Be sure to get the guide “Internet Distribution with SRT: A Long Extension Cable for Your ASI”

Steve:

Welcome everybody. Glad you’re here. If the high cost of fiber, or satellite, or line-of-sight requirements of microwave are causing you challenges in getting your stream from A to B, you’re in the right place. Today you’ll find out about using SRT for different applications, such as Studio Link, both distribution and contribution, and even repurchasing old equipment, if laying around, which you’re no longer using.

Steve:

But we do encourage you to enter any questions you have in the chat box. And at the end, we’ll have a Q and A session where we’ll go over those. So let’s get started. I’m Steve Doll, I’m the president of D2D Technologies, and I’m here today with two colleagues, Jessica Kelly, director of Business Development.

Jessica:

Hi everybody. Hi, Steve. I’m really happy to be here.

Steve:

And also, I have with us Jon Kipp, who’s the Broadcast Sales manager at Toner Cable. Hi, Jon, how are you doing?

Steve:

Okay. For some of you who may not be that familiar with SRT, I just want to spend a few minutes to just give a little background down for you before we start getting into some use cases. SRT stands for Secure Reliable Transport. It was developed by HAIVISION a few years ago, a while back before that, but a few years ago, they open-sourced it. D2D was actually one of the first companies to integrate it into our systems back in 2018, so we’ve been doing this for quite a while. And over time, it’s actually become widely adopted to the point now that HAIVISION’s actually actively working with the IETF, which is the standard’s committee for the internet. So, this will soon become an actual official internet standard.

Steve:

To go over a couple of the key features of SRT. One, it’s secure. So, you can use AES encryption to help encrypt your content as it’s going over the public internet. It’s also very reliable. Now this will be very much an oversimplification, but in a nutshell, what it’s basically doing is, on the receive site, there is a buffer. And that buffer allows enough time that if a packet doesn’t make it, the receive site can re-request it. In that way, it can arrive before the buffer drains out, so you don’t have any loss of video. Now that you have a little bit of understanding what SRT is let’s start getting to some of those use cases. One of the most common applications we receive from customers on SRT is for Studio Transmitter Link.

Steve:

And some of the reasons they have is, they don’t want to pay the high cost of fiber, they don’t have line-of-sight to use a microwave link so, SRT makes a great application for that. It reminds me of a couple of years ago, at NAB we had this station engineer who came up to Jessica, really excited like, “SRT, it saved my station.” If you can tell us about that, Jessica.

Jessica:

You’re talking about Ravi. Ravi came up to me and he hugged me at NAB. And I didn’t really know who the guy was because I talked to him on the phone a lot. But he came up, and he’s like, “Jessica, Oh my God. You saved my station because we had the transmitter signal from our studio to our transmitter.” And, he was struggling.

Jessica:

They were doing their best to get up on the air, and he couldn’t afford microwave. It was actually in San Francisco with Diya TV. They couldn’t get a microwave link, and so they were using the old style COP 3 SMPTE 2022 Forward Error Correction, and it just wasn’t doing the job. It just was dropping out, and he was losing all of his viewers. So I talked to him on the phone, and we sent him a couple of boxes, and sure enough, he was up on the air flawlessly. Since then, he’s expanded to six or seven different markets and bought a bunch more, and so those use cases are getting really common. Yeah. He was really happy.

Steve:

That’s great. And I think then Jon, you have a customer as well, who was using it.

Jon:

I do, thank you. Yes. Very similar story and ease of use is right. So I got a call from Bern, and he’s in his truck, and he’s driving up the side of the mountain. And every time I talk to this guy, he’s in his truck driving up the side of the mountain. He’s not an engineer, but he has a translator site, and he needs to get his information to the translator site. And so I said, “Well, I know just the thing.” And so we talked to Jessica and she said, “Yeah, okay. We’ll, send out two boxes, and we’ll get you hooked up.” And of course, he had one more thing that he needed to do; I’m sure you could talk more about that later, but basically end-to-end, he was set up. He could transmit into the next footprint, and also you enabled him the ability to change some of the PSIP information. So it wasn’t just that SRT connection, but it was a little bit more.

