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HyperDeck Studio Mini recording flickering image from laptop

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Edward Mantle
HyperDeck Studio Mini recording flickering image from laptop
on May 21, 2018 at 9:08:17 pm

Hi all,

I filmed an event recently where I tried to record the output of a client computer to a HyperDeck Studio Mini but got a flickering image. I was recording the presentation to save me some time inserting the actual slides in for an edited version mixed with my camera footage.

Just wondered if someone could help me troubleshoot as obviously the content wasn't usable for the final edit.

Unfortunately I don't have access to the same set-up until the next event so am looking for some obvious solutions I can quickly try the morning of the next presentation. Short of trying all new equipment that is!

Workflow:

PowerPoint on client laptop>
Mini DisplayPort to HDMI converter (client's own unfortunately so not able to test) >
HDMI splitter >
HDMI1 - HDMI cable > venue projector (which looked fine suggesting any issue was from this point onwards in the chain)
HDMI2 - HDMI cable > BMD HDMI to SDI Micro Converter >
SDI (Van Damme 30m cable) >
HyperDeck Studio Mini (which said the signal was 1080i 59.94)

Playback of the actual image I recorded looked almost a bit like aliasing. To clarify, not all of the entire image flickered, certain sections were worse. It was more pronounced on certain slides (to the point of being unusable). I didn't notice it for a while as I was monitoring on the small screen on the HDSM itself but did spot it on certain slides. However it looked so similar to some kind of aliasing artefact so I thought it was just a byproduct of showing complicated spreadsheets etc in tiny form and wouldn't be actually recording like that - my mistake!

I've tried the HDMI to SDI Micro Converter elsewhere and had no problems.
I've also tried the splitter and had no problems recording a video file (though admittedly haven't tried a .PPT)
I've also tried the SDI cable and again, no issues.

I wonder if it was something to do with the refresh rate/output settings on the laptop but assumed the HDSM would just decide what was most appropriate and capture that. (I know that I have to have specific/matching input settings for all sources when using something like the ATEM which made me think it might be related). Another thought is that it might be the recording codec on the HDSM - I was using lowest res 1080 proxies to make sure I had enough space for the 4+ hours of content. I'm sure I can rig up a way to test this myself before the event if that sounds like it might be an issue.

i also appreciate there are a lot of converters in that workflow and it's far from ideal as a set up, so if anyone has a better suggestion I'd be all ears!

Similarly if anyone has had any similar experiences with the HDSM and wants to make suggestions on what to try please feel free!

Thanks
Ed


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Jeff Pulera
Re: HyperDeck Studio Mini recording flickering image from laptop
on Jun 5, 2018 at 6:05:00 pm

Hi Ed,

Computers typically do NOT output with correct frame rates for VIDEO, for instance computer display output is 60.00fps rather than the proper 59.94 or 29.97 of video. Also, computers do not output INTERLACED video. So that, coupled with going through various adapters = not good results in recording. Most likely a Progressive signal was changed to Interlaced...or just looked like Interlaced...going to the HyperDeck, thus the flickering.

The HyperDeck is really looking for a video signal from a camcorder or video mixer meeting standard video specs, not a computer display signal. Perhaps try an . mp4 recorder meant to record video gaming screen from computer, usually less than $100 with HDMI input.

Important when recording computer/laptop output that the display resolution at least matches video frame size - either 1280x720 or 1920x1080 - and is not set to some off size like 1680x1050 (as my office PC is to match display).

Maybe look into using NDI (from Newtek) over the network. Free apps with lots of potential! Run NDI Scan Converter on the computer, which will send out the screen contents as NDI over the network. With another computer, you can RECORD using NDI IsoRecorder (records .mov file). Or use free OBS app with NDI plug-in and record NDI stream as .mp4 that way.

Of course there are screen capture apps that be installed directly on the computer, but I realize when you show up to videotape a meeting/event, you don't always have time/access to that computer to set up and test software. Goes back to using gaming capture box for simplicity via HDMI.

vMix Desktop Capture app (free) - https://www.vmix.com/software/download.aspx
Newtek NDI Tools (free) - https://www.newtek.com/ndi/tools/

HDMI recording box example - http://www.avermedia.com/professional/product/cr530/overview

Thanks

Jeff Pulera
Safe Harbor Computers


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Edward Mantle
Re: HyperDeck Studio Mini recording flickering image from laptop
on Jun 5, 2018 at 7:53:25 pm

Hi Jeff,

Thanks so much for such a detailed response. Really appreciated.

Oddly, this week I've managed to replicate the scenario (with the exception of not using the clients display to hdmi converter) and didn't have run into the problem. In fact the footage looks pretty good especially on the higher bitrate ProRes files. I'm planning to experiment with h264 after the 6.0 firmware update on the HyperDeck.

Still, I'll definitely check out the options you offered - that EzRecorder seems like a very useful thing to have in the kit bag.

Thanks again,
Ed


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