InfoComm 2010: The Accidental Streaming Show
For those of us who attend trade shows on an annual basis, it's hard not to compare one year's show to previous ones. Each year has its own appeal, 从地点到附带表演(派对)再到新发明的技术.
Attend the same event for several years, 虽然, and you'll get a sense of whether the show is growing, 死亡, 或者被困在地狱的边缘.
在…的情况下 InfoComm, a show for systems integrators who install technology in auditoriums, 教室, 公司董事会, 诸如此类, the show is not only growing, but also morphing into a mini-NAB show, 这与InfoComm主要因投影机枪战而闻名的日子相去甚远.
Some of the show's growth has been organic, 但其中很大一部分原因是多场展会将与会者聚集在一起. 姐妹秀， EduComm, 关注 the higher-education market; NSCA 关注 audio and audio delivery; and 3 dcomm 关注 . . . 你懂的.
当涉及到流媒体技术与系统集成行业的融合时，该展会也扩大了其重要性.
Four areas highlight this convergence: audio distribution, 数字标牌, rich lecture / media capture and telepresence.
We'll cover the last two in more detail tomorrow, 因为有许多与流媒体服务器和富媒体记录相关的公告. 对于本文, 虽然, 让我们来看看该节目对音频发行和数字标牌流媒体的影响.
数字标牌
This year's InfoComm brought a number of announcements, 许多人都专注于存储的增量增加和在单个播放器上设置播放列表的更好的用户界面, hardware boxes attached to a flat panel, or projectors for local play-out of centralized content.
数字标牌市场的高端是命令和控制显示解决方案, many for mission-critical corporate or military applications. 这些类型的设备, often filling an entire wall, 在墨西哥湾石油泄漏期间在休斯顿被广泛使用, 让岸上的人们看到封堵漏油的进展(或缺乏进展).
在命令和控制解决方案中，低延迟和非常高的质量同样重要. 最低延迟H.基于264或MPEG-2的编码器-解码器对在提供非常高质量的图形和非常低的延迟方面付出了沉重的代价. While this is changing, with the advent of more robust H.264编码，专有流编解码器的解决方案正在填补这一空白.
一个例子是 爱思创流媒体解决方案, 在爱思创收购了Electrosonic的产品部门后，更名为Electrosonic. The products aren't your typical streaming encoders, 他们也不使用典型的流媒体编解码器:Electrosonic在2009年推出了ES7100编码器/解码器，采用PURE3压缩编解码器，这更类似于数字电影解决方案，而不是基于浏览器的视频观看.
With this type of high-resolution, 低延迟压缩需要每秒6到150兆比特的带宽. 该公司还声称有一种“秘密武器”，可以使产品在不需要前向纠错(FEC)的情况下防止网络错误，而前向纠错(FEC)是用于卫星和无线分发的，以保证传输足够的比特来重建整个图像.
音频分布
音频分发的两个领域正在见证流媒体技术的显著增长.
The first is paging applications. One of the leaders in this space is Valcom, based in Roanoke, Virginia. The company has many years of experience in paging solutions for education, government and healthcare verticals, including paging systems for many airports.
几年前, Valcom开始探索一个想法，即办公室环境中的每个扬声器和麦克风都应该能够作为寻呼系统的一部分. 像这样, 他们在基于sip的IP语音和PBX电话系统之间建立了互连, 允许将紧急音频页广播到专用寻呼扬声器以及员工桌面上的电话.
"We use standards-based codecs and industry-standard components,Valcom总裁约翰·“杰克”·梅森在InfoComm上展示该公司的IP寻呼产品时说. "In the paging industry, 基于ip的分页的行业标准是单线InformaCast协议. 我们使用这个协议, 它还支持以太网供电(PoE)，为我们的IP扬声器提供内置时钟和对讲功能以及连接到电话系统的寻呼网关等功能."
“Valcom在开发扬声器固件方面与我们密切合作，以确保符合我们的InformaCast协议,肯·拜沃特斯说, executive VP of product development at Singlewire, in a January press release. ”学校, 政府机构, 卫生保健设施, 任何部署了Valcom寻呼的组织现在都可以轻松地将通知扩展到IP网络上的新端点和系统."
音频分发的第二个受益于音频流媒体的领域是专业的现场音频制作工作流程. 这里最大的进步是在数字蛇(用于在一束电缆中传输多个音频通道的单元)和分布放大(DA)解决方案领域.
Snakes are primarily used in the entertainment and worship markets, 与需要发送32或更多的平衡音频信号从舞台到混音控制台. One end of the snake sits on stage, in the form of a large box, into which all the microphones and instruments are connected, 然后聚合的电缆束蜿蜒穿过地板到达音响室.
The problem with analog snakes has always been bulk, 在某些情况下，聚合电缆的直径接近3英寸. Not only does this create a tripping hazard, 但它也使电缆本身容易受到损坏和串扰干扰.
Digital snakes have similar box on stage, but digitize all audio with low-latency uncompress audio encoders, sending up to 64 channels of 24-bit/96 kHz audio via a single Cat5 cable. 第二条5类电缆作为冗余故障转移选项:如果一条电缆断裂, 第二根电缆在两个字时钟周期(几毫秒)内接管，继续将声音不间断地传输到人耳. 更换电缆的成本最低，并且大大降低了跳闸危险.
Beyond the digital snake point-to-point solutions, 虽然, 这种类型的音频分布正在取代用于将模拟音频从一个位置路由到多个位置的分布放大器(DA)和矩阵单元.
可以把矩阵想象成一个巨大的配电盘或配线板，但具有数据处理功能. The beauty of encoding and packetizing audio over 以太网, 虽然, is the elimination of what could be a 12-20 rack unit piece of gear. 以太网 distribution eliminates the matrix altogether, as 以太网 can efficiently route packets to one or many decoder locations.
The solution also eliminates wasted ports on matrix units, which came in either 8 or 16 I/O card configurations. If one needs to set up a matrix to accommodate 17 inputs and 33 outputs, the matrix hardware requirement would be 32 inputs and 48 outputs. The remaining 15 inputs and 15 outputs in our example remain unused. 以太网, 相比之下, could have 256 devices in any configuration on each subnet: 1x255, 2x254, 237x19 - all these combinations are possible within 以太网 delivery.
InfoComm continues through Friday at the Las Vegas Convention Center.
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