Roundup Review: Looking at Sub-$2,000 Hardware H.264编码器

For the last decade, I’ve used a variety of H.264编码器用于直播事件, 典型的会议事件涉及一个或多个演示者和一个或多个计算机屏幕输入. 我的工作流程中最大的一个因素是活动场地的可用带宽. 我需要一个H.264，它将在1-3Mbps持续带宽的有限出站管道上获得最佳质量. 我写这篇文章的目的是为各种直播内容找到市场上最好的编码器, from relatively minor movement such as talking heads to fast-paced sports. I could not identify a single “winner” across all categories, 但我可以得到可重复的结果，你可以用在你自己的研究和比较这些和市场上其他编码器.

My typical pipeline uses a first-generation Teradek Cube 255, which has held up very well and served my requirements over the past 5 years. As we have entered the dawn of HEVC/H.265技术——市场上很少有价格实惠的编码器——我认为现在是比较H . 265当前股票的好时机.264编码器 that are available for under $2,000. There are certainly encoders that are much more expensive, 但我的大多数客户都需要可移植性和更低的成本来将直播添加到他们现有的管道中.

的竞争者

在各种各样的编码器中，可在测试期间进行此评估, I picked one encoder from four different vendors, each meeting the following minimum criteria:

3G-SDI和HDMI输入
以太网/局域网连接
AVC / H.264编码器
Web-configurable接口
Retail cost under USD$2,000, before applicable taxes and shipping costs

Here’s a brief overview of each encoder, from least expensive to most expensive.

Aja helo(1,295美元)

这个备受期待的进入H.AJA的264编码器竞技场最初有一些发货延迟，但最终在2017年2月发布. This encoder has a very simple and compact design. While its form factor was the second-largest in this roundup, the 直升机不是为安装摄像头而设计的吗. 它的机架安装设计使其成为一个紧凑的补充，现有的足迹更永久的a /V机架. All of the input and output jacks for video, audio, 网络, and power are on the back side of the chassis, 而更用户友好的推控制，使录音和流媒体和USB/ SD卡记录媒体是在正面. You can also store multiple presets and profiles for the encoder, making it faster to change from one configuration to another. 虽然直升机没有设计便携性的外形因素，也没有像Teradek Cube 655那样很好地安装在相机上, 您可以购买单独的电源适配器，从流行的电池类型运行直升机.

Discoverability of the 直升机 on the 网络 is relatively simple. If you’re using a Mac or Bonjour-enabled device, the 直升机’s address will be announced and available over Bonjour. 如果你有Safari浏览器, 您可以启用Bonjour发现并快速导航到直升机的web配置页面. If you don’t have a Bonjour-enabled device or browser, 您需要在笔记本电脑或台式计算机上使用AJA mini - setup应用程序来发现直升机. 此应用程序将报告直升机的IP，以便您可以在web浏览器中配置该设备.

The drawbacks of the 直升机 are few, but notable. The 直升机 requires all configuration to be done within a web browser user interface; there is no display and/or input control on the unit itself. 像这样, 在开始流式传输之前，您需要确保所有配置数据都已到位, unless you have a laptop on hand to connect to the same 网络 as the 直升机. The silver lining, though, is that the 直升机’s web interface is incredibly fast. Changes are near-instantaneous without laborious reboots of the hardware.

目前的固件似乎不支持b帧编码(在AVC / H的主配置文件和高配置文件中可用).264) very well, at least for typical RTMP pushes to streaming media servers. 最后, the output audio sampling rate is fixed at 48KHz; there is no option for using a different output sampling rate.

Matrox monarch HDX(1995美元)

I’ve been familiar with Matrox’s Monarch line for quite some time now, and have used the HDMI-only version of the 君主HDX 在很多场合. matrix有几款Monarch车型. HDX的价格略低于2000美元，它具有SDI和HDMI输入. 就像美国航空公司的直升机, 君主HDX设计用于安装在半永久性的a /V机架系统中，用于场地的常规和常规流媒体.

在君主HDX的后面板上，你可以找到所有的A/V输入和电源线插头. 在前面, you’ll find controls for starting and stopping streaming, as well as two USB ports and one SD slot for recording media.

君主HDX的可发现性需要matrix君主HDX Utils应用程序, 哪个报告IP地址, 设备名称, 序列号, 固件版本, and status of each 君主HDX on your 网络. Once you know the IP address of the 君主HDX, you can use that address in a web browser to log in and configure your streams.

君主HDX, 比如AJA 直升机, 只能配置一个网页浏览器，而不是一个内置的菜单显示和选项控制. 与直升机相比，君主的网络界面更新新设置的速度更慢. HDX是唯一的单元测试，有一个声音风扇运行时，只要单位上电.

OSPREY TALON G2 CONTRIBUTION ENCODER ($1,890)

This roundup provided my first opportunity to test an Osprey H.264编码器, and my research started just as the second generation, or G2,爪在预发布中. The form factor of the Talon G2, is like that of Teradek’s Cube family. While there’s no tripod or camera mount on the Talon G2, the form factor is small enough to fit in a camera bag. 这个单元是唯一可以从旧的rca风格的视频输入/信号进行编码的单元, 除了HDMI和SDI端子.

因为Talon G2有一个内置的触摸屏，可以在启动后显示设备获取的IP地址, there’s no need for a discovery tool to configure the device. The Talon G2’s web configuration is not as quick and responsive as the 直升机’s, but all of the necessary video and audio compression settings are available.

Teradek cube 655(1990美元)

The last unit tested in this roundup, and the most expensive, is the Teradek Cube 655. Teradek was one of the first “disruptors” to introduce lower-cost H.264编码硬件，Cube 655在早期型号(如Cube 255)的基础上进行了改进. The Cube 655 is designed for portable use; accessories allow you to mount the Cube directly onto a camera’s hot shoe or a tripod screw. While the Cube 655 doesn’t have an internal battery source, 您可以购买适配器，使您能够使用佳能流行的电池类型为其供电, 索尼, 日本胜利公司, 松下, 鲍尔和安东/.

就像美国航空公司的直升机, Cube 655的web配置页面可以被支持bonjourl的浏览器(如Safari)自动发现. The best feature of the Cube 655 is the built-in display and joystick, 它可以用来配置Cube的web配置页面中提供的几乎所有选项. 如果您想用网络浏览器配置该设备，Cube的显示器可以告诉您编码器的IP地址. 如果您想要灵活地更改编码或网络选项，而不需要连接到相同网络的设备, the Cube 655 may be the right choice for you.

测试过程及方法

针对视频点播(VOD)文件的各种版本运行定性度量相对简单. 这样做, you simply take a high-quality source file, encode it with different compression settings, 然后比较结果. With live streams, however, the process is a bit more complicated. 每一个小时.264硬件编码器需要接收相同的输入信号，并将压缩后的输出记录到文件中. Because not all the encoders tested can record to a locally attached storage drive, 我必须想出一个系统，通过网络记录出站压缩流.

减少网络变量, I set up Wowza Streaming Engine on my MacBook Pro, 它有一个固态驱动器(SSD)，可以轻松记录实时流，而没有任何磁盘I/O问题. On the same local 网络, I attached each of the H.264编码器. For source content, I downloaded high-quality 4K content from 4ksamples.com and downsized to Apple ProRes HQ 1080p 29.97帧/秒. Using Telestream Switch and Blackmagic Design UltraStudio Mini Monitor, I output the ProRes versions over SDI to a Convergent Design Odyssey7Q+. With the content recorded at high production quality, I could replay the same clip over SDI consistently to each encoder.

下一个页面