April 16, 2016 at 2:13AM

0

Handling Codecs

I've just bought the Panasonic GH4 after some discussion at Nofilmschool and I am amazed by that image qulitay I'm getting out of that little tiny camera body that just costs me about 1.100 €.

But here is the thing:

After shooting some footage (in cine 4K) of course I wanted to watch what I've shot on my computer. But my Mac failed playing it. It opened the files with QuickTime and after a few seconds the playback wasn't in realtime anymore. With VLC Player the files coninued playing in realtime but after about 20 to 25 seceonds there were some artefacts created by the decompression progress (I think it's the decompression because the artefacts were gone after playing the same part again, so my new camera isn't broken, puh).

I played 4K ProRes422 files on my Mac and they played just fine. This is the first time something like this happens. So I think it's definitely the decompression progress.

So what can I do to let the GH4 files play normally?

I use a Mid 2011 21.5" iMac with 2.5 GHz Intel Quad-Core i5, 12 GB RAM and AMD Radeon HD 6750M 512 MB.

Thank You for your help!

22 Comments

Please do check out our short movie as well. https://www.youtube.com/watch?v=2P8NsDx_BO8

April 16, 2016 at 5:58AM

0
Reply
avatar
nandhu manoj
director,cinematographer
80

You need a beefy computer to play 4k uninterrupted.

April 16, 2016 at 11:53AM

2
Reply
avatar
Cary Knoop
Member
2402

You will have to transcode your GH4 files to high bit-rate ProRes if you want smooth playback on an older computer. On Windows I transcode to the GoPro Cineform CODEC.

April 16, 2016 at 3:01PM

0
Reply
Guy McLoughlin
Video Producer
31904

Only if the the hard drive does not choke on the high bitrate.

Of course the real question is what is the point in playing 4k videos on a 21 inch screen

April 16, 2016 at 6:05PM, Edited April 16, 6:05PM

8
Reply
avatar
Cary Knoop
Member
2402

The 4K isn't supposed to stay 4K. It will be down convert to give some really nice 1080p footage or to punch in and punch out in some shots (of course the usual).

I'm just looking for some way to bypass the time with my old computer until I buy a new 5K iMac.

April 17, 2016 at 3:09AM

1
Reply
avatar
Eric Halbherr
Director, DP, Editor, Creative Storyteller
2085

What isn't the point?

Think.

April 17, 2016 at 4:18PM

1
Reply

We are talking high bit-rates of less than 30 MB/sec so almost any hard-drive made in the last 10 years can handle this playback rate.

The 4K playback problem stems from not having enough CPU / GPU power to decompress the 4K video stream on the fly, but converting your camera files to lower compressed high bit-rate files eliminates the decompression bottleneck and you will achieve smooth 4K playback on an average editing computer.

April 17, 2016 at 10:26PM

3
Reply
Guy McLoughlin
Video Producer
31904

I too have a GH4. My macbook is slightly new with higher spec and manages to play the 4K footage in real time.

I think problem you are having it the iMac trying to decode the h.264 file as it plays it. It would be best to transcode it into an edit-friendly codec such as ProRes, or DNXHD or the GoPro cineform codec. These will be much larger files, but they will playback much more smoothly. You can use all sorts of programs for this. I have used MpegStreamclip for years,

Also if you plan to edit the files in an NLE, the uncompressed files will work much better than the h.264 file. It's not any higher quality, it just runs more smoothly due to not being compressed. It may take a while to transcode all your footage but it is worth it to have a smooth edit experience. I would suggest putting your source footage on a separate drive for your editing. USB3.0 or Thunderbolt drives will be fast enough.

Good luck

April 17, 2016 at 4:57PM

0
Reply

Just a correction, ProRess and DNxHD are not uncompressed but they are generally easier to decompress than something like H.264.

April 18, 2016 at 12:33AM

0
Reply
avatar
Cary Knoop
Member
2402

Yeah, that's for sure.

