VTC software continues to evolve as computing capabilities increase, high-speed connectivity is made more readily available, and standards for compressing, transmitting, and decoding video improve. Through this evolution, however, several marked differences between products have arisen that drastically impact how products can be used. There are numerous trade-offs that must be considered when implementing software-based videoconferencing solutions.
As healthcare providers have become increasingly comfortable with telemedicine in general and video teleconferencing solutions particularly, they have become interested in seeing solutions that are available anytime, anywhere, without being limited to a physical location or a particular network. It is important to strike a balance between the interests of the clinical users and the capabilities of the products.
- Defining the Terms
- An Introduction to Standards-Based Videoconferencing Technology
- An Introduction to Consumer-Grade Videoconferencing Technology
- An Introduction to “Hybrid” Videoconferencing Technology
- A Note on Webcams
- Summary
Defining the Terms
This toolkit defines videoconferencing software as an application that supports real-time audio-video communication and operates on a personal computer or mobile device, though there are further distinctions that are made for the purpose of this publication.
What Videoconferencing Software Is
Videoconferencing software includes standards-based applications, referring to those that can communicate with existing videoconferencing endpoints and other videoconferencing systems that use standards defined by the ITU (International Telecommunications Union), their standardization sector (ITU-T), and other standards-issuing bodies. These standards are open (meaning non-proprietary), and can be used to facilitate communication between products from different manufacturers.
Videoconferencing software also includes consumer-grade applications, referring to those that only communicate through consumer-grade networks (the internet), with connections only available between personal computers that are running the manufacturer’s software. These applications may follow some standards, but do not support the range of ITU-T standards that would allow a full audio-video conference with another manufacturer’s videoconferencing product. The protocols used to communicate between these software clients are mostly closed (meaning proprietary). Servers and computers that facilitate communication between consumer-grade clients are controlled by the manufacturer.
A third set of applications has gained more traction within the videoconferencing market, bridging the lower price point and the distributed infrastructure of consumer-oriented systems with the interoperability of standards-based systems. These products, typically based “in the cloud,” are referred to as hybrid systems here for the sake of discussion.
What Videoconferencing Software Is Not
To further clarify what this section is addressing, it is important to define what is not covered. Web-based video applications are beyond the scope of this toolkit. This includes webinar software, which is often used to host online meetings and presentations, as well as the browser-based interfaces, and some of the newer, untested implementations of the nascent WebRTC standards. Also beyond the scope of this particular discussion are the various hardware-based endpoints, which are discussed in more detail in the Videoconferencing Overview. Some manufacturers provide all-in-one units that have built-in cameras and conferencing capabilities. These are condensed versions of traditional room-based hardware codecs, and are not meant to be a part of this discussion on videoconferencing software.
An Introduction to Standards-Based Videoconferencing Technology
The term ‘standards-based’ can be a loaded one when used to define a category of videoconferencing systems. If you look at a product sheet for any of the videoconferencing systems, you will see a veritable alphabet soup: E.164, G.711, G.722, H.263, H.264, H.323, SIP, CIF, VGA, QVGA; the list goes on. Further complicating the issue is the fact that some consumer-grade products support a handful of these standards.
To loosely define an application that garners the distinction of being standards-based, it is important to look at whether or not the system can communicate with other existing VTC equipment. Systems that cannot communicate with other VTC products with both audio and video are not considered to be standards-based and, aside from one special case, fall under the category of a consumer-grade system. An additional discussion on this topic can be found in the Standards section of this toolkit.
Overview of Standards-Based Videoconferencing Technology Infrastructure
While each standards-based vendor has its own specific hardware requirements to enable communication with other systems, and while they may implement different combinations or variations of the standards, there are several key functional components shared between the vendors. The following section describes what these parts are, and how they work together. Please see the review of individual manufacturers for exact product descriptions and requirements.
Starting with the end-user, the standards-based VTC system contains a client application. This is a piece of software that must be installed on the user’s computer. The software will be configured to communicate with a centralized computer, or gatekeeper. Users will log in to their client software, and the gatekeeper will ensure that their logon credentials are valid.
The gatekeeper, as mentioned above, authenticates users. It is also responsible for managing connections to other users’ client applications, hardware-based endpoints, and other connections within the system. These devices limit how many active video connections can be maintained at any given time.
For users connecting from a location outside of their organization’s network, such as a home or remote office, an intermediary device is often required. This device is called a proxy. It sits on the “edge” of a network, outside of the firewall and exposed to the internet. This device routes calls through the firewall and to the gatekeeper, allowing a user to connect to the video system as easily as if they were within the network.
