2019年8月20日
By 1月时特约编辑
专题文章

罗兰VR-1HD AV流混频器回顾

Roland的VR-1HD(1美元),495) is an inexpensive video mixing appliance that’s an alternative to software-based mixers like Wirecast or vMix. 在这篇综述中, we’ll look first at the basic hardware mixing capabilities of the VR-1HD, 然后看看一些高级的音频混音功能. We'll follow that with features available when you connect the VR-1HD to a computer, 包括记录, 流和一些额外的混音功能.

作为概述, the VR-1HD mixes audio and video 从 multiple sources and sends a configurable webcam-like USB stream to a computer to push to a live streaming service. 该装置具有适合广大用户的特点, 包括游戏玩家和音乐家, though my focus will be on more prosaic interviews and webinar-type productions.

视频I / O

该设备有三个视频输入，都是HDMI. 输入3是无延迟输入，可直通到HDMI输出, so if you’re a gamer you can route your monitor output through the board with zero delay. 除了Through输出, there’s a Main output which displays the live audio and video feed and a Monitor input you use to control the menu options and configure the outputs. You can probably live without the Main output if you’re space-constrained, but you should set it up the first few times you run the unit to get familiar with what it does and how it works.

您可以从任何HDMI源输入音频. 除此之外, there are two XLR/1/4" combo jacks with phantom power and a line input via RCA connectors. 此外，该设备还可以通过USB从计算机输入音频.

The onboard mixer contains volume controls for the two mics and line input, 但对于HDMI信号或USB输入的音频则不适用, 虽然你可以通过菜单命令设置这些级别. 你可以通过耳机插孔收听, 并将音频发送到任何监视器, 加上线路通过两个RCA插孔, 加上音频与现场USB馈送.

基本视频切换

图1 shows the switching surface with the three video inputs on the bottom right. 运行时, the buttons for all live feeds are lit; red if the feed is currently live, 白色，如果可用，但不是活的. As you would expect, you switch through the feeds by clicking each button.

图1. VR-1HD切换面

在三个输入的左边是自动开关按钮, which lets you select one of the four auto-switch options discussed below. 与所有可配置选项一样, you choose and configure your options via the Setup box in the middle top, where the Menu button opens the menu and the Value knob lets you move through and select your options.

视频输入的上方是场景部分, which lets you combine inputs via picture-in-picture or horizontal or vertical screen splits as shown below buttons A-E. The unit comes configured with the combinations shown below the buttons which you can customize to your liking by clicking the Scene Edit button and using the Value knob 从 the Setup section.

场景设置

My basic test configuration was two input cameras and a PowerPoint presentation coming in 从 a computer. 尽管我不需要配置任何输入, VR-1HD可以缩放, 规模, 位置, 然后调整亮度, 对比, 或任何输入的颜色值.

将输入组合成图中所示的图图2, you work with the buttons in the Scene box in the middle right of the switching surface (图1). Click the button to configure (I used Button A for 图2) and then Scene Edit, which exposes controls that you work through using the Value knob at the top of the unit. Here you choose the background and foreground videos and can adjust the size, 纵横比, 裁剪, 缩放比例, 以及小窗口的位置.

图2. The Roland makes it easy to configure picture-in-picture shots like this one, with PowerPoint coming in via HDMI 从 a computer and the video coming in 从 a camera.

I configured Button A for the picture-in-picture shown in 图2 and Button C for a side-by-side shot of the two video feeds. 制作过程中, the configured Scene buttons act like individual inputs that you switch to by pressing them, 就像使用右下角的三个输入按钮一样. So, 如果主机输入1, 客人输入2, 和一个并排的组合，你已经配置为输入C, 你可以通过按输入1手动切换三个镜头, 输入2, 或场景C, 哪些过渡到选定的镜头或场景. 对于制作人/表演者来说非常简单，也非常容易管理.

然而，过渡是非常时髦的. 例如, 切换到合成视频时, the two videos comprising the composited shot never appeared simultaneously. So, 如果你从单一镜头过渡到并排合成, the videos in the side-by-side video appear at slightly different times. You can minimize this by shortening the transition time but you can’t eliminate it; even with a zero transition time, 合成镜头中的一个视频将在另一个视频之前出现.

除了, 你有三种转换选择, 混合褪色(溶解)或黑色褪色(从黑色渐变), 或者，如果你将转换时间设置为零，就会出现切割. 但是只有过渡到, 从, and between composited scenes can be black fades; all others are mix fades or cuts. So, 如果你选择黑色渐变过渡, 当你从一个相机输入切换到一个场景或场景到场景, 你会得到一个黑色的退色, 但如果你直接切换摄像头输入, 你会被溶解或割伤. 您可以配置场景来模拟摄像机输入，以避免此问题, 但是你会失去三个场景. 不是一个节目的结尾，但有点不寻常.

标题和静态图像

You can create a title in any image editor so long as you output the file in 24-bit uncompressed BMP format. 你可以输入黑色或白色，我创建的标题如图所示图3 as a 1920x1080 white image in Photoshop with the text and red background shown. 你把标题复制到u盘上, 把它插到VR-1HD后面, 将图像加载到单元中, and display the title by pressing the Key button on the upper right of the unit.

图3. 输入和显示标题非常简单.

这对于一款游戏来说非常简单, 但是如果你要调换主人和客人的头衔, 你必须通过菜单系统来加载第二个标题, 如果你在制作和表演，这可能很难做到. 下面将讨论另一种软件.

To display images in the presentation you have to assign them to an input channel, 将HDMI输入从三个减少到两个. 您可以在单元中加载两个图像, but there’s no easy way to switch between them; you have to enter the menu system which, 再一次。, 如果你既是制作人又是镜头，会不会很麻烦.

整体, configuring and switching your video inputs will be simple for all users, 即使你在制作和表演. If your productions are image intensive you may wish to find a different alternative.

That’s most of the video side; now let’s look at audio.

音频混合

VR-1HD在控制界面的左侧管理音频(图4). Start by pressing the Level Setup button, which lets you set incoming dB levels for all inputs. 你可以看到mic1的单独音量控制, 麦克风2, 和Line输入, 加上主输出的输出控制, USB流, 和耳机.