Strange frame skipping problem.. can someone help? (DJI MAVIC PRO)

Report · May 09, 2017

Hello,

I just recently got a drone, the Mavic Pro from DJI and i had some issues with the footage in Adobe CC 2017.

Everytime i shoot a fly up with a small tilt down, it seems like Premiere Pro doesn't understand the .mov file.

The footage looks (almost) okay in quicktime player. but when i drop them in Premiere pro it starts jumping around like crazy at the moments where frames are skipped in the camera. The strange thing is when i cut the footage after the frame jump, the issue will appear later in the video (Where therefore wasn't a jump)

I tried different Premiere Pro versions (CS5.5 and CC 2015), also tried After Effects and Media encoder but all those programs seem to give the same problem. Strange thing is that the jumpiness is always a little different. Sometimes alot, like 4 quick jumps in a row or sometimes just once. And all that with just 1 single shot i made....?!

Sequence and camera settings are all okay (25fps 4k). Maybe seems like the SD card is too slow for the video but this SD card was included with the drone when it arrived. Tried another SD card (exactly the same type and speed), same problem.

Here's an example i made;

First you'll see the raw footage playing in Quicktime Player

Then i'll show you the problem (Frame skipping/jumping)
And in the end i cut the footage just behind the jump, and show you that the jumpiness appears in other parts too after cutting it.

Issue - YouTube

Can anyone please help me? I would be very very happy!

Thanks in advance.

Torre

Report · May 09, 2017

I am going to take a guess here: could it be that your footage your camera is shooting is shot in a variable frame rate? because if it does, premiere does not like it. you should drag you footage into mediainfo and check

see if it says constant in this tree:

if it does not, you will need to transcode your video first through a software that converts variable frame rate to constant. see this here thread: Re: Alternatives to Handbrake? Handbrake not converting Variable to Constant Like it used to

Report · May 09, 2017

It shouldn't be a variable frame rate... it's been shot on 25fps but maybe it has a problem with transfering it to the SD card.

The example screen capture I made is variable, that's because i captured it with Quicktime and it couldn't handle capturing while playing the video in Premiere. So you shouldn't use the example video to determine that i guess...

is there a mac version to check for contstant/variable fps? Or is it possible my SD card or the camera itself is something wrong with?

Report · May 09, 2017

is there a mac version to check for contstant/variable fps?

MediaInfo - Download

Report · May 09, 2017

Thanks, i'll check when i'm home again!

Report · May 10, 2017

try this advice from Neil: Re: Exporting 17 minute video, only 1kb when done?

Create a cineform proxy. The playback maybe related to the compression.

Report · May 10, 2017

thanks for the reply!

but if i make proxies with Media Encoder, Media Encoder itself is also having the frame jumping issue. so no matter how i export the original file, it'll always jump around!

seems like a dead end for me...?

Report · May 10, 2017

Are you saying you made proxies and the proxies exhibit the same jumpiness as well? If that's the case then the problem is in your source video.

Report · May 10, 2017

Yes that's exactly the problem! The strange thing is, if i just play the footage in let's say Quicktime player or VLC or the Finder, there are no problems with jumpiness...

on the other hand if i play them that way, you can see clearly that there is some big (faulty) compression going on in the top left corner. But without jumping occuring.

So yeah i guess the video file is corrupt then. But is this a camera problem or a transfer to SD card problem? I tried 2 different (same brand same speed etc.) SD cards from Lexar, one they gave me with the drone.

Should i try another SD card (faster)? Or should i contact DJI to repair my camera/buffer of the camera?

Thanks already for the advice!!

Report · May 10, 2017

Corruption is possible but unlikely. What do you see in the top-left corner of the source video when playing them in Quicktime/VLC?

It might be easier to get to the bottom of the issue if you could share a link to the source video here.

Report · May 10, 2017

It's in the youtube link, the screencapture i made. It's in my first post. I could post a wetransfer link to the original file in here. I'll post it here within 10 minutes.

Report · May 10, 2017

Here's the original file, the problem occurs at 22 seconds.
I'm really curious what you'll be able to do with it!

https://wetransfer.com/downloads/177bb45868430992e4584b65add4abea20170510151457/b74dba0055796d7e6640...

