Mivue 618 with pixalation

richardkhill

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Been using the 618 for a couple of weeks now, but a bit disappointed at the video quality, which can be quite pixalated. I'm recording at 2304x1296p @ 30fps. Admittedly I'm using a fairly old unbranded SD card (I don't even know what class it is) but could this be struggling to store the data effectively? I don't know what the transfer bit rate is.

Any suggestions on how to improve the video quality?

Below are a couple of sample screen shots; the pixalation is quite visible in the daytime shot, but harder to identify on the night shot.
Rainbow detail.png Night detail.png Micro SD.jpg

Thanks
Richard
 
Don't know jokiin. I assumed that the highest setting would produce the best results. I'll try it at 1080 and see if it makes a difference.
 
not always the best results from higher resolution if the bitrate isn't increased enough in that mode, often not
 
Ok. Just read your piece on memory cards. I'm going to get a branded class 10 card today and see what that does, along with a different resolution setting.
 
So, installed a new class 10 card and also did a firmware update. There seems to be marginal difference between 1296p and 1080p. There's still an element of pixalation!

I believe I've got the camera set at the optimum position, but would dropping the horizon and reducing the amount of blue sky possibly help?

Richard

1296p Screenshot
1296p.png
1080p screenshot
1080p.png
 
Our Mio 528 and 538 cams pixelate, being mostly noticeable at high speed and/or with flickering light through roadside trees. Most cams pixelate to some extent, although the Mio 5-series are more prone to it. I notice a 'frequency' in the pixilation; roughly twice per second.

But having criticised the greater tendency for pixilation in our Mio 5-series cams, it's worth noting that I find them to be reliable where other so-called superior cams have failed (e.g. Nextbase 402G).

I don't think changing the angle will make much difference to pixelation, although slightly lowering the angle might slightly improve overall video quality. The Mio 5-series mount (not sure about 6-series) tends to have only just enough adjustment to get the ideal view when mounted to the very shallow windscreen of a modern car (I modified a mount from another cam).
 
My wife has a mivue 518 in her car, which performs well at it's highest 1080p setting, so I chose the 618 based on this, and it's high 1296p resolution. Maybe I should remind myself that it is only a sub £100 unit after all, so shouldn't expect TV like quality. I'm beginning to wonder if I'm just setting my expectations a bit too high?!?

I'll drop the viewing angle slightly and see if that helps in anyway.

Thanks for your input 2000rpm.

Richard
 
The left hand window is the properties of a 1296p clip and the right hand window is a 1080p clip. Non of my 1296p clips show the Frame width/height or Frame rate in their properties!?

Bitrates.png
 
only info I could find suggests it uses an AIT chipset, not the greatest encoder out there, might be something you just have to live with
 
These are compression artifacts. The captured image has more detail than the bitrate can handle at this resolution. Excessive sharpening that seems to be going on intensifies this effect even more.

The most straightforward solution would be to increase the bitrate and reduce sharpening but there are no settings for this. Short of that, you can:
  • Reduce resolution to 1080p
  • Prevent sudden changes of brightness in the recorded material, namely:
    • Lower the angle so that the camera shows more of the road and less of the sky, which can dramatically change in brightness every couple of seconds
    • Use a circular polarizer lens filter
The SD card is unlikely to have anything to do with this. If it were too slow, the recording would just completely fail or have frozen frames.

On a general note, the kind of scenery as in your pictures (trees without foliage) is very likely to generate artifacts with any lossy compression. That being said, the manufacturer could do better: they opted for extra sharpening to make number plates more legible but could clearly include an option to switch it off.
 
Looking at the pictures, I think it is the reflection of dashboard (ribbed structure of the plastic) on to the windscreen. That's why the lower part of the video is most grainy. I have a Mio Mivue 618 and my videos (both 1080p and 1296p) are much sharper and brighter than yours.
 
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