B1W Low Bitrate BETA

TonyM

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A139, M1S
Following suggestions from a few DCT members last month, Blueskysea were quick to produce a Low Bitrate parking mode beta firmware for testing.

The camera records normal driving in 1080p30fps at 12Mbps. After 3 minutes without movement, the camera switches to 1080p30fps at 4Mbps. Upon detecting movement, it switches back to 12Mbps again.

Movement is detected using only the g-sensor, since there is no GPS to inform the camera that the car is moving. Activation of the sensor saves the current video file in the Event folder. If the car is struck by another when parked, it will also switch from 4Mbps to 12Mbps, since this would be registered by the g-sensor.

The benefit of recording at low bitrate when parked (compared to time-lapse or g-sensor activated recording) is to extend the available recording time on a memory card, whilst still recording at 30fps with audio. In testing, I found no difference in power consumption between recording at 4Mbps and 12Mbps.

Blueskysea have decided to enable the bitrate switch mid-file, rather than stopping the recording and starting a new file. Although there is a momentary video glitch in the current beta FW (comprising just a single frame) the benefit is that the recording is continuous so no information is lost, unlike some other cameras which lose a few seconds of potentially crucial evidence whilst switching modes.

Video Sample 1
4Mbps parking sample

Video Sample 2
Automatic switch from 4Mbps to 12Mbps

The low bitrate FW has been posted by @estore009 in this thread : https://dashcamtalk.com/forum/threads/b1w-low-bitrate-beta.38707/post-499732
 
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Although there is a momentary video glitch in the current beta FW (comprising just a single frame)
They got the image wrong, it should be a padlock icon marking the point of impact and hiding the 1/15th second switching time!

In testing, I found no difference in power consumption between recording at 4mbps and 12mbps.
I got 0.19 Amps when parked, 0.01 A more when driving. The most power efficient dashcam I know of.
 
I'm getting a file size, for 5 minute loop recording of 446 MByte for normal recording and 155 MByte for parking mode.

With the minimum 30% reserved space and a 64GB memory card, that gives 22 hours of parking mode recording (calculated rather than tested!). It would be nice to get a little over 24 hours, what do you think about reducing the parking mode bitrate a bit further? There doesn't seem to be any difficulty in reading number plates in your video examples! It seems to use a very good codec for low bitrate.
 
As we know, UK number plates are larger than the worldwide average. And those were good lighting conditions for a dashcam too. I think a lower bitrate is worth trying, but I would also like to see the reserved space have a lower minimum, if possible.

The low bitrate mode in that parked example above runs at 4.4Mbps. It's 33.5MB for a 1min file. The bitrate does appear to be slightly variable since the size of each clip is not exactly the same.

To get 24 hours recording at 4.4Mbps would require 49.9GB, or 78% of a 64GB card.

Alternatively, to fit 24 hours into 70% of 64GB = 44.8GB would require a bitrate of 3.9Mbps
 
I am using 32gb card. So I can barely get 1 day of footage. Though I must say the newer firmware has improved to be more stable. At least I am not getting total cut off now. Lower bitrate option would be nice. Give user a choice of 2 or 4mbps.
 
I am using 32gb card. So I can barely get 1 day of footage. Though I must say the newer firmware has improved to be more stable. At least I am not getting total cut off now. Lower bitrate option would be nice. Give user a choice of 2 or 4mbps.
2 would be too little, it would not cope with cars driving passed. I think around 3.7-3.8 so that we get just over 24 hours on a 64GB card would be about right. If you need more then you can buy a bigger card, I know it is a cheap camera but a 64GB card does not cost much these days, and does have twice the lifetime of a 32GB so is actually better value at typical prices. Actually, I'm currently using a 32GB as well.
 
Interesting results of the first tests of the new firmware with a Low bit rate. The B1W was connected to a 5000 mAh power bank (3300 mAh for 5.1V).
The full record from the start of the recording to the power failure due to the discharge of the bank's turn off was 8 hours 32 min.
Power Bank 5000 mAh B1W.jpg

Low bitrate B1W_Full consumption 5000 PowerBank.jpg
In this case, 493 files with a duration of 1 min were recorded in the DCIM folder, and the total volume of 16.9 GB.
38 files with a total volume of 1,34 GB are recorded in the EVENT folder (files were recorded during repeated B1W movements, accompanied by a file lock message)
Folder DCIM.jpg

Folder EVENT.jpg
Total for 8h 32 m parking occupied 18.24 GB of memory on a SD card!

