If you’re in the market for purchasing HD professional video equipment of any kind, you’ll eventually ask yourself,
“What is the difference between HDMI and HD-SDI?”
By this time, everyone knows what HDMI is. HDMI is a connection on every HD TV, BlueRay player, and PS3; but is it the best choice for us to use in the video production industry?
Here are 7 reasons why you may want to reconsider using HDMI:
1. History
HDMI was developed by a myriad of consumer electronics companies, movie producers, and cable providers. The primary objective of all these companies was not just to develop a cable that can transmit both audio and video within a single connection – though that is handy. These companies where looking for a way to protect their content and in doing so standardized the use of HDCP in all their components.
HDCP, or high-bandwidth digital content protection, is a type of security protocol that forces the source device (such as a BlueRay player) to generate a security key in order for the TV to display your content. This protection actually requires a handshake between the source device and the output device, which is often why most TV’s won’t even display an HDMI input on their source list when nothing is plugged in.
HD-SDI was created by the broadcasting industry to be the very best way to transmit HD video. Because of this, HD-SDI has no use for HDCP.
2. HDCP is SLOW
HDCP slows down the connection speed from input to output, this means that HD-SDI will respond quicker and smoother while video switching.
3. Connectors
HDMI connections are similar to those of USB in that there is no way to lock the connection in place; whereas HD-SDI uses locking BNC connectors that guarantee your cable won’t get pulled out.
4. Cost
HD-SDI uses standard coax cable (RG-6) which is drastically cheaper to produce than HDMI, which uses a proprietary cable.
5. Length
HMDI cables can only run up to 30 feet before they require some type of amplifier or repeater. HD-SDI can run to lengths of 300 meters before needing help.
6. Scalability
Because of HDCP, HDMI is not backwards compatible with VGA without a device that generates HDCP keys. HD-SDI can easily be scaled down.
7. Time Code
HD-SDI carries video signal and time code in one cable. HDMI has no time code support.
On the consumer market, HDMI does a fantastic job holding the position of being the standard HD video connection. In the professional video industry where things like quality, durability, speed, time code, and flexibility are all must haves, HD-SDI is the way to go.
Can you think of another benefit of using HD-SDI?
Paul Clifford (@PaulAlanClif) says
I agree. HDMI was designed to help Hollywood, not people who make videos.
Chris Rouse says
Thanks for writing this. I really don’t like how many churches I see installing HDMI for their projectors. They end up having to use extenders that don’t always support HDCP, so then their signal turns to garbage because it isn’t stable. HDMI really don’t work well with
Tommy Scully says
Thanks Guys!
Michael Rueber says
HDMI has 8 channels of audio HD-SDI has 16 channels.
It is possible to fix and make your own HD-SDI cables.
Martin Perea says
Does HD-SDI transmit both video and audio signal?
Tommy Scully says
Yup, HD-SDI carries audio and video
Michael says
You seem to be talking about HD-SDI here, but the more recent version 3G-SDI (which is required for 1080p signals) cannot carry an audio signal IIRC. Also there are plenty of displays, recorders, and projectors that will work without HDCP now with HDMI 1.3 and 1.4. And HDMI doesn’t just require active converters from VGA because of HDCP, it is because HDMI controllers are generally purely digital, whereas VGA is always purely analogue; HD-SDI and 3G-SDI have the same issues.
However, SDI definitely does have the advantage in cable length potential, with 1000 ft. over copper or dozens of miles over optical cable before needing a repeater; a big plus over the puny 30 ft. of HDMI, especially for projectors in large rooms that need hidden cabling.
However, this is largely a moot point because we have DisplayPort, if only more media device manufacturers would use it, you don’t see it much outside of gaming PCs and CAD workstations. We just have to wait for v1.3 that will incorporate 4K at 120 Hz or 8K at 30 Hz up to 30 ft. or at 60 Hz up to 100 ft. as well as variable refresh rates, then v1.4 that will define a DisplayPort over fiber optic specification, but that won’t be for at least 5 years.
