4K or not 4K? That is the Question

4K TV and video have been around for a while now. In the mainstream drone world it was probably the Panasonic Lumix GH4 camera which took 4K to new heights of popularity.  On smaller rigs the GoPro Hero 4 also made 4K available, followed by the DJI Inspire 1. Broadcast and cinema 4K cameras were available long before the GH4 was launched in early 2014. But how much is 4K being used? Do clients want it and do drone camera operators want or need to shoot it? I haven't splashed out on a 4K telly yet. Have you? Before we get too heavily involved in the pros and cons it's worth spending a little while talking about the technical details. First of all, and just to complicate things, not all 4K video is the same and not all 4K cameras are the same.

 Higher definition means big data

There are two main sizes of 4K Ultra High Definition image. The size that will appear on a 4K TV in your living room is 3840 X 2160 pixels - that's exactly 4 times the size of a Full HD picture (1920 X 1080) with the same aspect ratio of 16:9. Just to complicate matters Cinema 4K is a wider picture, measuring 4096 X 2160 (aspect ratio 1.9:1) and, as the name suggests, is used in the film industry. Digital_video_resolutions_medium-version-e1443609740801.png "Digital video resolutions (Video CD to 4K)" by TRauMa At the recording, editing and post production end of things the amount of data that has to be handled is enormous. To give you an example, Cinema 4K at 30 frames per second will capture and astonishing four and a quarter billion pixels per second (4,246,7322,800). An uncompressed Cinema 4K recording needs a bit-rate of more than 500 megabits per second (MB/s) and will produce a mind boggling 1.7 terabytes of data for every hour of recording. So that's where the different codecs come to the rescue. They convert reality into digits that the computer can store and it's the codecs and their associated bit-rates that determine how accurately those numbers represent the original image. Therefore higher bit-rates generally produce more accurate video. However bit-rates also determine the size of the file. Higher bit-rates create larger files.

Data and brain bottlenecks

So you can see, with all this data flying around there are going to be bottlenecks occurring in your workflow. In fact there's a bottleneck occurring in my brain at the moment so I'm thinking that it might be a good idea to write a separate blog about the processing of 4K video. However with all these brilliant drones with 4K capability landing at the moment and even 4K video available on phones, it's worth deciding if Ultra High Definition is worth worrying about in the short term. Phantom-3-Pro-and-Inspire-1.png The Phantom 3 Professional and the Inspire 1 The DJI Phantom 3 Professional and the Inspire 1 are both capable of recording 4K but the vast majority of users will end up viewing their video on a 1080 HD TV. Even if you do have the luxury of a 4K television you'll only get the benefit if you play it straight from the camera or memory card. Of course it can be edited but that can throw up the bottlenecks I mentioned earlier. Some users say they are shooting in 4K but editing in 1080 because their editing hardware and software can handle Full HD more easily. (Most people won't even have a monitor that can show off 4K in all its glory.) They even claim the final picture quality is better than if it had been shot on 1080. With both the Phantom 3 Pro and the Inspire 1 you do have the option to shoot in 1080 anyway. It certainly means you can squeeze more minutes onto your memory card and your editing programme will be happier dealing with it.

Higher bit-rates for the professionals

The GH4 and the new X5 cameras for the Inspire up the ante because of their higher bitrates for 4K so they're likely to be used by pro operators who are more likely to have the processing power in their editing suites. The new X5R for the Inspire is a serious camera for the film industry. It can produce lossless 4K RAW video but has the ability to handle it with a bit rate of 1.7 Gbps (maximum 2.4 Gbps) and to store it on a removable, half terabyte solid state hard drive tucked into the base of the gimbal. Great for really serious post production. It also still has a micro SD slot, which can simultaneously record smaller, proxy files. Zenmuse-X5R-SSD.jpg The DJI X5R with removable SSD Both X5s have a similar sensor to the GH4 - a micro four thirds 16 megapixel. On the GH4 4K resolutions can be recorded as MOV or MP4 files in high bitrate 100 Mbps codec. When recording at 100 Mbps, you will need an SDHC/SDXC memory card capable of handling the transfer speed. The X5 camera is 60 Mbps like its predecessor the X3. For more detail on the two new X5s and the Inspire range check out my earlier blog.

What do the pros think?

I'll be talking to professional videographers and editors for the next blog to find out how they organise their workflow but I've already had a word with the main man at Chris Davies Photography. Chris is a film maker as well as a photographer who owns two DJI Inspires and two S1000s. He also has a Phantom carrying a 4K capable GoPro Hero 4. The octocopters carry a MoVi  M5, which takes either a GH4 or a Canon 5D MkIII. But here's the big surprise - Chris has never shot anything in 4K. "1080p gives me the quality I need," says Chris. "There's no call for 4K films yet and I don't have the processing power or storage to handle it. The files sizes would be far too big." Chris-Davies-e1443610765628.jpg Chris Davies flying his DJI S1000, MoVi M5 Chris makes his own films about outdoor sports including mountain biking and fell running and very good they are too. (See below.) He's often on the road for up to two weeks at a time, travelling to exotic places. That means that at least once a day he's having to backup all the video he's shot onto at least one but usually two hard drives. "I have to back them up because this is my living so imagine the amount of storage I'd need for 4K files."

Uploads take hours and hours

Even 4K uploads to websites like Vimeo and YouTube aren't worth considering at the moment as far as Chris is concerned. He says it would take him hours and hours to upload 4K and, even if people have hardware capable of playing the big files, most don't have a 4K display. Chris says he would certainly shoot in 4K if he was handing over his footage to a production company with the processing grunt to deal with it and he's also not ruled out using it himself in the future. It would be interesting to hear your thoughts on the merits of 4K. When everyone's technology catches up with UHD it will be well worth having but in the meantime ... Inspire-Chris-Davies-Photography-e1447426890184.jpg A DJI Inspire in the mountains - Chris Davies Photography