During the operation, the B1W consumed 3039 mAh of the capacity of the power bank, the total energy consumption was 15.329 Wh
The average power consumption is 1,789 Watts, or 0,149 Amps (over a 12 volt circuit).
Low bitrate B1W_9.jpg
When powered by a car battery, the flow rate would be 1,266 Ah (3,039 Ah*5V/12V), or just 2% of the battery capacity of 60 Ah.

And yet - the transition to a low bitrate works very well, without stopping the recording, in the picture in the Bitrate Viewer this can be seen
Go to a low bitrate file #10.jpg
The team of @estore009 and B1W continue to amaze! (y)

PS: uh-uh, I almost forgot - the transition to the Parking mode is accompanied by the inclusion of a Red indicator
 
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20% - 25% reserved space should be enough for most users, as would nearly 24 hours recording time for a 64GB card.

It seems to me that 'serious' dashcam owners use 64GB or larger cards with almost nobody using smaller than 32GB cards. So even at 20% there is enough space for a day's locked files, and one day's time is sufficient to retrieve them if necessary. Amazed at how well this cam has been developed (y)

Will join the party this weekend, as mine is still in the dead minivan and I need to redo how the workvan is set up anyway.

Phil
 
Yes.
I cant recommend using smaller than a 64 GB memory card for 1 camera or 1 channel in a dual system.

I have just ordered one of these to expand on my test suite of memory cards, they are the cheapest endurance cards you can get here.

 
Hope they fare better than your past Kingston cards! I hope to be getting a couple 128GB cards soon myself.

Phil
 
Low bitrate works just as well at night as it does during the day. Note that on a smooth car park surface, the B1W sometimes takes longer to register movement before switching from low bitrate to normal recording. This will vary from car to car, and depends on driving style etc.

I have my B1W g-sensor sensitivity set to Middle.

Video Sample 3
Automatic switch from 4Mbps to 12Mbps (night)
 
Low bitrate works just as well at night as it does during the day. Note that on a smooth car park surface, the B1W sometimes takes longer to register movement before switching from low bitrate to normal recording. This will vary from car to car, and depends on driving style etc.

I have my B1W g-sensor sensitivity set to Middle.

Video Sample 3
Automatic switch from 4Mbps to 12Mbps (night)

Does the this night video taken with CPL lense on? I just received my CPL lense and installed into the cam and now displays are darker which is expected considering the lense itself is dark. Just hope everyone looks better during day time tomorrow. LOL
 
Does the this night video taken with CPL lense on? I just received my CPL lense and installed into the cam and now displays are darker which is expected considering the lense itself is dark. Just hope everyone looks better during day time tomorrow. LOL
No, I don't have a CPL for my B1W.
 
What do you think about 1080p15 @2Mbps?
I might be worth a try if the hardware supports it. It might need to be closer to 3Mbps to maintain the same level of detail. (Same reason 1080p60 does not require twice the data rate as 1080p30).
 
It might need to be closer to 3Mbps to maintain the same level of detail. (Same reason 1080p60 does not require twice the data rate as 1080p30).
Sure. Normally lower framerates means more differences between frames but it does not make any sense (that much) for parking mode.
 
What do you think about 1080p15 @2Mbps?
If there is much movement then 2Mbps is not enough to redraw the frame in a reasonable time, 3.5Mbps is about the minimum sensible and a bit more is desirable. I don't think that 15fps will help much, better to keep it on it's current 25fps, if there is not enough bitrate then the codec will reduce the fps of background detail anyway, if there is enough bitrate then it is best to use it on a good framerate.

I think 24 hours on a 64GB card is sufficiently low anyway, why do we want more than that at the expense of quality/fps?
 
I need a translation :unsure:

If you step through the B1W low framerate video as a large vehicle passes through the frame then you will find that it takes a few frames to redraw the background as it becomes visible again, the number plates on the passing vehicle will however get full detail in every frame. If the bitrate is too low then it will take a long time to redraw the background, still wont miss the moving number plates though.
 
Will this feature work at 720p? In general is using 720p (this feature motwithstanding) not advisable?
 
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