BRAW Footage Choppy / Lagging?

Hi all,

I have a student that is experiencing a strange issue with footage shot on BMPCC 6K.
He mistakenly shot in 29.97 for the entire production. While importing to Resolve for dailies, he realized every other frame or so had the media offline logo (resembled a strobe effect). I asked him if it looked that way during capture, and he said he never played back on set. We tried adjusting project FPS, other settings, and even made a new project but it didn't work. We then deduced this issue to possibly a faulty cable attaching the SD drive to the camera.

However, we put the footage in Premiere, and it worked! The kicker now was that the footage was very choppy (only moving every 7-10 frames while the timecode ran) and lags. I tried looking to see if there was a pattern in frames where the footage would move, but it's not consistent. It is not a Premiere issue as he has worked on the project in several locations with the same issue, and the rest of his class seem fine working in the program with similar footage. I did the following to make sure the issue was the footage:

Made a project with proper settings for 29 FPS
Interpreted the clips as both 29.97 and 23.976 in the settings. Didn't work well, but the footage did pick up ever so slighty.
Played with the 'Frame smoothness' option where the frames blend into one another to make the image flow better.
I tried clearing the cache and resetting preferences.
I tried 'speeding up' the clips.

None of this worked.

I made sure the Blackmagic Raw driver was the latest and ran it with some raw footage and it still lags.

Strangely, a few of the clips are fine. However, 85% of his project footage seems to lag. Another detail is that often the clip will start smoothly, but after a few seconds, it will begin to lose those frames. The footage was transcoded from BRAW to Prores without success, and it was viewed on both Windows and Mac. With all things considered, I am definitely of the belief that it's a footage issue and not the frame rate. However, what caused the footage issue?

Has anyone ever dealt with an issue like this? Can this media become usable?

Thanks in advance for your help!!

[Peter Chamberlain]

Can you check the original file and see if its actually recorded every frame, or there are drop frames?

There's an option on all BMD cameras to stop playback in the event of dropped frames. Select that option, and try recording with whatever media you used in the case of the choppy/lagging playback. Odds are, recording will stop after a few seconds -- on account of dropped frames. If so, the material described above is almost certainly full of dropped (missing) frames. The recording media can't keep up with the camera frame rate.

It appears that Premiere is better at handling playback of the footage, but as you note, that's not satisfactory either -- and couldn't be, if in fact dropped frames are the reason.

Can you check the original file and see if its actually recorded every frame, or there are drop frames?

Hi Peter,

The SSD drive he used to film on set has since been wiped, but we have all of his files copied and stored on other hard drives. I took those BRAW files from the hard drives and opened them with BRAW player, and they were still choppy / dropping frames.

There's an option on all BMD cameras to stop playback in the event of dropped frames. Select that option, and try recording with whatever media you used in the case of the choppy/lagging playback. Odds are, recording will stop after a few seconds -- on account of dropped frames. If so, the material described above is almost certainly full of dropped (missing) frames. The recording media can't keep up with the camera frame rate.

It appears that Premiere is better at handling playback of the footage, but as you note, that's not satisfactory either -- and couldn't be, if in fact dropped frames are the reason.

Hi John,

That makes so much sense - I'll check the camera he used and test that out in 29 FPS. He checked it out from the University, and I don't believe other students that used the camera have experienced this issue (They all shot in 23.976 / 24), so I'm fully with you on that the camera likely couldn't keep up with the frame rate he had set.

I appreciate your help!!

It's normally not the camera that can't keep up, but the media. Did he use one from the official list?