Steve:

Correct, we actually can do that once we get it from point A to point B. If, for some reason, point B it’s a different geographical location, if you change your major or minor number of your channel call letters, any of that information we can change before we pass it on to the downstream equipment. So there’s a couple of great uses of using SRT as a Studio Transmitter Linking. It’s a good way to get away from the high cost of fiber or if you’ve run into issues with line-of-sight with microwave. Another great application, we come across is for more of a distribution application for hub-and-spoke where you have content you want to distribute it to multiple places across the country, or even across the globe. We have a recent customer that came up who wanted to do that, Global Bible Network. Can you tell us about that, Jessica?

Jessica:

Oh yeah. Steve Aldrich. He’s a great use case. He wanted to send up… They were just a small little network, and they wanted to send out their message to everywhere in the U S., And so it was really great for Steve because all he had to do basically is he got… One of the units is a hub, and then he programmed all the other ones, they could do DHCP. So he was able just set all of his spokes up at Home or at the Library there, and then just mail out the Flex-3000 boxes already set up. And so the customers were able to just take the box, plug it into the wall, into the ethernet and then come out ASI and then go on the air with Global Bible Network’s message. And it was really, really a great scenario. And Steve loves us. He keeps buying them. They’re great.

Steve:

Yeah. That’s a great thing to point out there where you can set up the DHCP or CHP and have everything pre-configured so that when each end of the spoke receives their unit, they basically plug it in, it automatically connects, and they’re immediately on the air with getting ASI across the public internet. I think Jon, one time you had the reverse, instead of hub-the-spoke, it was more of a contribution application where it was going spoke-the-hub. Can you tell us about that?

Jon:

Exactly. Our friend, Kevin, had a really unique set up where he needs to come almost the reverse of the image there. So we’re coming from the transmit sites, and we’re doing competence monitoring, but to bring back those signals from different geographical locations like that, it’s really expensive to do unless you can use the public internet. So, this was a perfect situation. I wasn’t sure at first when we first started talking about it that you guys could do that, and was happy to find out that on the receiving end, instead of having to have a one-to-one relationship, you actually have a server that can receive multiple streams coming in at the same time. So that’s what they were able to do. They were able to do confidence monitoring by sending their receive signal over the public internet back to the hub.

Jessica:

Great. So they were just using SRT to basically make sure they’re on the air and have confidence and QC that everything was good. So basically it was like the drawing, they just reversed the arrows.

Jon:

Exactly.

Steve:

It does make a great return path just to give you that confidence that yes, you are the… Whether it was something else, like microwave or fiber that you do have that confidence return path to let you know that it is getting out to the transmitter.

Jessica:

Brilliant.

Jon:

And the great thing about it is the distance doesn’t really matter. So for anybody that’s running… As we know engineers that are responsible for a state, they could absolutely use this at all of their transmit sites and then centrally be able to tell with confidence, “Hey, yes, I am on the air over there.” And to save in bandwidth, they could even use one of the sub channels to do so. So you’re not bringing the whole pipe. You just need to see one. And this is a great way to do it. It lowers the cost by using the public internet.

Jessica:

Right. Good point, Jon. Yeah,

Steve:

Pretty great. There’s a couple great ways of using SRT, both in hub-and-spoke or spoke-the-hub for distribution or contribution, and it’s a much more cost effective way for distribution than using the more previous standard of satellite, which can get very expensive. This can really reduce your operating costs by going to an SRT distribution. One more use case we want to go over. And this one’s a bonus. It’s two in one. One, it’s a contribution, but also they had this really cool way where they’re able to reuse all the equipment they just had laying around, didn’t use any more. They thought it was basically useless or probably going to get rid of it in the near future, and SRT allowed them to reuse it. If you can tell us about that, Jessica.

