February 2008 | Volume 11/ Number 2
The Many Worlds of Video over IP
By: Richard “Zippy” Grigonis
Like voice, video was originally an analog technology. Advancements in digitization, compression and packetization technology have brought video into the digital and IP world. Digital video and audio signals can now be captured, digitized, compressed and streamed with a video codec (such as an MPEG-2, MPEG-4 or Microsoft (News - Alert) VC-1 transport bitstream), and then carried by an IP network such as the LAN, WAN or public Internet encapsulated in a stream of IP packets using RTP (Real-Time Protocol).
There are several forms of video-over-IP, each varying in function and quality.
As anyone who has visited YouTube (News - Alert) can attest, Internet Video is delivered over the public Internet to PCs (generally speaking) or mobile devices, but never to a TV screen (unless you’ve rigged some kind of special configuration). Since most Internet videos are not even of standard definition in quality, showing an Internet video on an HDTV would be not a great experience anyway. Most Internet videos are short, amusing (or revolting) items made by amateurs, though some are quite serious in nature. News organizations in particular now make Internet videos available.
Most Internet videos are streaming videos from a server, though in some cases one can download and run files, particularly in the case of higher quality/higher definition videos.
Microsoft makes enabling technologies in this area, such as Windows Media Server used by many content companies to distribute streaming media or download-and-run files. Microsoft also makes the Windows Media Player client, which can be found in just about every PC in the world, and which even runs in set-top boxes and mobile phones and other devices. (Windows Media is usually preloaded on phones and PDAs running either Pocket PC Phone Edition or Pocket PC 2003.) Its longtime competitor is the RealVideo mobile player from RealNetworks (http://www.realnetworks.com). RealVideo is available for the Palm OS, Symbian (News - Alert), and Pocket PC phones. Various Nokia models are sold already equipped with the RealVideo mobile player.
The highest quality form of Video-over-IP tends to be IPTV (News - Alert), since it’s a full-featured pay TV service, the more elaborate successor to analog and digital cable TV. It offers hundreds of HDTV channels and thousands of video-on-demand titles. It supports theatre-quality surround-sound, faster channel surfing, and all the niceties of Video-on-Demand [VoD] and digital video recording. IPTV systems have a rich electronic program guide that would make YouTube blush.
IPTV can be implemented in a digital video broadcast format - basically a cable TV-like environment with a personal video recorder (PVR), VoD and some interactivity, or else it can be implemented as a service under the auspices of IMS (the IP-based Multimedia Subsystem). This would occur if the IPTV service were part of a triple or quad-play services bundle (e.g. TV, Internet access, IPTV phone, mobile phone) which is a cinch for IMS as the service infrastructure.
Vendors of set-top boxes for IPTV include Backspace Communications (http://www.backspace.tv), Cellrun (http://www.celrun.com/eng/), Cisco Systems (News - Alert) (http://www.cisco.com), Eagle Broadband (http://www.eaglebroadband.com), Humax Digital (http://www.humaxdigital.com), Pace Micro Technology (http://www.pacemicro.com), Tilgin (News - Alert) (http://www.tilgin.com) and Wisembed (http://wisembed.com).
IP videoconferencing was once a rather primitive affair that a hobbyist rigged up between two PCs. (Yours Truly couldn’t get a successful IP video connection throughout most of the 1990s.) That’s why the U.S. government stuck with multiple ISDN BRI-based videoconferencing adhering to the ITU H.320 standard for so many years. Now, however, we have high bandwidth, high definition videoconferencing that operates over IP networks, first based on H.323 (in 1996) signaling and later on SIP (Session Initiation Protocol). Such systems include those by LifeSize (News - Alert) (http://www.lifesize.com), which can use your existing 128 Kbps to 1.5 Mbps broadband connection. The company’s latest, most compact unit, LifeSize Express, offers 1280x720 resolution at 30 frames per second, is based on the H.264 standard and provides H.263, H.263+, H.235 and H.239 support for interoperability with many standards-based video communications systems. Its dual-stream support (H.239) is for sharing PC and multimedia content. It also offers IP-to-ISDN connectivity with the LifeSize Networker enhanced gateway. The system has a high definition microphone or optional integrated super wide-band speakerphone compatible with most IP PBX systems.
