Networking Basics (Chapter 9)
Book
- 7 Aug, 2024
- 153 Views
- 0 Comment
The main bottleneck most IP video users confront is a limitation of bandwidth. In video production you will deal with limitations on the network infrastructure and limitations from your ISP. In remote production, you should always have an idea of the bandwidth your production requires and the headroom you are leaving for flexibility.
WAN Bandwidth Considerations
Technology Type | Typical Speed Range | Suitable Resolutions | Equipment Needed | Notes |
3G | 384 Kbps – 2 Mbps | Up to 480p | Mobile device, modem | Least reliable, phased out |
Basic DSL | 1-5 Mbps | 480p – 720p | DSL modem | Limited availability |
4G LTE | 5-30 Mbps | 720p – 1080p | Mobile device, modem | Widely available |
5G | 50 Mbps – 1 Gbps | 720p – 4K | 5G enabled devices | Widely available |
WiFi | 10-100+ Mbps | 720p – 4K | Router, wireless NIC | Subject to interference |
Ethernet | 100 Mbps – 1 Gbps | 720p – 4K | Ethernet cables, ports | Most stable connection |
Cellular Bonding | Varies | 720p – 4K | Bonding device | Enhanced reliability |
Multiple- SIM Cards | Varies | 720p – 4K | Multi-SIM device | Enhanced reliability |
Upload speeds are crucial, as they determine the resolution and stability of your remote production. Connections range from older 3G mobile data, which can handle up to 480p resolution at speeds between 384 Kbps to 2 Mbps, to modern 5G networks that boast speeds from 50 Mbps to 1 Gbps, enabling high-definition and ultra-high-definition streaming. Intermediate options like 4G LTE offer reliable 720p to 1080p streaming at 5-30 Mbps, suitable for most mobile streaming scenarios.
For fixed internet options, Ethernet provides the most stable connection with speeds typically ranging from 100 Mbps to 1 Gbps, ideal for professional setups requiring the highest video quality. WiFi, while broadly available, may suffer from interference, making it less reliable for professional uses despite supporting speeds up to 100+ Mbps. Advanced techniques like cellular bonding and routers with multiple-SIM cards enhance connectivity and failover capabilities, making them valuable for high-stakes live reporting and events where connection disruption can easily be a problem.
LAN Bandwidth Considerations
You should always have a strong understanding of the bandwidth available on your LAN. Four areas where bandwidth can be limited include the cabling you use, the networking equipment (router, switch, or wireless access point), the Network Interface Card (NIC) on your computer and the upload/download speeds from the Internet Service Provider (ISP).
Ethernet cables are at the heart of many IP-based video production systems. Ethernet cables don’t usually extend beyond 328 feet (100 meters), though they come in a variety of quality types noted below.
Category | Bandwidth |
Cat-5 | 100 Mbps |
Cat-5e | 1 Gbps |
CAT6 | 10 Gbps |
CAT7 | 10 Gbps |
CAT8 | 25 Gbps |
Most video production setups that use ethernet for video connectivity require CAT 5e cabling or greater because regular Category 5 cabling only supports up to 100 megabits per second of data transmission. CAT 5e supports a full gigabit, or 1,000 Megabits, of data transmission. Higher end CAT cabling can offer up to 25 gigabits of data per second.
Ethernet connections are easy and convenient to use for a variety of applications. For one thing, network connected devices can provide bi-directional connectivity to send and receive communication. You can also connect all the devices on your network to the internet, opening up many possibilities for connectivity around the world. Most commonly installed networking equipment supports gigabit connectivity, but higher bandwidth networking gear is becoming more common every day. Unfortunately, if you have 10/100 networking infrastructure, you will have a hard time using it for IP-based video production. There simply isn’t enough bandwidth on these older networking systems to support HD-quality video transmission.
The good news is that gigabit networking equipment has become the industry standard and there is a good chance that this is the type of technology you have already installed. A gigabit network switch with a full throughput backplane can send approximately 1,000 megabits of data to each device on your network. You should never use 100% of the available bandwidth on your network because you need to reserve “headroom” to avoid network congestion and failure. Network bandwidth headroom recommendations can vary widely but generally, most IT professionals recommend 30% to 60% depending on what the network is used for. Consult your network administrator before adding IP video traffic to your LAN. NewTek suggests NDI® traffic should not take up more than 75% of the bandwidth of any network link.
