A139 Pro Road Trip - to HDR or not to HDR?

[Nigel]

I guess what I'm wondering is if I go through the trouble of dropping all the HDR footage onto an HDR timeline and the correcting any SDR footage to look correct alongside the HDR footage, will it all look "correct" regardless of if people are watching in HDR or SDR.

I think that has to be a no, which will be a problem for you. Realistically, you would have to convert the SDR footage to HDR too, at full brightness, before the conversion back to SDR for non-HDR displays would work. But is it wrong to do that? I think it is OK to do that, it actually allows people to more easily see the detail in the shadows and clouds, and it will look OK, but then your non-dashcam footage will not look right, so I'm not sure it is really possible, maybe you need two versions of your video, one for HDR and one for SDR!

 

[naruhodo]

Ahh, one person has seen the light . Now you understand real HDR!

I suspect most people can't see it
And even for those that can, there is another striking difference between a proper 1000 nit HDR screen and feeble 500 nit semi-HDR devices that seem to be quite popular at the moment, even this MacBook Pro is only half HDR!

I'm not trying to defend Apple (not a fanboy), but I'm not sure I understand your comment about MacBook Pro being only half HDR.

I have a MacBook Pro 16-inch M1Max. It's true that for most standard viewing the screen brightness is 500 nits. But when the operating system recognizes HDR videos (as it does, for example, in YouTube videos with the HDR cog, that section of the screen (the video display only, but not other parts of the screen), actually does brighten automatically to 1000 nits sustained and 1600 nits peak in small areas of sparkle as required. The change is visually striking – it can't be missed.

Additionally, there is a 3rd-party system utility app called "Vivid" that brightens the entire screen to 1000 nits sustained regardless of whether or not anything being displayed is encoded as HDR. When this utility is launched, the entire screen can be brightened on demand (with a combination keystroke or menu) to 1000 nits sustained . I have found this to improve the display of SDR material... it just makes videos appear more natural to me. It makes me think that Apple was being too conservative – perhaps trying to enhance battery life – not allowing this option from the OS display preferences. No matter, having 1000 nits on demand via the Vivid app is a great option to have.

(BTW, I enjoyed traveling with you in the Cambrians. Thanks.)

 

[Nigel]

I'm not trying to defend Apple (not a fanboy), but I'm not sure I understand your comment about MacBook Pro being only half HDR.

The MacBook Pro I have here is only 500 nits max, which I do find a bit disappointing compared to 1000 nits, it is not enough to replicate sunshine! Clearly there are other models that do better, I did say "this".

I have found this to improve the display of SDR material... it just makes videos appear more natural to me. It makes me think that Apple was being too conservative – perhaps trying to enhance battery life

I think they are just conforming to the definition/specification of HDR displays, which requires that SDR is displayed with a brightness equal to an old CRT tube display!
That sounds a useful utility.

(BTW, I enjoyed traveling with you in the Cambrians. Thanks.)

Glad you enjoyed it, that is what really matters for this type of video.

 

[Panzer Platform]

@Nigel @Vortex Radar
I’ve been following your guys’ conversation about HDR, and editing, and 99% of it is above my head. lol
This is why I maintain unlisted Playlists for every dash cam I test that has raw files uploaded directly to YouTube without any editing, or manipulation.
So if a consumer buys a dash cam after watching one of my YouTube reviews his raw uploaded footage to YouTube “should” look identical to mine.
I always put the link to the Playlist of raw clips in the description box of my reviews.

https://www.youtube.com/@PanzerUnlisted/playlists

 

[Panzer Platform]

From a review perspective, as nice as it'd be to show people all the extra dynamic range available in HDR, if it's not going to be available for people when they copy the video file to their computer and load it into a video player, I wonder if any conversion would be misleading given that it wouldn't be representative of what people would see on their end.

Right which throws a whole wrench into the system regarding sharing footage for people to view that is representative of what people will see if they buy the camera too.

Yes.

 

[Panzer Platform]

Perhaps if you add some caveats regarding what people are looking at including the processing you have to do to get there and what they'll natively seen straight out of camera, that would help to avoid any dashed expectations regarding what people see and what they'll get.

Yes.

 

[Nigel]

When I use the term “editing,” it’s a generic term that applies even to something extremely simple like concatenating multiple files, but I understand how you mean it.