Report · May 10, 2017

Thanks for the file. The video plays smooth on my MPC-HC viewer (Windows) but freezes for a second at around 24 seconds into the video, which usually means corruption. Each viewer will handle this differently - some will be jumpy around the corrupt section while others will freeze during the interval. To verify I ran the file through ffprobe with full debugging enabled (-loglevel 48) and it reported an invalid NAL size at just past 24 seconds into the video, which indicates corruption. Here's the ffprobe output right after the last valid frame - this is just a snippet:

-FRAME-
media_type=video
stream_index=0
key_frame=0
pkt_pts=606000
pkt_pts_time=24.240000
pkt_dts=607000
pkt_dts_time=24.280000
best_effort_timestamp=606000
best_effort_timestamp_time=24.240000
pkt_duration=1000
pkt_duration_time=0.040000
pkt_pos=181914058
pkt_size=229451
width=3840
height=2160
pix_fmt=yuv420p
sample_aspect_ratio=1:1
pict_type=P
coded_picture_number=605
display_picture_number=0
interlaced_frame=0
top_field_first=0
repeat_pict=0
-/FRAME-
ype:1 pic_struct:0
[h264 @ 00000000025e7200] Invalid NAL unit size (0 > 816088).
[h264 @ 00000000025e7200] Error splitting the input into NAL units.
[h264 @ 00000000025e7200] nal_unit_type: 9, nal_ref_idc: 0
[h264 @ 00000000025e7200] nal_unit_type: 6, nal_ref_idc: 0
[h264 @ 00000000025e7200] nal_unit_type: 1, nal_ref_idc: 1
[h264 @ 00000000025e7200] ct_type:1 pic_struct:0
[h264 @ 00000000025e7200] Frame num gap 1 511
[h264 @ 00000000025e7200] no picture ooo
[h264 @ 00000000025e7200] nal_unit_type: 9, nal_ref_idc: 0
[h264 @ 00000000025e7200] nal_unit_type: 6, nal_ref_idc: 0
[h264 @ 00000000025e7200] nal_unit_type: 1, nal_ref_idc: 1
[h264 @ 00000000025e7200] ct_type:1 pic_struct:0
[h264 @ 00000000025e7200] no picture ooo
[h264 @ 00000000025e7200] nal_unit_type: 9, nal_ref_idc: 0
[h264 @ 00000000025e7200] nal_unit_type: 6, nal_ref_idc: 0
[h264 @ 00000000025e7200] nal_unit_type: 1, nal_ref_idc: 1
[h264 @ 00000000025e7200] ct_type:1 pic_struct:0
[h264 @ 00000000025e7200] no picture ooo
[h264 @ 00000000025e7200] nal_unit_type: 9, nal_ref_idc: 0
[h264 @ 00000000025e7200] nal_unit_type: 6, nal_ref_idc: 0
[h264 @ 00000000025e7200] nal_unit_type: 1, nal_ref_idc: 1
[h264 @ 00000000025e7200] ct_type:1 pic_struct:0
[h264 @ 00000000025e7200] no picture ooo
[h264 @ 00000000025e7200] nal_unit_type: 9, nal_ref_idc: 0
[h264 @ 00000000025e7200] nal_unit_type: 6, nal_ref_idc: 0
[h264 @ 00000000025e7200] nal_unit_type: 1, nal_ref_idc: 1
[h264 @ 00000000025e7200] ct_type:1 pic_struct:0
[h264 @ 00000000025e7200] no picture ooo
[h264 @ 00000000025e7200] nal_unit_type: 9, nal_ref_idc: 0
[h264 @ 00000000025e7200] nal_unit_type: 6, nal_ref_idc: 0
[h264 @ 00000000025e7200] nal_unit_type: 1, nal_ref_idc: 1
[h264 @ 00000000025e7200] ct_type:1 pic_struct:0
[h264 @ 00000000025e7200] no picture ooo
[h264 @ 00000000025e7200] nal_unit_type: 9, nal_ref_idc: 0
[h264 @ 00000000025e7200] nal_unit_type: 6, nal_ref_idc: 0
[h264 @ 00000000025e7200] nal_unit_type: 1, nal_ref_idc: 1
[h264 @ 00000000025e7200] ct_type:1 pic_struct:0
[h264 @ 00000000025e7200] no picture ooo
[h264 @ 00000000025e7200] nal_unit_type: 9, nal_ref_idc: 0
[h264 @ 00000000025e7200] nal_unit_type: 6, nal_ref_idc: 0
[h264 @ 00000000025e7200] nal_unit_type: 1, nal_ref_idc: 1
[h264 @ 00000000025e7200] ct_type:1 pic_struct:0
[h264 @ 00000000025e7200] no picture ooo
[h264 @ 00000000025e7200] nal_unit_type: 9, nal_ref_idc: 0
[h264 @ 00000000025e7200] nal_unit_type: 6, nal_ref_idc: 0
[h264 @ 00000000025e7200] nal_unit_type: 1, nal_ref_idc: 1
[h264 @ 00000000025e7200] ct_type:1 pic_struct:0
[h264 @ 00000000025e7200] no picture ooo
[h264 @ 00000000025e7200] nal_unit_type: 9, nal_ref_idc: 0
[h264 @ 00000000025e7200] nal_unit_type: 6, nal_ref_idc: 0
[h264 @ 00000000025e7200] nal_unit_type: 1, nal_ref_idc: 1
[h264 @ 00000000025e7200] ct_type:1 pic_struct:0
[h264 @ 00000000025e7200] no picture ooo
[h264 @ 00000000025e7200] nal_unit_type: 9, nal_ref_idc: 0
[h264 @ 00000000025e7200] nal_unit_type: 6, nal_ref_idc: 0
[h264 @ 00000000025e7200] nal_unit_type: 1, nal_ref_idc: 1
[h264 @ 00000000025e7200] ct_type:1 pic_struct:0
[h264 @ 00000000025e7200] no picture ooo
[h264 @ 00000000025e7200] nal_unit_type: 9, nal_ref_idc: 0
[h264 @ 00000000025e7200] nal_unit_type: 6, nal_ref_idc: 0
[h264 @ 00000000025e7200] nal_unit_type: 1, nal_ref_idc: 1
[h264 @ 00000000025e7200] ct_type:1 pic_struct:0
[h264 @ 00000000025e7200] no picture ooo
[h264 @ 00000000025e7200] nal_unit_type: 9, nal_ref_idc: 0
[h264 @ 00000000025e7200] nal_unit_type: 6, nal_ref_idc: 0
[h264 @ 00000000025e7200] nal_unit_type: 1, nal_ref_idc: 1
[h264 @ 00000000025e7200] ct_type:1 pic_struct:0
[h264 @ 00000000025e7200] no picture ooo
[h264 @ 00000000025e7200] nal_unit_type: 9, nal_ref_idc: 0
[h264 @ 00000000025e7200] nal_unit_type: 6, nal_ref_idc: 0
[h264 @ 00000000025e7200] nal_unit_type: 1, nal_ref_idc: 1
[h264 @ 00000000025e7200] ct_type:1 pic_struct:0
[h264 @ 00000000025e7200] no picture ooo
[h264 @ 00000000025e7200] nal_unit_type: 9, nal_ref_idc: 0
[h264 @ 00000000025e7200] nal_unit_type: 6, nal_ref_idc: 0
[h264 @ 00000000025e7200] nal_unit_type: 1, n
-FRAME-
media_type=video
stream_index=0
key_frame=0
pkt_pts=638000
pkt_pts_time=25.520000
pkt_dts=638000
pkt_dts_time=25.520000
best_effort_timestamp=638000
best_effort_timestamp_time=25.520000
pkt_duration=1000
pkt_duration_time=0.040000
pkt_pos=191481888
pkt_size=211873
width=3840
height=2160
pix_fmt=yuv420p
sample_aspect_ratio=1:1
pict_type=P
coded_picture_number=637
display_picture_number=0
interlaced_frame=0
top_field_first=0
repeat_pict=0
-/FRAME-
al_ref_idc: 1
[h264 @ 00000000025e7200] ct_type:1 pic_struct:0
[h264 @ 00000000025e7200] no picture ooo
[h264 @ 00000000025e7200] nal_unit_type: 9, nal_ref_idc: 0
[h264 @ 00000000025e7200] nal_unit_type: 6, nal_ref_idc: 0
[h264 @ 00000000025e7200] nal_unit_type: 1, nal_ref_idc: 1
[h264 @ 00000000025e7200] ct_type:1 pic_struct:0
[h264 @ 00000000025e7200] no picture ooo