There are many different types of network switches that can support various levels of bandwidth. While gigabit is the most popular, today you can purchase a 10-gigabit ethernet switch that provides transfer speeds of 10,000 megabits per second. Access to higher bandwidth devices will become more and more common.
NDI HB | NDI HX 3 | |
Codec | SpeedHQ | AVC (H.264) and HEVC (H.265) |
Bandwidth 1080p60 | ~130Mbps | ~H.264 (62Mbps) H.265 (50 Mbps) |
Bandwidth at 4K60 | ~250Mbps | ~H.264 (110Mbps) H.265 (84 Mbps) |
Glass-to-glass latency | Very low | Very low |
Platform Integration | CPU, FPGA | CPU, GPU. FPGA |
Quality | Almost lossless | No visible compression artifacts |
Note: actual bandwidth usage may vary.
Knowing how important bandwidth is to any NDI project, it’s nice to know that you have some options to optimize bandwidth. The chart above shows the two main types of NDI video: NDI HB and NDI|HX. NDI HB is considered the full bandwidth version of NDI which can take a 3 gigabit, fully uncompressed video signal, and compress it down to 125-200 megabits without producing noticeable digital artifacting. This type of compression is what makes IP video production possible on a gigabit network infrastructure.
In most cases, the compression effect is “unnoticeable” to the human eye and seeing the video side-by-side is a worthwhile experience. The final destination for many live video sources is a content distribution network like Facebook and YouTube. Therefore, many users already plan to compress the entire video stream with Real Time Messaging Protocol (RTMP) or Secure Reliable Transport (SRT) before it reaches viewers.
To further advance what’s possible with IP-based video production, NDI released the “High Efficiency” version of NDI called “NDI|HX.” This version of NDI can compress a 1080p video source down to a mere 12-50 Mbps depending on the quality selected. NDI|HX is available in compression ratios of low, medium, high, and ultra depending on the source. All NDI sources include a “low bandwidth” option that is available in most NDI compatible software and hardware solutions.
Computers’ with limited bandwidth or processing capabilities can quickly connect to NDI sources in low bandwidth mode. This is easily accomplished in most video production software solutions that support NDI. For example, when you add an NDI input in OBS, you get the option for “Highest” or “Lowest” bandwidth. Inside of vMix, you can switch to low bandwidth mode by right clicking the input. In fact, vMix allows you to discover NDI|HX sources and swap them on the fly. This is a great way for producers to conserve bandwidth and computer performance and connect to new sources on the network.
Pro Tip: Make sure to clearly name each unique NDI video source on your network. When you are reading through a list of NDI sources it is helpful to have groups of sources organized into categories. When you create NDI groups, each source will be nested inside of an organizational group which is discoverable in the network.
As you can see, there is a big difference between using NDI HB and NDI|HX sources on a network. While each NDI source will take up available bandwidth when it is used, NDI sources that are not in use will not take up any bandwidth. Therefore, you can think about NDI video sources like sockets that you can connect to at any time. When you connect to an NDI source, you are adding bandwidth through the computer’s incoming Network Interface Card (NIC).
To visualize this idea on a Windows computer, open your computer’s Task Manager and look at the network utilization percentages for each process on your computer. Look at Activity Manager on a Mac computer to do the same thing. In Task Manager, there is a column that shows the network usage for the computer’s NIC. There is also a “Performance” view to see bandwidth usage on a chart as shown below.
The table below shows a common NDI® video use case. In this example, you will get a sense of how bandwidth accumulates in an NDI® production environment.
Example:
NDI Device Examples (1080p60fps) | Bandwidth | Accumulated Bandwidth | Total % of Gigabit Network Switch |
NDI Screen Capture on Laptop for PowerPoint slides | 125 Mbps | 125 Mbps | 12.5% |
2 x NDI Monitors for camera operators | 125 Mbps / Each | 375 Mbps | 12.5% / Each |
vMix System output in 1080p60fps | 125 Mbps | 500 Mbps | 12.5% |
NDI Monitor in Overflow Room | 125 Mbps | 625 Mbps | 12.5% |
5 x PTZOptics NDI|HX (High) | 12 Mbps / Each | 685 Mbps | 1.2% / Each |
Suggested Headroom | 250 Mbps | 910 Mbps | 25% |
Total Usage | 91% |
As you can see, the bandwidth required for IP video projects easily adds up. Because networking equipment is so much more affordable than traditional switching hardware, many NDI® users find themselves building networks for video production.
