NTRsupport Videoconference
Whitepaper
NTRglobal
Torres Diagonal Litoral · Josep Pla, 2 Edificio B3, 1ª Planta
08019 Barcelona (Spain)
Tel. +34 93 445 07 00 Fax +34 93 445 07 01 www.ntrsupport.com www.ntrglobal.com
Offices in Barcelona - Boston - Dallas - Heidelberg - London - Madrid Milan - Paris - Poznan - Santiago de Chile - Stockholm - Tokyo
Overview
The NTRsupport Videoconference is a real-time video and audio interface that allows you to see the person you are talking to as you would were you using a video phone. It is a full duplex and doesn’t require any set-up.
NTRsupport Videoconference is currently provided as an ActiveX control, and is supported by Internet Explorer 5.5 or higher. It is integrated into the NTRsupport solution, using NTR’s plug-in architecture.
NTRsupport’s Videoconference feature is a small component (of approximately 100 Kbytes) that includes a rich features audio-subsystem, video capturing with adaptive compression-technology, and a thoroughly-tested communications-core that allows you to connect from virtually anywhere and at virtually anytime, without prior configuration or problems with proxies or NAT connections.
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Technical Description
NTR Component
NTRsupport Videoconference is packaged using the same “Common Module Architecture” used by NTR’s ActiveX control and other components. Should one wish to use the Videoconferencing tool during a remote control session it is not necessary to install a new ActiveX control, because each of NTR’s components (video, voice and remote control) are based upon the same ActiveX container. Figure 2 illustrates NTR’s Common module architecture.
Figure 2: NTR’s Common module Architecture
This application architecture ensures that the latest versions of NTRsupport are downloaded automatically upon their release. This ensures that NTRsupport remains at the forefront of technological changes without the need for user intervention. In the near future, the ActiveX technology used will be replaced by an EXE version.
As previously mentioned, the size of the NTRsupport Videoconference feature is approximately 100 Kbytes (images and components). The download time is less than 2 seconds when using a standard low-end ADSL connection. Internally the component consists of 8 concurrent threads. Together these manage connectivity, video and audio, and result in a reliable, adaptive video-conferencing tool with audio.
Compression H323
Active X / .exe
VIDEO
AUDIO
Compression GSM 16Packaging & encryption Communications manager
Video Details
NTR’s Videoconference component captures video from virtually any windows-compatible webcam or video source, and converts it to a common internal format.
Compression quality and FPS (frames per second) are adapted according to available bandwidth, image movement, response time and the CPU usage of both computers.
NTRsupport Videoconference has unique quality-enhancements to provide a rich user-experience (for example, some video filters are applied to the received image in order to enhance the image quality).
Figure 3:
NTRsupport Videoconference on the Client’s side
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Audio (Voice over IP) Details
NTRsupport also offers Voice over IP. This means that if one of the user, the visitor or the operator doesn’t have a web cam but they do have a full-duplex audio-board, speakers and a microphone, they can still establish a high-quality voice-communication.
This technology is embedded in the common plug-in which is downloaded when the client accepts the operator’s request.
The Audio feature uses standard GSM-compression with simple 16 bits and its own post compression, which gives it higher sound-quality than that of a conventional telephone. Internally it uses a multi-process buffer that is adjusted automatically accordingly to the performance of the equipment and the communication lines. Its own algorithms detect silence, and capture and generate comfort noise (CN) in order to reduce bandwidth.
These transmission algorithms, based upon TCP encapsulation of standard RTP, offer fluid communications between continents, with exceptional quality and with minimum bandwidth-usage (8 – 12 Kbps).
In the near future, NTRsupport users will be able to connect and communicate with public-telephone users by using the Voice over IP tool.
