回顾:Epiphan Pearl生产切换器

预算有限, 没有工作人员, 以及每年五次会议的主题演讲, 升级我的流媒体设置对我来说是一个缓慢的过程. I did my first few streams single-camera using the Livestream Broadcaster. 广播公司, 比如特雷德克立方体(它与之非常相似), is a handy little box that connects to your camera via HDMI and proved very easy to set up and use and extremely reliable for me. 我的广播流的问题是单源设置, which meant I had to either follow the presenter and ignore the presentation, 在同一个镜头中捕捉两者(两者都不太好), or to swing the camera over to the screen every time the presenter advanced the slide deck.

一般, 我采用的方法是只展示演示者, 单独捕获幻灯片, 然后迅速组装起来, composited version online as soon as possible after the keynote to erase all memory of the single-source version. 鉴于我在这些会议上的其他生产职责, 以及会议酒店视频上传的缓慢速度, “as soon as possible” wasn’t always fast enough: As one keynoter told me in 2014 after seeing the single-cam archived stream online just after his keynote, “我的演讲中有247张幻灯片! 你害我失去了一次TED演讲!”

Not knowing I had such power, I vowed then and there never to cost anyone a TED Talk again. 我的下一个设置涉及到Epiphan AV的几个变化.io Video Grabber devices, which connect DVI sources to a laptop via USB 3.0用于在电视直播中切换或合成. 因为我的相机输出HDMI和HD-SDI, and I typically get a presentation via a split VGA signal from the presenter’s laptop, this setup also required a couple of small adapters to convert the signal to DVI, but it generally worked pretty well when I didn’t have both sources connected to the same USB bus.

But this setup became less reliable in practice the more times I had to disconnect and reconnect the devices, and the camera signal captured via HDMI and converted to DVI always seemed to lose some vibrancy in translation (下面的图1). 但可以肯定的是，对于低于1000美元的解决方案(包括2av).io单元和Wirecast Pro软件), this bundle proved a very cost-effective way to deliver a competent live-switched stream, 总的来说, 评论家们都很友善.

图1. 在左边, the image of a conference panel captured to SDHC in 50Mbps XAVC by the Sony PXW-X70; on the right, 与Epiphan AV拍摄的图像(大致)相同.io via HDMI/DVI/USB to Wirecast Pro and recorded at Wirecast’s uncompressed setting. 注意右图中柔和的色彩和失去的清晰度. 单击图像以查看其全尺寸.

进入主显节珍珠

当一个主显派的代表看到我在用AV.io setup to live-switch two-camera booth interviews at 流媒体 West last November, 他提出借给我一本Epiphan Pearl的评论书(下面的图2), 一个全功能的生产视频切换器，需要两个SDI, 两个HDMI, 和两个VGA输入, and allows the user to switch and stream them and record ISO and program feeds as well.

图2. Epiphan Pearl产品视频切换器(建议零售价4875美元)

Jan Ozer做了一个 useful 教程 on how to operate the Pearl for 流媒体 Producer 去年9月. Jan produced his 教程 within the friendly confines of his own home office; I wanted to test it out in the field at the Computers in Libraries 2016 conference, in front of an unforgiving live online audience and at least one high-profile keynoter whose future TED Talk eligibility might hang in the balance (下面的图3).

图3. 戴夫·斯诺登, CSO认知优势, presenting his live-streamed opening keynote at Computers in Libraries 2016. 珍珠号正在流媒体和录音. 单击图像以查看其全尺寸.

正如简在他的 教程, you can switch media sources on the Pearl using its built-in touchscreen, 但真正的动作发生在网络界面上, 你可以通过以太网连接珍珠来访问吗, 进入系统状态, 注意显示的IP地址, 然后在浏览器中输入以下内容:http://192.168.0.1/admin(或者其他地址加上/admin), 然后以管理员身份登录(除非设置密码，否则不需要密码).

Epiphan建议将笔记本电脑通过无线连接到Pearl上. 在我测试的活动场地, my in-house A/V tech told me that a firewall would prevent me from connecting to the network set up for the stream via wireless, so he had to provide me with an Ethernet switch so that I would have a hardwired connection to both my laptop and the Pearl. 如果你要开着珍珠上路, 我建议你随身带一个，以防没有现成的.