Jessica:

Yeah, absolutely. This was one station. Actually, there’s been a couple, but it came about when a guy says, “Hey, I can use my satellite receivers, which are no longer being used anymore,” basically any IRD that has an ASIN, because it’s already gen-locked into the station. Audio and video is already plumbed into the production switcher and into audio and everything else. So basically his satellite receiver became an SRT receiver. And what he wanted to do was set up a remote studio at a newspaper. And they wanted to do live shots every day from the newspaper back to the station and they were tired of live shots looking like this and everything else. So he was able to use SRT to go from the newspaper, from his little home studio, from the newspaper studio back to the station. They could put them on the air and it doesn’t look like a Zoom call. It looks really professional, and it’s broadcast quality. It’s like a long extension cable for your ASI. And so now they’re using those all over Chicago to do live inserts, and it’s really taken off.

Steve:

Okay, great. So we’ve spend some time here going over some great applications for SRT, including Studio Transmitter Link. It’s not just from the studio to the transmitter, we have a lot of customers who are using it from the studio to maybe a regional cable head-end that they want to send it to. So there’s more plays anywhere you want to go point to point over distance. It works as a great application. Also it has distribution, contribution and hub-and-spoke type applications, and also allowing you to take some of that old equipment laying around and be able to take that over the IP, convert it to ASI and send it into things like a satellite IRD you may have there laying around that you can reuse.

Steve:

So now we’ve gone over that and I think it’s the time now we can get on to some of these questions that people have. And as I was saying before, feel free. If you have any questions, you have the chat box there, just feel free to put them in and we’ll just start answering them as we go. We’ll just keep answering until all the questions have been answered to everybody’s satisfaction. So let’s get started.

Jessica:

Let’s see, we got one. Okay. So we’ve got a question here. Typically, what’s the overhead? So if I want to send a 10 megabit signal across the internet, an HD live shot, how much extra bandwidth do I need? Well, that’s one of the questions.

Steve:

It can definitely be network dependent. But typically it runs about 25% is the rule of thumb. So if you have a 10 megabyte streaming, you go about 12 and a half, and if you have a full ATFC stream at 19 4, your base want to go somewhere in the 23, 24 megabit range is a good rule of thumb.

Jessica:

Yeah. Okay. Yeah. That’s a good one. Let’s see if we got any other questions. So they want to know, another good question. Can they max in some streams at the other end? So if they’re going from station to transmitter, can they take it in like a sidelight feed at the end of the red, box them in and rebrand them and put them out over the air, just for that particular translator?

Steve:

Sure. Yes. The flux bands are capable at their full multiplexer. So when the stream comes in, you can max another existing ASI streams, IP streams already have there, at the facility or at the tower, wherever the devices are at. And so then we can do all the table manipulation, create new PMTs, tables for all the new programs so you get a full multi-program transport stream, at least. So you can basically pick and choose which programs from each input that you want to put on to the final output.

Jessica:

Brilliant. Let’s see. Let me throw a skull through here, a couple more. Oh, here’s a good one. What’s the latency? Is it good enough for contribution?

Steve:

Yes, it’s definitely good enough for contribution. Once again, similar to the overhead, it’s very network dependent. But if you have a good solid network, it’s typically in the order of 3-400 milliseconds on the overhead. And a good rule of thumb is basically do a ping test. You would actually see in our Standard’s Panel, when we’re on a connection, we’ll actually show the roundtrip time, which is basically the equivalent of ping. And if you basically go about four times that amount and you set that for your buffer, which is basically how long your rates will be, so that’s how long it’s going to buffer for. So if you have your ping time’s say 60 milliseconds, so if you put about 250 milliseconds for your buffer size, that’s also is going to be about the time of your latency.

Jessica:

That’s crazy. That’s really good latency. You got to figure, nowadays people are using banded cellular for live shots. And that can run in seconds, like four or five seconds in some cases. I’ve seen it run up as high as 20 seconds, which is really awkward on air. This is almost as good as a microwave shot, a Marty shot, which is just outstanding. That is good enough for contribution. That’s even better than Zoom, for that matter. Yeah. That’s a great question. Can the units go bi-directional? In other words, can it go in two different ways?

