Mobile Services Will Depend On Advanced Compression Technologies
Customers are seeking robust encoding solutions that are futureproof and can be easily adapted to meet the needs of a marketplace where mobile content delivery requirements are emerging to join demand created by HDTV and IPTV. The objective is achieving whatever is necessary to ensure a superb viewing or online experience for a demanding audience and doing so at the right bit rate and the right price.
Much attention in satellite circles is focused upon the pending launch of the digital video broadcasting-satellite service to handheld specification as well as the migration from MPEG-2 to MPEG-4 advanced video coding (AVC), also known as H.264, to help meet these delivery needs.
“A full migration will take some time,” says David Price, vice president of business development at Sunnyvale, Calif.-based Harmonics Inc. “The greater the legacy infrastructure, particularly in MPEG-2 set-top boxes, the more difficult the decision to switch over to H.264. As cost-effective MPEG-4 standard-definition and high-definition set-top boxes become available — they are now starting to come in at less than $100 — operators will become more likely to switch.”
The migration is being driven by the growth of bandwidth-hungry services such as a new mobile TV platforms in Europe, including a joint effort by SES Global and Eutelsat Communications as well as a program between partners Alcatel-Lucent and Madrid-based Telefonica. SES and Eutelsat plan to and commercialize S-band payloads aboard the Eutelsat W2A satellite, scheduled to be placed into orbit in 2009, that will support mobile services. Alcatel-Lucent and Telefonica have been engaged in a pilot project launched in October that offers mobile interactive broadband TV and multimedia services in Spain.
According to Philippe Lainé, solution strategy director at Paris-based Alcatel-Lucent Mobile Broadcast, an electronic service guide and rich media are included in the MPEG transport stream which can be broadcast via Ka-band or Ku-band satellite to repeaters or directly to mobile phones via S-band or by alternatively using terrestrial transmission modes. “Video encoding is handled in variable bit rate mode for improved coding efficiency,” he says. “This mode provides a bit rate adapted to current requirements. Slow scenes with little details require a low bit rate for good video quality, whereas fast scenes and complex pictures need much higher bit rates. Bit rate smoothing is applied up to a limited extent, according to channel constraints.”
Service, User Experience Issues Loom Large
Quality of service and quality of experience issues will be major factors in this transition, especially with industry-wide emphasis on achieving maximum bandwidth efficiency. The quality of the user’s experience is more of a subjective evaluation of image and sound quality, while quality of service entails narrowly defined network performance parameters or contractual obligations which, if not achieved, can lead to damage claims.
“As IPTV operators confront increased competition from cable and satellite, they are discovering that video quality can be a fundamental differentiating factor and yet has been widely overlooked. IPTV operators have also found that there are many parts of the systems where video quality and packet flow can be compromised, right down to the physical layer,” Sunnyvale, Calif.-based Multimedia Research Group Inc. says in its report, “IPTV Video Quality: [Quality of Service and Quality of Experience],” released in February. “There can be impact on the quality of the video itself; upon [quality of service], which relates to error-free delivery over the network; and [quality of experience], which has to do with latency and responsiveness.”
According to Steven Hawley, IPTV senior analyst at Multimedia Research, the whole concept of IPTV video quality is really misunderstood, because Internet video for ephemeral purposes is often confused with the high-quality content offered by media companies. Fortunately, the entire codec vendor community has embraced forward error correction and there are architectural approaches involving full-time test and measurement. Hawley urges IPTV operators to forego MPEG-2 and proceed to MPEG-4 from the start. “You should decode everything into a single common format prior to encoding and bundling the outbound feed for distribution,” he says. “Ensuring the least amount of garbage in is a necessity. It is important to compare the raw input to the final output and maintain multiple points of comparison downstream. Ideally, video input and output should be indistinguishable, and for IPTV there is no exception to that rule.”
Microsoft is eager to emerge as a top IPTV and broadband TV solution provider. In early March, a spokeswoman for Thailand-based Shin Satellite Public Company Ltd. confirmed that the Microsoft Windows Media encoding platform had been selected for a new video-on-demand service delivered via the IPStar broadband satellite to special set-top boxes attached to IPStar terminals. This project involves Shin Satellite’s subsidiary, IPStar Australia Pty Ltd., which has partnered with ReelTime Media Ltd.
