Max Recording Time and Size of SD Card

[pdmike]

So I turned the camera on when I left for work at 6:45 a.m. It only takes me 15 minutes to get to work. I parked the car and walked away from it at 7:00 a.m., leaving the camera in parking mode. I returned to the car at 5:15 p.m. I took a look at what had been recorded on my cell phone. The recording started around 1:00 p.m. and went up to the time I was checking it, 5:15 p.m., which means that the videos that were recorded from 6:45 a.m. up to 1:00 p.m., had all been recorded over. Oh yes, I had started with a newly-formatted SD card at 6:45 a.m.

I am using the 16GB SD card that comes with the camera. It looks like an SD card that size only has a maximum recording capacity of a little over 6 hours and then it begins recording over itself.

I typically start my dashcam when I leave for work a little before 7:00 a.m. and run it for 11 hours or so, either in normal mode or parking mode (mostly parking mode while I am parking it at work). I would like it to have a max recording capacity of at least 12 hours. What size SD card should I get to accomplish that?

P.S. - for the RTFM people here, I did go through the manual and was unable to find anything on this particular subject.

Edit Note: While at work, I park the car on a busy street. Cars are going by constantly.

 

[kamkar]

There are a calculator here but that are just geared towards single channel cameras.
https://dashcamtalk.com/recording-time-calculator/

But 16 Gb are nothing for a dual channel camera you would want 128 Gb / 64 Gb for each channel, this should give you around 8 hours recording ( 2 channels 16 hours in total )

 

[DashOto]

Yep, I use a 16GB too.
Only holds a couple days of my work commute.
FWIW I use Full HD @30fps - quality is still good enough for my needs.
Also should mention I normally only get files taking up memory from the front cam, so if you're running both cams... upgrade that memory card!

Here's a link from BlackVue about SD recording times & video quality

 

[pdmike]

Thanks, guys - but in parking mode, the cameras should not be recording at all unless someone smashes into my car or some catastrophic event like that happens, right? As such, they shouldn't be using up any space of the SD card while the car is in parking mode, right? So might I be able to solve the problem without having to pop for a larger SD card by adjusting the sensitivity settings so they are as insensitive as possible? I think we have been through this sensitivity issue before, and it has been determined that you can't eliminate parking mode recordings no matter what you do with the sensitivity settings when your car is parked on a street with moving cars going by all the time.

 

[jokiin]

when you rely on motion detect there's a very fine line between 'misses stuff often' and 'records constantly' something that's very hard to get right

 

[pdmike]

when you rely on motion detect there's a very fine line between 'misses stuff often' and 'records constantly' something that's very hard to get right

So what are you saying here? Aren't you always relying on motion detect when using parking mode? I don't care if the cameras miss stuff constantly in parking mode, so long as they record when a major event happens. What can I do to achieve this?

 

[kamkar]

Thats right, the camera are going full tilt when in parking mode but nothing reach the memory card before a event trigger a recording, so from a memory card perspective nothing go on when parked, unless there are a trigger event.
Thats why power use and camera internal heat generation in parking mode and in regular recording mode differ little from regular recording, cuz writing to the memory card or not take very little power.

Most cameras set aside some percentage of the total memory card space for event recordings, only camera lately where i have dabbled in parking mode are the little cheap B1W.
And the B1W reserve 30 % ( or more,,,, adjustable ) for events, so it only have 70 % of whatever size card you put in it for every day recording.
But i am not sure if these Blackvue cameras do the same

 

[jokiin]

it's a trial and error thing to find what works best for you, there's no perfect setting

 

[pdmike]

Thats right, the camera are going full tilt when in parking mode but nothing reach the memory card before a event trigger a recording, so from a memory card perspective nothing go on when parked, unless there are a trigger event.
Thats why power use and camera internal heat generation in parking mode and in regular recording mode differ little from regular recording, cuz writing to the memory card or not take very little power.

Most cameras set aside some percentage of the total memory card space for event recordings, only camera lately where i have dabbled in parking mode are the little cheap B1W.
And the B1W reserve 30 % ( or more,,,, adjustable ) for events, so it only have 70 % of whatever size card you put in it for every day recording.
But i am not sure if these Blackvue cameras do the same

OK - but I go to my car at the end of the day, and I have nothing but solid videos, one after the other, recorded non-stop, all afternoon long. Why? Because passing cars trigger the cameras to actually record what is going on. In other words, every time a car goes by, it's a "triggering event," and cars go by non-stop. It's a very busy street. I don't want passing cars to cause a video to be recorded. I only want a MAJOR event (car crashes into mine, for example) to get recorded.

