)

Vs.

Digital Microwave Transmission which is the technology utilized by the Boxx.

The Boxx Meridian (Boxx) has been around for quite awhile and is still likely the production’s first choice for wireless needs. At the heart of the Boxx is a modular antenna system in which different versions can be connected to the Rx depending on how demanding a range is required. These antennas run the gamut in size and price but this standard high gain antenna is widely used and is what I have on all my systems.

For the most part, I’ve had great results with it. I recently did a feature film that required free roaming cameras, seeing 360 degrees, and traveling up 600 feet within one shot. The photographic demands of this project would have been impossible without the Boxx and the systems performed remarkably well which allowed us to focus on imaging and not shot logistics. 

THE GOOD:

Very solid construction. Even damaged, the equipment still works.

The Tx was smashed doing a vehicle shot but it still worked fine even with the interface rendered inoperable. Boxx is tough.

The Tx and Rx are the same size. Tx easily fits on camera in-between battery and camera body. It comes standard Anton Bauer but can be adapted to IDX. Both the Rx and Tx are 6.5-18v DC and can be powered with a variety of accessory cables. In my experience, the Boxx Tx is the easiest wireless transmitter device to power on camera. Rx can be outfitted to several antennas depending on range needs (see website for details). With the high gain antenna, in the right conditions I’ve experienced incredible ranges around 600 feet. We’ve shot boat to boat, vehicle to vehicle, and helicopter to land and generally had great results. Users of Boxx Meridian systems have even reported going building to building in Downtown Manhattan. Granted signal quality is substantially degraded at these distances but as long as the transmission is strong enough to be detected by the Rx, it will output what’s available. The image doesn’t always need to be pretty; sometimes what’s most important is to just get an image up by any means necessary. The Boxx excels at this.

The Tx and Rx are switchable between a number of different frequencies which is useful if you’re in an area with a lot of RF contamination and are experiencing poor signal. Additionally, you can use this functionality to gang multiple receivers to a single transmitter.

It is a zero latency, zero delay system. Using the Boxx, dual system audio will sync up perfectly with picture at video village / client monitors.

The Rx is extremely mountable and easily powered with Anton Bauer or IDX with an adapter. The antenna is physically bright white and big enough to be seen in the background though which can be problematic when needs to be hidden in a multi-cam scenario. 

A VERY IMPORTANT QUESTION - CAN YOU PAINT THIS VIDEO SIGNAL?

That is, can you generate accurate color correction data using this wireless video signal? The answer is yes you can to a certain extent. The Boxx Meridian outputs an uncompressed, 10 bit, 4:2:2 video signal that is compliant to SMPTE 292M. The carrier is identical to a cable based signal. Successful wireless camera painting is of course entirely dependent on signal quality and if an acceptable image cannot be achieved then making critical color and exposure decisions is not advised. At it’s worse though, the Boxx’s transmission quality has little effect on video color (chroma). You are much more likely to experience signal degradation in the form of a softer, grainier image along with a little macro blocking and other artifacts. The best case scenario with the Boxx, you can’t even tell you’re wireless. However finding a frequency that will allow for this can be a tricky and time consuming endeavor. The equipment is also prone to many difficult to troubleshoot environmental conditions and sometimes it can be difficult to get the best image for the situation. “Wireless engineering” with Boxx Meridian is a judgment call.

THE NOT SO GOOD:

These systems aren’t cheap. A basic kit will set you back around 18,000 USD.

The number one problem with the Boxx Merdian though lies in the Tx. This unit does not have any reclocking signal amplification hence no loop-thru SDI which is a badly needed feature. Because the signal is not amplified in the Tx, if a degraded signal from say faulty cable is input, the user will almost certainly experience transmission problems. I’ve experienced this numerous times with techno cranes and vehicle rigs where it was impractical for me to mount the Tx on the camera. Long runs of cable full of barrels (the cable you’ll find in the arm of a crane!) will not provide a strong enough signal to the Tx for successful transmission. Because of this lack of signal amplification, the Tx is very prone to all input cable related problems. Whatever cable feeds the Tx from the camera needs to be as short and as new as possible. Worn cables can present a problem. Also, BNC elbows are not recommended for the same reason. Knowing this shortcoming can help you troubleshoot inevitable connection issues that will arise between the Tx and Rx.

