How to record computer screen output?

[Warren Kawamoto]

We have a gig coming up next month, it'll be a fast paced workshop with 1 projector and screen, with about 30 different presenters. How can we record what's being shown on the screen? We would prefer not to have a camera pointed at the screen, a video capture device between the laptop and projector would be ideal. The plan is the shoot a closeup of the presenter with 1 camera, and capture his slides with the device, then edit them split screen in post. Since there will be 30 presenters with 30 laptops/devices, we can't go around collecting decks from everyone. So the big question is...what device is best to capture their slides in real time?

Off the top of my head, I would imagine that most would use laptops with VGA out, others may have HDMI out. I could get a VGA to HDMI adapter, then record to this
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If their laptop has HDMI out, then the adapter would be bypassed. Another concern was that some HDMI devices may not show up on screen if they're not HDCP compliant. So...what hardware do I need to successfully capture anything/everything that comes down the line?

[Stephen Brenner]

You might want to consider the El Gato game capture hd system.
It's fairly inexpensive and the results are good.
I use it record satellite broadcasts where the satellite hdmi output goes into
the device and it sends an hdmi signal to the TV. The usb connection sends
the image to the computer for recording. You would need a double hdmi
output from your computer. First hdmi goes to the device which sends it
on to the projector, so you would actually use the screen as your main
monitor. Second hdmi goes to a monitor that has the recording software
running. If you wanted more control over what goes on the projector screen,
you might have to introduce a switcher in the line going to the device.

[Oren Arieli]

I'm thinking you'll want to put an Atmos Ninja in-line with the projector, and have everyone connect their HDMI output to your Ninja. I'm not sure how it handles loss of signal, so it would likely need someone to wrangle the box and keep an eye on the remaining capacity. You should check how well it works with non-standard (1920x1080) screen resolutions. Sounds like a scary proposition when you're dealing with 30 different systems. For safety sake, I would still roll a camera on the screen (which helps with timing as well). Don't even get me started on people who use their hands as pointers, which are useless when you're doing a screen capture or slide deck insert.

Atomos 4.3" Ninja 2 Video Recorder (Full Version)

[Seth Bloombaum]

Originally Posted by Warren Kawamoto

...Since there will be 30 presenters with 30 laptops/devices, we can't go around collecting decks from everyone...

I'd suggest you collect what slides you can to backup recordings.

If possible, it may be best to staff a position for Powerpoint management across 30 presenters... or even a handful. It's a lot of coordination.

Not to mention those presenters who say: "Can you just drop this photo in my deck? My admin usually does this, but it's a late revision, and she's not here, and the AV people always do it. You're AV, right?" (video staffer grumbles something about having other fish to fry) Presenter: "Wow, watch the attitude!"

[Andrew Smith]

I was involved in running a symposium in 2015 and one of the best things we did was to have everyone send their PowerPoint presentations in ahead of time. These were then assembled in to one master presentation file with everything in run-of-conference order, including slides for breaks such as lunch.

It. Worked. Flawlessly.

It also made sure that people were organised beforehand.

Andrew

[Vince Pachiano]

As a backup, I would use another camera to record the screen and the audio onto a single medium.

If you were to get the PPT slides, you need an iron-clad method to sync the Presenter and the PPT slides
If you were to in-line record the Projector, what if you lost one feed for 30 seconds, and when it picked up again, all you hear is, "And in this slide..." You need a record of what slide was showing.

[Jack Zhang]

You're ignoring the elephant in the room:

Open Broadcasting Software (OBS)

It encodes directly to a H.264 MP4 file (it doesn't just livestream to gaming and art streaming websites) and is one of the top alternatives for screen capturing. Consider it one of your backup recordings. You can have a onboard mic audio record for sync. For PowerPoint, it will only raise bitrate as needed. If you have audio in the presentation, you may want to use those as your sync points in the presentation and mute the onboard mic, and worst case scenario, sync on the slide changes.

It's portable if you grab the ZIP version (no browser) from the changelog page on the Multiplatform "Studio" version.

[Andrew Smith]

Ignore? I didn't even know it existed!

This looks insanely great. Chances are that it might not give the variable-frame-rate wobbles in the recorded file that cause the playback to go out of sync in an NLE.

Very interesting! Must play with this adorable new baby elephant thing ....

Andrew

[Jack Zhang]

There's even options for hardware accelerated encoding that might have a better chance of encoding a constant frame rate vs x264. If the processor has Intel QuickSync or the GPU has Nvidia NVENC, it supports hardware accelerated encoding.

[Jay Massengill]

Nice software suggestion Jack.

What about a presentation that isn't PowerPoint based, and is native to that presenter's computer, and it's a Mac and they didn't send anything ahead of time and won't let you put any recording software on their computer? It seems like there would be someone out of 30 who might be a problem.

Hopefully Warren has some major pull with the client who can get as much compliance as possible, especially ahead of time.

So have multiple backups to the software recording in place, including a good camera shot of the screen with strong, clean audio with either no delay or at least a known amount of delay if it's a really big venue.

I'd have the inline recorder ready as well, along with adapters such as Thunderbolt to HDMI and others like Display Port and DVI.

A stereo isolation transformer with unbalanced to balanced conversion is good to have also if any presentations have embedded sound.

Who is handling the House PA duties? Is it separate from audio-for-video or all integrated?

It is important to have very clean, high-sensitivity mics that do NOT go to the PA system as a backup going only to your recorder if there is a problem with the house sound.

[Jack Zhang]

Grab the portable version, however I'm not sure that can be done on Mac OS...

It's easy with the Windows version with the ZIP file, but the Mac version still has to be installed.

[Andrew Smith]

BTW, the standalone version zip file is giving me errors when I try to unzip it via Windows. Any suggestions?

Andrew

[Jack Zhang]

Try using 7zip. It may be using compression algorithms Windows is not familiar with. Check the filesizes too, if it seems small, the file didn't download fully.

[Warren Kawamoto]

Thanks everyone for your suggestions! I'm still trying to untangle the requirements for this gig. 30 presenters, some will have Windows with powerpoint, some will have Macs with Keynote, others may have proprietary devices that are locked with HDCP. Getting a presentation ahead of time is not ideal because of how quickly their industry standards change. (It changes daily, so presenters may be changing their slides up to the last minute!) At first I thought it was a one man job, but now it looks like a highly skilled dedicated team is required. Holy cow

[Andrew Smith]

At least you know beforehand, and can demonstrate that you have done your homework on this one.

Yeah, we help you look good! :-P

Andrew