 

[pdmike]

it's a trial and error thing to find what works best for you, there's no perfect setting

Yeah, I guess so. Thanks.

 

[kamkar]

Parking mode as i understand it ( have not really ever used it in any camera so far ) seem to me more a case of not getting too many trigger events ( motion detect ) many of them probably false trigger that do nothing but eat up storage space for events.
In general as i understand it motion detect are always too sensitive no matter the setting, only a few cameras i have heard off where you have been able to set sensitivity so low that something big can not trigger a event.
So i would rely on G - sensor when i get to try parking guard, and that should suffice, in my little tests with the cheap B1W i found the g sensor to be so sensitive that me kicking rear wheel steel rim with my foot ( waring snickers ) would trigger a event, but still wind and buses and trucks + the ever present noisy as hell Harley Davidson motorcycles passing by on the highway 12 - 15 feet or so from my parked car dident trigger.
The B1W amazed me in this with its sensitivety, so fine a trigger i am sure a door to door ding on a parking lot will get recorded too, but this ofcourse i have not been able to test without denting my own car, so i just kicked rear rim and was amazed that triggered cuz after all you can not kick a wheel that hard without hurting your foot.

 

[jokiin]

OK - but I go to my car at the end of the day, and I have nothing but solid videos, one after the other, recorded non-stop, all afternoon long. Why? Because passing cars trigger the cameras to actually record what is going on. In other words, every time a car goes by, it's a "triggering event," and cars go by non-stop. It's a very busy street. I don't want passing cars to cause a video to be recorded. I only want a MAJOR event (car crashes into mine, for example) to get recorded.

from the image sensors perspective a crashing car and a driving car don't look any different, if you turn it down enough that it doesn't trigger from the traffic then it's going to miss most stuff, you can use G-Sensor, that will detect the cars that end up crashing into yours

 

[pdmike]

OK - G-sensor. I didn't know that. Will fiddle with that one. Thanks.

 

[kamkar]

Yes motion detect are too flaky for parking guard.
G sensor can be a pain too if you use it while driving cuz then potholes ASO will trigger a event too that you dont really need to save unless that pothole was a really nasty one.
So i would only use G sensor while parked, and always record while driving as i dont need a sensor to tell me i have been sideswiped or rear ended while driving, in which case i would just use the manual event button to lock that event.
If you have a larger memory card these things get to be of little consequence as your assigned memory space for events and regular driving will be large and hold quite a few files before the camera start to recycle in that assigned memory space.

say events take 30 % of a 128 Gb memory card, thats over 32Gb assigned just for events, and in a single channel camera thats some 4 hours or recording, and 4 hours are fine if your camera dont trigger all the time as you are experiencing at the moment, but as it is now 4 hours well thats just 4 hours if it trigger all the time, and thats not much in that case.

So i would try and disable motion detect and go with g sensor alone, maybe do a little testing when the car are parked and "armed" kicking the wheels or give the car body a little push resembling a slow speed parking lot collision.

On my B1W i was able to see a LED starting to flash when a event was going on, so easy for me to detect if my event experiments worked.

 

[kamkar]

Some people seem to want their dashcams to only record on events, and thats why dashcams can have motion and or G sensor live when driving regular.
So motion well that will trigger all the time when you drive, so you might as well just record all the time.
G sensor as i said can be triggered by potholes and even your driving style as i also experienced when i experimented with this on my Luaks LK7500 back in the day.
Fortunately i was able to enter custom trigger values in the lukas, so after a few days of tweaking i was able to just have 1 - 2 event files created on a 45 minute drive, but far from all dashcams allow for custom trigger values.

And in the end i just dropped it cuz i was always recording anyway, so why have any events created at all, it would only be a major event where i get knocked out that will be on interest, but even that dont batter with a large enough memory card and rescuers ASO arriving they will turn off the car as the first thing ( some modern car even do that automatic as i understand it, so a airbag event will also mean engine cut off )

So in the end i just experimented with motion and G sensor in parking mode ( the lukas had that for both driving or stopped ) so i had the driving events OFF and the parking events ON.
In which case when the G sensor dident detect anything for a few minutes it put the dashcam in parking mode, i could then try to sneak up on my car, and motion would trigger as soon as i got within FOV of the camera.

I have this video from back then, down below in the footage you can see the mode the lukas are in.
This was mainly a test to see how little light motion detect could work in, the lukas dident have prebuffered parking mode.