April 19, 2016 at 12:54PM, Edited April 19, 12:55PM

0
Reply
avatar
Eric Halbherr
Director, DP, Editor, Creative Storyteller
2085

Well, then I have to buy some new hard drives to store the 3.5 times bigger ProRes LT files next to the 4K H.264 from the GH4 until I buy a new 5K iMac.

April 19, 2016 at 12:54PM

0
Reply
avatar
Eric Halbherr
Director, DP, Editor, Creative Storyteller
2085

Well you better do a test because it may turn out the ProRes version has has problems as well.

Despite what people claim here H.264 decodes pretty quickly when regularly playing a video. The real problem is mostly scrubbing in an NLE because of the interframe compression of H.264.

April 19, 2016 at 1:52PM

5
Reply
avatar
Cary Knoop
Member
2402

Yes, definitely always better to test these things out before purchasing.

It's true, h.264 should decode fine for normal playback, but speaking from my own experience with underpowered machines, ProRes just seemed to work better.

In terms of working in a NLE, without a doubt the ProRes wins over the LongGOP nature of the h.264 codec. Even with a higher spec machine it's worth considering using ProRes for editing. I've found it can reduce rendering time when adding effects.

April 19, 2016 at 5:31PM

3
Reply

Playback at 4K will put serious strain on an iMac. Are your using Premiere as your editing system? Throw it onto a timeline in Premiere, then in the lower right-hand corner of your monitor window there is the option to scale down the resolution for playback. You can go 1/2, 1/4, 1/8, etc. Just scale it down to the point that your computer can handle it without skipping frames.

April 19, 2016 at 3:21PM, Edited April 19, 3:21PM

0
Reply
avatar
Maury Shessel
Editor
87

Yes, I already tried that.
The problem with that is that, even if I lower the resolution, the computer has to decompress the files first and than it has to scale them down secondly. It wouldn't make any difference in playback.

April 20, 2016 at 12:07PM

2
Reply
avatar
Eric Halbherr
Director, DP, Editor, Creative Storyteller
2085

Your real solution is to get a faster laptop or even better a decent desktop computer.

April 20, 2016 at 1:19PM

0
Reply
avatar
Cary Knoop
Member
2402

Yes, of course. But that would cost me some money and I was looking for a solution that would be not as expensive as a new computer at least for an interim period until I buy new computer.

April 21, 2016 at 6:25AM

0
Reply
avatar
Eric Halbherr
Director, DP, Editor, Creative Storyteller
2085

You could always use lower resolution proxies.

April 21, 2016 at 1:40PM

0
Reply
avatar
Cary Knoop
Member
2402

You have few options here. Upgrade your system, transcode to Prores or DNx or a proxy workflow. Its the nature of things once your system becomes outdated. No way around it. Part of buying new cameras is knowing you have the hardware to properly deal with the footage afterwards.

April 21, 2016 at 1:38PM

0
Reply
avatar
Josh.R
Motion Designer/Predator
723

I'd throw all your files into Adobe Media Encoder, make some low bitrate 1080p proxies and relink the original files after editing (but, if possible, before color correction / grading).
Use some raw files to check out how far you can crop in still having satisfying resolution.

For multicam (or very complex) projects I even use proxies with only 640x360 and switch to 1080 when everything is more "flat".

April 21, 2016 at 2:17PM

0
Reply

Talking about proxys PP CC 2016's new proxy workflow might be a very interesting feature to work with as a solution for that kind of ishue.
So maybe that will be the way to go in the future.
Nethertheless this feature isn't out yet. Until it is I'll continue decoding my GH4 H.264 footage into ProRes 422 LT. And at the time the proxy feature will be released I will probably have a new computer as well.

April 21, 2016 at 2:19PM

0
Reply
avatar
Eric Halbherr
Director, DP, Editor, Creative Storyteller
2085

You can do proxies already, the new workflow is simply a way to make it a little bit easier to work with.

April 22, 2016 at 11:22AM

0
Reply
avatar
Cary Knoop
Member
2402

Your Comment