GH4 How much delay on HDMI output of the GH4?

R

rz786

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Has anyone measured the delay of the video signal on the HDMI output of the GH4? I'm looking for a camera to use for a live relay, and the output delay is very important. I've been using a 1080i/60 camcorder with 2 frames delay (which is okay), but the higher resolution cameras I've tried so far have 4-5 frames delay (not okay). For the GH4, I'm interested particularly in 4:2:2 8-bit output at 1080p/60 resolution.

The way I test delay is to run the timer at http://tft.vanity.dk/inputlag.html on a laptop that's positioned in front of a 1080p TV, point the camera at the laptop screen, connect the test camera's HDMI output to the TV, and then take a picture of both screens with a DSLR camera on a fast shutter setting. This is an example of a picture showing delay of ~66 milliseconds (4 frames) on a camcorder I've tried:

1ysf80.jpg


It may take a few tries to get clear numbers in the picture because there's no sync between the TV and monitor refresh rates.

If someone could please try this (or a similar method) on the GH4, I would appreciate it very very much!
 
I imagine it's important to remember devices down the chain can add latency too. This was one of the reasons I replaced my Zacuto & Alphatron EVFs with a Kinotehnik for HDMI monitoring.
 
Bern Caughey said:
I imagine it's important to remember devices down the chain can add delay too. This was one of the reasons I replaced my Zacuto & Alphatron EVFs with a Kinotehnik.
Click to expand...
Yes, the camera is only a small part of our live relay system. By itself, a 66 ms delay is acceptable. But I've also got HDMI<>SDI converters and a PC-based video mixer, and the overall delay with my 1080i camera is 140 ms and slightly noticeable on the TVs. I tried a Canon HF-G30 camcorder, which added another 60 ms, and then the delay becomes very noticeable and unacceptable IMO.
 
I did a test using a slate after I noticed my Zacuto HDMI EVF was laggy. I changed various settings, hertz, resolutions, frame rates... and they all gave me the same results. Here's what I found:
2 Framed delay from live image to the back of the Camera
6 Frame delay to Small HD AC7
9 Frame delay to Zacuto EVF

There are rumors that Panasonic is releasing firmware this month to fix some HDMI issues but we will have to wait and see.
 
I have no way of measuring it, but would guess the delay between my ninja blade and the camera lcd must be 6 or 7 frames. You wouldn't want to use it in your situation, imho
 
i did some tests when the shogun came out. the lag of the gh4 hdmi-output in all resolutions is about 3-4 frames. on a fast external monitor you should not expect much more.
 
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