思绪之流:在阿姆斯特丹获得高清晰度

Getting high in Amsterdam isn’t anything out of the ordinary. 事实上, with its ubiquitous "coffee shops" and lax laws on psychotropic substances, Amsterdam is something of a mecca for the young traveler who wants a bit of excitement.

但在今年的IBC展会上, held in early September in Amsterdam’s RAI Congress Center, the broadcast world was looking to get high in a completely different way. 除了对高清电视的追求, 哪个运动得很好, IBC 2007 also pushed the envelope for high-definition video across the net and IPTV walled-garden delivery systems.

除了高清流媒体, 虽然, two other highs were being sought: high availability in terms of server uptime and high efficiency in terms of delivery system robustness. As streaming tools move from novelty to mission-critical, these two highs will also be key to maintaining the total streaming delivery experience.

高清晰度.
A year ago I noted a trend toward high-definition acquisition and HD streaming delivery. 最后一英里过去是(现在仍然是)一个问题, and various approaches—from better compression to more robust fiber-based last-mile solutions—are being tried. But the trend was there, and this year’s IBC showed it growing by leaps and bounds.

Two areas that were of particular interest were file-based (hard drive or solid-state medium) video cameras and HD encoding cards. 而丁肝病毒, a high-definition video format based on the popular MiniDV tape-based video cameras, 已经有一段时间了吗, the format is flawed in that it primarily captures 1080i in a 1440x1080i format and then extrapolates up to 1920x1080i. 该格式，以及较低的比特率H.264格式称为AVC-HD, 是否适合消费者和半专业应用程序, 高清摄像机的价格在8美元以下,000美元(许多低于6美元),特别吸引人. But tape-based workflows place additional steps in the process, especially if the only output will be a digital streaming file. That’s why Sony’s announcement that it’s bringing high-end HD cameras that record on solid-state media down to the HDV price range is of particular interest. Sony’s XDCAM EX will ship in November (by the time this article comes out) for less than $7,000, 这使得它的价格与佳能的XL H1相同. 索尼的设备, which records on PCI Express cards—meaning that it will fit in PCI Express slots now available on newer laptops as a replacement to the older PCMCIA slot—will record full 1080p signals.

高清捕捉卡也很有趣, with some of the HDV cameras allowing for direct HD-SDI output from the camera head. 这就是ViewCast的原因, which has lost some of its lead in the encoding card space, had a welcome announcement at IBC when it said it would ship its new HD encoding card immediately. 鱼鹰-700 HD, first demonstrated at the National Association of Broadcasters (NAB) conference in April, 记录分辨率为1080p, 1080i, 和720 p. 该公司, which ran the risk of losing a prime slot in the encoding card market if they didn’t get into HD, 表示该卡可以同时编码SD和HD. ViewCast also announced that its Niagara encoding platforms will now support Adobe Flash 8 and H.264以及微软的VC-1 SMPTE标准.

高可用性
在最基本的层面上, as broadcasters look to move their workflows from black boxes and electromechanical devices to file- and server-based devices, they’re concerned about the reliability of these PC-based devices. Those broadcasters who are kicking the tires of new equipment want to see that things can be done better, but not at the expense of reliability; after all, many of these PC-based devices are replacing black-box gear that’s worked well for 30 or 40 years.

The most apparent result of the move towards high availability was evident in the upswing in the number of vendors displaying "white box" or private-label servers at IBC as well as those who are selling mass storage solutions. 一些公司, 特别是那些拥有大型工作流解决方案的公司, are bundling servers together with software as their own solution, but more often server companies are staying separate from the software companies that put their software on a standard Linux, Mac OS X, 或Windows服务器配置.

One company following this latter trend is Digital Fountain. 该公司 is best known for its Quality of Service (QoS) offerings for large file delivery via the use of Forward Error Correction (FEC) algorithms that allow a full file to be reconstructed from less than the original amount of data. 该公司’s FEC has been adopted by the DVB-IPTV (Digital Video Broadcasting-IPTV) standards body as an IPTV FEC solution; the company, 然而, 缺少高可用性选项, so Digital Fountain’s broadcast play required creating the broadcast equivalent of "bulletproof" or "Five 9s" uptime. 该公司 sought out a partner with a history of high-availability software solutions for IPTV head-end deployments and settled on a new partner relationship with Milan-based Neptuny. 海王星的高可用性软件, 与Digital Fountain的FEC软件捆绑在一起, 被称为ToughStream服务器. Digital Fountain claims ToughStream Server provides enhanced QoS or on non-QoS networks with uptime guarantees and failover switches of around two seconds.