1920x800/540 video mode?

[nutsey]

Another 1920x800 video with centered horizon.

 

[Nigel]

This seems to be about one's approach toward whatever they consider optimal usage. For me, a dashcam is an evidence gathering device so I want it to clearly show where my vehicle is as well as what is happening nearby around it. I do not need to have images from a quarter mile away nor do the images need to be perfect in color or focus; they just need to be present and identifiable and cover as much area as possible while doing this. Those images also need to capture the conditions of traffic control devices where possible. I really don't care if it shows the dashboard or sky or the hairs in my nose- none of that is directly relevant to my purposes.

Where this subject does become relevant to me is if the excess image area or coverage has any adverse affect on the performance of my cams. Which we know that excessive sky in the FOV can do, and also dashboard reflections. And perhaps even in processor performance which is a hard limit we're working within. So if in losing some of the unneeded capture area (such as my nose hairs) lets my cam perform better that's a good thing. But if it detracts one bit from my being able to see and view the things I deem necessary to it's function as an evidence-gatherer then it's a bad thing. I'm not recording for cinematic purposes nor am I concerned about the recording's aspect ratio for viewing pleasure purposes.

You must clearly have visible some reference point(s) to your vehicle in order to have important factors like your lane position, apparent distances. and traffic signal conditions clearly visible in the recording or it's not going to show what needs to be seen to assist you in a traffic incident. Having the front corners of your car visible is by far the best way to clearly show your lateral lane positioning regards road markings. Having only a centerline reference from a center-mounted cam does not do this; but only shows your relation to the lane center which is not important in terms of legality. If for whatever reason you can't capture your front corners they you have an even greater need to get some kind of side references in the view to better show you were within your lane limits. My minivan has a sharply sloped front so I had to aim the cam downward more than I preferred to in order to capture those critical reference points. It was OK as I could still capture all overhead traffic signals, but just barely, and barely is enough here. Luckily dashboard reflections weren't a problem in doing this. In my big workvan I can aim higher and get a better capture of everything so I do.

Long before dashcams I was involved in a crash where a woman had wildly crossed the centerline in a sharp curve then was attempting to get back over when the impact occurred. Momentum of her vehicle carried her back over into her lane post-impact so there was no clear evidence by vehicle positioning to prove her claim or mine regards who had crossed the line- it could have been either of us. What saved me in that case were my skidmarks, which started in my lane then jolted over at the impact point at the edge of my lane. It was raining and my tracks were almost washed out when the Cop arrived; had he been a couple minutes later in arriving I would have had no proof of my story versus her lies. If I had a cam in that crash it would have showed her wildly across the centerline and the point where impact occurred, but without having reference to the corners of my car I would still not been able to prove that at impact I was fully in my lane; the sharpness of the curve would have made a centerline reference only useless for evidence purposes.

It was a crazy crash and would have made an equal to some of the Russian vids as she was not only in my lane, but at one point was almost completely in the lane beyond that with her car well heeled over from cornering forces as she flew along at a reckless speed. As we all sat in the Cop's car while he was writing it up she claimed I was flying and that she never left her lane. The Cop, rather miffed, said "Lady, I saw his skidmarks and there's no way you weren't in his lane. It doesn't matter how fast he was going, you weren't supposed to be in his lane so it's your fault completely" She opened her mouth to say something and the Cop jumped in and said angrily "I don't want to hear another word from you. This was your fault and you're going to be charged with it." It was all I could do not to laugh out loud at that point but I managed to stay composed. This crash totally convinced me of the huge importance of being able to show the front corners of my car when I later got into dashcamming. It doesn't matter at all if you see my dash (or my nose hairs) but it matters greatly that you can clearly see me within the limits of my lane in all circumstances. Here in the Southern US we have some quaint words and phrases and one of them is "wrong-headed". I think it's meaning is obvious so don't be wrong-headed in thinking about what your cam captures and it's importance

Phil

Going to have to fit those fender flags to mark the actual corners of the car!

Just checked the rules, they will have to be rubber ones if they are mounted actually at the corners.

 

[Dashmellow]

Well then we need a 360 degree view so that the fenders are properly visible, although it is still hard to see any contact unless the camera lens is outside the cabin, or you have a very rectangular car!

One I posted a couple of weeks ago, not much of the hood visible in this one, but enough to be a reference, and since my car has curved edges rather than 90 degree corners it is always going to be impossible to see where the real front of the car is unless I put a camera in the radiator grill - now there is an idea, I have a waterproof remote camera waiting for a use...

360 degrees?!! So, now you're changing the subject and dodging the question. Amazing! The topic under discussion here as posed by the OP is whether a format such as 1920 x 800 video capture ("no-hood-and-no-sky mode" in the OP's words") is adequate FOV coverage or even of any interest to dash cam users and the facts and consensus presented so far demonstrate that it is not. And while having a mere sliver of one's hood/bonnet in the FOV is perhaps useful as a reference point it is only of marginal value.

