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  1. #1
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    Paralenz videos "running fast" - wrong framerate?

    Had the Paralenz for about 6 months now. It's a bit hit & miss though and resets it's settings randomly. As there's no monitor, it's hard to tell by looking at it.

    Anyway, I managed a dive in Loch Ness (dark, featureless, little life, more like cave diving). I was filming using the Paralenz for most of it, but the videos (1080p @ 30fps) seem to be running at twice the speed. Slowing them down in VLC to half speed seems to be about the right speed, but now rather jerky.

    The other videos from the rest of the week don't seem to be like that.

    Any ideas?

    VLC's Media info:
    Codec info: H264 - MPEG-4 AVC (part10)
    Resolution: 1920x1090
    Display resolution: 1920x1080
    Frame rate: 29.970030
    Decided format: Planar 4:2;0 YUV
    Last edited by Wibs; 12-10-2019 at 05:14 PM. Reason: Media info

  2. #2
    bottlefish Stuart Keasley's Avatar
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    If the footage is faster than it should be, tgat would suggest that frames have been dropped, either in recorded footage or at playback. The most likely explanation I can think of is a dodgy SD card, that can't keep up with the write speed, although in my experience this tends to lead to a failed recording as opposed to dropping frames but carrying on.

    Are you playing back the original footage, or has it been imported into a program?
    Please visit bottlefish for my personal web site, Quay Cameras to chat to me about the cameras and kit that I sell

  3. #3
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    Copied it from the Micro SD card to a Mac. The footage is smooth, just running at double speed.

    Maybe it just needs a reset.

    I should do a test.

  4. #4
    bottlefish Stuart Keasley's Avatar
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    Testing is always helpful

    If it's playing back 30 frames a second then playback will be smooth, the problem is that the 30 frames it's playing back were captured over more than a second, so it then looks speeded up.

    Slowing down the footage corrects the speed, but then it reduces the amount of frames shown per second to the point that it looks jerky.

    VLC is pretty good, but perhaps worth trying a different app as well. Handbrake sometimes gives a little more info....

    https://handbrake.fr/

    Also, see if you can bring up the original timecode display, it may give you a bit more info... You should see a display showing hours:mins:seconds:frames, frames should count from 1 to 30. If it skips, then the footage is missing frames.
    Last edited by Stuart Keasley; 12-10-2019 at 10:16 PM.
    Please visit bottlefish for my personal web site, Quay Cameras to chat to me about the cameras and kit that I sell

  5. #5
    Established TDF Member JimmE's Avatar
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    I have heard from others with a Paralenz that it is rather more “fussy” about SD cards than most cameras - check which brand/speed rating your card is and perhaps try another?


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  6. #6
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    I ran a test video filming my iPhone timer; playback all correct.

    Reviewed the (pretty lousy) videos which looks like they're running at the right speed, it's just the EIS (electronic image stabilisation) is off -- one of the quirky resets that the Paralenz does -- which gives the images a Charlie Chaplin affect as I wobble the camera around. The lack of any fish or vegetation doesn't give any movement reference. So it's obviously me.


    Loch Ness is a weird place to dive. Clear visibility - no particulate - but with that peat staining which attenuates all light, my narrow beam only reaching about 3 metres. Very little life, some small fry and no vegetation below a couple or three metres. The torch doesn't penetrate far and there's no back-scatter from a tight signalling beam, so you need a wide beam to light up around you. Thankfully with the Anchor Light's combined video and sharp beam works well, just like in a cave/mine.

    One of the oddest things was the blue light on the torch -- apparently for luminescence on coral -- simply didn't work in the peaty water! The light modes require you to cycle through the modes to go back; one of is the blue light which on a wreck can be quite bright. In that water it was barely visible, literally extending to a few inches. The red light was a different matter.

    TBH it was a really spooky place to dive, especially alone, with my 'captain' on my shoulder reminding me that he thinks he can hear Nessie coming up behind :-)
    Last edited by Wibs; 13-10-2019 at 11:47 AM.


 

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