Steve says
Michael,
Are you saying HD-SDI will not transmit 1080P?
“HD” (Full HD) IS 1080P
jastin mathew says
hello, im having two handycam with hdmi and av out. i want to recored church prayer meeting in computer. so please guide me how to do and what equipment to be used and software needed
Sam Hones says
Hi, AV has been around a long time (I am thinking of composite, the cable which uses Y for video, red and white (or red and black) for left and right audio channels.
We are still recording video straight to computer, using AV output. One of the cameras even has the old small VCR tape.
Whenever you want to time unlimited recording, I have found one thing in common: take out the recording media. That will stop the camear switching off or going to sleep.
Here is how we connect: 3 camcorders’ video output ends up via phono to BNC adapter at 3 of the inputs of a CCTV switcher (bought here in England from Maplin for about £30. available options are 4 up to 16 inputs). The switcher has got an adjustable dwell time from 1-15 secs. (I found that Commercial TV never shows a scene longer than 20 seconds). The fourth channel is fed by a VGA to composite converter. (When we have Bible College, the guy at the front shows Powerpoint from his laptop. The signal is split between projector and VGA to composite. The purpose is, to be able to switch what’s being projected and when as an override into the recording video (unfortunately in the editing stage I replace Low resolution Powerpoint with High res output).
I have used a different switcher before wher you could set the dwell time individually per input up to 90 secs, but unfortunately that unit displayed the camera number in the corner without the possibility for that to be turned off.
I’ve found Debut from NCH to be an excellent Program for recording (settings for MPG being used). One output signal from the CCTV switcher goes via Haupage HVR 1900 into the PC, the other goes upstairs via composite over Cat5 adapters including sound from PC, to feed a Sony combination VCR/DVD recorder and TV. The DVD recording is used as backup. (DVD format needs to be DVD+. This also applies to DVD’s made from the PC recording. DVD- isn’t accepted and playable by some DVD players.)
The sound comes from the Sounddesk (Yamaha LS9) via Di box (reduces interfering signals – took ages to figure out) to the Line In on the PC. Using camcorder sound tends to be VERY echoey. It might catch some wha’ts being said (perhaps from the congregation – some might be better than nothing) But it’s impossible to get rid of echo once it’s there. Camcorder sound mixed in for congregational worship singing can work quite well.
(Subsequent editing and output to various formats including DVD-ISO and Youtube in Movie Plus by Serif.
We bought a Panasonic HC-V520 about a year ago. Great camera, huge optical zoom, but: Any new, up to mid range camcorders now sold no longer come with IR remote. Some come with a WiFi over mobile phone control which is really fickle (standard WiFi works on 2.4 Ghz, the same frequency as Bluetooth and Microwave. i.e. the microwave will interrupt the WiFi signal and then you have to reconnect again from scratch. If you do use WiFi remote control, the AV/HDMI output will stop and you only get an image on the mobile till WiFi is turned off (I’m desperately trying to build an adapter that sits on top of the camcorder to wiggle the zoom by remote, leaving outputs intact.)
The next thing I am looking at is changing to using HDMI output via HD-SDI and to PC with new capture unit. I am hoping to be able to feed SDI signal through the switcher as its connections are BNC anyway. Currently one of the cameras’ video signal comes from the other side of the church with a Composite via CAT5 adapters both ends
PC used is: AMD 4core 8GB 64bit Win7 Pro, with 1TB Hdisk
Hopefully this has given you some info. I take the point that some might appear clunky but then I didn’t spend thousands and it still gets the job done.
