The best segment length or does it matter?

GJHS

GJHS

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Dash Cam
Mobius A & C, SJ4000, M10, Mini 0806, Innovv C3,4, Xiaomi Yi
When I first came to this forum, I was researching the mini 0801 and remember reading that the best segment length is 5 mins because it's harder for the camera to constantly create new files. So when I got my Mobius, I set it accordingly.
Yesterday I was looking though the RC Forums on the initial thread started to announce that the Mobius would be coming. @Mtz asked if the segment length would only be 5 mins because for dash cams is too big. Which, of course, made me ask what is ideal? Is there a difference?

For reference
http://www.rcgroups.com/forums/showthread.php?t=1890774&highlight=mobius new
 
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I'm a newbie on here but i have mine set at 1 minute - on the grounds that if there is an accident and you have to show the police anything, its easier to go back and review a minute or possibly review two x 1 min video segments, as that's probably the only bit thats relevant to most accidents. If there's a 5 minute segment then there's a lot to wade through if time is of the essence. you can always save/lock those last 5 x 1 minute segments anyway. Ideally i'd probably opt for a 2 minute segment but i only have 1, 3 and 5 mins to chose from.
 
I like to keep mine to about 3 mins although my TF2 is 5 min only.
It is defiantly more manageable that way. Luckily the TF2 Event Record is a 1 min clip.
 
It depends on what device you intend to play the said clip. If you are going to play it on the cam itself, the shorter the segment the faster you will be able to navigate through it, given the limited processor and data I/O speed of the cam. The same goes for smartphones, WiFi connections and partially tablets. It you will play it on a laptop, the longer segment the easier your DC's life will be when recording. During finalization stage of a completed segment file and opening the next one the cam's CPU is under higher load than usual due to overhead of flushing data buffers to the memory card, updating its TOC and doing other relate tasks. It also continues to process video data at the same time. Higher CPU load translates into more stress for power supply components and it causes the insides of the cam to heat more.

YMMV of course, this is just some observation.
 
Suzysue said:
I'm a newbie on here but i have mine set at 1 minute - on the grounds that if there is an accident and you have to show the police anything, its easier to go back and review a minute or possibly review two x 1 min video segments, as that's probably the only bit thats relevant to most accidents. If there's a 5 minute segment then there's a lot to wade through if time is of the essence. you can always save/lock those last 5 x 1 minute segments anyway. Ideally i'd probably opt for a 2 minute segment but i only have 1, 3 and 5 mins to chose from.
Click to expand...

+1., a lot easier to look thorough a 1 or 2 minute file than a 5 or a 10 minute file, myself I've noticed I've settled down to a 2 minute recording for the above reasons
 
Mine's set to 5mins - basically, I'm recording all day long & fill up the card. I can fit more footage on a 32GB card in 5min segments than I can in 1min segments.
If you are pulled over by the police, would they be happy to stand and look at 1 minute's footage for something trivial?
If, on the other hand, something serious has happened then I doubt anyone would mind waiting a bit longer whilst you fast forward through a 5 min file. (if fast forward is twice normal speed then, at most, you would be waiting 2 minutes)

Also, how easy is it to view footage on a tiny screen at the roadside? Especially when many cams won't even power up without being plugged in & cables are routed inside plastic trim etc, so the police would be reliant upon having a laptop or a tablet - or maybe even pulling the card & putting it into a smartphone.
And, as Foureyes says, your camera is working overtime when it is saving files. If it is saving a file and the g-sensor indicates a bump (which, with most = pothole), the cam is working even harder. (not to mention cams with added extras like GPS data to add to the file)
 
I make a mental note of the time of any noteworthy happening & jot them down as soon as it's safe.
This way, when I come to look for them later, I can quickly find the correct file - it's then simply a case of clicking & dragging the marker to the correct point.
Easier to scroll through 100 x 5min clips than 500x 1min clips.

How do these cameras actually do the work?
Do they record everything they see into a virtual file then save it when the time comes - every 1 min or whatever you've set it to?
How long does it take to transfer a 1min clip?
If this is the way they work, then a 5 min clip will obviously take 5x as long to save.
However, if it takes 20s to transfer a 1 min clip & 100s to transfer a 45 min clip, the cam only gets a 40s break for 1 min clips - but a 200s break for 5 min clips (when I say 'break' I mean a rest from all the extra work).
Also, if you then chuck in a few bells and whistles, such as gps and g-sensors, your cam will have to work harder for longer to be saving all this extra info.
 
The write process is continuous only difference with shorter segments is files are deleted more often when it comes time to recycle
 
OK, thanks for that. I wondered because my home cctv seems to perform a write/delete to the hard drive at regular intervals (drive light flashes every 30s).

So a dashcam is not working harder at recording differing file segments - but it is still working harder on shorter segments as it has to preform more deletions.
Are there any 'figures' for how hard the processor/cam is working during each process which would indicate which filesize might be better?
 
sludgeguts said:
I make a mental note of the time of any noteworthy happening & jot them down as soon as it's safe.
This way, when I come to look for them later, I can quickly find the correct file - it's then simply a case of clicking & dragging the marker to the correct point.
Easier to scroll through 100 x 5min clips than 500x 1min clips.
Click to expand...
I have been putting my hand in front of the camera a few seconds after hitting the save button. This way I can view the video high speed at stop and that point. Sometimes it takes a while before I can review clips and I almost always forget why I saved it.
 
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