Furthermore, this notion that one's front facing camera cannot document whether the vehicle makes contact with another vehicle or pedestrian unless one has an outside-the-cabin camera or the assertion that one would require a "rectangular car" is unmitigated nonsense! And now you are suggesting "fender flags to mark the actual corners of the car"? Jeez!

A good front facing camera with an adequate FOV and decently corrected lens will provide a reasonably low distortion image, very little dash board in the FOV and excellent lateral coverage on either side of a vehicle even with curved front fenders. No "rectangular car" required.

As seen in the image below, if a vehicle were to strike either side of the front end of my vehicle (or the "actual corners") or I were to strike something or someone with mine it will be captured and there will be a documented reference to my general surroundings both higher and lower and side to side. Adequate documentation of one's surroundings while driving is a vital aspect of capturing dash cam footage.

As I've previously mentioned (and @SawMaster has highlighted as well) the coverage one can acquire of the lateral sides of the front end of your vehicle, the hood/bonnet of your vehicle and your vehicle's reference to its surroundings will depend on the type and design of the vehicle you drive along with the FOV of your camera. The goal should always be to use your dash cam's capabilities to capture as much useful documentary evidence as is possible, laterally and to some extent vertically. The idea that intentionally cropping the FOV your dash camera can see because you think it is somehow more efficient is simply counterproductive.

Of course, as I've also previously mentioned, if shooting a cinematic "Panavision/Cinemascope" style FOV is your preference then by all means go ahead and do so, but most dash cam users employing any critical thinking and common sense will likely avoid such a practice.

 

[nutsey]

I prefer 1920x540

Please take a look at this video (unedited 1920x540p30 20Mbit/s): https://my.pcloud.com/publink/show?code=XZkCVt7ZJA3784frguFjK1AzvflJqH1APYby

 

[kevindd992002]

1) So here's what I have for my A129 front camera:

Dropbox - File Deleted - Simplify your life

www.dropbox.com

It's a lot of reflection but I barely see my hood there, which based on the discussion here is needed as a reference. Is there anything else I can do? The front camera is installed like so:

32CB2DA2-2ECC-4603-8D44-CEECEE87B99F.png

Shared with Dropbox

www.dropbox.com

Do I also need the CPL filter even though I read that I should not use it if I have m windshield tinted?

2) Here's my rear camera's video:

Dropbox - File Deleted - Simplify your life

www.dropbox.com

Anything I can do to avoid the defroster lines?

 

[Dashmellow]

So here's what I have for my A129 front camera:

[Is there anything else I can do? The front camera is installed like so:

I would suggest tilting your camera lens downward to include more of your car's hood/bonnet. The general rule-of-thumb is 40 degrees sky and 60 degrees coverage below the horizon. This will also improve the exposure your camera captures when you have a large section of bright sky in the image.

Often a CPL combined with a tinted windshield will create an unwanted rainbow effect. If your CPL is working well and you don't see any unusual rainbow effects in the image you should be fine with it.

 

[nutsey]

Often a CPL combined with a tinted windshield will create an unwanted rainbow effect.

I guess it's about the light loss. You can easily get -2 EV with a CPL and a window tint at the same time.

 

[Nigel]

Please take a look at this video (unedited 1920x540p30 20Mbit/s): https://my.pcloud.com/publink/show?code=XZkCVt7ZJA3784frguFjK1AzvflJqH1APYby

I'm not sure what I'm supposed to be looking at?

As a movie it looks good. As a dashcam video, since I can't see the front of your car I can not judge distances, you might have a 45 degree FOV lens or 145 degree!

To keep those traffic lights in the FOV while also having the front of your car in the FOV, you might need to move the camera a bit further down your windscreen, having it at the very top of the windscreen means you can't get both the car front and tall traffic lights. For people with short bonnets/hoods, it becomes very difficult and then maybe your 800 makes more sense than 540.

 

[Nigel]

I guess it's about the light loss. You can easily get -2 EV with a CPL and a window tint at the same time.

The problem is that some plastic tints circularly polarize some of the light which doesn't combine well with a CPL. I think a linear polariser filter is OK, but I've not seen anyone test that yet...

 

[Dashmellow]

I guess it's about the light loss. You can easily get -2 EV with a CPL and a window tint at the same time.

The CPL/Tinted windscreen/Rainbow effect I'm talking about is a phenomenon in physics called "birefringence".

See these two posts for an example and a more thorough explanation.

https://dashcamtalk.com/forum/threads/viofo-a129-modified-firmware-mods-archive.35826/post-453920

https://dashcamtalk.com/forum/threads/viofo-a129-modified-firmware-mods-archive.35826/post-453932

 

[Michael_K]

I would suggest tilting your camera lens downward to include more of your car's hood/bonnet. The general rule-of-thumb is 40 degrees sky and 60 degrees coverage below the horizon. This will also improve the exposure your camera captures when you have a large sections of bright sky in the image.

Often a CPL combined with a tinted windshield will create an unwanted rainbow effect. If your CPL is working well and you don't see any unusual rainbow effects in the image you should be fine with it.

40° & 60° ?
Do you mean 40% sky and 60% land?
Please elaborate.