Connectivity Strategies for Video & Voice over IP (VoIP)
NTRsupport uses various strategies to ensure connectivity regardless of interference from firewalls or NATs (network address translations). To ensure a fluid VIDEO and VOICE connection, multiple concurrent connections are secured directly through the NTRsupport server.The Video & Voice components first attempt to contact their interlocutor concurrently through various TCP ports, and if a direct connection cannot be found, the program attempts to find a proxy or gateway in the network that offers the desired connectivity. Through the NTRsupport administration, it is also possible to assign a port to a specific operator (for static NAT configurations).
If the connection is not made within a few seconds, an attempt is made to establish a connection through the NTRsupport server (in parallel, without ceasing the attempts of the first strategy) and also through standard ports (configurable from the NTRsupport administration). This kind of connection is not as efficient as a direct connection, but secures connectivity even
between two NAT users.
This strategy ensures connectivity in almost every case without intervention or configuration by the customer.
The core of the NTRsupport application and the Videoconferencing and Voice over IP features use plug-ins developed in highly optimized C++ (and some assembler code). The components use C++, VB, JavaScript and VBS with COM and MTS technology.
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Key Features
Quality Indicators
Quality indicators are shown during the transmission, communicating to both parties the quality of the video being transmitted.
Figure 7 : Video Quality Indicator Figure 8 : Audio Quality Indicator
High Quality on Demand
Should a higher quality be required, for example to view a document, it is possible to set up the option “Send high quality” by pressing the shift key.
Quality Adjusted to the Performance of the Equipment
NTRsupport Videoconference feature uses an adapting multi-process buffer that automatically adjusts according to the performance of the equipment and the communication lines. The Video feature uses algorithms to detect silence and to capture and to generate comfort noise (CN), therefore reducing band width.
Image Freeze
It is possible to freeze the video being displayed as a still image.
Video Filters
Various filters are applied to the video received to enhance its quality.
Webcam Compatibility
NTRsupport Videoconference supports 99% of webcams, including models RGB, YUB, i420 (among others).
Voice Quality
The Voice and sound being transmitted and received offers a higher quality than that of the conventional telephone.
Single Plug-in
The NTRsupport Videoconference feature is supported by the “Single plug-in” architecture, which is also used by each of the components of NTRsupport. With this architecture it is only necessary to download this plug-in once. Once it has been downloaded to be used by one of the features, it should no further downloads are required for the use of the other features.
Movement Sensitive
An advanced compression-algorithm is used to detect movement. This has the advantage of sending less information when few movements are detected. The standard H.263 has been used to ensure compatibility with future versions and products.
Minimal Bandwidth
The consumed bandwidth is less than 16 Kbits/sec. The number of frames per second (FPS) is automatically adapted to the available bandwidth depending on movement.
Bandwidth Adaptability
The video transmission automatically adapts quality and FPS according to available bandwidth.
Small Download Size
External libraries are not used, which ensures that downloaded sizes are kept at a minimum.
Advanced Connectivity
An advanced connectivity-strategy allows the Videoconference Feature to bypass most proxies and firewalls and to establish video conference through double-NAT connections.
Secure Transmission
Communications are encoded with a world-recognised security-algorithm (AES 256 bits). This establishes a private and safe connection-channel over the Internet.
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Technical Specifications
Compression
With Voice over IP the component uses standard GSM compression with simple 16 bits and its own post-compression technology. For Video the component includes the standard post-compression code H.263, allowing any operating system from Windows 95 to XP or 2003 to be used without any code or driver installation.
Plug-in Size
The size of the NTRsupport Videoconference module is about 100 Kbytes, including all images and components.
System Requirements
o Hardware: The minimum requirements recommended to use NTRsupport Videoconference are a 400
MHz CPU with 128 MB of RAM in additional the minimum required by the operating system. o Software: Microsoft Internet Explorer 5.5 or higher
o Bandwidth: NTRsupport uses variable bandwidth which fluctuates according to the options selected.
For VoiceIP, should the user talk constantly, the maximum bandwidth would be approximately 14 Kbits/second; however, should the user talk approximately 40% of the time, the plug-in detects the silence and therefore does not send information. In this case, the average bandwidth would be around 8 Kbits/second.