Companies formerly known for their audio conferencing expertise, such as Polycom (News - Alert) (http://www.polycom.com), have also entered the videoconferencing market. Polycom offers such devices as the ViewStation SP 128 and SP 384, simple integrated systems for small conference rooms, executive suites and professional offices. Small enough to sit on top of an S-video or composite monitor, the ViewStation SP 128 supports up to 128 Kbps over ISDN and up to 768 Kbps over IP. The ViewStation SP 384 supports videoconferencing at up to 384 Kbps over ISDN and up to 768 Kbps over IP.
For medium to large video conferencing rooms, Polycom’s ViewStation 128 runs over ISDN at 128 Kbps or over IP at 768 Kbps. Polycom’s ViewStation H.323 is exclusively configured over IP and can run at up to 768 Kbps. Finally, the Polycom ViewStation MP, a medium-to-large videoconferencing solution, can connect up to four locations at once; It supports ISDN calls up to 512 Kbps or IP calls at 768 Kbps and includes embedded web capacity and an Ethernet hub. Polycom offers various other models capable of IP-based video conferencing.
Video Share (VS) is also known as Push-to-Video (P2video or PTV). It’s a service that enables a user in the process of making a voice call to stream live or pre-recorded one-way video from a handset to any another party on the call.
A form of this technology is Connect Push-to-Video by Movial (News - Alert) (http://www.movial.com) that combines Presence, Instant Messaging (IM) and multimedia. A user opens the wireless application and logs onto the system, and sees a list of online contacts that are available. A Push-to-Video dialog can be initiated to the selected person or persons, or a simple instant messaging dialog can be established. Using Push-to-Video and IM in tandem creates active dialogs among multiple users. Movial’s Connect Push-to-Video is not only available for SIP/IMS, but also for existing presence standards such as IMPS, OMA and XMPP.
MobileTV (Out of Band Video)
Perhaps the most ambitious form of video-over-IP is watching video (such as TV broadcasts) over mobile phones. This can be done by using one of four Mobile TV broadcasting standards: DVB-H, DMB, ISDB-T and MediaFLO. The most popular of these is DVB-H (Digital Video Broadcasting — Handheld) an ETSI (News - Alert) standard for bringing broadcast services to handheld receivers. It can work in an IP environment and with handheld, battery-powered receivers. It can call upon various audio and video coding schemes such as H.264 and it complements other existing broadcasting technologies.
DVB-H is part of the “IP Datacast” (DVB-IPDC) set of technologies designed to deliver any type of content to mobile devices over IP, in conjunction with broadcast network output reformatted for MobileTV reception. DVB-H and its accompanying protocol set are “radio agnostic” and could as easily work with CDMA services and handsets as with GSM.
Envivio (News - Alert) (http://www.envivio.com) a technology provider of IP video convergence solutions ranging mobile to HD, in 2007 introduced its 4Stream IP gateway for IPTV and mobile TV service providers. The 4Stream IP Gateway is part of Envivio’s all-IP Convergence (News - Alert) Generation video headend, which features the Envivio 4Caster C4 IP video encoders and the 4Caster M2 Mobile TV encoders both with IP input, as well as the 4Manager network management and redundancy system. This headend solution, supporting an all-IP infrastructure, provides a multi-service platform that can handle devices targeted by service providers who control both fixed and wireless networks. The complete solution offers flexible routing, simplified management and redundancy, requires little space and is easier to manage and deploy than today’s traditional IPTV and mobile TV headends.
The 4Stream IP gateway is a dual receiver and demodulator which feeds IP video networks with video services coming from satellite, cable, terrestrial networks. Each 1U high rackmount unit is a gateway that receives encrypted MPEG-2 streams and can process two full transponders, replacing up to 24 professional decoders. The IP outputs are received by Envivio C4 and/or M2 encoders. The Envivio 4Manager manages and monitors the gateway as well as other components in the system via a comprehensive web browser. IT
Richard Grigonis is Executive Editor of TMC’s IP Communications Group.
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