More information on 10bit 4K 4:2:2 via micro HDMI on the GH4 without external box


Picture: EOSHD Forum, by Orangenz

Panasonic have confirmed that the GH4 (quite amazingly) outputs 10bit 4K 4:2:2 from the onboard micro HDMI port without the YAGH external HD-SDI unit.

However there are still benefits to using the HD-SDI outputs.

Here I have more details on how this whole thing works and what external recorders might be in the pipeline to offer 4K recording on the GH4…

The YAGH accessory box for the GH4 actually takes video entirely from the micro HDMI port on the GH4, which is why it can offer 10bit 4:2:2 through the full sized HDMI port it offers as well as HD-SDI.

Until now I’ve been no great fan of using external recorders. I found the quality gains to be virtually zero with DSLRs, no increase in colour depth or resolution and as for compression even with the Sony FS100 at just 24Mbit/s I was hard pressed to tell the difference between the externally recorded 220Mbit/s footage and internal AVCHD codec in terms of outright quality.

Clearly with the GH4, the 10bit 4K is going to grade fantastically well as there is a signal strong enough to pad out those huge ProRes files. Finally!

I am super excited to get my hands on some of the first GH4 units when they go to version 1.0, which is why I am waiting on Panasonic before I put some footage out there.

At NAB 2014 I fully expect there to be some more affordable 4K external recorder solutions. The Convergent Design Odyssey 7Q does not accept a 4K signal via HDMI, only SDI so I’m going to focus my attention on what arrives at NAB. The Atomos stand should be particularly interesting to GH4 owners.

So what are the benefits of buying the YAGH external box? Well aside from the robustness of the connections compared to the wobbly Micro HDMI port on the camera itself, the box still has a host of advantages. Especially in terms of audio, the balanced inputs, quality pre-amps and phantom power of XLR will be a ‘must-have’ for onboard audio recording. No need to sync from a separate device, just plug the mics straight into the camera side of things.

Then there is the length of the cable runs to a monitor (say for the director or multiple screens in a video tent). On larger productions this will be needed and with SDI you get a range of hundreds of feet compared to HDMI which degrades at anything over 7ft or 2m.

Timecode is not in the HDMI output from the camera, but it IS in the HD-SDI output from the YAGH (data is transmitted through pins on the bottom of the camera).

So if you want to run long cables from robust connections, with timecode – then the YAGH is for you.

If you need the best quality professional audio recording and don’t want to sync in post from a separate recorder, the YAGH is also for you

If you just want to shoot the highest quality 4K from the GH4 then you can just buy a monitor with built in 4K recorder. But I urge you to wait a until after NAB to choose one. I think a little patience could be very useful. Remember that file sizes are going to be HUGE with the 10bit 4K files, but at least with the GH4 unlike the Blackmagic Production Camera we have the CHOICE of a thinner 8bit 4:2:0 codec which offers great quality with much smaller file sizes if you don’t need the higher colour accuracy or more robust image for grading.

The GH4 really does offer everything doesn’t it?