With more organizations adopting IP-based solutions to handle video distribution, there is often confusion about the difference between AV-over-IP and IPTV technologies. This is not surprising, given that both are IP‑based video technologies with the primary goal of distributing video signals over a network to enable playback, be that external television streams, internal video streams, digital signage content, or other sources.
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Much has been said about the capabilities of AVoIP as an emerging option in recent years, while IPTV is a more established technology within the marketplace. There are, however, distinctions in the way the two technologies operate, which leads to variations in the potential costs involved in an installation, as well as the functionality available to end users. So, what are the key differences between AVoIP and IPTV, and what considerations should an integrator have in mind when specifying a system?
Compression Considerations
The network is the foundation of both systems, so the first aspect to consider is the network to be used. An IPTV signal uses roughly between 3-15 Mbps of bandwidth for a video. For reference, an HD stream uses approximately 3-6 Mbps, while a 4K stream could be in the region of roughly 15 Mbps or more.
With AVoIP signals, this is more likely to be measured in gigabits per second (Gbps), placing significantly more burden on the network. For an HD signal, it could be in the region of 800 Mbps-1 Gbps; a 4K signal could be up to 6 Gbps (or more).
As a result, an AVoIP solution requires significant bandwidth to display streams, which may overwhelm an existing network and require additional network infrastructure investment from the start. In contrast, IPTV systems can generally run on an existing network.
To counter network congestion, IPTV reduces the size of video with high levels of compression. The misnomer is that with high compression you get less quality, but there is so much information in a digital video stream that it can maintain very high quality. For example, broadcasters are compressing H.264 and MPEG-2 video over 200 times, but it is still suitable to broadcast for high-quality viewing. In many instances, there is a negligible visible impact, especially given recent advancements in compression.
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AVoIP employs very little compression—or none in some cases—which ensures a high-quality signal. Of course, this also explains why its bit rate is so high.
Playback and Latency
IPTV uses ISO industry standard formats, such as MPEG-1, MPEG-2, MPEG-4/ H.264, and HEVC, which allows playback on TVs, computers, and mobile devices. By using these industry standards, IPTV also allows the mixing and matching of products together. It’s possible to use a different manufacturer’s encoder in an IPTV system, for example, which can give integrators more flexibility.
AVoIP devices can only play on a monitor, which requires a proprietary hardware decoder with an HDMI out. And because AVoIP is proprietary, there is a tendency to be locked into a specific manufacturer, which could cause additional issues when looking to scale up a system.
However, AVoIP is known for having excellent low latency, essentially real time from encoder to decoder. With no compression, no heavy calculations must be made by the encoder and the decoder. There are some projects—such as a surgical application or competitive esports gaming—where this extremely low latency is vital to ensure exacting movements are timed with the image.
Many applications, however, suffer no issues with the minimal latency (~350ms) introduced by compression in an IPTV system. There are also IPTV solutions that deliver sub-frame latency, glass-to-glass real time, with very minimal delay.
If a facility wants to take in entertainment channels from a cable system or DirecTV, those feeds are already compressed in industry standard formats. An IPTV solution can take these feeds as they are and distribute them; all it takes is a gateway to receive and send the video out over a network. With AVoIP, a set-top box is needed that sends HDMI to an encoder in every case. All sources need to be re-encoded.
Make Your Choice
Need to record video? IPTV solutions will record in a native format, but AVoIP requires a third-party product to achieve this functionality. Plus, if a company wants to reach out to remote sites over the internet (via WAN streaming), this is not possible with AVoIP. With IPTV, as an industry standard supporting low bit rates, it’s very simple to stream to remote sites or mobile devices.
Before specifying an AVoIP solution, which can involve significant expenditure, planning, and infrastructure upgrades, it is worth looking to see if an IPTV system can fulfill the use case required. Effective IPTV solutions have been implemented in many verticals, including corporate, healthcare, transportation, education, hospitality, and sports venues.
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There are some scenarios where a zero-latency, low-compression solution is critical—and in such cases, an AVoIP solution is likely the best option. However, many installations are suited to IPTV, which offers additional benefits such as "time shifting," which allows the ability to pause streams on an individual device without pausing them across the entire network. IPTV offers further options to deliver an enhanced, customized experience for both management and end users, with the ability to stream to various devices including computer desktops, mobile devices, set-top boxes, and directly to SmartTVs.
IPTV can also be a more cost-efficient solution, with an existing IP network likely capable of handling streams, instead of requiring significant network upgrades. Choosing an experienced integrator partner with understanding of the respective technologies will help to deliver the right technology for the application at hand.
