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Flickering in recorded video

Discussion in 'Inspire 1 Help' started by Trumple, Jun 9, 2015.

  1. Trumple

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    Hi all,

    First off, I'm a Phantom 3 Professional user. I'm aware I'm posting in an Inspire forum, but I feel that you might be able to help me because:
    • The app for the P3 and Inspire are the same
    • The camera is of similar capability
    • Inspire has been around a lot longer and the users here might have experienced the same problem
    • Inspire users are typically "power" users so may be more experienced with video shooting

    I posted this on the Phantom and DJI forums to no avail. The problem I have is that my recorded video appears to "flicker" or "pulse" periodically. It seems to be more apparent in bright situations, but is also present in low lighting conditions, so I do not believe that it is influenced by shutter speed.

    Here's the best example I have:


    Take a look in 1080p and fullscreen - you should notice that the grass and trees all "pulse" periodically (~1s).

    Here's an example in low lighting conditions:


    Excuse me fiddling around with the camera settings in this one. It's less apparent in this one, but in the raw footage it's very obvious.

    What I've tried:
    • Switching to advanced mode to set the ISO/shutter speed manually
    • Setting the white balance to different presets (thereby disabling auto mode)

    I've noticed something though: the EV value seems to jump around by itself depending on the lighting conditions in advanced mode. I thought the EV was based on the aperture (fixed in this camera) and the shutter speed, so why is it jumping around? Could that explain this effect?

    Thank you for any help. I'm a total camera noob so please feel free to suggest things which might seem blindingly obvious to you. Please note that this effect happens in the raw footage too, so we can't blame YouTube.
     
  2. damoncooper

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    You should be able to lock the exposure which may be what's causing your flickering.

    Top right in the pilot app.
     
  3. Trumple

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    Thanks for the suggestion - I tired that today with no luck!
     
  4. Figbar

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    I've tried a ton of stuff dealing with this issue. ND filters....shooting 100 iso 60 fps - 4k 30 frames. I've tried all the custom settings, lowering sharpness, contrast, etc. No auto white balance. I'm still not happy with the Inspire 1 camera

    I do video professionally...and I shoot a lot of grass...videos for the Scotts Miracle Gro Company. I have edited in Premier, AVID and Final Cut, After Effects. I've come to the conclusion that my Inspire1 camera is not really that great...I have to work really hard to get it to look good. I think that DJI has not critically focused on their proprietary cameras. The vision plus camera is horrible. I don't know how similar the Phantom 3 Pro camera is to the Inspire Camera, but I am getting the same results you are...especially looking at turf. I wish I could be more encouraging.

    Having said all this...I am still very pleased with my Inspire1. I'm thinking a better camera that fits into this turnkey system will come along. Video is critical to me...I had a Phantom / GoPro setup...DSLR Pros Sundance Edition...it was a pain in the ass.

    Keep asking and experimenting...just sharing my experiences with the Inspire camera.
     
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  5. Trumple

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    Thanks Figbar. I take this to mean that this is a problem with all Inspire 1 cameras? Or are you saying that yours in particular is a bad one?

    I think the two cameras are very similar, and I believe (based on other threads in this forum) that the problem comes down to the codec. I, too, shoot a lot of tress grass etc. so I notice it a lot.

    I'm not displeased with my P3P - I would say most people don't even notice the problem. I showed it to my housemate for a good few minutes and he had no idea what the problem was despite me explaining it.

    Additionally 1080p doesn't share the same issue, so that is a workaround if that's acceptable. I might limit myself to 1080p around grass, trees etc. and 4k elsewhere.
     
  6. Figbar

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    This is just my opinion about the Inspire camera...based on my extensive (and exhausting) testing...so please don't take this as absolute.
     
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  7. Trumple

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    Thanks Figbar. I understand, but in your efforts to solve the issue, have you come across footage that does not have the issue? I ask because it seems many people are able to shoot grass and trees just fine, yet we are not:
    http://forum.dji.com/forum.php?mod=viewthread&tid=19927

    Unless the footage in that thread does have the issue and I just can't see it.
     
