My Action 4, when it splits between 4G files loses a few frames while it goes from one file to another.   This is a nightmare if you're trying to sync up multiple cameras or externally recorded audio for a a long camera session.   

I have my Action 4 mounted to a motorcycle and an external sound recorder under the seat (to avoid wind noise).   When I leave the house, I beep the horn on the motorcycle to give me a "sync point" between the recorder and the camera.   Easy to line up in an external editor for the first clip, but then, when there's a split and the next clip starts, I need to treat that independently and, since I'm riding a motorcycle at the time, I often don't notice and neglect to put an easy to find audio marker in for the subsequent clips.

Totally undersatnd why the files have to be split, but if you could make it so no frames are dropped during a split, that would make it MUCH easier to sync audio back in.   Now, for a long day of riding, I'm trying to sync up 1/2 a dozen clips with a single audio file; especically if I forget to beep the horn, it's a real hassle to try to get everything to line up for the 2+ clips.

Hi there. Thank you for reaching out. We will coordinate this concern with our relevant team for further clarification. Please note that the DJI Osmo Action 4 already optimized the video splitting feature and the video only split when they reach approximately 16GB in size, if this is not your case, please let us know. We will keep you posted.

Try to join the clips first in a lossless joiner, eg:

https://github.com/mifi/lossless-cut#readme

DJI Paladin Posted at 3-16 21:32
Hi there. Thank you for reaching out. We will coordinate this concern with our relevant team for further clarification. Please note that the DJI Osmo Action 4 already optimized the video splitting feature and the video only split when they reach approximately 16GB in size, if this is not your case, please let us know. We will keep you posted.

Thank you for the reply.   I'm seeing that behavior (split at 16G) so appears to be working correctly.   The issue is there are a few frames dropped, which means if you sync audio on clip 1, by clip 3-4, you're far enough out because of the slight pause between recordings that your sync is off.   

If I had to guess, it appears to just be a few frames dropped, so maybe a .1-.2 second delay between the end of one recording and the start of the next.   If you join the files, you can see the split, but you have to be looking for it.   However, with audio, just a few frames off and it's very distracting, people talking in particular, it's easy when it's off even by a few frames.

Michael Fink Posted at 3-19 17:22
Thank you for the reply.   I'm seeing that behavior (split at 16G) so appears to be working correctly.   The issue is there are a few frames dropped, which means if you sync audio on clip 1, by clip 3-4, you're far enough out because of the slight pause between recordings that your sync is off.   

If I had to guess, it appears to just be a few frames dropped, so maybe a .1-.2 second delay between the end of one recording and the start of the next.   If you join the files, you can see the split, but you have to be looking for it.   However, with audio, just a few frames off and it's very distracting, people talking in particular, it's easy when it's off even by a few frames.

What editing software are you using? I use Adobe Premiere Pro and others use Davinci and I've not seen any issues when joining, its seamless.

Bashy Posted at 3-19 18:19
What editing software are you using? I use Adobe Premiere Pro and others use Davinci and I've not seen any issues when joining, its seamless.

Davinci.  

You're seeing no gaps at all, no frames lost between files?   Can you try recording a really accurate clock and see if there's a frame dropped when you go between segments?   Like a stopwatch accurate to the 100's of a second, that should allow you to catch a frame drop.   

I'm not sure I'd ever notice if not for the audio sync problem.   It's close to seamless, but just a few frames gone has a noticeable impact on audio when you're trying to sync a long recording across multiple clips.

Michael Fink Posted at 3-19 17:22
Thank you for the reply.   I'm seeing that behavior (split at 16G) so appears to be working correctly.   The issue is there are a few frames dropped, which means if you sync audio on clip 1, by clip 3-4, you're far enough out because of the slight pause between recordings that your sync is off.   

If I had to guess, it appears to just be a few frames dropped, so maybe a .1-.2 second delay between the end of one recording and the start of the next.   If you join the files, you can see the split, but you have to be looking for it.   However, with audio, just a few frames off and it's very distracting, people talking in particular, it's easy when it's off even by a few frames.

Hi there. Thank you for your response. We have received a response from our relevant team. Kindly provide us with the operation video showing on how you sync the video and audio. Also, please provide us the original video files (two split clips) to us for further checking. Please keep us posted. Thank you.

DJI Paladin Posted at 3-20 22:17
Hi there. Thank you for your response. We have received a response from our relevant team. Kindly provide us with the operation video showing on how you sync the video and audio. Also, please provide us the original video files (two split clips) to us for further checking. Please keep us posted. Thank you.

I just did a long recording yesterday; fitting them together with audio sync in Davinci last night I can't find a gap anymore.   It seems like, at least yesterday's recording, there wasn't a frame lost between file splits!   I did just replace my Action 4, this is the first recording on the new camera, so perhaps it was something not working right in the one that had problems?

Not sure, but, for now, it appears to be functioning correctly.   I may try taking video of an accurate clock to verify, but, at least for my recording yesterday, it does appear that it was completely seamless between clips.

