A119s night video stutter

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j__h

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I just got an A119s (from Amazon OCD Tronic seller) and am seeing some weird framerate/stutter behavior on night videos. This is using the 1080p/60FPS mode and a new high endurance Transcend 32GB SD Card (from Monoprice) formatted in the A119s. Daytime video so far seems fine.

(Download mp4 of first video: https://mega.nz/#!fpxGyQRY!oZMWDXCOdlwXzUK_Tb2hCqaud0QzTAVJpxZSGAe2Vuk)

Notice around the 2 second mark in the first video:
 
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j__h said:
I just got an A119s and am seeing some weird framerate behavior on night videos. This is using the 1080p/60FPS mode and a new high endurance Transcend 32GB SD Card formatted in the A119s. Daytime video so far seems fine.

Notice around the 2 second mark in the first video:
Click to expand...
Nothing wrong with the A119S it is your computer buffering (bit rate) Copy file to a folder then view it and it will run smooth with out studder
 
I see the same single stutter at around 2 seconds on the first video on both my computers (one is quite powerful) with files on an SSD and in multiple formats also seen on the youtube video. Are you saying that you see no stutter in the posted videos?
 
I see the stutter, better if you can share a raw video though rather than uploading to YouTube as they re-encode the videos which makes working out the problem more difficult

better description might have helped also, no idea what a 'jank' is 😵
 
Title changed to stutter. I have heard "jank" used to described issues in videos related to frame timing, but it seems it is not in widespread use (or really not used at all), sorry about that.

Tried using the "upload a file" but that was unsuccessful. Is there a file uploading service that is commonly used by this forum?

Edit: uploading now to Mega.nz
 
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j__h said:
I see the same single stutter at around 2 seconds on the first video on both my computers (one is quite powerful) with files on an SSD and in multiple formats also seen on the youtube video. Are you saying that you see no stutter in the posted videos?
Click to expand...
NOTHING WRONG WITH YOUR CAM IT IS BUFFERING LOWER YOUR BIT RATE ON YOUR COMPUTER
 
Sutton said:
Nothing wrong with your cam it is buffering lower your bit rate on your computer
Click to expand...

If I may ask how have you made this determination? I would have thought that Youtube would already have knocked the bitrate down to more than reasonable levels, but I still see the issue in the same position of video even if I lower the video quality settings significantly (on Youtube that is). I also would have thought local playback with original ~20Mbps files would be fine given I do have a reasonably powerful system .
 
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It is definitely stutter on second 2 on your first video. And it is NOT related to your computer.
BUT it is so invisible that I paid attention only after you wrote that it is on second 2 and I replay it again and again.
Is it so disturbing you ?
I was more worry about your odometer in the middle of the picture. I have A119s WITH CPL and have mostly the same effect (on top right side on the picture) and I really don't like.
All idea to pay $15 for filter was to prevent such things.
 
>Is it so disturbing you ?
Yeah, as a device to record proof to possibly be used in a court of law I do not want it to be missing data (or in any way be under suspicion of manipulation). That also was just one instance, I see it a lot in the videos my device is recording at night.

> I was more worry about your odometer in the middle of the picture.
The reflection is actually from a Bluetooth FM transmitter and the LED light on the power adapter for the A119s itself. I can modify/turn those off later but they don't affect the merit of the data like missing data does.

Your dashboard might have a brightness adjustment, could be something to workaround the reflection slightly.
 
j__h said:
Yeah, as a device to record proof to possibly be used in a court of law I do not want it to be missing data (or in any way be under suspicion of manipulation). That also was just one instance, I see it a lot in the videos my device is recording at night.
.
Click to expand...

although it is annoying you have a duplicate frame issue, it's not missing anything, just one frame was repeated

try it at 30fps and see if you get the same result
 
Hello everyone,
It's just the camera switching between 60 fps to 30 fps then back to 60 fps.
look at the blur of the road markers.
 
I just stepped through the frames and sure enough it looks to start duplicating frames. Not just a single frame duplication but every other frame is a duplication for a long time period. I presume this is to increase the exposure time for low light areas where 1/60 ms is not enough and is keeping 60 FPS video but actually running sensor at 30FPS (as Dan8 mentioned). Actually, whenever I drive under a street lamp the camera goes to a true 60 FPS and when I leave the streetlamp the camera switches back to 30FPS (and frame duplication).

I had looked at other A119(s) videos and did not see similar, maybe I just need brighter headlight?

Edit: Yes, as Dan8 mentioned looking at the line markings you can clearly see when frame duplication occurs the lines get longer, this matches the theory that the exposure time goes up.
 
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This was adjusted in the A119 firmware from memory, may not have been looked at yet for the A119S, it's a fairly common approach to have frame doubling in low light situations when running at 60fps
 
jokiin said:
This was adjusted in the A119 firmware from memory, may not have been looked at yet for the A119S, it's a fairly common approach to have frame doubling in low light situations when running at 60fps
Click to expand...

Yup, and it seems perfectly reasonable.

I spent some more time looking at frame by frame stepping and it almost looks like it is not done quite optimally (or just a sensor limitation?). When looking at it frame by frame it appears that the system switches to frame duplication a few frames before the sensor has actually switched to longer exposure. There is even a frame (that gets duplicated) which shows quite high noise right before it switches to longer exposure. This makes the effect when switching from short exposure to long exposure appear worse.

Here is another download, this one shows frame by frame snapshots with annotations to the file names describing what appears to me to be occurring. Use a photo viewer that you can use keys to step forward and back for best effect.

https://mega.nz/#!K55kHY7J!97tC_jEBJMzbRYlgadrvXAT7IjKTem5VkNcXcH0hzX8
 
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There's a couple of different ways to handle this, there's no right or wrong answer as to which is the best method but having a user selectable option would possibly be a better option and let the end user decide which they prefer, frame doubling, switching frame rate or locking the frame rate, each has advantages and disadvantages in different scenarios
 
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