 

[M8TJT]

Let's get a couple of things absolutely straight.
'Motion detection' is only activated in parking mode. It detects any movement in the video frame. Nothing to do with the car moving by being bumped etc.
G sensors detect shock on the car caused by bumps, knocks etc. There are three G sensors, Up/down, left/right and forwards/back. The sensitivity of them is separately settable in Normal and Parking modes.

By default the G sensors are set a lot more sensitive in parking mode when compared with 'normal recording'.

I have found that the motion detection detects pretty much anything moving around the car even when set to minimum sensitivity, thus, if like the OP (Post #4) you park on a busy road with lots of traffic, it will pretty much be triggered,/recording all the time.
The fix is to switch it off and 'rely' on the G sensors, as even at minimum sensitivity, movement detection pretty much continually triggers.

I have set the vertical G sensor in normal driving mode to 1. This cuts down quite a lot on the 'false alarms' due to pot holes, but still has a reasonable sensitivity to sideways/ fore and aft to trigger if I am hit from the side/behind etc.

But to summarise in the words of Chief Brody, 'Your'e gonna need a bigger boat'. Or in this case, a bigger (much) SD card if you want to keep loads of recordings. (I have a 128GB in mine)

 

[bpsmicro]

To add to M8TJT's accurate summary, you also have to remember that for a 2-dimensional sensor like a camera, "movement" doesn't actually means that things have to be moving. Unless there's a super-complex algorithm in place (and there isn't in something this small/cheap), all that motion detection does is take the first JPEG frame, then the next JPEG frame and does a rapid bit-wise comparison of the pixels. It counts how many pixels are different between the two frames, with "different" meaning that the RGB color difference is greater than some threshold.
So, what I'm getting at, is that if there's a flashing/flickering light in frame, that's "motion" as far as the algorithm is concerned.
And typically, overall "sensitivity" (what you adjust in Settings) relates to how many frames need to have differences before the flag gets set to start recording.

While we don't know the math built into the BV cameras, we do know that even at sensitivity '1', it takes less than a 10th of a second of "movement" to set the flag. Most of us (well, okay, all of us) would prefer the ability to de-tune that sensitivity even more, with the proviso.

But even then, if there's a flag waving or tree leaves swaying ever so slightly in the breeze, that's constant motion. Or a bird flying by, a large insect or raindrops sliding down the glass. That's all "motion", and will be detected, and will cause a recording.

 

[jokiin]

It's not movement as such, it's contrast, so a change in lighting will trigger the sensor, for example park in the dark and your typical flashing security LED on the dashboard will cause the camera to record constantly, no movement but the changes in lighting will keep triggering it

 

[pdmike]

Some people seem to want their dashcams to only record on events, and thats why dashcams can have motion and or G sensor live when driving regular.
So motion well that will trigger all the time when you drive, so you might as well just record all the time.
G sensor as i said can be triggered by potholes and even your driving style as i also experienced when i experimented with this on my Luaks LK7500 back in the day.
Fortunately i was able to enter custom trigger values in the lukas, so after a few days of tweaking i was able to just have 1 - 2 event files created on a 45 minute drive, but far from all dashcams allow for custom trigger values.

And in the end i just dropped it cuz i was always recording anyway, so why have any events created at all, it would only be a major event where i get knocked out that will be on interest, but even that dont batter with a large enough memory card and rescuers ASO arriving they will turn off the car as the first thing ( some modern car even do that automatic as i understand it, so a airbag event will also mean engine cut off )

So in the end i just experimented with motion and G sensor in parking mode ( the lukas had that for both driving or stopped ) so i had the driving events OFF and the parking events ON.
In which case when the G sensor dident detect anything for a few minutes it put the dashcam in parking mode, i could then try to sneak up on my car, and motion would trigger as soon as i got within FOV of the camera.

I have this video from back then, down below in the footage you can see the mode the lukas are in.
This was mainly a test to see how little light motion detect could work in, the lukas dident have prebuffered parking mode.

With regard to your video: As an aside - I live in Los Angeles. This is the first time in my life I have seen a totally empty, parking facility.

 

[pdmike]

Unless there's a super-complex algorithm in place (and there isn't in something this small/cheap), all that motion detection does is take the first JPEG frame, then the next JPEG frame and does a rapid bit-wise comparison of the pixels.

"This small/cheap?" Excuse me, but this is a Blackvue DR 750S-2CH. I don't consider it small or cheap. To me, a small/cheap dash camera costs less than $100.00. I got one of those once but quickly saw what I got and tossed it. Delivery price of my Blackvue was just under $500.00, including the Power Magic Pro. I am not disputing what you are saying about more advanced cameras having the super-complex algorithm you refer to, but suggest using "more complex" rather than "small/cheap" might be better.