Special Delivery: High-Def Video
If you’re reading this, you’re probably interested in distributing high-definition streaming video. It certainly would be great if there was a clear roadmap to deploying high-definition video, but the market is young and no such roadmap exists. There are, however, exploratory efforts that present useful case studies about technology selection, production, and monetization. While they don’t tie into a cohesive whole, the stories of these high-definition pioneers do provide valuable insights into what works and what doesn’t.
WUSA-TV is the Gannett-owned CBS affiliate in Washington, D.C. It broadcasts on local channel 9 and on the web at www.wusa9.com. The station made technology headlines by becoming the first D.C. station to broadcast the 2007 State of the Union Address live in HD, and it distributes all evening newscasts live in HD and SD. You can view archived copies of the State of the Union Address in gorgeous HD at www.wusa9.com/hd.
I spoke with Brian Franco, a computer systems analyst in charge of WUSA’s streaming video efforts. In addition to its HD offerings, the station is very aggressive with distributing video through other avenues, including SD feeds of the live broadcast in three SD resolutions available as multiple-bitrate video (1.5Mbps, 500Kbps, and 56Kbps). Streaming efforts, in general, are hampered by the associated rights issues, which makes it tough to stream videos aired from other sources, like sporting events shot by other networks. Since there were no copyright issues involved with the State of the Union Address, it was a natural choice for the station’s first major HD undertaking.
WUSA-9 broadcast the address at 1366x768 (16:9) resolution, at a video data rate of 3192Kbps, with stereo audio encoded at 192Kbps. From a workflow standpoint, the station received the high-definition pool feed via HD-SDI and encoded the video into HD VC1 format using Digital Rapid’s StreamZHD encoder. The company also used two Digital Rapids DCR-Stream SD encoding boards to produce the SD streams. After encoding, the company shipped all streams to Akamai, the station’s content delivery network, for all live and on-demand streams. WUSA-9 uses this same encoding workflow for its daily live broadcasts, but it pulls the feed from its Sony MVS8000 Switcher and uses a slightly lower video data rate (2808Kbps).
The station also packages most individual stories as podcasts that can be watched on a computer or downloaded to an iPod. Since the station acquires and broadcasts in 16:9, the podcasts are delivered as 320x180 MOV files encoded with MPEG-4 video and AAC audio compression. Franco reports using MPEG-4 to save encoding time and to ensure compatibility with older iPods.
Franco chose Digital Rapids hardware for a number of reasons, including the fact that deinterlacing and noise reduction occurs in the hardware, reducing the load on the encoding stations, which are Dell PowerEdge 2900 servers driven by a Dual-Core 3.0 GHz Xeon processor. The ability to produce multiple-bitrate files in real time was also critical. For its on-demand files, the company sends a QuickTime reference file to a watch folder, where it’s picked up by an Anystream Agility system, which produces the necessary video files and ships them to Akamai.
WUSA-9 chose VC1 for the majority of its video because it had the most proven live encoding capabilities and support for multiple-bitrate video distribution. WUSA-9 uses the Advanced Profile for VC1, which requires users not running Vista or Media Player 11 to update their codecs. Franco reports that most users had no issues with this, though some users in locked-down organizations did report problems. Franco does tweak the registry settings to enhance video quality, but he says that the effectiveness of tweaking is very scene-dependent. Franco commented that Silverlight is on his radar, but using Microsoft’s new technology will have to wait until it fully supports multiple-bitrate streaming.
WUSA9 targets local cable modem owners for its HD offerings, since most can download at least 5Mbps. The number of actual viewers is still fairly low, about 20 to 30 each day, though the station registered 415 hits on the State of the Union speech, with a high of 40 to 50 concurrent users. This is very low compared to the 20,000 iPod downloads per month, but obviously it’s a start.
Franco says that the initial HD deployment went smoothly because he spent 2 months pumping video through the system, including high-motion sports video that was much more challenging to encode on the fly than typical talking head footage. For those considering HD deployment, Franco recommends a similar test cycle, along with buying the best encoding hardware and computer platform available—in particular a card that preprocesses on board, like the Digital Rapids cards his station uses.
Hulu (www.hulu.com) is an advertising-supported online site that offers a variety of video content, including complete television shows, clips, movies, and movie trailers from a variety of content companies, including NBC, FOX, MGM, and Sony. Representative content includes current hit shows like The Office and Prison Break, and older classics like Miami Vice and The A-Team. The video will be available on the Hulu site and distributed through Hulu partners AOL, Comcast, MSN, MySpace, and Yahoo!. Hulu is one of the first websites to adopt Adobe Flash Player 9, enabling its users to view H.264 files in the Flash Player. I spoke with CTO Eric Feng.
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