GoPro 4 Black high fps stuttering problem (on i7 4790k)

[Luc Spencer]

Hey guys! A friend of mine just bought a GoPro 4 and has experienced some issues with it.

First of all, the 1080/120p footage does not play back smoothly in VLC Player. It does for a few seconds after you open the file, then it all becomes stuttery and impossible to watch. It's worse for 720/240p. Even when imported into Premiere, it does the same thing when trying to watch it in the timeline.

Before anyone says my PC is not potent enough, the CPU usage while attempting to watch the video is at around 20-30% (i7 4790k).

The second issue is that when slowing down 1080/120p footage to 25% in Premiere, which would be the equivalent of 30fps, it does not look smooth AT ALL. I have uploaded a clip on youtube showcasing this:

YouTube (Short URL)

My workflow was this:

1. Imported Gopro file.
2. Used the "create new sequence from clip" option.
3. Using time remapping, slowed down the clip to 25%, then back to 100%. Did this a few times throughout.
4. Exported in 1080/30p.

Am I doing something wrong? I will add that interpreting the footage to 30p produces the same stuttery motion. My friend is about to return his GoPro, so any help is greatly appreciated.

PS: the memory card is a Sandisk MicroSD 32GB SDHC ULTRA, class 10, UHS-I, 60MB/s.

PPS: after a few seconds at 25% speed, you can clearly see the stuttering issue is much worsened (watch second 8), even though there were no changes to the speed in the timeline. This has to be the most frustrating problem I have ever encountered in video editing. And it's not even my GoPro!

[Jeff Pulera]

GoPro clips can be difficult to play even on very fast computers. Best method is to transcode using GoPro Studio software that will create an .avi or .mov file (use .avi for PC) using the Cineform codec (GoPro bought the Cineform company). During the transcode, there is also a checkbox for fisheye removal if needed. The transcoded files are much larger, but play back easily on most any system.

In Premiere, just use a 30p sequence with the 120p clips and set speed to 25% and that should provide perfectly smooth slow motion since there is no interpolation as no frames need to be repeated. Use 20% speed in a 24p sequence for smooth results there (one frame of clip = one frame of playback).

Thanks

[Luc Spencer]

Thank you for clearing this up, Jeff. I had no idea what to blame - the camera, the memory card not being fast enough or my PC, for the same reason (although judging by the CPU usage while playing a vid, I really doubted that one).

Might I ask one last question? We have an upcoming project which will require super slow motion in post. It will also require color grading and therefore an overall GOOD image quality. IQ is paramount. What setting would you recommend to film in, on the GoPro? 1080/120p or 720/240p? I'm just worried that at 60mbps, 240p will look very... chunky and poor, and will be ungradeable.

Any sort of advice will be greatly appreciated, thank you.

[Jeff Pulera]

I have a GoPro 3 and best speed is 720p60, and honestly I've not used the unit much at all. Therefore, I can't comment on the quality of the various high framerate options on the newer unit.

In theory, shooting at the highest possible frame rate would benefit the slow-motion process in post. However, is there a quality hit on the image when recording at the higher frame rates? That I don't know.

Thanks

[Noa Put]

Originally Posted by Jeff Pulera

GoPro clips can be difficult to play even on very fast computers.

I have the same issue with my gopro 2.7k and 4k files, they both stutter in Edius while my higher bitrate gh4 4K files don't, now I just convert them to Edius own HQX format and then all is well. Not sure why that is.