Just to verify, that is the expected behavior, correct?   No frames lost between clips?   Are there any restrictions on that; is the device fast enough to split a 4K120 file without losing a frame (I was recording at 4K30 yesterday)?

Michael Fink Posted at 3-21 04:07
I just did a long recording yesterday; fitting them together with audio sync in Davinci last night I can't find a gap anymore.   It seems like, at least yesterday's recording, there wasn't a frame lost between file splits!   I did just replace my Action 4, this is the first recording on the new camera, so perhaps it was something not working right in the one that had problems?

Not sure, but, for now, it appears to be functioning correctly.   I may try taking video of an accurate clock to verify, but, at least for my recording yesterday, it does appear that it was completely seamless between clips.

Hello, Michael. Thank you for keeping us posted. We're glad you have received your replacement unit and now using it without experiencing any issues. Please note that we can only confirm the issue after we perform further analysis on the unit, which is why we are asking for a video showing the problem. If you run into the same issue again, please record a video showing the issue and send it to us so we can provide you with an accurate resolution. Should you have other inquiries, feel free to contact us. Have a nice day.

DJI Paladin Posted at 3-21 22:25
Hello, Michael. Thank you for keeping us posted. We're glad you have received your replacement unit and now using it without experiencing any issues. Please note that we can only confirm the issue after we perform further analysis on the unit, which is why we are asking for a video showing the problem. If you run into the same issue again, please record a video showing the issue and send it to us so we can provide you with an accurate resolution. Should you have other inquiries, feel free to contact us. Have a nice day.

If the problem pops up again, I'll update, but, for now, it looks like it's working as expected.

Just one final question, is there any limit to the frame rates/resolution to get gapless splits?   Should I be able to record at any supported resolution/frame rate and get a gapless split?   I've only tried it on 4K30, so just want to understand if there are any limits I need to be aware of.

Michael Fink Posted at 3-22 03:54
If the problem pops up again, I'll update, but, for now, it looks like it's working as expected.

Just one final question, is there any limit to the frame rates/resolution to get gapless splits?   Should I be able to record at any supported resolution/frame rate and get a gapless split?   I've only tried it on 4K30, so just want to understand if there are any limits I need to be aware of.

Thank you for your response. If you are referring to the video splitting mechanism of the DJI Osmo Action 4, considering the inconvenience of viewing many 4GB videos after recording a large-size video, Osmo Osmo Action 4 has optimized the video splitting feature. Now, videos will only be split when they reach approximately 16GB in size. There is no restriction on the resolution, as long as the files reach 16GB, the video-splitting mechanism will apply. Hope this helps.

DJI Paladin Posted at 3-23 05:11
Thank you for your response. If you are referring to the video splitting mechanism of the DJI Osmo Action 4, considering the inconvenience of viewing many 4GB videos after recording a large-size video, Osmo Osmo Action 4 has optimized the video splitting feature. Now, videos will only be split when they reach approximately 16GB in size. There is no restriction on the resolution, as long as the files reach 16GB, the video-splitting mechanism will apply. Hope this helps.

That's the behavior I'm seeing, and it appears to be doing the splits without dropping any frames, well done!

My question is; can the Osmo do gapless splits at any supported resolution/frame rate?   I've only ever tried it at 4K/30FPS, I'd just like to know if there are any frames lost when the Osmo splits 4K/60 (or other higher speed supported recording frame rates).

Thank you!

Michael Fink Posted at 3-23 06:33
That's the behavior I'm seeing, and it appears to be doing the splits without dropping any frames, well done!

My question is; can the Osmo do gapless splits at any supported resolution/frame rate?   I've only ever tried it at 4K/30FPS, I'd just like to know if there are any frames lost when the Osmo splits 4K/60 (or other higher speed supported recording frame rates).

Thank you for the clarification, Michael. There should be no dropping frames when the video splits in any resolution. If you experience any, feel free to send us the details of the issue so we can coordinate it with our engineers for further investigation. We appreciate your valued support.

DJI Paladin Posted at 3-23 22:07
Thank you for the clarification, Michael. There should be no dropping frames when the video splits in any resolution. If you experience any, feel free to send us the details of the issue so we can coordinate it with our engineers for further investigation. We appreciate your valued support.

That's great, thank you very much for the follow up.   Just did a long recording today at 4K60, went together just like it should, not a single frame lost.   

You can consider my question/issue solved, really appreciate the help!

You might suggest your product guys add this as a feature (gapless file splits) for the Osmo.   For people using external recording, this is a big, big deal!   

Michael Fink Posted at 3-24 11:33
That's great, thank you very much for the follow up.   Just did a long recording today at 4K60, went together just like it should, not a single frame lost.   

You can consider my question/issue solved, really appreciate the help!

You are very much welcome, Michael. We're glad that the issue has now been isolated. Rest assured that I will take note of this suggestion of yours. Feel free to contact us if you have other inquiries. Have a nice day ahead!