Microsoft Windows Media Video is Microsoft’s implementation of the Society of Motion Pictures and Television Engineers VC-1 encoding standard, and the Windows Media Encoder 9 Series can create VC-1 Advanced Profile content. Since VC-1 is optimized for decoding performance, it ensures a superior playback experience regardless of bit rate or resolution, says Tim Harader, senior business development manager for Microsoft’s Consumer Media Technology group.
“These scenarios range from the PC to set-top-boxes, gaming systems, and wireless handsets,” says Harader. “Bandwidth capabilities and scalability make VC-1 ideal for the mobile space in particular,” he says, adding that VC-1 offers low complexity, which reduces costs, conserves battery power and provides better heat dissipation for consumer devices. “Because VC-1 is easily implemented, it can be added to silicon that already supports H.264.VC-1 minimizes the complexity of decoding HD content through improved intermediate stage processing and more robust transforms. As a result, VC-1 decodes HD video twice as fast as H.264 while offering two to three times better compression than MPEG-2.”
Harader emphasizes that while VC-1 and H.264 are more complex to decode than MPEG-2, VC-1 Main Profile requires 25 percent fewer cycles than H.264 Baseline, according to a study by the 3rd Generation Partnership Project, the multinational 3G mobile phone standards collaboration group.
According to Steve Bae, an analyst with ABI Research of Oyster Bay, N.Y., Sirius Satellite Radio’s Backseat TV service launched in March is a significant offering in the automotive infotainment market. This will be offered exclusively in 2008 Model Year Chrysler Group vehicles. Sirius has been developing this video service for years and in early 2004 Sirius and Delphi Corp. demonstrated in-car mobile video transmissions via an S-band satellite radio network using Microsoft Windows Media Video 9.
“Backseat TV is offered at a very attractive price of $470 on top of the DVD rear-seat entertainment system, which in a Dodge Caravan costs $900,” says Bae. “On other Chrysler group vehicles, the DVD rear seat entertainment systems are priced at lower than $1,000. Considering it includes overhead LCD screens and one year of the service, it is a bargain compared to DVD rear seat entertainment systems on higher end vehicles which can easily cost over $2,000.
“Although video quality and reception are still in question, Sirius Backseat TV will stimulate the rear seat entertainment market,” Bae says. “At this point, how Sirius will utilize its limited frequency spectrum is unclear, but the proposed XM-Sirius merger will resolve some constraints and featured services such as Sirius’ video and XM’s traffic data will certainly benefit.”
Roll Out Of AVC In Full Swing
According to Matthew Goldman, vice president of technology, compression systems, at Oslo-based Tandberg Television, AVC rollouts are going well with direct-to-home satellite and IPTV deployments leading the way as Tandberg, in the process of being acquired by Ericsson for $1.6 billion, introduces its second-generation encoders. “This has, in turn, accelerated the cable telecommunications industry interest in using AVC — not only to remain competitive but also to help address the expected bandwidth demand that increased interactive and dedicated services such as will require,” he says. “For customers that have a space bandwidth constraint, interest in AVC is also increasing for contribution and distribution applications.”
Mario Rainville, assistant vice president of marketing at Scopus Video Networks Ltd., says the pace of AVC rollouts depends on the market segment, with the bandwidth savings provided by AVC translating “into either costs savings, a wider channel offering or simply just an enabler to deliver video services for networks on which MPEG-2 was not practical. … As most of the industry has already made the move to digital MPEG-2 video systems, it is important to offer a migration path to AVC,” he says. Scopus’ UE-9000 Universal Encoder addresses AVC compression as well as the migration from MPEG-2 by allowing simultaneous MPEG-2 and AVC compression, enabling broadcasts in both formats.
According to Ian Trow, vice president of technology at San Francisco-based Envivio Inc., video quality and suitability for transmission over packet switched networks has been key to establishing MPEG-4’s benefit over MPEG-2. Envivio is launching its new 4Caster M4, which offers up to four 3rd Generation Partnership Project channels — a set of international mobile content creation, delivery and playout standards — in a single unit. “Functionality expectations include closer integration with video headend server infrastructures, interfaces with encryption and third-party conditional access systems as well as directly processed content presented as an MPEG-2 [transport stream] to the input of an encoder,” says Trow.