Steve:

Correct. That is possible that you can. Because then you can have the… Some way it’s similar to what Jon’s application earlier, where they’re using SRT as the confidence back haul. You can actually use SRT both directions and send it on SRT then also still come back with a confidence return just to make sure it is making the full round trip. And that you are all on the air at the transmitter site.

Jon:

I have a question regarding that.

Steve:

Sure.

Jon:

So the overhead in that scenario, is that just additive? So if it was about 25% more for single way, is it the same number or does it curve off?

Steve:

Is that on the bi-directional?

Jon:

Mm-hmm (affirmative).

Steve:

You’d need that overhead both ways, to both ends maybe to be re-requesting packet. So you would need that. So you’d take your… Say you had a 10 megabit stream going each way, that’d be a total of 20. So you still need about 25% on top of that.

Jon:

Okay.

Jessica:

Oh, okay. Yeah. That’s good to know. Another question here. We’ve got, do you need an encoder and a decoder for this setup?

Steve:

Actually, no, you don’t. We’re actually ex… So basically in a typical application, we would take the output of the encoder, say an ASI encoder would feed into a D2 Flex gateway at the studio, then we send out over IP. Then when it gets to the far end, we would take that IP and send it back out to ASI then you might have a decoder there that you want to decode it before you display it or what you want to do. So basically the encoders and decoders are on either end of us. And we sit in the middle, creating that public internet pipe to get you between the encoder and decoder, if they’re at two different locations.

Jessica:

It’s probably worthwhile to clarify though that we don’t do base band, you have to already be encoded. We can’t put HDMI or SDSC or HD-SDI into our unit. So you do need an encoder and decoder at the other end. Think of it like a long extension cable for your ASI.

Steve:

Correct. So it is true that you don’t need for this specific SRT, but at some point for us to feed into our box, it does need to be encoded first and decoded downstream. The flex system itself does not encode or decrease.

Jessica:

Yep. That was a good question. Jon-

Jon:

Michael Lloyd has a question. Michael Lloyd’s asking if we have a CATV headend where we had successful applications for receiving local broadcast via antenna, and then going SRT to another headend. And yeah, we were talking about that a little bit earlier in the scenario where it was spoke-the-hub. Mike, that’s exactly what they were doing. It’s good to see you on here by the way, Mike. And so they were receiving different transmit sites with an antenna coming down and to a digital tuner and then handing off ASI, I think all of them, but it could hand off IP as well into the DTD box and then SRT back.

Jessica:

Great question.

Steve:

Okay, lets see. If there’s any more questions. One just came in. “So does it have to be ASI or can I just take TSO IP on one side and ASI out on the other or just TOS IP TOS IP?”

Steve:

Correct. It can be TSO IP. So it doesn’t have to be ASI coming in or ASI going out. We can take just regular TSO IP, going around the plant, send it to the flex. We patch it up for SRT, send it across the public internet. But the other end where you receive an SRT, we can then output it either as ASI or back to just a regular TSO IP.

Jessica:

Great. Yep. Cool. Did you see one, Steve?

Steve:

I just saw another one here that somebody’s asking about redundancy. So that’s something we’re actually working on now, and we should have come out here shortly in our new release where what this will do, there’s a couple of different flavors of it. So it’s worked really well if you had two different ISP. So let’s say at your station, you have a full bar Comcast connection and 80 and DNT connection to the box and basically send the stream out over Bolt. And then the Receive unit will receive both, and if one goes down, it’ll automatically switch. And depending on which one you do, it could be seamless announcing list. There’s two different methods of doing it. One is based on the SMPTE 2022-7 Hitless Redundancy from the [Cap in 00:19:59] cap through standard. What this does is that the band basically sends both programs all the time, and then we’ll just automatically switch over with no hits from one to the other.

