Simultaneous multiple HDMI outputs

Hi, I am having a problem and would like to know how I could solve the following situation:

I am using a Macbook Pro M1 and I want to send images directly from the Macbook (using two HDMI outputs of this same Macbook) to two stacked projectors (both projecting the same image received from these two HDMI cables coming from the Macbook via Ebo).

1 - Is it possible for eOutput to recognize the 2 HDMI outputs (the 2 projectors) at the same time?

2- I tested sending a single HDMI signal from the Macbook to another Macbook running Resolume, so that from this other Laptop running Resolume the split for the two projectors could be done, obviously it worked, but with a problem, and a big problem: I had a significant loss in the quality of the projected image. What could be going on?

3- This third question is a little different from the main question, but it is also very important, because it also refers to the quality of the final image that the public will see.
All my videos were originally created in ProRess 422HQ 1920 x 1080 30 fps, and then converted (using AVF Batch Exporter) to HapQ, keeping the same settings as the original. I have noticed, that the videos do not run smoothly, I notice several stutters all the time, as if the machine has no processing power (obviously the M1 PRO has plenty). What can be happening?
Something to do with the conversion from ProRes to HAP?
Something to do with “# of Chunks” (kept Off (default)?
Is this an Ableton glitch?

Any help to help me solve these issues would be greatly appreciated, I have a big show to premiere next month.

1 Like

Hi Andre,
Thanks for your message. I will try to answer them below:

  1. EboSuite only has 1 output window, but that window can span multiple physical outputs. It cannot automatically copy the output that is sent to one physical output to another. Here are a couple of ways to achieve what you want:
  • use an hardware hdmi splitter: this is the best way I think, it just works and doesn’t ask anything of macbook
  • set the output to fullscreen on the first hdmi output, also put an eVideoOut device on the master and route that syphon stream to the second hdmi output using a max patch (we can make that max patch for you if you’d like)
  • set the EboSuite output to span both hdmi outputs. Put an eTrackTransform on the track with the video and make sure it fills the first screen and put an eVideoOut after it (do you play 1 track or multiple video tracks a the same time during your performance? with multiple videos the situation is a little different) . Create a new track and put an eVideoIn on it (make sure it uses the previous track as source) and make sure with eTrackTransform that it fills the second screen.
    I can make an example set of this if you want.
  1. Can you explain how you send the hdmi signal from one macbook to another? You need an hdmi capturecard to do that and to be able to handle the data it will probably recompress it in realtime.

  2. In our tests on a M1 laptop (I think it was the M1 Max) there was not a notable difference between Hap and Prores while using EboSuite. So my first advice would be to just use Prores in your case.
    I do not understand though why it would stutter, the first thing that comes to mind is that it might be an harddisk issue. What kind of harddrive are the HAP files stored on? It really needs to be an SSD and if it is on an external drive, then does it have a high bandwidth connection to your mac?
    Yes, experimenting with the Chunks might improve your performance, but it is hard to say beforehand what the best setting will be for you. I will also depend on the details of your mac (e.g. how many cpu cores) and also on details about your composition (e.g. how many videos you play back at once). For now my advice will be to use prores, since the performance of this has been greatly improved on M1 systems.

I hope these answers will help you further and depending on what you will choose as a next step we are here to help.