GH4 HDMI out for FPV

Discussion in 'Cameras' started by Steve Maller, May 5, 2014.

  1. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    I second the motion, Mr. Maller, he of the UAV Grief Counseling Fame. (Edit: That TJ keeps his metal and we give him an asterisk.)

    I was talking to a colleague the other day about the HDMI specification and it is (as we've seen) a bidirectional protocol -- in other words the GH4 "knows" (for some value of "knows") what device it is connected to and modifies its behavior based on that. Unfortunately because HDMI claims to be an "intelligent" or "smart" protocol, it falls under Johnson-Laird's Sixth Law: Any device with "intelligent" or "smart" in its name is not.

    If you have the DMW-AVC1 cable connected as you describe above, what's on the other end of the cable, Steve? Nothing?

    Andy.
     
  2. Steve Maller

    Steve Maller UAV Grief Counselor

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    :)

    For my test, I had the RCA composite cable end plugged into my SmallHD display with the SmallHD's Composite setting enabled.
    And unlike your typical testing environment, I was securely connected to a cup of Peets Sumatra, fresh-ground and brewed slowly in my kitchen.
     
  3. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    You'll get different results if you go with Illy coffee. :)

    It will be interesting to see if you get the same response from the GH4 if you're connected to your HDMI to CrapDef® converter. I suspect the converter will self-identify differently from the SmallHD. Just a hunch.
     
  4. Steve Maller

    Steve Maller UAV Grief Counselor

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    Just to be clear, the DMW-AVC1 cable does not connect to the HDMI port. It's a composite video connector/cable that plugs into the GH4's A/V port, not unlike the composite cable for the Canon 5D Mark III that provides an alternative to the Canon's HDMI port.

    In this graphic from the GH4 manual, the HDMI port is #24, and the A/V port is #23.

    Screen Shot 2015-07-05 at 11.00.07 AM.jpg
     
  5. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Aha. So it's emitting a CrapDef® signal at the outset. Got it. :)
     
    Steve Maller likes this.
  6. Chris Delaney

    Chris Delaney Member

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    Folks, Ive read all 8 pages of posts here. Here is a pic of my setup. 20150707_131649_resized_2.jpg

    Immersion vtx with 5v going to usb. I have the camera HDMI REC OUTPUT set to auto. She is currently on 4k24 24.00Hz (Cinema)

    Nothing, Any help would be appreciated. I am on FW 1.1 wanted to try it before updating.
     
  7. Chris Delaney

    Chris Delaney Member

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    What vtx did work and what didnt? thanks
     
  8. TJ_Sheridan

    TJ_Sheridan New Member

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    I've been off-line for a few weeks and am just getting back to the task of setting up my M5.

    Here's what I've learned with further testing.
    G7 is an awesome camera, and the HDMI output port works great, but as with the analog video port, it SHUTS OFF the external feed once you start recording, even the HDMI port. UGH! Why?!

    So for aerial work the G7 is not a useful camera if you're pulling your primary video feed from the camera itself. It would still work great as a dumb camera if you used a secondary FPV camera or something for your video feed.

    I purchased the Hyperthin HDMI cable for my tests, and found that Andy's statement 7 posts back is absolutely true. My HDMI monitor is a smart monitor, and it refused to accept the HDMI video feed from my GH4. As that is my only HDMI monitor, I haven't been able to get live video from the GH4 working.

    I also purchased two different HDMI to RCA video converter boxes from Amazon, and neither of them will convert the video signals from the G7 or GH4. They both were epic failures.

    I'm heading out now to drive to a friend's house. He has an HD monitor that he knows will work with the GH4 & Hyperthin cable, and he has an Amazon converter box that he knows works. So I'll take my cameras up and test everything with his gear.

