Is it normal for Car DV (dashcam) video to be in multiple files?

Discussion in 'SJ7 Star' started by Bob, Jan 23, 2018.

  1. Bob

    Bob New Member

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    I'm playing around with my new SJ7 Star camera and decided to try it out as a dashcam last night. The video created was in many small files of no set length but approximately 4 to 5 minutes long each. Is that normal? I was shooting in 4K. Loop recording was NOT turned on.

    Just as a test, this morning I shot a "regular" video in 4K this morning without changing any settings (other than not using Car DV mode) and it created one large file as expected.

    BTW, I was very impressed with the quality of the dashcam video(s). Last night it was very dark and foggy. The video was actually much clearer than how it was to the eye when driving.
     
  2. Jason

    Jason Moderator

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    Short answer - yes.




    Long answer Yes, action cameras use fat32 as the base filesystem for the SD card which has a maximum filesize of 4gb. The action camera starts a new file before it hits that. This behaviour is still used on exfat formatted sd cards
     
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  3. Bob

    Bob New Member

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  4. Jason

    Jason Moderator

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    SJ7 has a F2.0 lens where as most other action cameras have a F2.8 aperture lens. That means it gets twice the light whicj helps at night
     
  5. RBEmerson

    RBEmerson Humbled by events

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    That's puzzling. Are you sure the videos weren't interrupted? Typical non-stop 1080@60 fps should give about 3.9 Gb files lasting just over 14 minutes. DV should give regular file sizes with a regular duration. What firmware version are you using? If it's V1.21, try V1.20 and repeat what you did earlier.
    that's good.
    See an ophthalmologist. [/wink]
     
  6. Sulev Svilponis

    Sulev Svilponis Elite

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    Just turn off the Loop recording!
     
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  7. Sulev Svilponis

    Sulev Svilponis Elite

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    I record all my driving videos with regular video mode (or time lapse mode). Never in the Dashcam mode.
     
  8. RBEmerson

    RBEmerson Humbled by events

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    Sulev, read what the OP wrote!

    The point behind DV is that when the chip is full, the first file previously written is overwritten by the file currently being shot. In other words, think of the files as a long list written on one piece of paper, with new files being listed regularly. When the bottom of the page is reached (full chip), the top of the list is crossed out and the new file is listed in its place. The result is you have the last x number of hours stored on the chip, not the full trip.

    If you want to record the entire trip, DV is not the way to go. A 128 Gb chip, shot at 1080 @ 60 fps, will last for 6-8 hours of driving (30 fps will allow more video, but the image won't be quite as good - lots of streaking). Or, as suggested, you can use time lapse to record much more than that. The playback will have to be slowed down to make any sense of what went on. Shooting one frame/second effectively speeds thing up by (my math is wretched on this but I think it's) a factor of 10. Or not.
     
  9. Sulev Svilponis

    Sulev Svilponis Elite

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    Nobody talked to you, clueless RBEmerson!
     
  10. JAY11

    JAY11 New Member

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    hey! Jay here! I didn't know about this 4 gb size limit. As a result few seconds of videos are missed in between. What would you suggest me to do?
    Any workaround to overcome that? Or should I keep time?
     
  11. RBEmerson

    RBEmerson Humbled by events

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    @JAY11 Are you 100% sure about the gap between files? What firmware version are you using? I accidentally shot in DV mode and didn't see the gap between 3 minute files.

    I'll test this with V1.21 (just released - see the support page for the file).
     
  12. JAY11

    JAY11 New Member

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    Sorry. It was not shot on DV mode. I almost didn't see the thread. It was a regular 1080p 16:9 with gyro on. I am on 1.18 now. I had 1.20 when I bought it but went back to 1.18 thinking that might solve my wind noise issue. (It didn't btw). I think it's that FAT32 limitation for which I am getting multiple files.
     
  13. RBEmerson

    RBEmerson Humbled by events

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    I've mentioned before shooting 500 Gb of video with the SJ7 in 1080@60 and EIS on. The only gap issue, which was resolved with V1.20, is a two frame dropout in the audio. But there aren't any video dropouts. I shot with 64 and 128 Gb SD's. No problem found.

    Check out the latest video I posted to YT. Good luck finding the seam. Hint: it's not where I pull of to the left side of the road. [/grin]
     
  14. RBEmerson

    RBEmerson Humbled by events

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    FYI, I shot some dashcam, loop=3 min, video with no gaps found in the video. There is the one frame audio dropout, which will sound like a very fast click.
     
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  15. Damian Holt

    Damian Holt Moderator

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    I thought the audio drop out had been fixed in 1.21?
     
  16. RBEmerson

    RBEmerson Humbled by events

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    My error - sorta. The dropout is on the last frame of the old file, not the first frame of the new file.
     
  17. HR-Mike

    HR-Mike New Member

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    Did anyone manage to set video duration in dashCam mode for more than 2 minutes?
    For me, every single video is always 2 minutes, regardless of settings in the "loop record" menu where there are different duration options.

    One more thing.
    Does anyone know if the camera in Dashcam mode registers an "accident" by locking a file during which the G-Force increase is detected
    (V.1.21)
     
  18. RBEmerson

    RBEmerson Humbled by events

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    You should be able to get up to 5 minutes per file. Check the options.

    AFAIK there is no accelerometer tagging.
     
  19. HR-Mike

    HR-Mike New Member

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    Yeah I know that id should be 5 mins, but it doesn't.
    It acts just like the Dash Cam options has settings of their own.

    Njaahhh .... DashCam loses its meaning if it does not take the accelerator data (since it has a gyro sensor).
     
  20. HR-Mike

    HR-Mike New Member

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    As a biker, first I want to congratulate you on riding through the Grossglockner region (I have it on to-do list because it's only about 650 km from my home).
    I've seen the whole video, but I'm interested in entering and exiting the tunnel - how you set the "metering" because it seems to me that adaptation to light takes a bit too long.
     

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