The Boxx Meridian can transmit, receive, and distribute HD Component, HD-SDI, SD-SDI, and Composite video. It can be switched between PAL and NTSC and can input and output all standard SMPTE video formats. I put this in NOT SO GOOD because at this point, all we're using is HD-SDI. Having all these other inputs just adds unecessary cost and weight to the system. 

The standard high gain antenna (see image above) is housed in quite a flimsy plastic which is very easily damaged. It’s also blinding bright white which makes hiding it from the camera problematic.

You gotta get creative.

In my experience working with these on an almost daily basis, I think they’re pretty good. Not perfect, but reliable enough. I have occassionally encountered serious frequency problems but the success I’ve had with them far outweighs any time lost to troubleshooting. In practice, you can count on a good strong signal 150-200 feet. Any range greater than that is very much more subject to environmental conditions.

NEBTEK MICROLITE

From Nebtek >>>

The Microlite from Nebtek is a very impressive COFDM based system that has been available for about a year now and is very popular with Video Assist / Playback Operators. The Microlite's incredible range is it's strongest feature. 

THE GOOD:

The Tx is tiny, unobtrusive, uncluttered with unnecessary inputs, easy enough to power, and as mentioned, the range is incredible - about twice what you get with the Boxx. I refer to the Microlite as my “get out of jail free card” and have used it in multi-cam situations where there’s enormous distances between cameras, or where one camera splinters but stays within range.

The Rx is small, mountable, and easy to power with either Anton Bauer or IDX batteries. Power draw is very low.

Tx and Rx can switch between 12 channels. This can be used to find the optimum frequency for a particular environment or to gang multiple Rx to one Tx.

THE NOT SO GOOD:

The kit costs about 20,000 USD.

Most importantly, the Microlite is NOT an uncompressed wireless system. It achieves such incredible range by encoding into a more efficient H.264 carrier and is then transmitted. It is decoded up reception and then output as HD-SDI video. As far as the video engineer is concerned, this introduces two problems –

The first being latency. The process of encode, transmit, decode introduces a noticeable frame delay. Video that has gone through the Microlite will lag behind sound so will not be in sync at Video Vilage. For some, it’s an acceptable amount. For others, not so much. One solution to this is to delay audio to meet the delay in video but this is not something I’ve seen implemented.

The second problem with the Microlite for the video engineer is that this compression introduces a bit of contrast that isn’t in the actual signal. Picture processed through the Microlite is slightly punchier than if displayed over a video cable or through an uncompressed system like Boxx. Highlights tend to look a little more blown out than they actually are and shadows appear darker with less detail. Additionally as the Microlite wireless signal is degraded over longer distances, it gets warped, delayed, and chroma shifts. For this reason, critical quality control and camera painting using the Microlite is not advised. This is equipment is intended strictly for monitoring only.

In keeping with my earlier statement – many times, what’s most important is to just have an image on the monitor regardless of quality and in these challenging situations, the Microlite is an extremely valuable tool.

TERADEK BOLT

Bolt site >>>

THE GOOD:

The Bolt is brand new and still trickling out to market. I pre-ordered so have had a system for about a month and have been testing.

These are cheap - the “Pro” system has a built-in L-ion battery that will power the Tx for 90 minutes, is only 2490 USD. This includes the dual ouput Rx and a few power cables.

The Bolt is tiny. And so light, the operator won't even know it's there. 

The Bolt is the only HD wireless video Tx that has a HD-SDI Loop Thru. The Bolt is a 3G-SDI, Uncompressed, Zero Latency wireless system and Teradek claims ranges of up to 300 feet.