  8. Figbar

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    Not really...I'm looking at the stuff I'm shooting critically...on a broadcast monitor...I get those blotchy patterns on turf regardless. I have not really had the opportunity/time to analyze other folk's raw/native footage. It's OK...at this point, I've pretty much accepted the camera for what it is, thinking there will be a new iteration in the near future. Do I want to spend more cash on this stuff...no...but if I can get a really great camera to work with the Inspire...now that would be something.
     
  9. amkorp

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    Check to see if you are in PAL video mode.

    If you are switch it to NTSC and see if the flickering stops.
     
  10. Figbar

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    I'm in NTSC...the app used to not let me do this...but I'm in NTSC...thanks.
     
  11. SimAir

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    I just got the inspire1 and the first thing I noticed about the video was the flicker. Really disappointing.
    My phantom 2 with a 4k gopro shows no flicker at all. Feels like a metering issue or sampling rate.?, but from these postings it seems to be a lager issue.
     
  12. damoncooper

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    The issue below was communicated to DJI. Not sure if it's the issue you're seeing but worth noting. It has to do with the H.264 encoding approach used in the Inspire X3 camera.

    --------

    Basically, the current H.264 compression has an 8 frame sequence with 1 inter-frame followed by 7 p-frames. The inter-frame is encoded with full detail. Then, the 7 following p-frames encode only what's changed since the inter-frame. When we hit frame 9 the sequence resets with another inter-frame followed by 7 p-frames. The problem is that p-frames only predict forward from the inter-frame. So once we hit the 9th frame (the inter-frame for the next sequence) the scene's compression changes dramatically because it's been 7 frames since the full scene detail was recorded. If it's possible hardware-wise, DJI could solve this by using b-frames. B-frames are encoded bi-directionally, meaning they look to the frame before them AND after them to encode their detail. For example, even if just the 8th frame in the sequence was a b-frame, this means it would be a mix of the frame 7 (a p-frame) from sequence 1 and the 9th frame (an inter-frame, and the beginning of sequence 2). Since this b-frame would be encoded as a mix between the two frames (before and after it) it would help to smooth the transition from sequence to sequence.

    If the Inspire 1 hardware could handle it, there are actually some better algorithms.

    A recommended fix might look like:

    1) inter-frame
    2) b-frame
    3) p-frame
    4) p- frame
    5) b-frame
    6) p-frame
    7) p-frame
    8) b-frame frame

    9) NEW SEQUENCE inter-frame

    Or at the very least, if you could just ask if b-frame encoding is possible for the Inspire 1's H.264 compression. It would alleviate the flickering problem and be very beneficial to everyone who uses the Inspire 1.
     
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  13. SimAir

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    Would Mp4 format use the same compression scheme? or is the format just a wrapper?
    Thanks for the info
     
  14. damoncooper

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    No, MP4 and mov are just containers. The encoding / encryption is set in both cases to H.264.
     
  15. The Editor

    The Editor Moderator
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    Let's also not forget the pathetic bitrate of 60mbps which is woefully inadequate for 4k and we get a mix of things that severely limits the platform.
    My guess is DJI are not going to be able to utilise b-frames as the x3 is already maxed out both hardware and software wise - look how hot the thing runs :eek:.
    To put any more loading on it would mean you would have to wear oven gloves to handle it!.
    They COULD possibly go to H265 but there would be a lot of perplexed customers not knowing what to do with the resultant file.
    Unfortunately (and I have said this before), DJI should have stuck to what they know best - UAV's. They are world leaders and innovators in their field but they know absolutely nothing about cameras and it really shows they are clueless! :mad:
     
  16. damoncooper

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    X5 can't come soon enough
     
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  17. jlo

    jlo

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  18. mikimauz

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