NOTE: All bugs for the GH5 footage are fixed by the latest version of Premiere Pro 2018 (12.0.0). If you have a CC subscription and a Panasonic GH5 be sure to download the latest version of Premiere Pro to effectively edit GH5 footage. However, due to the nature of h265 compression as explained below, even the most powerful machines will struggle and transcoding still may be necessary.
On our first day with the Panasonic GH5 v2 firmware, everything went smoothly. Upgrade was fast, battery charged, and now ready to go out and test some anamorphic lens footage with the Isco Micro. In summary, the GH5 v2 firmware has us really excited about shooting anamorphic with this camera. The ability to shoot 5k at the full height of the sensor in 4:3 mode in 10 bit with in-camera anamorphic desqueeze makes this the best DSLR in the market right now to shoot with anamorphic lenses.
However, editing is going to be a bit of a challenge. The latest version of Premiere Pro CC 2017- if footage can even import at all- would crash or display colorful art in place of where footage actually should be. DaVinci Resolve Studio 12.5 and above will import the footage. But, even with a beefy i7 system and the latest Pascal NVidia GPUs will not come close to realtime playback. Sluggish, slow, and choppy playback don’t even begin to describe it.
Note that the free version of DaVinci Resolve will NOT play back h265 or work with timeline resolutions greater than 4k anyway.
Quick summary and solution to slow GH5 playback
The interframe Long-GOP encoding structure of GH5 h265 footage makes it mathematically difficult for even the fastest CPUs today to decide footage in real-time. You will need to convert your h265 footage to an intermediate editing-friendly codec such as ProRes (Mac) or CineForm (PC).
For PC, use Shutter Encoder or Handbrake to transcode your footage to Cineform RGB or ProRes 442.
For Mac, you can use Editready or Handbrake as well and transcode your footage to ProRes 442.
Davinci Resolve Studio ($299) can also work, and will allow you to trim your media.
Any of the current Adobe CC tools (Premiere Pro, Media Encoder, After Effects) will either crash or be extremely unstable at this time.
The reasoning: HEVC
The Panasonic records most footage in h264 wrapped in either .mov or .mp4 containers. h264 isn’t an ideal editing or capture codec like ProRes, DNxHD, or our preferred CineForm. But, modern editing hardware and software are well capable of handling multiple h264 streams and applying effects in real time.
However, to compress this much resolution and color information, Panasonic had to utilize HEVC (h265). As the next generation of h264, h265 packs a lot of information- 50-60% better than h264 especially at higher resolutions. Moreover, the h264 codec is incapable of a greater resolution than 4096 x 2016. h265 allows for a maximum encoding of 8192 × 4320 at 120 frames per second.
Most new hardware includes native support for decoding (and sometimes encoding) h265. This includes some of the latest NVidia (Pascal) GPUs, Intel processors, and even dedicated chips on mobile devices. This means that provided that the playback software supports it, a separate processor designed specifically to process only that task handles video decoding. The player can do so smoothly while using a minimal amount of other system resources.
The basic Movies & TV app in Windows 10 with a Pascal GPU can play back all GH5 footage, even 8k h265 at full framerates, without even breaking a sweat.
The problem: GH5 Interframe Long-GOP encoding
Unfortunately, most modern editors do not utilize the GPU for playback. While many effects can be offloaded to the GPU- opacity, scaling, curves, and more- the playback and render engines utilize the CPU instead. At high resolutions, h265 is an intense calculation. Panasonic makes this even more difficult by using interframe Long-GOP compression to squeeze every bit of quality and efficiency out of the compression.
Interframe Long-GOP works by encoding one complete frame and then storing only the data for pixels in the image that have changed. This drastically compresses down the amount of data stored by the codec.
For playback, the CPU has to first decode the complete frame, store it that frame to RAM, and the call up the data for each of the next set pixel changes for each frame until the next complete frame.
So cutting through the technobabble: something as simple as loading a frame in the middle of the clip means a long series of intense calculations. On top of that, other odd bugs and issues between software and GPU make editing functionally impossible. Even on a spec’d out top of the line system.
The solution: You need to convert to an intermediate codec
No one likes proxies, but for now, the quickest and easiest solution is to convert your GH5 v2 anamorphic lens footage into a much less efficient (read: larger file size) but much less intense codec designed for editing. If you’re on a Mac, ProRes 442 will be your pick. If PC, install and choose the Cineform codec. These codecs are easy for the CPU to decode- just be sure you are running them off of a fast enough hard drive or even better, a solid state drive.
CPU manufacturers need to develop faster processors need to become significantly faster. Developers need to reengineer playback engines of editors to use the GPU for faster playback. Until then, we will not be able to work efficiently with the direct footage from GH5 anamorphic.
If you are interested in learning more on working with anamorphic lenses and DSLR, please check out our anamorphic tutorial blog for more anamorphic tips and tutorials!