BTW have a look on the web for Vineyard Norden. The guy there has made several very useful Youtubes. One thing I gleaned was that extending HDMI over twin line CAT5 doesn’t work as well as HDMI via SDI and back HDMI
God Bless
John McDermott says
One word of caution you said “The next thing I am looking at is changing to using HDMI output via HD-SDI and to PC with new capture unit. I am hoping to be able to feed SDI signal through the switcher as its connections are BNC anyway.” Be aware that, even though your switcher has BNC inputs, the switcher has to be able to accept the HD-SDI digital format. If you plug an HD-SDI camera into an analog switcher you may wind up with no pictures at all because the switcher doesn’t know what to do with the signal.
Just a thought and I am aware you may know this already.
God Bless
Sam says
Thank you very much for that point. I wasn’t sure this would work, so it’ll need another look
Jimmy says
Hi Tommy,
What do you mean by “video switching” in point number two?
Thanks,
dukeFLOP says
I’ve been contemplating using either Aja’s T-Tap boxes or BMD’s UltraStudio MiniMonitor boxes to connect Macs (either MBPs or Minis) to BMD switchers using the SDI connectors — I am only concerned about if there will be any lag and whether or not I can select the proper resolution for input as I believe all the inputs have to be the same and be what the output needs to be in the BMD switchers as there are no scalers. I do AV (among other things) and am trying to put together my own system and BMD’s prices are I ticking but if they do not provide what I need, even a good price does me no good! I am sure I can set my cameras to output 720 or 1080i so I’m not concerned about this too much, but I am concerned about the Macs as often they do not present the resolution needed for the situation — often 720 is cool but sometimes client insists on 1080 for whatever the reason/s. I have used the DAC-70 to change resolutions with success but I don’t know if it’s been out long enough to trust in a critical show situation — if the show craps out I’m in trouble! BMD has it’s share of “horror” stories and is still pretty new on some levels but I also know pros that swear by it (as long as you do what it says it does and not try to use it for something else) which is where my concern comes in — also, as far as I know, HDCP is only over HDMI and not via MiniDisplay Port correct. Any thoughts would be greatly appreciated — Thanks —
Duke
Dave Barak says
I’m not claiming I’m an expert in video technology, so please correct me if I’m wrong. An earlier post here said 3G-SDI was required for 1080P. I don’t think that’s right. I routinely feed 1080P out of my Panasonic AF-100 into an Atomos Samurai recorder via HD-SDI. I don’t think the AF-100 is recent enough to be equipped with 3G-SDI (and I hadn’t even heard of it until last year).
Dave Madsen says
This has been a great thread for me. I am with the Mass Comm department at a small private college, and we’re trying to determine the best way to connect new HD cameras to our switcher. After reading all of this, I’m confident in my decision to use good old coax with BNC connectors for an SDI connection. Thanks to all who contributed here!
anton says
Tommy…can do one here for Optical Fibre vs HD-SDI?
jenson says
Thanks for the details.
We are making HD- COFDM transmitters, including HDMI and SDI input port.
Our camera transmitters are mean for moving application, so with the HDMI connection the camera man can’t run , but it is very easy to run cameraman with SDI connector even crowd surfing is possible.
Finally we concluded that HDMI cable is not suitable for any moving application.
Rich W says
I just found a software product called vMix that incorporates all the switching and mixing functions into the computer. It seems to work great (I’ve only been working with it for 2 weeks). It supports multiple inputs: it seems only to need a fast computer (CPU >2.9Ghz) with a good GPU (video card to do the rendering) and it has all the features that we’ve ever wanted.!
Vanessa says
Check out http://www.thorbroadcast.com for different products that may be able to help you. You can also contact their engineers for setting up custom equipment. It is a bit high end, but it works.
Chris says
So, how do we use SDI to connect a computer or DVD player to projector? I am unfamiliar with SDI and there aren’t any BNC connectors on the projector, etc. How should this work?
Thanks!
Sam says
Let’s assume that your output is HDMI and your input at the projector is HDMI and you need to cover a long distance reliably i.e. cabled is better than wireless. Get yourself as I did from ebay:
1x MINI 3G HD 1080P HDMI to SDI Video Converter adapter BNC Adaptor Audio from HDMI to HD SDI,
1x BNC cable from the above adapter to the adapter below
1x 1080P HD MiNi 3G SDI HD-SDI 3G-SDI to HDMI Video Converter Adapter HDTV Monitor. That’s it.
