Choppy footage as a result of slow USB-C cable. What to do?

Hi!

I just recently bought a Black magic pocket pro 6K and shot an event the other day, with a Samsung T5 disk.
Some of the material is 25 fps some is 50 fps. Both in Prores, HQ, Ultra HD 3840x2160, project frame rate 25 fps, "stop rec if frame rate drops" is off.

When looking through the footage it looks ok for about 15 seconds then gets choppy. Both when played back from my mac and from the in-camera-playback. I've been trying to convert the footage, but it's still choppy.

My only conclusion is that I wasn't using the cable that came with the T5 disk. The one I used is probably much slower and therefore the footage got choppy due to that.

Does anyone have any idea of how to fix the footage in any way? Really need to make it work. Kinda desperate here.

Sorry, your source media has dropped frames and can't be fixed in the true sense. Try setting the clips to use optical flow and speed warp, and render them in place. You might get away with it, depending on what you shot. I recommend always using stop rec if frame rate drops. In my experience, if there are any frame drops at all, there will be a lot of them, and the footage will be more or less unusable, so you should switch media immediately.

It’s also worth mentioning here that the Samsung T5 is not on BMD’s list of recommended media for that camera, codec, frame size and frame rate. It can’t record the data rate necessary to keep up without dropping frames. Stick to media from the recommended list for your camera, codec and frame rate and you won’t encounter this problem.

It’s also worth mentioning here that the Samsung T5 is not on BMD’s list of recommended media for that camera, codec, frame size and frame rate. It can’t record the data rate necessary to keep up without dropping frames. Stick to media from the recommended list for your camera, codec and frame rate and you won’t encounter this problem.

Not correct. One could just as easily use media from the list, with the same bad cable and get the same problems.

The T5 should handle that data rate easily, even at 50fps.

Testing and labeling are the keywords here. Either label all your bad usbc cables, or cut them with scissors…

Either label all your bad usbc cables, or cut them with scissors…

I like tying a knot in them as a reminder they are "knot" good, if I can't immediately discard them.

Not correct.

You’re right. It is supported for UHD ProResHQ, not for full quality BRAW. Sorry. I read the OP's codec as BRAW, rather than ProRes. My mistake. That’s what I get for having multiple threads open in different tabs all at once.

… I like tying a knot in them as a reminder they are "knot" good...

Novel idea!

The Samsung cable are notoriously bad and if you search the forum you’ll find many post about it causing drop frames. The Kondor Blue are solid cable. https://www.amazon.com/KONDOR-BLUE-Tran ... 165&sr=8-3

Back in the day you had to copy the frame right beside the dropped frame and paste it over the dropped frame manually. Most of the time people won't notice depending on what you shot.

How much footage? Manually repairing a couple hundred drops could be tedious but doable. It would be easier with time code reference. Maybe Scene Cut Detection would be helpful if the tool could detect cuts based on dropped timecode. I might try and create an interim frame by overlaying the frames adjacent the gap and setting opacity to 50%. Creating a simulated motion blur between the two frames, and inserting a temporal frame to correct cadence, not perfect, but neither is a 3:2 pulldown.

If there are thousands of breaks or if multiple continuous frames are dropped it could be curtains. Maybe try and repair the nastiest portions manually then fall back on optical flow once the process becomes mind numbing.

Good Luck

If you really get stuck, I have a contact who uses machine learning tools to fix random cadence problems. DM me if you'd like his info.