 

[Dashmellow]

40° & 60° ?
Do you mean 40% sky and 60% land?
Please elaborate.

As I said, "40 degrees sky and 60 degrees coverage below the horizon". So, below the horizon line is "land".

ho·ri·zon
(hə-rī′zən)
n.
1. The apparent intersection of the earth and sky as seen by an observer.

 

[nutsey]

As I said, "40 degrees sky and 60 degrees coverage below the horizon".

Isn't it valid only if the vertical FOV is 100 degrees?

 

[Dashmellow]

Isn't it valid only if the vertical FOV is 100 degrees?

Instead of degrees another way to think of it would be 40% - 60% based on 100% of the vertical size of your frame. That might really be a better way to put it actually.

 

[Nigel]

Do you mean 40% sky and 60% land?

Yes!

 

[Dashmellow]

Please take a look at this video (unedited 1920x540p30 20Mbit/s): https://my.pcloud.com/publink/show?code=XZkCVt7ZJA3784frguFjK1AzvflJqH1APYby

Nutsey, I think your panoramic dash cam video looks really cool, as do @Nigel's. As I've mentioned previously in this thread I can really see the appeal of shooting video like this. I just think it is not a good idea if our goal is to capture as much visual information as possible from our dash cams in the event of a mishap.

Here, I've used the same screen shot I posted above but I've isolated a precisely 1920 x 540 pixel section to mimic the frame from your video.

To my thinking it makes no sense to intentionally eliminate large areas of the potential image we can capture given the magnification we have available from any given focal length lens and sensor size for the reasons I've elaborated above.



Edit: For anyone who wants to get unusually persnickety about this screen grab image, it is off by 1 pixel - 1919 x 1081. The 540 pixel vertical crop is precise.

 

[Nigel]

Nutsey, I think your panoramic dash cam video looks really cool, as do @Nigel's. As I've mentioned previously in this thread I can really see the appeal of shooting video like this. I just think it is not a good idea if our goal is to capture as much visual information as possible from our dash cams in the event of a mishap.

Here, I've used the same screen shot I posted above but I've isolated a precisely 1920 x 540 pixel section to mimic the frame from your video.

To my thinking it makes no sense to intentionally eliminate large areas of the potential image we can capture given the magnification we have available from any given focal length lens and sensor size for the reasons I've elaborated above.

From that argument I wonder why you don't record in 4:3 aspect ratio since a lot of dashcams have a 4:3 sensor. There is a compromise to be made and 4:3 is not a good compromise for most vehicles, 16:9 seems to have excess sky and dash on a lot of our videos but works nicely for some, 32:9 does work for me since I have my dashcam mounted relatively low on a low height car, but looks like it is significantly too flat for your tall vehicle. What we need is an option in the settings menu that we can customise to the vehicle.

It also depends of the FOV of the dashcam, with a narrow angle dashcam even I would not want 32:9, in fact my dashcam is wider than most.

 

[nutsey]

Nutsey, I think your panoramic dash cam video looks really cool, as do @Nigel's. As I've mentioned previously in this thread I can really see the appeal of shooting video like this. I just think it is not a good idea if our goal is to capture as much visual information as possible from our dash cams in the event of a mishap.

I think it can be useful for dedicated cams intended for better license plates recording. I mean it can be used if you already have one for capturing overall road situation including overhead lights and signs.

 

[Dashmellow]

I think it can be useful for dedicated cams intended for better license plates recording. I mean it can be used if you already have one for capturing overall road situation including overhead lights and signs.

Yes, I was going to mention that concept. Two cameras that capture different views can be very useful. A group of us here have been using both traditional FOV dash cams simultaneously with telephoto dash cams and this is very effective. I wouldn't be without this capability at this point. I can see where a panoramic view along with a typical dash cam focal length could be valuable.



BTW, returning for a moment to a previous discussion in this thread, note the height of the traffic signals.

 

[Dashmellow]

From that argument I wonder why you don't record in 4:3 aspect ratio since a lot of dashcams have a 4:3 sensor. There is a compromise to be made and 4:3 is not a good compromise for most vehicles, 16:9 seems to have excess sky and dash on a lot of our videos but works nicely for some, 32:9 does work for me since I have my dashcam mounted relatively low on a low height car, but looks like it is significantly too flat for your tall vehicle. What we need is an option in the settings menu that we can customise to the vehicle.

It also depends of the FOV of the dashcam, with a narrow angle dashcam even I would not want 32:9, in fact my dashcam is wider than most.

Why on earth would anyone want to use 4:3 aspect ratio when we almost universally use dash cams with 16:9 sensors? This is appears to be another one of your distracting irrelevant arguments. I do agree with you that much depends on the FOV of the lens one is using. In my view, many dash cams on the market have lenses that are far too wide to be practical. For a standard dash cam I prefer something in the neighborhood of 120º horizontal.

Look, if you or anyone else enjoys shooting narrow frame panoramic dash cam video, by all means do so, but I would argue against it and believe most people will find such a compromised vertical FOV to be impractical and counterproductive.