GH4 HDMI OUT to External Recorder

TheTrickster said:
BUG!

I can confirm that the GH4 is outputting incorrect framerates at the HDMI port in relation to those it's recording.
1080p25 is outputting 1080p50
1080p30 is outputting 1080p60


1080p24 is outputting CORRECTLY at 1080p24


Plugged the GH4 directly in to my TV (1080p) and it tells me what it's receiving (1080p60) when the camera is recording 1080p30
Click to expand...

I wouldn't typically call that a bug. A lot of cameras piggy back 25p on a 50i or 50p path and 29.97 on a 60i or 60p path. In the past it was always 60i to make it a broadcast standard signal (or 50i). The problem is a lot of external recorders and computer capture cards don't take 50p or 60p.

Is there a 50i or 60i option on the GH4 for those modes? On my GH3 I can use 60i for the HDMI output signal. To a recorder it doesn't matter if the signal is 6oi and you are shooting 29.97p. Each frame will look the same anyway.

It sounds like Panasonic was smart enough to make the 24p output special because that was always a pain with HDMI anyway. Typically it would sit inside a 60i or 60p signal and required 3:2 pulldown.

So in a way it kind of makes sense why Panasonic would make a special 24p HDMI output path but leave 25p and 29.97p in a typical video standard path. Not that 50p or 60p are broadcast standards. Thats why there should hopefully be an option for 50i or 60i in those situations.
 
Still waiting for my cables.
Anybody can confirm monitoring externally 1080p25 while recording internally 4K25p is possible?
 
For those of you interested in a GH4/Ninja combo - I can confirm there is an interlaced output from the GH4 when in avchd mode, and 10 bit 422 is selected over hdmi - it's either 50i or 60i depending on selected system frequency. This should be good for both 25p and 30p recording with an atomos unit, as I believe ninjas will perform pulldown with an interlaced stream from 50i and 60i. Any other mode (eg .mov) on the GH4 produces a 50p/60p stream over hdmi. Therefore I'm inclined to think it's more Panasonic's problem than an Atomos one, as the Atomos spec clearly states that 50p/60p are not supported framerates.

It seems a curious choice on Panasonic's part to output 50p over hdmi when one chooses a 25p codec (other than avchd) - perhaps we can hope for a firmware upgrade to address this, as the camera is clearly capable of outputting both interlaced and progressive streams. As it stands, I don't think anybody is going to be able to record 4k at 25/30p internally and 10bit 422 1080p over hdmi at the same time.

Bill
 
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mr bill said:
For those of you interested in a GH4/Ninja combo - I can confirm there is an interlaced output from the GH4 when in avchd mode, and 10 bit 422 is selected over hdmi - it's either 50i or 60i depending on selected system frequency. This should be good for both 25p and 30p recording with an atomos unit, as I believe ninjas will perform pulldown with an interlaced stream from 50i and 60i. Any other mode (eg .mov) on the GH4 produces a 50p/60p stream over hdmi. Therefore I'm inclined to think it's more Panasonic's problem than an Atomos one, as the Atomos spec clearly states that 50p/60p are not supported framerates.

It seems a curious choice on Panasonic's part to output 50p over hdmi when one chooses a 25p codec (other than avchd) - perhaps we can hope for a firmware upgrade to address this, as the camera is clearly capable of outputting both interlaced and progressive streams. As it stands, I don't think anybody is going to be able to record 4k at 25/30p internally and 10bit 422 1080p over hdmi at the same time.

Bill
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That is typical of how many cameras output 25p or 30p and not just a GH4 thing. 30p over a 60i HDMI output is identical in quality as long as your recording is 4:2:2 or better on the external device. When you edit just conform or interpret the 60i videos to 30p and the NLE will think they are just 30p videos. The NLE will just use both fields together instead of thinking it should display a single field at a time. Very easy to do in Premiere CC and FCPX.
 
Yes, but can't the GH4 switch to a 50i HDMI output even though you are recording 25p? If you are shooting 50p then you may be sol because many HDMI recorders do not recognize 50p. That isn't a GH4 issue but the fact that 50p HDMI is non standard and many devices do not yet support it. None of my capture devices will capture 50p or 60p either. You have to search for a capture device that actually does support capturing of 50p or 60p at 1080p.

Another option is HDMI output of 1280x720. Then you would get 50p. Obviously not a great solution but that is what you have until you can find a capture device that supports 50p/60p capture at 1080.
 
This is EXACTLY the problem we are discussing. The GH4 does not output 50i/60i in any mode other than if you select avchd - it's all 50p/60p over hdmi unless you're recording 24p. What we would like is a firmware upgrade to offer 50i/60i in all modes
 
If you plan on recording externally why is there a disadvantage to selecting AVCHD then? The internal format doesn't matter since you will be recording externally. Now if you want to reord both internally and externally I could see this as an issue but if you can live without the internal recording then set the camera to AVCHD and record externally in the exact same quality as if the camera was set to mov internally. Yes a workaround but one that isn't too difficult to use and shouldn't affect the quality at all.
 
This, way back when, was the point - to be able to record a high bit rate, best res possible 1080p back up internally, as well as output to an atomos device.
 
