Weird timecode format when exporting subclips

[vladm22698643]

Hello,

I am having a weird problem when transcoding subclips from Prelude. When I ingest the footage back in Premiere, the timecode of the footage is all messed up and displays a 3 or 4 digit number (ex: 3311 or 477.. etc) instead of the actual duration in a timecode format (00:00:00:00). The original clips are displaying fine in Prelude before transcoding. I don't know what the issue may be since I haven't seen this before. Is it maybe an export preference, or is it a bug?

I also tried to export a clip straight from Media Encoder using the same settings and when imported back in Premiere, the timecode is as expected, looking at the bottom clip in the image (GOPR0631). Also when importing the transcoded clip from Prelude two other subclip files come with it, which obviously I don't want, since I already pre-selected in Prelude and I just want all the subclips I defined treated as individual new files. 

Any input is highly appreciated!

[Ann Bens]

This might be due to the odd framerate.

[vladm22698643]

It kinda confirms it, as I tried to export other clips in 23.976 from Prelude and it shows up fine. The framerate is 48fps and it's the majority of the footage. I have had only issues so far dealing with 1920x1440 / 48fps footage. Quicktime DNxHR didn't work at all with 48fps. I have used Cineform instead, which seems to work, but I do get this timecode issue. Any ideas or workarounds I might try? maybe a different codec?

[Ann Bens]

I have no idea how to fix this or any workaround.

The original footage is gorpro?

[vladm22698643]

Yes, it's gopro footage indeed.

[Ann Bens]

Gopro uses constant framerate if I am not misstaken.

So the framerate should read 48 fps and not 47.95.

I think something went wrong in Prelude.

How about making subclips is Pr.?

[excited_Genie16B8]

23.976 x 2 rounds out to 47.95, so the reported frame rate makes sense.

But nothing uses 47.95 for playback, so it seems a safe assumption that this footage is only for use when slowed down to 23.976.  It's not intended for real time playback.

[vladm22698643]

The footage was indeed shot to be conformed to 23.976 afterwards. However not all the 48fps shots will be used for slowmo. We intedend to keep some 48fps shots in the 23.976 timeline, and let Premiere drop the other half, so it will become 23.976. That's the reasoning behind shooting at 48, to be flexible and have both options: either conform to 24 for slomo or use the 48 in the 24 timeline for non slomo shots.

Another alternative would have been to conform everything to 23.976 beforehand and time stretch it back to original speed, for non slomo shots. The result seems to be identical from a few tests, however from a workflow standpoint the latter method is not really an option at this point, since it will mess up all the subclip in and out points. The logging and pre-selection was done in the original 48fps in Prelude.

[excited_Genie16B8]

not all the 48fps shots will be used for slowmo.

I think that was a mistake.  Shoot realtime footage at the proper frame rate, shoot slow motion shots at a higher frame rate.  Yes, it means you need to make that decision when you shoot.  Don't try to shoot in a way that allows you to change your mind later.

[vladm22698643]

I have tried exporting the subclips from Premiere, the same thing happens as it goes via Media Encoder anyways. Media Encoder doesn't have the option to set 48fps, for any of the quicktime transcoding codecs I tried (DNxHD, CineForm, Miraizon ProRes). The only way I managed to export the 47.95 was to match source in Media Encoder and it worked properly with CineForm and ProRes only, so I went with CineForm, but the timecode issues are still present with both codecs.

I don't know if it's a Prelude issue, since it's displayed as 47.951 in Prelude, Premiere and Media Encoder.

[excited_Genie16B8]

My guess is that this footage is supposed to be slowed down to 50%.  Have you tried Modifying the fps to 23.976 before export?