So I've never posted here but have heard many great things, I figured I'd take a shot. Apologies in advance if I'm asking in the wrong spot or something that has already been answered, I looked but didn't see anything and it's pretty niche.

I am wondering if it is even possible to have a raspberry pi pass through an HDMI signal, specifically only if there is an HDMI signal at it's input and to just send that same video out. Additionally, if there is no HDMI signal I want the Pi to send out a blue screen or static image HDMI signal that can pass audio. Below is the scenario I'd like to dig into but I'm fairly new to Raspberry Pi and coding in general and before I take a deep dive into it I wanted to know if it was even possible or if there are inherent hardware limitations that I don't know about because of my relative ignorance of this platform.

I have a video signal coming from a camera, when that camera is on it's HDMI video goes to an audio injector ( link here ) that embeds audio into the HDMI signal and then goes to a recording device ( link here ) where it can be viewed live and recorded.

My issue is that when the camera is turned off I still want to record that audio stream but the HDMI signal isn't there for the audio inserter to work with. There isn't any way for the audio inserter to create an "blank screen" HDMI output with just the audio there so the audio never makes it to the recording/viewing screen. What I would like to make is a system that sits in between the camera and audio inserter that knows when there's an HDMI signal coming from the camera and just passes it through and when there isn't one the Pi makes an HDMI stream with a static image or colored screen that gives the audio inserter enough to work with to send the audio upstream to the recording/viewing screen.

I don't necessarily care about the video that is being displayed when the camera is off, I only care about the audio so if there's something that I've overlooked like a way to enable standalone audio embedding I'd be glad to go down that road too.

Hopefully I haven't created a wall of text so large it'll get ignored and again I'm new here so any etiquette that I've missed let me know and I'll be sure to keep that in mind going forward. Thanks.

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  • 2
    I don't think the pi has a hdmi input?
    – user10489
    Jun 23 at 5:01
  • if you are worried about a wall of text, then don't include paragraphs like the first and last one ... they have nothing to do with the question
    – jsotola
    Jun 23 at 5:39
  • @user10489 Indeed, the Pi has no HDMI input. Perhaps make that an answer? Nothing else needs to be said.
    – joan
    Jun 23 at 8:28
  • I'm honestly kind of surprised by these comments because a quick Google search turned up a few options for a raspberry pi HDMI input. I'm also not quite sure why this post has been voted down, it's a legitimate question Here is a link to one of the HDMI in Boards I found for reference. a.co/d/gxpT1gs
    – Bricksauce
    Jun 23 at 15:52
  • @Bricksauce: That's why I didn't write this up as an answer. I think I only have half the answer. The other half is, can an HDMI input be added and can the pi process and pass through the results? Note that the pi doesn't have an audio input either (as far as I know).
    – user10489
    2 days ago


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