Note that it is also possible to create a virtual private network (VPN) connection, bypassing the need to use a proxy device. The VPN option may result in performance concerns, and can add a layer of complexity when handling outside connections. This may be problematic, especially if people who do not already have network credentials need to access the videoconferencing system, such as patients or consulting physicians from another organization.
With these basic components, many systems can support in-network videoconferencing. A room-based device can communicate with a user at home, software clients can communicate with one another, and other basic needs are met.
To be able to communicate with other networks and video systems, or to be able to communicate with different manufacturers’ infrastructure within a single network (such as a new software system from Manufacturer A to a legacy room-based system from manufacturer B), additional devices are needed. These devices, called gateways, help to translate between different communication standards and video formats. These gateways can help connect calls from SIP to H.323 systems, or transcode (convert) from an H.264 SVC video stream to straight H.264.
The infrastructure described so far will only allow point-to-point communication in most manufacturers’ systems. To support multiple simultaneous users in the same video conference, a bridge is required. Note that bridges are sometimes called multipoint control units (MCU). This device manages connection speeds to each different end-point, sending the amount of video data that can be supported. Some configurations may show all “bridged” conference attendees on one screen, while others may show only the active speaker.
Most of these systems will support content sharing with others engaged in the video conference, which means that applications and documents can be viewed within a conference session. Additionally, features such as instant messaging, contact list management, and other communication tools are included with the infrastructure described above.
Other devices can be a part of the video infrastructure, such as recording and streaming devices that capture and play back video conferences, but they are not required to support basic videoconferencing needs and videoconferencing software systems.
It is important to note that the various components of a standards-based videoconferencing system do not necessarily need to be housed, hosted, and supported within an organization choosing to utilize standards-based videoconferencing. Numerous service providers offer to manage VTC systems, requiring organizations to make a decision based on various trade-offs between control, cost, and support.
An Introduction to Consumer-Grade Videoconferencing Technology
Using the term ‘consumer-grade’ to describe software for videoconferencing can be, as with ‘standards-based’, a contentious issue. In this particular context, ‘consumer-grade’ reflects the fact that video traffic is transmitted over the internet, that the products do not openly communicate with other systems, and that they neither require nor allow the installation of organizationally-managed infrastructure devices within the end-user’s network.
“Consumer-grade videoconferencing” is not a reflection on the appropriateness of the technology for use in healthcare, but an acknowledgement of the different way in which these products operate. Consumer-grade videoconferencing products may use various standards in their operation. Depending on the manufacturer, these may include encryption standards for protecting calls, the H.264 video standard for encoding and decoding, SIP for managing voice-only calls, or various text- and file-transfer standards for transmitting instant messages and documents.
Overview of Consumer-Grade Desktop Videoconferencing Infrastructure
Not all consumer-grade videoconferencing software operates in the same way. As these are closed, proprietary systems, the exact inner-workings of their infrastructure are not always clear. That said, there are several features that each product has in place to initiate and control video calls between client applications.
As can be seen in the diagram above, the components required to support consumer videoconferencing software are significantly reduced in comparison to the standards-based systems.
The client application is installed on the end-user’s computer. It is preconfigured to communicate with a central server that is managed by the manufacturer of the software. The end-user has control of various features, such as the logging of instant messages, call records, and which users of the manufacturer’s software can be contacted, including those who are outside of an organizations network of preferred providers and users.
The client application communicates with a centralized authentication server. This requires communication with an internet-based service that is hosted by the manufacturer of the product. As these are not a part of an organization’s own infrastructure and network, they cannot connect to domain controllers for user accounts or other authentication features.
Call routing, similar to the gatekeeper function of the standards-based systems, is managed by the manufacturer of the product. This may include servers hosted by the manufacturer, or may utilize other peer-to-peer “node” computers that are running the manufacturer’s software. Using nodes can help bypass certain problems with communicating through firewalls, but raises some concerns about where the traffic is being routed. Manufacturers may use encryption to ensure that the call initiation and the conferencing session cannot be captured by any intermediary systems.
Once a connection is established, many of these systems try to create direct connections between the client applications, reducing the bandwidth demands on any of the controlling devices. In some situations, such as where a firewall may be preventing a call from being performed in such a direct fashion, the call may continue to be routed through intermediary routing devices.