If your output is HDMI and your input VGA (usual computer monitor output) then you need a hdmi to VGA converter and bear in mind that HDMI carries video AND sound, whereas VGA carries video only. To extend VGA to VGA you can use what are sometimes called baluns and found under vga over Cat5/6 (computer network cabling): so this would be HDMI to VGA converter, then a VGA over CAT5/6 transmitter, computer cable up to 100 mtrs (300ft), then a Cat5/6 to VGA receiver It’s not unusual in running whatever (VGA, Composite, USB . . .) over CAT5/6, that sender and receiver are identical units. Again have a look in ebay, also Google Muxlab,
In the case of HDMI to composite, then those are available, too and do shop around as they needn’t cost the earth, some around the £30 mark.
Marek says
There are HDMI cables with locking screw (used in medical equipment) but HD-SDI still wins.
Leo St. Sauveur says
Thanks for the Article.
HDCP IS a royal pain. There is one misstatement in the article, SDI is a high bandwidth digital signal. Other than for short runs, RG-6 Cable (which has been tailored for Analog signals) is NOT what is needed.
Depending on the bandwidth,a type of Digitally optimized Coax is required, with true 75 ohm low loss BNC connectors at the ends. While this cable has the same dimensions as RG-6 it’s characteristics are completely different.
Christopher A. Roberts says
Thanks Tommy!
The article was very informative. I need more advice on video equipment if you have any.. It is such a big investment to try and get into the field of professional video production, but it is worth cost when it is for His glory.
joshua says
Well for me as professoinal producer of video, HDMI is not, what I want to see in the studio or on the set. This fragile connector runs out of seat, when you just look at it, or if the cameraman pans the cam too quick.
So we are simply using the coax/triax solution for us, with good cables and BNC connectors, not only on the cameras but also on the main production switcher.
HDMI is fine for home use, in the prof sector absolutely useless.
David Hansel says
Tommy, I appreciate your advice posted July 22, 2013 in your article “HDMI vs. HD-SDI.” But, i do have a question. In the article you wrote in point 4 that “HD-SDI uses standard coax cable (RG-6).” However, on June 30, 2017 Leo St. Sauveur wrote that “Depending on the bandwidth,a type of Digitally Optimized Coax is required, with true 75 ohm low loss BNC connectors at the ends.”
In my church, we want to raise our streaming output from 720p up to 1080p. Our cameras are capable of streaming 1080p and have both HDMI and HD-SDI outputs, but we are currently using HDMI with HDMI-CAT5e converters to overcome the distance issue (150+ ft). When we move up to 1080p we want to provide a good signal path, and it’s here where I am confused about what cable to use. I read in Leo’s post that while RG-6 cable is “tailored for analog signals” and has the same physical dimensions as the digital cable “it’s characteristics are completely different.”
Leo did not provide a label, name or specs for the cable that looks like RG-6 but has different characteristics. If there is such a cable, can anyone enlighten me on the industrial name, label, or numerical code of what the cable is. I very much would like to compare that cable to the specs of the standard RG-6. Thank you to anyone who can provide an answer.
nehem says
I ever use camera that have SDI output, and i use rg6 cabel. It is work fine. If you wonder, just try it for 5 or 30 meters.
Nicholas says
where can i find a quality rg6 cable in NY?
Miguel says
What do I need to improve my video quality when I stream to Facebook, we had cameras with Hdmi and SDI output we are using SDI, we has the roland HD 50 mixer we using vMix to stream on facebook our internet uploaded signal is up to 10mps but we still don’t have that crispy image, what do you think guys we are missing. Thank you for you help.
ART DE JOSE says
I think it is just settings for live.
Make sure it’s 720p and the bitrate settings of 4000