Report · May 10, 2017

Thanks a lot! i really appriciate it!!

So what would be causing this corrupt files? Is it the camera itself, the buffer, the SD card?

This problem happened like 10 times within 20 different flights. Almost only happens when i fly upwards with the drone while tilting slowly down with the camera.

I know this isn't a drone or DJI forum but maybe you would know what would be causing this problem.

I'm going to contact DJI about it aswel!

Report · May 10, 2017

Corruption is usually caused by SD cards but if you're seeing it consistently for a particular type of camera movement it may indicate a bug in DJI's H.264 encoder for that type of motion.

Report · May 10, 2017

Alright, thanks a lot again!

one last question, would you say this is a bug for the general h264 encoder DJI uses or rather a bug particularly for my drone thus a factory mistake?

I know people with the same drone and they all say they never experienced this before. also never have i ever seen this problem on other forums/groups.

Again thanks a thousand times!

Report · May 10, 2017

It could be either - a fault in your drone which leads to faulty output of the H.264 encoder (or corruption of the output further downsteam to the media card) or a problem endemic to the model in general. The fact other people don't see the issue isn't definitive that it's unique to your copy - sometimes bugs require a very specific set of circumstances to manifest.

Report · May 10, 2017

I'm going to contact DJI about it. My guess is it shouldn't be like this because it's not possible for me to use it professionally if i'm never sure if my shot is going to be corrupted or not.

Thanks for your time and knowledge!

Report · May 10, 2017

It's likely due to the compression method used by DJI for their 4K footage. See this:

https://forums.adobe.com/message/9500809#9500809

Strange frame skipping problem.. can someone help? (DJI MAVIC PRO)

1 Correct answer