When data flows, it is already streaming. In the context of video, this chapter deals with two specific kinds of streaming:
- Wireless transmission within a set or studio
- Live transmission over the internet
In very basic terms, this is how streaming works:
Your camera produces data. This data is encoded (transcoded or converted) into a format suitable for wireless streaming. A device capable of producing a wireless hotspot is necessary to stream this encoded video. Such a device is called a router.
The solid lines in the image are cables. A broadcast monitor usually does not have wi-fi built in, so it needs data the ‘traditional’ way, as we have already seen.
The router can route data two ways – wireless or via cables. The wireless stream is received by a device capable of wi-fi, either a receiver, a tablet, mobile or computer.
If this video stream is to be passed on to the internet, you need a modem. A modem is the gatekeeper between a device and the internet. In many ways, it is just like the encoder. Its job is to convert data into a format that the internet understands.
If you don’t need wireless, you just encode your data and then route it via a modem to the internet for live streaming.
For wireless on set, create a wi-fi hotspot or zone, and the data will be confined to this region.
Since our wireless system is confined to a limited area, our wireless system falls within the WLAN (Wireless Local Area Network) classification, under the specific standard: IEEE 802.11
Henceforth, whenever I mention ‘wireless’ I mean IEEE 802.11 and nothing else.
The main challenges of any wireless setup
Before moving on, you should be aware of the major issues regarding wireless:
- It doesn’t have the bandwidth that cables have
- The latency of wireless transmission tends to be greater than cabled transmission, all things being equal. But I feel this is a temporary problem, since radio and microwaves travel at the speed of light, while electrons are much slower!
- Maximum data rate falls with distance
- Flaky Security
As I have discussed in my post on uncompressed footage, the data rates over cables are extremely high. On the other hand, the most common wireless protocols and their maximum data rates are as follows:
- 802.11a – 54 Mbps
- 802.11b – 11 Mbps
- 802.11g – 54 Mbps
- 802.11n – 600 Mbps
- 802.11ac* – 1300 Mbps
*The current ‘king’ is 802.11n but 802.11ac routers are already out and are the future
In real-world performance, one can expect 802.11n to provide an average maximum of 300 Mbps (37.5 MB/s).
Now take a look at the data rates of the cameras in this guide, covered in the chapter on Media. How many file formats fall within the limit imposed by 802.11n?
Except for the cameras recording RAW, uncompressed and Prores 4444, all other codecs fall within this range.
What’s the catch?
The catch is, if you’re streaming wireless on a set, you want it to be real-time. This means, there’s no time for somebody to take the media out of the recorder or camera, and then put it into a reader, and then stream it.
To get real-time streaming, you’ll need to read data off the SDI, HDMI or Component ports of a camera (or recorder or external monitor looped through). Problem is, uncompressed HD-SDI is 1.5 Gbps, so there has to be a way of compressing this data in real-time (just like external recorders do), but for the specific purpose of streaming it. Enter the encoder:
For a general purpose HD-SDI or HDMI encoder+router, try the:
The Cube compresses data in the H.264 codec to up to 10 Mbps (only 5 Mbps for wi-fi) and can create a wi-fi zone with a maximum line-of-sight range of 300 feet (91 meters).
It can also record this compressed ‘proxy’ to an SD card for quick editing.
If you only want to transmit wireless data to a decoder, you could use the:
This way, an SDI monitor can be used to monitor your feed remotely. Of course, it goes without saying that the feed you’re getting is heavily compressed.
To view video off the Cube on an iPad or iPhone, you’ll need an app called TeraCentral. Unfortunately, it is only available for Apple devices.
If you want to use this with a camera like the Red Epic (with only one BNC), it might be better to get the Teradek Brik, which has an HD-SDI loop through.
Is all this in real-time? No. The latency introduced by this system is around 1/8th to 1/2 a second. If you’re shooting 24p, that’s about 3-12 frames. That’s pretty good, even for a task like focus pulling. Imagine the first AC with his or her own iPad or wireless EVF!
