Many of us participate in video conferences several times a week, making the convenience of a webcam—as opposed to other options—paramount. I produce most of my live training with a webcam because the quality delta between a webcam and other options is negligible when presented in postage-stamp-sized videos. But what setup should you use for a really important conference or a call that will be distributed to many viewers live or on demand? 这就是事情变得有趣的地方.
Such was the case for a recent interview with marketing personnel from BaishanCloud, a leading global cloud data service provider with more than 500 points of presence in China. The conversation focused on best practices for live streaming and global distribution and involved technologies like hardware H.264/H.265 encoders, QoS and QoE, and multiple CDN delivery.
不幸的是, I was in the middle of shooting some video tutorials on the ATEM Mini Pro and my office was a mess, so I couldn’t use my normal webcam-based setup. First, I tried the embedded webcam on my Mac display, but I was unable to make the exposure work. 具体地说, I was lighting the training set with LCD lights, and the Mac webcam always seemed a touch brighter than I wanted. I tried reducing the intensity of the light panels, but the webcam kept compensating by boosting the gain.
I switched to my Logitech C922 Pro Stream webcam and got the same result: overexposure to an almost garish level. 澄清一下, both webcams have been serviceable in the past, but something about the lights I set up for the training shoot was freaking them out. We actually filmed a couple of takes with the Logitech webcam, but when the BaishanCloud marketing folks started editing the recordings, 他们问我有没有别的选择.
幸运的是, I was shooting one camera angle of the ATEM tutorial with a Sony a6300 DSLR, which of course was connected to the ATEM Mini Pro. I tried connecting the ATEM Mini Pro output to the Mac Mini I was using for the Zoom conference, but the Zoom software didn’t recognize the input. I’m sure that was a glitch that I would have been able to correct, but rather than debug while others were waiting, 我换成了
solution I knew would work: the Epiphan AV.io 4K, which is my go-to USB capture device.
我连接了a6300， AV.io, and Mac Mini, and Zoom recognized the AV.io立即. 质量的提高是惊人的, compared not only to the overexposed output from the webcams but to most other webcam output I’ve seen in the past. 在重新录制采访之后, 我的主人, 伊芙郭, took a frame grab for the company’s marketing purposes. She sent a copy for my review, and I was impressed with the quality of her video. I asked about the source and, not surprisingly, learned that they were using a Sony a6400 DSLR.
Note that using a DSLR instead of a webcam is more technically challenging, particularly if you like to customize exposure-related settings such as ISO, 快门速度, 和光圈, 像我一样. 看看现在的图像, 比我想的要暗一些, which often happens when you’re rushed when setting up your lighting and exposure. Unless you’re very comfortable with camera operation, you may be better off with a webcam. 然而, if your boss or a co-worker has to look good on camera, and you can drive the camera (or have someone drive the camera for you), 单反相机是最好的选择.
The bottom line is that some shooting conditions are so severe that a webcam simply won’t cut it; you need a device that offers more control. There are also times when video quality really matters, particularly when you’ll be one-half screen or even fullscreen. In both cases, a DSLR like the a6300 (or a6400) just might be the perfect solution. Or, find a DSLR that you can connect to your computer as a webcam. Although Sony offers a download that supposedly makes the a6300 work as a webcam, I couldn’t make it work when I tried in the past, 所以我用AV.io.
Using a DSLR instead of a webcam will typically produce better results, but it’s also more technically challenging. Note that the image of the author (left) is a little on the dark side.
If you're charged with configuring your encoding ladder, there are a few datapoints you should have nailed. The most important is the VMAF score of the top rung of your encoding ladder.
2021年7月9日