So uncompressed, zero delay wireless HD for 300 feet for 2490 USD? There must be a catch right? 

THE NOT SO GOOD:

First off, and I always find cases like this to be interesting, I’m not entirely convinced the manufacturer knew how the Bolt would actually be used on the set as there are some puzzling power and ergonomic issues.

The power draw is mismatched as the Tx is 6-12v and the Rx is 6-28v. In all other wireless video systems, both Tx and Rx are 12v and easily battery powered. In the case of the Bolt, both Tx and Rx have 2pin Lemo inputs but the kit only comes with one Anton Bauer P-tap to Lemo cable. Because Lemo is a common connector, custom cables can be made easily enough but this is a bit of a pain. Given the cables that come in the kit, they assume your camera has a P-tap output (the Alexa’s battery plate does not!) and that you will power the Rx from an AC outlet using the included 2pin Lemo to AC Adapter. I’ve never been in a situation where powering my wireless Rx with AC was even remotely practical. If you're wanting to power the Bolt Rx with a battery, and you will, you’re going to have to get creative. 

Mounting the Tx and Rx. The Tx has a 1/4-20 receiver so is mountable enough on smaller cameras but on the Alexa in studio mode, your only real option is mount it with a cine arm. Or..

..find a place to wedge it in. 

The Rx has a 1/4-20" receiver as well though it requires a threaded thumb screw that is included in the kit. 

In practice, with any wireless video system Rx placement is crucial. This is why most available systems have very mountable, very easily powered Rx that can be placed on a C-stand wherever it needs to go for the best connection with Tx.

Here's the Bolt working in (relative) harmony with the Boxx.. mounted on a stand of course.

So in order to start testing, I had to get creative. I had Steven Zuch Enterprises custom make me the cables I needed. I got an additional P-tap to 2pin Lemo (because one is never enough) and because I’m working with Alexa, a 2pin Lemo to 2Pin Lemo to power the Tx from the camera’s 12v output. For the Rx – it can be powered off an Anton Bauer battery via the P-tap to Lemo cable. But how to get it onto an Anton Bauer battery plate? And then how to get the whole contraption onto a stand?

This is what I came up with using spare parts from B&H.

The Universal Anton Bauer Gold Mount Battery Plate can be dual locked to this Matthews Mounting Plate with 5/8" receiver. This setup will allow the Bolt Rx to be both battery powered and mountable to a standard C-stand. 

First attempt - I velcored the Rx to the battery but came back after an hour to find that it had melted off so I ended up just using a bongo tie to keep it all together. Not the most elegant solution but it works.

The next issue, and one that I’m in the process of looking into, is the Bolt outputs some sort of irregular video signal. It is uncompressed but it’s not standard to SMPTE. Blackmagic Designs video hardware doesn’t like this output and won’t recognize it. Additionally, the Raptor Playback system won’t recognize it so if this is what your Video Assist Operator is using, there will be dark screens at video village. In a situation like this, the Bolt can’t be used unfortunately. I’m currently out of the country so haven’t been available to fully dig in and figure this out. I’m curious to run its output through a Decimator MD-DUCC..

..and see if it could be used to get the Bolt output into a more normal video signal.

UPDATE 1/19/13: Teradek is aware of the issue and working on firmware to resolve. 

And most importantly - range and image quality. The image quality is really quite good with the Bolt. Similar to what you get with the Boxx in that degraded signal will look grainier and grainier until it just cuts out. I found the Bolt’s range to be pretty reliable at 50-100 feet but this is with of course with getting the Rx into an ideal position in relation to the Tx. Anything beyond 100 feet signal quality is substantially degraded and I could not get a connection at 200 feet. Evaluating the real range capabilities with all these systems though is difficult as all experience problems and are subject to environmental conditions.

Each pair of Bolt Tx and Rx are married to a single frequency at the factory. This means that you can’t change the channel to find a better frequency. However, the pair will automatcally jump to another channel if too much interference is detected. 