Organizations must decide if they are comfortable with the lack of control that they may have over these products. Again, please refer to the discussion on consumer-grade software in the medical environment for more information.
Note that not all consumer-grade videoconferencing software supports having multiple participants in a single videoconferencing session, which may make the software less than ideal for some settings. Additional features, such as instant messaging, file transfers, and contact list management are included with this software. Note that file transfers include the actual sending of files, as opposed to content sharing (as found with standards-based software), which shares a read-only view of the file without allowing for the viewer to interact with the file directly.
An Introduction to “Hybrid” Videoconferencing Technology
Manufacturers have responded to shifts in technology and business needs by developing products that blur the lines between consumer-oriented and standards-based solutions. They offer the distributed hosting and internet-based connectivity of consumer-oriented systems with the interoperability of standards-based platforms. While the exact technologies that provide the foundation of the hybrid systems may vary, they are generally comprised of several components that do not interoperate with other products, and an intermediary gateway that routes traffic to and from standards-based products.
Overview of “Hybrid” Desktop Videoconferencing Infrastructure
Hybrid videoconferencing systems are designed to offer the decentralized infrastructure of consumer-oriented videoconferencing with an optional interface that allows for the software systems to communicate with standards-based platforms. The core infrastructure of these products is often cloud-based, with some manufacturers utilizing their own servers or taking advantage of other cloud-infrastructure providers. In simpler terms, this means that the hardware running the VTC infrastructure is shared between multiple organizations, though the connections are kept separate through various resource-provisioning controls. As more connections are made, more shared resources are dynamically allocated. This allows for service providers to offer their products at a lower cost.
The videoconferencing client connects with the authentication and communication servers in a manner similar to the consumer-oriented products, though they do not typically depend on the presence of intermediary nodes that they do not control. These various platforms typically allow point-to-point communications and multiparty calls, with call traffic being routed through their intermediary servers.
The hybridity of the system stems from the implementation of gateway devices that allow users of their distributed system to communicate with standards-based products that utilize various standards in establishing and maintaining the video calls. It is important to note that these products do not interoperate with other software products that are not built with standards-based interfaces.
There is some uncertainty about how these products are perceived in relation to HIPAA requirements for Business Associate Agreements, as many of the product manufacturers claim exemption under the conduit exception of the HIPAA Privacy Rule. As with any technology used within the field of telehealth, it is important to review the impact of implementing the technology with legal and corporate compliance personnel.
A Note on Webcams
Desktop videoconferencing software requires a video and audio device of some sort in order to effectively work. These may be built into some computers, such as laptops, or they may be USB devices. Built-in cameras and microphones are of variable quality, and may not be ideal for telehealth programs. The quality of the camera will play an important role in the quality of the images viewed in a videoconferencing session; a great network connection will lose much of its benefit if the video quality is too low.
Some USB-based webcams are advertised as having the ability to provide “high-definition” video streams. There is some ambiguity around these claims, as there are limitations in how much video data can be sent through a USB 2.0 connection. While their sensors may be able to capture an image that qualifies as high-definition, extensive compression must be applied, or else the frame rate must be reduced to one that falls within the limitations of the USB standard. Additionally, the stream of high-definition video places an enormous strain on a computer’s central processing unit, and may be a limiting factor in how high the image quality can be.
One solution that has been applied to work around this issue is to provide hardware support and image processing within the camera, and then use proprietary data processing that reduces the strain on the CPU and the limits of the USB transfer speed.
Another common solution is to utilize USB 3.0 devices, as the USB 3.0 standard has a data transfer rate sufficient to support the transmission of high-definition video. Note, however, that both the camera and the computer require USB 3.0 for the device to effectively work. Older computers or newer computers that lack the (typically blue) USB 3.0 port will not be capable of processing the higher throughput of the high definition devices and may introduce problems when attempting to stream the video data.
Summary
Desktop videoconferencing is still relatively new in the world of telehealth. Organizations are finding an increasing demand to provide the ability to connect their providers, their patients, and their partners with always-on video capabilities. These new technologies are requiring organizations to assess needs, product capabilities, and the new risks posed by changing videoconferencing modalities. Standards-based videoconferencing solutions have the promise of interoperability, while the consumer-grade products provide free and ubiquitous access to video conferencing for a wide range of users. Educating healthcare providers, organizational leaders, and curious patients is an important aspect of implementing this technology.
Additional information is available throughout this toolkit to inform decisions on choosing between these two classes of products, educate readers on differences between the products specifications, and more.