GoPro 120fps video

Many DSLRs, most phones, and virtually all drones unless you get one of the "pro" models that's like an octo-copter carrying a frickin' big camera, record video files in long-GOP. As in "group of pictures".

Why? With a specialized chip to do the encoding it's fast, and the result takes less space on the media card.

What is it? There are "complete" i-frames every 9 to 36 frames. Inbetween are p and b frames. Those aren't actual frames, they're only datasets of 1) the pixels that have changed since the last iframe or 2) the pixels that will change before the next iframe or 3) both!

For playback, the system has to decode and decompress a bunch of frames to get the data to create each particular frame. Frequently people will say "but my video player app doesn't struggle with it!" which is irrelevant. The player is only playing back one video file, it doesn't have anything else loaded into RAM/cache files and isn't juggling a hundred tasks simultaneously.

For an NLE that is by design loading a ton of stuff into RAM/cache already, and juggling all the data to create a sequence from a bunch of different clips and a ton of code ... throwing that load onto the system in addition is ... problematic.

Some systems have the hardware bits (especially some Intel CPUs) to handle this pretty well. Some have enough bits to do ok with one 'stream' of it, and some just plain choke trying to run the NLE with long-GOP media.

For nearly all systems, 8K RED raw files are a lot easier to handle.

That's why other options are useful, as a practical matter. I don't care about attitudes like "the flipping NLE SHOULD be able to do this!" ... I only care about what works now on each system.

So there are several very workable options, and if you do them intelligently do not add hardly any extra seconds to your worfkflow but make the editing much faster and easier. And some even make exports much faster.

One common pro process is transcoding prior to import ... many of the colorists I know simply do this with any long-GOP clips that are part of a grading project. Period. And they work on massive hardware. That can run four to six streams of 8K RED. Setting up say a Watchfolder in MediaEncoder, so you can simply drag a folder of media to that folder, and walk away to go to lunch or sleep while the app creates the t-codes and parks them where you've told it is sweet.

Then just use the t-codes.

There are several ways to use the original files in part of the process in Premiere.

First, import the originals, and do your basic cutting to the sequence. Then when you have your sequence pretty much cut, before doing advanced trims and such, do a full "render & replace" operation specifying something like ProRes422 (if you have 10 bit media) or ProResLt for pretty much any drone 8-bit media. 

Premiere will make full clips of that specified codec, and use them both for any further work in the sequence and for exports. This way effects can be applied without straining things, and ... if the chosen render codec is the same as your export ... then it can use those renders for much of the final export process.

Second ... make proxies. After importing the long-GOP stuff, select it in the bin, right-click "Creat Proxies" ... try a half or quarter resolution.

Then when you work with sequences, add the Proxy icon to your Program monitor control block. And turn Proxies 'on' so the system uses those for playback rather than the originals.

You can find information about that in the program's documentation and help files, I think by hitting F1 on your keyboard.

Neil

Hi Neil.

First of all thank you for looking into my query and reverting.

I understood the first and second point that you mentioned and I'll take those steps this time. 

But I have few doubts regarding the 3rd point. 

• How did you reckon that the footages are drone long-GOP "interframe" beacuse I would like to know for future references. 
• Also, how do I transcode long-GOP to ProRes, DNx, or Cineform, prior to importing?? 

Can you please help me with these doubts? 

Thank you.

First, don't use the "Interpret" setting for this ... that, according to engineers, is more intended for 'cadence' changes.

Second, sometimes when you drop say 120 on a 24fps timeline, Premiere simply handles it as slo-mo. Not always though.

And when it doesn't, use the Speed/Duration control, and set a percentage. Which is a bit of a pain at first, so many of us have little cards with the correct percentage already figured out on them.

My math may be wrong, and I'm not at a computer to test, but I think putting 120fps on a 24 fps sequence is running it at 20% ... as always, test first!

And third ... that is drone long-GOP "interframe" meaning it's some of the WORST media for editing/grading ever conceived. 32 frames or more have to be decoded and decompressed and stored to RAM to get each frame to display. Most of the colorists I work with have massive "iron", computers with many cores, mulitple MASSIVE GPUs, and probably 256GB of RAM. They always ... always ... transcode any long-GOP to ProRes, DNx, or Cineform, prior to importing into their Resolve or Baselight app to grade.

You might get better performance by doing a full render & replace to ProRes or DNx or Cineform on the timeline as a first step. Then add effects & such.

Neil

https://youtube.com/shorts/8R4SK3C8_aU?feature=share 

I am attaching the link of my render here for a clearer explanation.