Well I don't know what to tell you then. I gave you some options. While not perfect you will have to choose one option for now.
 
hdmi output problems

hdmi output problems

I am also experiencing issues with GH4 hdmi output:


I did a live shoot/broadcast yesterday (http://youtu.be/W_lchUnz77s) with two GH3's and a GH4 connected to a Black Magic switcher (I don't know the model of the switcher). The GH3's were a breeze to set up, but the hdmi was very finicky on the GH4. After trying all settings and two different cables, I could not get the GH4 to send a video signal in MOV mode that the Black Magic switcher would recognize. However, the audio signal did pass through; just the video won't cooperate. I eventually stumbled upon using AVCHD to get the video signal to be recognized (as others have mentioned in previous posts). Even when set to AVCHD, I had to insert my Zacuto Z-Finder monitor between the GH4 and switcher to get a video signal that the switcher would recognize.

FWIW, I also can't get the hdmi signal to properly playback recorded videos on my home televison unless I put the Zacuto between the GH4 and the tv. Without the Zacuto, video playback has inverted colors. BTW, the GH4's video/audio signal DOES pass through properly to the tv when the GH4 is in record mode, even without the Zacuto in the signal path. I never have these hdmi issues with my GH3.

I will follow this thread, and hope a solution is forthcoming.
 
This is likely due to the GH3 like most cameras before it using a standard everyday 1080i hdmi signal which everything on the planet can recognize. The GH4 going for quality seems to be forcing the use of 60p in most cases which most Blackmagic devices will not work with. Not really a limitation of the GH4 but a limitation of most HDMI devices out there that have refused to support 1080p 60p. None of my Blackmagic devices will work with 1080p 60p either.

Yes it would be nice if Panasonic would have given us better options to choose 60i over 60p for the hdmi path on the GH4 but they did not. Eventually when more HDMI devices accept 60p this will no longer be an issue. Seems like the only option for now is to use the camera in AVCHD mode and make sure it really is doing interlaced output or use 24p. Another option would be to set the camera to 1280x720p. This would still give you 60p output for live video work albeit with lower resolution. A Blackmagic switcher should be able to recognize that.
 
Thomas - Thanks for your post, as it explained a lot about hdmi and the GH4 that I wasn't aware of. I will try your suggestions.
 
GH425P_Settings.jpg

Here's the 'how to' guide from Atomos for recording from the GH4 onto their Ninja line. Please be aware you have to go into record on the GH4 as well as the ninja to enable pulldown. They'll be posting a video 'how to' shortly.
 
Hi all. Just curious if anyone has more experience with the GH4 10-bit 24p to an external recorder (particularly PIX240i but others if relevant)? My issue remains: PIX only recognizes signal as 10-bit and also the Picture Profile to the PIX looks different than to the internal card (in 8-bit mode). Can anyone confirm that they get a true 10-bit output from the GH4 to external recorder?
 
http://vimeo.com/99808847

Confirmation the Atomos is unable to record 10bit 422 1080 in either NTSC or PAL from the GH4. Apparently the GH4 outputs an interlaced 50i stream (not a 25psf image, but interlaced) in these modes.
 
The Gh4 will record 10bit 422 in 24htz mode progressive to the ninja. But you won't be able to record to the card internally unless you set the camera to 8 bit out. I do it all the time. Also, make sure to set your luminance to 16-235.

Now for other frame rates. In 60htz or 50 htz modes it sends the signal out as an interlaced wrapper. You can still record either 8bit or 10bit, but you will have to deinterlace in post. This is the feature they need to fix on either panasonics side or atomos side.

Now get this. I've done lots of shooting in 24 htz mode 10bit out to recorder and put it up against recording 420 8bit 4K internally and dropped both into a 1080 timeline and applied the same color grade and I don't see much of a difference.
 
Sorry dustylens, just to clarify - you've shot 10bit 1080 to a recorder, and also shot internal 4k, and on a 1080 timeline they look very similar?
 
mr bill said:
Sorry dustylens, just to clarify - you've shot 10bit 1080 to a recorder, and also shot internal 4k, and on a 1080 timeline they look very similar?
Click to expand...
I shot 10bit 422 out to the recorder that recorded 1080P Prores from the 24htz setting set at 4K. The steam was set to downsample through HDMI to 1080 to the recorder. I then shot the same scenes internally at 4K 420. Placed both the Ninja 1080p footage and the 4K 420 footage into a 1080 timeline and applied the same grades. They look nearly identical. Now, science will say that the Prores captured 1080 footage will hold up better and it should. But the resolution and pixel data from the 4K also holds up. So my personal conclusion for the work I do says that if finishing to 1080, dropping the internal 4K 420 footage into the 1080 timeline will give me what I want without the recorder. But this is just based on what I tested and saw. I will say that the 1080p ninja recorded footage is very very sharp for 1080. It's a true 1080 image.

Now when the shogun arrives, totally different story.
 
Considering the number of pixels sampling a scene, is there a benefit to downsizing the internally recorded 4:2:0 4K file to a 1080 422 or 444 colour space? Would that retain more/better colour info from the 4K file?
 
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