This situation underscores the importance of understanding network backplanes. A network backplane refers to the internal data-handling capacity of a network switch, which is crucial for managing the total volume of traffic generated by all connected devices. When multiple high-bandwidth devices, such as NDI cameras and monitors, are in use, a switch with a higher backplane capacity, like 10G (Gigabits), can handle the aggregated data flow without causing bottlenecks or performance issues, especially as you get closer to the network switch bandwidth limit.
The bandwidth usage for devices like NDI cameras and monitors can quickly saturate a network. To prevent this, it’s essential to factor in not just the internal traffic but also any external connections, such as internet access for systems like vMix. By doing so, network designers can ensure that the overall network remains robust, reliable, and capable of supporting both current and future demands.
The diagram above shows how your computer is connected to your local area network. Each device connected to the LAN can request and receive information from the internet through your router. Until NDI® 5.0, almost all NDI® video traffic happened inside of the LAN. Today, NDI® Bridge and NDI® Connect allow you to securely connect with video sources outside of your LAN.
In order to live stream from inside a LAN, computers use upload bandwidth to stream video to a Content Delivery Network (CDN) such as Facebook. Once the live stream is hosted by a CDN, your computer can use download bandwidth to preview the live stream and view comments from live viewers. Video production software running on your computer like OBS or vMix can connect to multiple NDI® sources on your LAN and then uses those sources to produce a live stream which goes out to the world using RTMP. RTMP is the primary protocol used for encoding video sent over the public internet to CDNs like YouTube.
Once your local area network is set up the way you want it, transitioning to the cloud can be very easy. In the diagram above, you can see that Hive Studio is set up at a remote location to control the cameras on a LAN. Two PTZ cameras are connected directly to the existing production PC and one camera is connected directly to the remote computer over the internet. Hive-Linked cameras are capable of direct connection without the need for a computer to connect the sources to the cloud.
In this diagram, the far end is outputting NDI video to a vMix computer. In this scenario, the Hive Studio is providing remote camera control, color correction and system management, while the vMix computer is using the video sources for video switching and graphics. The vMix computer in this instance, will receive the NDI video sources from the Hive Studio computer on the remote network. Hive works as a bridge between the networks providing additional remote production features.
One of the nice features of the cloud is the ability to connect to multiple studios from around the world. In this diagram, a single remote computer can manage multiple studios connected through the internet. You may also have a single production studio with multiple remote operators located around the world. Remote production allows you to be creative, flexible and cost-effective as you construct new workflows that can adapt to the specific needs of your project.
KEY TAKEAWAYS FROM THIS CHAPTER:
- Bandwidth Limitations: The primary bottleneck in IP video production is bandwidth limitation, which can arise from both the network infrastructure and the Internet Service Provider (ISP). Understanding the bandwidth requirements of your production and ensuring sufficient flexibility is crucial.
- NDI Technology: NDI HB (High Bandwidth): Supports compression of a fully uncompressed 3-gigabit video signal to 125-200 megabits, facilitating HD video production on gigabit networks. NDI|HX (High Efficiency): Allows further compression of 1080p video down to 8-50 Mbps, suitable for varying quality needs and available in multiple compression ratios.
- Monitoring Network Usage: Tools like Windows Task Manager and macOS Activity Monitor can be used to monitor network utilization, helping manage and optimize network performance for video production.
- Live Streaming Setup: Video production software like OBS or vMix can connect to NDI sources within a LAN and use RTMP to stream video to CDNs like YouTube and Facebook, leveraging both upload and download bandwidth effectively.
- Cloud Integration: Cloud-based systems allow connecting multiple studios globally, enhancing the capability to manage and operate remote productions across different locations. This supports a flexible, creative, and cost-effective approach to constructing new workflows tailored to specific project needs.