I don’t think the Bolt is nearly as robust a system as the Boxx or the Microlite. Its performance shows promise but there are a lot of workarounds to make it functional in a real production environment. But it’s also 1/10 of the price of the more expensive units. If no on-set video other than say, a director’s monitor is required, the Bolt might be a good fit. This seems to be its intended use.   

I’m still trying to figure out how I’m going to use these. Perhaps as a backup for the Boxx. Or assuming there is a way to normalize the signal, it’s potentially a great way to get video to a handheld director’s monitor or even to transmit wirelessly to video village. That would actually be ideal. The Bolt has potential but so far, I won’t be able to use these as a replacement for my other wireless systems.

BOXX ZENITH

Product site >>>

The Zenith wireless system is designed for wireless ENG and HD live productions where range and signal reliability are essential. The unique network capability of the system allows for an almost infinite shooting area by deploying inexpensive receiver nodes wired with Category-5 cabling. Inexpensive repeaters can be created to bounce signs around corners.

The bandwith is adjustable (between 5-40MHz) and one of the strengths of the Zenith system is its ability to navigate around interference when operating in “wide-bandwith mode” making the link robust and extremely stable.

Zenith is fully configurable via a Web interface and statistics can be monitored on portable devices allowing the operator the flexibility to configure either system from a laptop for optimal HD wireless transmission within any environment. Zenith provides a scalable modular solution allowing trade offs between budget and performance. 

New to market so have not had a chance to test. This seems to be Boxx’ answer to Microlite – a compressed system with latency but with incredible ranges. 

IDX WEVI / CAM WAVE

Product site >>>

Not really worth discussing in my opinion. This is late model technology though they are still in use. The range is terrible as is the signal quality. These are affordable at 3549 USD. The Tx is large and the Rx is not nearly as mountable as the Boxx or Microlite.  

PARALINX ARROW

Product site >>>

This is an HDMI based wireless system that was intended for use with HDSLR’s. It was not intended for any serious monitoring other than perhaps to a single display within a very short distance of the camera. It serves no purpose for the needs of the DIT or Video Assist Operator working in larger production environments. The price is $1199.

ABELCINE WIRELESS VIDEO SOLUTION

Product site >>>

I have not used these but am curious. Perhaps Andy would give me a demo sometime. 1499 USD.

ANTON BAUER AB-HDRF

Product site >>>

Catchy name. Have not used. 21,599 USD.

SWITRONIX RECON

Product site >>>

Have not used. Price and ergonomics seem similar to the WEVI. 3095 USD.

TRANSVIDEO TitanHD

From Transvideo site >>>

State-of-the-art Digital HD/SD wireless transmission system

• Ideal for video-village, news, sport, digital-cinematography and body-rigs

• Latency bellow 5ms

• Accepts HD/SD SDI, composite & HDMI

• Low power consumption

Transmission Range

The transmission range varies depending on the topology of the location, performance remained excellent within an open field line of sight test from 200 feet (60 meters). It can be reduced by walls or interferences with other systems.

Audio & Metadata Transmission

TitanHD includes audio transmission where 2 channels are embedded in the SDI signal or 2 analog balanced inputs. SDI embedded Timecode and Tally transmission are possible in place of one audio channel (if any embedded in the SDI). Several other possibilities are available to remote basic functions (Tally and GPIO).

Link

The selection of a channel can be manual or automatic. In P2P mode the link is possible only between one receiver and one transmitter. In Broadcast mode up to 6 receivers can be linked to a single transmitter, but data transmission from receiver to transmitter (S/N ratio, GPIO) is not possible.

I have not used this product. Key features - Low latency and HD-SDI Loop Thru at 9085 USD. 

BMS - BROADCAST MICROWAVE SERVICES

The BMS company offers a wide and diversified product line for Government, Surveillance, Law Enforcement, and of course Motion Picture Filmmaking ;)

BMS DR25xxHD

With wireless Video Assist solutions from BMS, waiting for dailies is a thing of the past. Using license-free 5.8GHz COFDM wireless technology, BMS can transmit live footage in almost any environment with a delay as low as 40ms (one frame). This low-latency, high definition capable system allows directors and crews to see the action as it happens, just as the viewer will see it.