Steve:

Now the one downside of that is double the bandwidth. So if you’re sending a full ATSE transport stream at 19.4 megabits, it’s basically going to duplicate it. So you’re looking about 40 megabits. So you do need to make sure you have enough bandwidth. And the other way of doing this is, it’ll set up both routes but only send on one. So the other one will be ready to go, so it can switch on an instant. And that one, you have a couple of options, really disciplines on how big you want to make the receive buffer for your latency. If you’re okay with a longer latency, versus if you have a shorter latency, you could have a breakup, when it goes to Switch, because you may not have enough time to switch it over.

Jessica:

All right’

Steve:

If you do, but it would be a brief sub second, you may see some breakup on the screen, you wouldn’t actually lose your total video. It’d be very brief. Or if you’re okay with having a longer latency, maybe a second or two, you can increase that latency, and that’ll give it enough time that it can switch over to the other one without taking any hits on there.

Jessica:

That’s great because having options for redundancy is a great thing. No two redundancy scenarios are the same. Some people want an instant seamless switch, and other people don’t really care, as long as you don’t go dark. So it’s great to have those options. It’s fantastic.

Steve:

Okay. I agree. And when I was thinking about doubling the bandwidth of that 40 megabits. One thing, it’s always good to check. When you’re good to do SRT is that you do have the, especially the uplink band with Google running the stations and your different customers will have 50 megabits down, but they only have 10, 50 megabits up and they’re trying to send a full transport stream in, and that’s just not going to work. So you need to make sure, especially that you do have enough bandwidth on the uplink side because a lot of times people have a lot more downlink than uplink,

Jessica:

Great point. I had a customer the other day that called me. He goes, “I’m taking hits and I’ve been arguing with the cable company and it turns out…” He’s like, “I’m doing a speed test and I’m getting like 50 megabits down.” I said, “Oh yeah, check your uplink.” And sure enough, his uplink was throttling and that’s quite honestly, some of the biggest caveat, it’s getting the uplink speed. And if you have that, SRT works amazing. That’s a good point.

Jon:

So Derek Freeman has a question. Did you see that, Steve? It just came-

Jessica:

Oh sure, I’m just going to look at that and see… In that case, I guess an example, we were talking earlier where we’re rebuilding the tables, I guess it was flexing multiple streams together. He’s asking about PSIP information can be manipulated in the Flex-3000 locally. That’s a great question. That’s just two. As far as PSIP, there are two different kinds of services. The Static, it’ll definitely do the static where whatever programs you take from the different inputs and combine to the output, it’ll create your PMT or your path for that specific stream and allow you to go in and set your major, minor numbers, all that information. But in addition to that, we also do the dynamic PSIP, which is your channel guide information. So once we have your new customized, tailored, output stream made up of components of your input, we also work with Titan TV, Grace Note, and recently it was DSI. Is it Digital …?

Jessica:

Display Systems. Display Systems International, yeah.

Steve:

There’s another one where we’ve just start about operating with. So any of those, if you have an account there, you just plug your credentials into the unit and it’ll just automatically pull your schedules down every day and create all your chunk and information as well.

Jessica:

Yeah, that makes PSIP easy. There’s a lot of advantages to having your PSIP downstream before your transmitter and after your encoder, because number one, you don’t need a $60,000 encoder to put in PSIP. Number two, if it dies, you could put any encoder in there. And the other one is, if your encoder goes off the air for some reason, you’re still a placeholder for your station. So you might be black but at least, your station isn’t gone completely. So there’s some serious advantages to using us for PSIP as well and that’s probably a whole different webinar.

Steve:

Yeah. So flip for that one, coming in the near future.

Jessica:

I had one more question in here. Let me see. Oh, can SRT go multi point? In other words, like we talked about doing the spoken-and-hub, is it a different stream every time or is it multicast?