    At this point, I'm learning that all of this "high-end" expensive gear is really not all that much better than the inexpensive FPV stuff I've been using all these years. It's all a bunch of voodoo witch-doctoring mumbo jumbo. Ya gotta sacrifice a frog and drink concoctions of fly-wings and bat blood, and do a chant dance to the FPV GODS before you can get anything to work. It's ridiculously stupid and depressing. At this point I've wasted thousands of dollars trying to get this gimbal working and have nothing but a headache to show for it. And I haven't even gotten to the point where I'm mounting it to an aerial rig, for heavens sake! I'm still just trying to get it all functioning as a hand-held unit!
     
  9. John Sciarrino

    John Sciarrino New Member

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  10. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    My experiences are that there's HDMI and HDMI. To be specific there are several different alleged "standards" for HDMI (to wit 1.0, 1.1, 1.2, 1.3, 1.4 and 2.0), but different vendors only implement certain parts of the HDMI standard (or so it seems). HDMI is also a bidirectional interface so that the signal source (camera) is "aware" of what is connected to the other end of the HDMI cable and modifies what it does based on what it thinks (or hopes, or guesses) might be at the other end of the cable.

    The net effect is that whether device A works with device B is as certain as winning in Las Vegas.

    This was brought home last week when I connected up a new Samsung TV to a current version Tivo and the audio suffered from random dropouts (total silence a few milliseconds long) making the TV unwatchable. The fix: Tivo recommends turning OFF the consumer electronics control (CEC) portion of the HDMI "standard" because it causes problems. For which read, either Samsung or Tivo has not implemented the full HDMI 2.0 standard although both vendors tout the fact that they have. Why they would not actually implement HDMI-CEC (which allows the TV to control the Tivo or vice versa, I presume) remains a subject of mystery.

    I think this might be the voodoo to which you're referring TJ. But you are absolutely right -- although personally I've not had to go with offing a frog -- the flywings and bat blood yes, but no frogs yet.

    "The nice thing about standards is that you have so many to choose from." Andrew S. Tanenbaum

    Andy.
     
  11. John Sciarrino

    John Sciarrino New Member

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  12. Chris Delaney

    Chris Delaney Member

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    I broke down and bought the kopterworx version and it works flawlessly. I have posted pics on the multirotorforum of what the board looks like. You gotta either buy the kopterworx or find a "hdmi2av" that has the same version board. Problem is, of all the white box sellers I contacted not one is willing to confirm what board is inside. They all say buy it and return if it don't work. Too much hastle specially living in Canada.
     
  13. Howard Dapp

    Howard Dapp Active Member

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    As mentioned in a previous post, there are two hdmi (white box) converters sold by amazon, one is only able to convert a 720p signal to composite and the other is able to convert both 720p and 1080p. We all want the 1080p box, especially for the GH4 since its hdmi signal is 1080p. Both boxes look identical so there is no way to tell the difference up until recently. A company named Tendak offers the 1080p version that we want. Just search Amazon for Tendak converter. Photos showing the difference attached. image.jpg image.jpg
     
  14. Chris Delaney

    Chris Delaney Member

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    To confuse things even more my box said 1080 right on the package and it doesn't work. Kopterworx version on left. Notice the heat sink and 2 capicitors. 1080 box on right. Does not work. 20150713_171354.jpg
     
  15. Chris Delaney

    Chris Delaney Member

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    Sorry wrong pic. Here is the right one 20150713_171344.jpg
     
  16. Chris Delaney

    Chris Delaney Member

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    Howard. Have you confirmed the tendak works with the gh4? Thanks.
     
  17. Howard Dapp

    Howard Dapp Active Member

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    Yes, the Tendak 1080p converter works with my GH4.
     
  18. Chris Delaney

    Chris Delaney Member

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    do you need to supply power?
     
  19. Howard Dapp

    Howard Dapp Active Member

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    The GH4 powers the converter without any additional power. Regardless of this I power the converter box with 5v...just as added insurance.
     
  20. Chris Delaney

    Chris Delaney Member

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    Ok thanks. Good find.
     

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