IPTV and mobile are two core markets for Envivio, thus, the emphasis for the company now is on multi-channel capability, multi-profile output and direct MPEG transport stream processing. “While HD broadcast distribution has resulted in MPEG-4 being adopted over MPEG-2, a multi-standard scenario in which both MPEG-2 and MPEG-4 coexist depending on the playout platform and distribution infrastructure is the application we see being commonly adopted,” says Trow.
New York-based On2 Technologies Inc. tested its TrueMotion VP6 encoders with XM Satellite Radio in early 2005. XM remains On2’s only satellite customer to date, but Sam Vasisht, On2’s vice president of marketing, says the company has emerged as a well-positioned competitor in the encoding market and is targeting mobile video at very low data rates with its new VP7 encoder. China Mobile is testing the new encoder in 10 provinces.
“Mass market devices benefit from progressively lower power codecs, such as VP7,” says Vasisht. “Ultimately, content creation will drive format adoption. This landscape is shifting, and traditional Web-based formats are making inroads on devices and migrating to more mainstream video viewing experiences. There is a likelihood that higher-performing, lower-cost alternatives such as Flash, TrueMotion, and others will, at minimum, coexist or even preempt H.264 in certain applications or geographies.”
Fighting To Maintain Video Quality
According to Rainville, MPEG-4 real-time video compression is contributing to a greater quality of experience by enabling video deployments in environments where it was not possible before and by providing greater video quality for equivalent bit rates. “A lot of operators have migrated their networks to IP with MPEG-2 to simplify operations and are now in the process of integrating MPEG-4,” he says.
Provisioning an IP network with more bandwidth than needed to reduce the risks of degraded quality of service and activating forward error correction mechanisms can help to compensate for lost packets are important steps, says Rainville. Because “the MPEG encoder is the source of the video delivery, Scopus implemented Pro MPEG forward error correction on the IP output in order to minimize the potential unreliability of the IP transport,” he says. “The IP delivery infrastructure is crucial to deliver an acceptable video watching experience. For network operators, they must consider the tradeoffs for bandwidth.”
Denial of service attacks have to be considered as well, says Goldman, who identifies them as a common system-wide quality of service problem. Users must provide security against malicious actions, such as denial of service attacks which may cause failures in the operator’s headend or prevent consumers from accessing the content they want to view, all of which are perceived by the consumer as poor quality of service.
“Packet loss and the lack of service guarantees are the biggest challenges to the carriage of video over IP,” says Trow. “The effect of packet loss varies according to the error rate on the network and where in the compressed bit stream the signal is corrupted. Packet loss results in anything from minor picture impairments to complete picture loss, with the video needing to resynchronize on a reference frame before video is displayed again.”
For these reasons, Envivio supports IP prioritizing mechanisms, including a defined class of service — a feature of multi-protocol label switching — and the use of real time protocol, which often is used in conjunction with real time control protocol, to help with audio synchronization and quality of service management and real time streaming protocol, according to Trow.
As for single encoder solutions, these may not always meet the needs of a particular service provider. DirecTV Inc., for example, uses a mix of encoders, including Tandberg’s EN5990 and Harmonic’s Divicom MV 100 MPEG-4/AVC HD encoders and Grass Valley’s Vibe SD encoders, to deliver its standard-definition and HD satellite-based content.
“Our objective is to use the equipment that yields the best consumer experience,” says DirecTV spokesman Robert Mercer, who adds that DirecTV’s MPEG-4/AVC transition has been quite successful. “We introduced this new compression technology and together with other technology suppliers have been obtaining continuous improvements. As the technology matures and the compression technique is refined, we have been seeing additional silicon integration. The result is lower hardware cost and additional performance.”
The flag is up and the race is on. The next wave of digital, IP-based content is beaming out to customers around the globe. All of this content needs to be encoded, protected and delivered on time in pristine condition. Profits depend upon it.