Steve:

Correct. It is a different stream each time. So the multicast is, different routers will quickly shut down a multicast before it can get out onto the open internet. So, it does require. So if you are doing a hub-and-spoke type application, so that one we were discussing with Global Bible Network where they’re going from the hub into, I think they’re up to like 22, 23 spokes, it is really… I think they’re just sending a single program and I think maybe five megabits, but that is really going to be five times 23 is the total bandwidth that’s going to use up. Because each one, even though it’s one piece of equipment creating all the different routes, it is still separate bandwidth for each one.

Jessica:

Right? Yeah. That’s a good point because the way that SRT works is point to point. So that way the packets… If for instance, packet number 500 is missing, it has to go back and ask for that packet again. And that’s what makes us so resilient is, each location is its own buffer base. So, to set it multicast would just clog up networks. So point to point is really the best thing, also it makes it more secure. But it’s a good question.

Steve:

Great. Do we have…? Looks like that’s all we have here. So here’s your last chance. If anybody has a question, if you want to go ahead and type it in here and we’ll give you a minute or so…

Jessica:

And if not, I’m not calling anyone.

Steve:

Yeah, definitely. Feel free to contact us anytime. You have myself, Jessica, Jon, any of us are always available if you have any additional questions or if anybody wants to schedule a one-on-one demo or if you even want to demo our pair, we have a very good demo policy. Just order it on a 30 day money back guarantee. So if you want to test out, we send a pair out to you, test it out in 30 days, either sending in as fax or sent us a check, preferably a check, but… But there has definitely been situations where the network just has not been stable enough. Somebody trying to put it up on a mountain somewhere and the network’s constantly going up and down and they’re just… You’re just not going to make it work over the public internet. And so in that case, if it doesn’t work. No problem. Just send it back to us.

Jessica:

Yeah. I won’t even bill you for a month. I trust you.

Jon:

So for mobile applications, once you’re set up with DHCP and you have your SRT requirements placed in a box, can you just send that box anywhere? Does it matter anymore? Or do you have to do anything more to it than that?

Jessica:

Now you could stick a FedEx label on and send it, and then you could get the box. I could hand it to you. And all you have to do is you basically just plug it into the wall.

Steve:

It depends a little bit how you configure it, if you configure out in Default way, so there’s… In any case, one of the systems will be a listener and one will be a caller. And the way we typically default set them up is the Send unit is the listener and the receiving is the caller. So there’s space and think of it as a client server where you show the recipients of the client, and it’s calling into the servers, requesting the stream. What’s really nice about this, especially for a hub-and-spoke… So how you configure it, basically on the listener side, it’s just listening on a UDP port coming in on the network. And then on each receive site, you basically put in that port number and wherever the signal’s coming from, that location’s public internet facing LAN address. And then it requires you to put a port forwarding on the Send side so that when the calls come in, it knows to forward that port on to a particular IP address within the lab which is IP address of the Send unit.

Steve:

But what’s nice since they’re all calling into that public address, as Global Bible Network did, if everything would be pre-configured, you already know the port number, you already have the address, you’ve plugged it in, set it up for DHCP. So then you just slide things out all across the country. Each station receives it, plugs it in. It connects, starts pulling the stream, just take it out ASI or IP into whatever downstream device you need to go to.

Steve:

I think we’ve lost your audio there, Jessica.

Steve:

Did you come unplugged?

Steve:

Somehow we’ve lost your audio, but I think we’re getting closer to being about done here. I haven’t seen any additional questions come in. So I guess at this point, we’ll go ahead and wrap it up and say, if anybody has got any questions, we’re always available. Feel free to contact us and hope you’ve enjoyed learning about all these different ways to use SRT from Studio Transfer Links, contribution, distribution, repurchasing old equipment. And once again, thanks for joining us and have a great day.

Jon:

Thank you, Steve.

Jessica:

Thanks guys.

Jon:

Goodbye everyone.

Steve:

Oh, you’re back.

Jon:

Thanks you, Jessica.

Steve:

All right. Have a good day, everybody.

Jessica:

Bye-bye.