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Video Recording Bitrate Bug in DJI GO

Discussion in 'Pro/Adv Discussion' started by AchillesPDX, May 2, 2016.

  1. AchillesPDX

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    Not sure where else to put this, but it's a fairly significant bug that totally just screwed up my shoot.

    I've got a Phantom 3 Advanced running the latest 1.8.80 firmware and the DJI GO 2.7.1 app on my Nexus 7 (2013)

    Ordinarily, the drone shoots wonderful 1080p60 footage at 60mbit/sec, HOWEVER, if you leave the app open and the controller on, and power down the drone to change batteries, when it reconnects you'll only be recording 1080p60 footage at 26mbit/sec (which looks like complete garbage).

    Has anyone else encountered this? The only solution I've found is to completely exit the DJI GO app between battery changes and re-launch it by re-connecting the controller to the tablet.
     
  2. AchillesPDX

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    And I just realized I wasn't running the latest DJI GO version. Will do another test and report back.
     
  3. AchillesPDX

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    Great. I made it worse. Now it only records at 26mbit/sec

    Wonderful. Any way to roll back the DJI GO app to 2.7.1?
     
  4. alokbhargava

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    Great catch.

    I use normally 4K, 24 fps so didn't notice this bug.
     
  5. MikeyOnline

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    This is a complete guess so I hope to avoid lashings if I'm wrong... but what kind of SD card is in it? Maybe the transfer rate isn't stable at 60Mb all the time so sometimes it's dropping back?

    Mike
     
  6. Bigs

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    I have this exact setup, I'll have to look into that more over the weekend and post back.
     
  7. AchillesPDX

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    Interesting thought - It's a "PNY U3 High Performance 64GB High Speed MicroSDXC Class 10 UHS-I" and I looking through my previous footage I have one file from March 13th that's at 26Mb, with all the rest at 60Mb except now starting on April 28th where I have several at 26Mb. I guess I need to do some further testing.
     
  8. AchillesPDX

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    Wow... I'm going to lose my mind. It's completely random whether it records at 26Mb or 60Mb now. I had powered the drone down, closed DJI GO and turned everything on and now it does 60Mb, whereas 15min ago it was doing 26Mb.

    Not sure what to do at this point. Anything shot at 26Mb is totally useless because of the compression but I'll have no idea if it's good or not until after I've shot it.
     
  9. MikeyOnline

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    Yeah, that's just something I wondered: I wondered if the software might test the transfer speed and fall back based on the results. Plus, maybe the new 2.8.2 software is more "sensitive" in that test if that's what it's doing. Even a regular class 10 card is supposed to be 10MB/s minimum though (which should be around 100Mb/s) so I'm not sure that's it. Wonder what factors kick the bitrate down? Might not hurt to try a different card. Maybe the P3 just isn't "happy" with that one and is getting a slow transfer rate for some reason.

    Mike
     
  10. Oso

    Oso

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    Plus the P3 is hardware limited to write at a maximum of 7.5MB/s.
     
  11. MikeyOnline

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    FWIW I just checked mine and they're all 60Mbps but I've been running 4K/30. I've got a test flight later today (new battery so I stay close to home on the first flight) so I'll set mine to 1080/60 and see what happens.

    Mike
     
  12. AchillesPDX

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    Mike, this is an Advanced though, not sure if you'll see the same error or not.
     
  13. MikeyOnline

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    True, but you never know. I'm just playing today so I'll try and see. I'll fly it a little while, bring it back, power down the P3P but leave everything else on, take the battery out and put it back in (as you would if you're putting in a new battery), and take off again and run another video. If mine's at 60 Mbps of course we'll know nothing. But if I see 26, that's good data. :)

    Mike
     
  14. AchillesPDX

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    Starting to think it's the firmware being really picky about the SD Card and there also seems to be some kind of correlation with heat. I need to do further tests, but it seems like when I leave the P3 powered off for a while to cool down and then immediately start shooting video as soon as I turn it on, it's fine. But if it's been turned on for a while and has warmed up, then it only does 26Mb. I might roll back the bird to the 1.7 firmware to see if it's more forgiving, but it's looking like I'll probably need a different SD card.
     
  15. MikeyOnline

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    Doesn't the Advanced come with a 16GB like the Pro? Still have it?

    Mike
     
  16. AchillesPDX

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    It does - but it's been repurposed and is in my Raspberry Pi at home, so I can't test it until later tonight.
     
  17. rockydog

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    The P3A doesn't shoot at 60 Mbs...maximum bit rate is 40Mbs. In1080p, bit rate at 24/25/30 fps is 26 Mbs and bit rate at48/50/60 fps is 40Mbs
     
  18. Oso

    Oso

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    It sounds weird, but try this. Switch from video mode to camera mode in the app, and then back to video mode and see then if it goes back to 60Mbps. I think that's how to work around this bug.
    Of course it's hard to call it a bug when the P3A is not supposed to have 60Mb/s anyway - officially I mean.
     
    #18 Oso, May 2, 2016
    Last edited: May 2, 2016
    Trackman1 likes this.
  19. Oso

    Oso

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    Since I think December with FW 1.5 and the GO app out around that time the P3A has had 60Mb/s as well even though DJI officially lists it as only a max of 40Mb/s.
     
  20. rockydog

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    I stand corrected...I was going by this chart:
    date-rate-info-for-video-tut.png