Is it possible to record video at 4K?

Just wondering it is possible to record video at 4K.
Thanks,
Jeff

Hi jeffsarge,

Do you mean to make a screen capture?
If so: yes, you can make 4K captures.

The easiest way is to use screen capture software like Syphon Recorder (see the EboSuite manual ‘Record the video output’ or QuickTime Player). But you can also use an external recorder.

If you use screen capture software the quality (frame-rate) of the recording depends on three factors:

  • size of the recording (4K in your case)
  • quality of your hardware, mainly disk speed (SSD highly recommended), GPU power (dedicated graphicscard highly recommended), CPU power and available RAM.
  • complexity of the composition you’re recording, if it contains for example many/complex ISF filters/generators, resolution of ISF filters/generators,many HD/4K videos, complex video triggering, many LFO’s and Envolope Followers etc.

To make good recordings, you’ll have to find out what your system is capable of and if needed adjust the composition to make it play and record smoother. I often use 1280x720 videos when I make a screen capture and reduce the resolution of the ISF filters/generators if possible. I also remove tracks that are not really neccessary.

Thanks, Jeroen. I wonder if there is anyway to generate a frame accurate offline render?
Or an edl that could be used in an editing app to reconfirm clips at high res. Unfortunately that solution wouldn’t include any generated effects.
Jeff

Hi Jeff, yes, that would be very interesting. We even made it for early prototypes of EboSuite already. So it is on our list and we will make it in the future. But there are many things we are working on, so it will take some time.

@Jeroen

Hi! I am currently recording 4k screen capture with syphon and it works well with one frustrating exception: the audio is not in synch. And by that I mean the audio happens all at once over the span of a few seconds in the recording as if it’s been sped up 100x. I’m using ebosuite for a very specific purpose and it works fantastically for that, but the footage has to be manually lined up in editing software without the audio. I have questions about this, but here are my specs:

Mac Mini
6 core intel i5
eGPU with Radeon 5700xt
64Gb Ram

When I export, both the integrated graphics card and the eGPU show somewhere between 80% and 100% usage in activity monitor and the CPU is also maxed out the entire time.

Here is my question: if I used a mac with better specs or built a hackintosh with more CPU power and GPU power, would my projects export with audio? Or could that be an issue with syphon itself?

Hi @Scott , if getting a desktop PC is an option perhaps you could go for a 4K HDMI PCI capture card(like the ones from Blackmagic Design) in a mid-spec desktop with a SSD drive and windows.

Then you can use mac mini for the performance and PC for recording sound+video.
In this case audio should be in good sync as well.

Syphon Recorder will always be heavy on resoruces because it has to transfer huge amounts of data from GPU to CPU, compress it and transfer to the disk.
For a 4K movie it would be 3840x2160=8294400 pixels, then x4 for RGB+Alpha, and then multiply that with a desired FPS.
So for a 30fps 4k Movie Syphon Recorder would need to compress about 1GB of data per second, and also write most of that to the hard disk.
At the same time, EboSuite needs to read and decompress a lot of data as well.

So in total, it’s a lot for one machine, and frame drops are likely. Two machines should be able to handle it better.

1 Like

@nesa Thanks for the reply!

I appreciate the detailed suggestions. I do have a windows PC for streaming and a capture card like you mentioned.

Unfortunately, my number one priority is to keep the alpha channel and I can’t figure out how I would record on a separate computer with alpha channel.

If my current computer is a 3.2Ghz 6 core intel and I upgraded to a 3.7ghz 10 core, do you think that would be enough of an improvement to get audio working? On paper thats nearly double the power.

I forgot to add that the things I’m exporting are not very complex. Mostly alpha channel with small, single color graphics popping up around the screen.

@nesa I forgot to add, since I do have the Blackmagic Quad HDMI recorder, I have the inputs for recording alpha channel and main content simultaneously via two HDMI inputs. I’ve read that this is possible with some software in certain workflow situations, but I’m not sure this is possible with ebosuite. If it is, that would be very exciting

@nesa Ok sorry! One more question. If I were to have something like Final Cut or Davinci on the same computer, could I use one of those softwares the way I’m using Syphon Recorder?

hi @Scott , good questions:)
Sorry I missed the important detail about alpha channel - that is not straightforward with a capture card as far as I know.

About Syphon Recorder audio - I’m not sure if the speed up effect you are getting has to do with the CPU(although it could). Some other users also noticed weird issues with Syphon’s sample rate settings or similar - it would be best to check Syphon Recorder forums for support(Recorder itself is a closed-source project, so we can’t do much about it).
If you lower the ebosuite resolution, say to 640x360, does syphon still record sped up sound? If it does then we know it’s not about the CPU.

Now brainstorming about Alpha capture through HDMI.
I’d go for a max patch/device that has a syphon input, separates alpha and rgb, and displays them in two output windows - you can then route those windows to different hdmi outputs and set them to full screen(I’ve attached a quick’n’dirty device that does this).
You’d still need to manually put them together in the video editing software though, but at least everything should be in sync.

As far as I know, Final Cut doesn’t have a syphon input - dunno if Davinci does? If you run into a plugin for syphon input into these apps please let us know, that would be awesome.

hope this helps!
alpha-split.amxd.zip (276.7 KB)

cheers,
nesa