Powered by the lightweight, compact NT5723SDHD transmitter, the Video Assist system offers the closest substitute to a wired camera available. The DR2558HD receiver offers a small, easy to operate receive station that outputs SDI at standard or high definition. The DR2505HD offers the same capability, plus additional amplification to allow for distant antennas, potentially increasing reception range.

A smaller, Nano version of this system is also available. 

I have no expereince with these wireless systems and have not been able to locate any pricing on them.

TERADEK CUBE

Product site >>>

The Cube is an interesting product. It is not intended for any real serious monitoring as it is wifi based so is heavily compressed with lots of latency. It is mostly used to impress clients on commercial shoots so they can watch on their iPads. Prices vary but the HD-SDI kit is 2690 USD.

RED MEIZLER MODULE

Product site >>>

Coming to market. 13,000 USD. The RED Meizler Module is a very progressive piece of gear and I’m curious to see how it will hold up in terms of range, signal quality, and overall reliability. While this functionality isn’t built directly into the RED camera, I’m guessing most owner/op’s will buy these so many RED sets will become wireless by default. To RED’s credit, building this functionality into their flagship product is very forward thinking. Just as the Alexa Plus and Studio have wireless lens control built-in, perhaps Arri’s next camera will include HD video transmission as well.

WIRELESS VIDEO SERVICE:

RF FILM

Company site >>>

RF Films is a company providing state-of-the-art wireless video technology as a production service. I’ve never worked with this company but have heard the ranges and quality is incredible. Each system comes with a dedicated microwave technician and distances of up to six New York City blocks have been reported. I’d like to learn more about this service and how it works. 

There are of course, even more options available and more coming soon so if you would like to add anything to this post, please email me (bennettcain@gmail.com).

Disclaimer - In best practice, the smartest and safest way to do color critical quality control is always over a video cable so if this work is to be attempted wirelessly, using any system, proceed with caution.

THE FUTURE:

Moving forward, it’s my hope we continue to see less and less cable on the set and equipment footprints that get smaller and smaller. I’m of the opinion that less is more and am always striving to streamline and simplify. In the case of video cables, fully wireless sets can’t come soon enough as far as I’m concerned.

Regarding the wave of higher-than-HD resolution cameras we’re about to be bombarded with:

As is the case for existing RED and Arriraw workflows - a 1080 video on-set workflow combined with in-camera evaluation tools - will tell you just about everything you need to know about the imaging. We’ve been working this way with these high-resolution cameras for years now and have been doing just fine. I await with bated breath the inevitable marketing storm that will say the ONLY way to work with these cameras is to monitor and scope in 4K. Our existing video infrastructure, monitoring, and evaluation tools are firmly entrenched in 1080 video and to rebuild all of that industry wide will take time and capital. Additionally, higher than HD resolution monitoring is currently excessively large, expensive, virtually nonexistent, and difficult to work with as it can require up to 4 cables from imager to display. All of this will change of course but I’m quite certain we’ll be working with 1080 video on the set for some time to come. It's my opinion that these wireless video systems will continue to be viable for the foreseeable future.

HEALTH RISKS:

I would be remiss if I didn’t mention the potential, and supposed, cancer risk involved with being bombarded with ultra high frequency RF. The problem is at this time the data is hugely inconclusive. Any one of these vendors will tell you it isn’t much worse than talking on a cell phone for a few hours a day. But this is exactly what one would expect them to say. And just like the debate on the safety of cell phones, no one can say for certain just how dangerous, if at all, these wireless video systems really are. This is quite a problem and I’ve had a many a discussion with nervous camera operators who would prefer not to have a wireless video transmitter by their head all day or in the case of Steadicam, by their groin. I can’t say that I blame them. It is definitely something to be aware of.

If you're interested, here is the follow up to this article >>>