What if you want the absolute best? Check out the Teradek Bolt:
The Bolt is a wireless 3G-SDI system capable of sending 4:2:2 1080p60 video at up to 300ft, with zero delay. It does not encode like the Cube. What you’re getting is uncompressed monitoring.
There are more solutions out there, like the Boxx Meridian, but the Bolt really hits the sweet spot.
Cheaper alternative for DSLRs
What if you have HDMI but can’t afford a professional solution? Check this out:
Here’s a video of how this works:
However, don’t get your hopes up. HDMI is a very ‘slippery’ standard, and just because everything looks good on paper doesn’t mean it might work in practice. If you’re going this route, be ready for many hours of hacking and/or trouble shooting.
Actually this advice is applicable for any wireless solution in general. Even the most expensive solutions disappoint sometimes on the field. Unlike home wireless networks this one has to move around, sometimes in tough conditions.
We’re not there yet, technologically. I would warn anyone from relying solely on a wireless solution. Always have a backup.
Streaming live over the Internet
Streaming over the internet is a far bigger problem than streaming wireless on set. Why?
According to Akamai’s State of the Internet report for 2012, the average broadband speed of the world is 2.6 Mbps. The US averages about 6.6 Mbps. The key word here is ‘averages’.
This means that there are as many people under the average as there are over it, simply put. Even if somebody has access to an 8 Mbps broadband connection, there are times when the traffic forces the actual speed to be much lower.
For these reasons and more, I put a 1 Mbps cap on the video data rate to ensure maximum viewership. Think about this: DVD has a maximum bit rate of 9 Mbps approximately. The average is somewhere around 6 Mbps or so.
So the hard-hitting truth is, if you want maximum viewers, with no ‘buffering’ interruptions, you are not going to get DVD quality. Wait a minute. DVD is SD, not HD. 1080p under 1 Mbps? That’s tough. But it’s being done, and these challenges will be overcome as technology and broadband improves.
There are two broad ways to stream over the internet:
CDN stands for Content Delivery Network. It’s a service that holds your data and distributes it to all your viewers. Let me explain:
Your hosting provider for your website restricts the maximum file size that you can upload, or the total bandwidth that you can consume. A CDN is such a provider, but for large files. You store your large files with them, and you know many people will need access to those files at some point.
Let’s say you upload a video that is 100 MB in size. That’s about 10-15 minutes of video at 1 Mbps.
If only one other person watches your video, the bandwidth you have used is 200 MB (100 MB to upload and 100 MB for download).
What if a thousand people watched your video? The bandwidth is 100 MB + 1000 x 100 MB = about 100 GB!! Can you imagine what will happen if a million people watched your video, at the same time?
What’s your data plan per month? What’s the fair use policy of your internet provider? Do you understand now that you cannot stream video professionally on the internet from a small server via a consumer connection? You could do it to a small group, but professionally? Forget it. Your ISP and/or hosting service will shut you down.
That’s why CDNs exist, and the undisputed world leader (and not the cheapest either) is Akamai.
The parts of a DIY solution are:
Rule of thumb: The advantage of DIY is that you have total control over how your video is encoded, packaged and distributed. If you are guaranteed many consistently paying viewers or subscribers this is the way to go.
For a general encoder, try this:
For excellent software, try the world leader:
Use an OVP
OVP stands for Online Video Provider. Youtube is one, but doesn’t exclusively stream live yet. There are many vendors who offer live streaming, but the two power houses are:
For a simple encoder for basic live streaming, try this:
For a full professional setup, try this:
Rule of thumb: Use OVPs when you don’t have a good idea of how many viewers you’ll get, or if your start-up budget is low.
For low data rates, CDNs tend to be super expensive. In fact, some CDNs won’t consider your business if your data is not in the order of Terabytes per year.
Whether DIY or OVP, choose your solution wisely. It’s not easy to change midstream.
Wow, this has been a long chapter. We have covered most of the important rigs and setups, and now it is time to pack everything into bags and cases.