If you’re looking at different ways of converting that leads to the output video looking different in terms of colors, luminance, etc. then the discussion does go beyond semantics.

What I was trying to say is that the video data in the file is still the same, effectively all that has changed is the colour profile stored in the file header, which tells the display how to display the data. The profile stored by Viofo is not a good match to the data, only good for compatibility, Rec 2020 is a better match, at least for a sunny day. There are a few complications to achieve upload to Youtube, such as converting to H265 HDR10, but all I was trying to do was replace the Rec 709 in the header by Rec 2020 so that I get a more realistic display of the data when displayed on a display that is capable of displaying it more realistically. Note that my conversion is only correct for video recorded on sunny days, certainly not when used indoors.

I think doing this makes sense for a movie, it wouldn't be wrong to also do some colour correction and actually modify the data to make it look how I want it to look, but if you make one of your reviews in HDR and keep most of the content at sensible brightness, an automatic conversion to SDR for "old" displays is going to make most of the content look dull. Maybe the sensible way to deal with this is to start a second Youtube sub-channel, and when you have a dashcam that provides decent dynamic range (maybe only Starvis 2 sensors), then you post both on the HDR channel and a separate version on the SDR channel, I assume FinalCut will allow reasonably easy conversion between the two outputs while keeping all content looking good. At some point, maybe not too far away, we will get dashcams that can optionally output Rec 2020 and you will then have to solve this problem if you are going to post a review with actual dashcam footage.

 

[Panzer Platform]

Maybe the sensible way to deal with this is to start a second Youtube sub-channel,

Yes.
I would love to watch Ariel's 2nd YouTube channel content. lol
Vortex Extras?
Vortex BTS?
Vortex Unlisted?
Vortex After Dark?

 

[Dex_]

For recording accidents, I agree, in fact it is best to have the sky a little over exposed so that the rest of the image has more detail, but if you are making a movie then you don't want the clouds over exposed, thus I suggest we need a "Movie" setting in the menu.

+1 vote for "Movie" from me!
Mostly I would like better quality for Youtube video/Instagram Reels/Save my family trips than for number plates reading with overexposed at other screen parts.

 

[Panzer Platform]

+1 vote for "Movie" from me!

Cast your vote here;

Viofo Improvement Wish List

If there is a voice command in new models, Yes, it is worth listing improvement wishes here so that they may be implemented for new models. I suspect the reason why the A119 series stops when WiFi is turned on but the A229 doesn't is that the A119 has to reduce the bitrate when wifi is on...

dashcamtalk.com

 

[JardaB]

Static scene HDR

In a dark scene, the HDR image loses contrast. In a sunny scene, the difference in resolution is not significant

HDR behaviour in moving scenes will be important for us - I need to find suitable comparable conditions for the test

 

[CaptureYourAction]

@Nigel hope you don’t mind me posting this question in your HDR thread, but didn’t want to start a new thread just for this. There is a Reddit member claiming that the A139 Pro has some form of autofocus built into the sensor. Anyone heard of this and/or are familiar with this? Reddit thread is linked below.

https://www.reddit.com/r/Dashcam/comments/15ux5fy/_/jwsqbz4

 

[Nigel]

@Nigel hope you don’t mind me posting this question in your HDR thread, but didn’t want to start a new thread just for this.

Perfectly good place for it, I like going off topic!

There is a Reddit member claiming that the A139 Pro has some form of autofocus built into the sensor. Anyone heard of this and/or are familiar with this? Reddit thread is linked below.

It is true that the A139 Pro has PDAF (Phase Detection Array AutoFocus built into the sensor, but it is only the detection part of it - the PDAF sensor, there is no focusable lens. Since in a dashcam you want everything in focus all the time, a focusable lens would be useless! The sensor is there for cameras that do have autofocus.

I guess you could argue for a focusable lens to correct high temperature focus drift, but very often the temperature related problems can't actually be corrected by refocusing the lens since it is the individual elements within the lens that go out of focus rather than the whole lens.

The sensor does have lenses built in, the design of which is related to the PDAF, which may be causing some confusion, but these are not focusable lenses.

On the issue of the shroud, because of the very wide angle lens, the shroud would have to cover most of the windscreen to fully work, which would mean that the driver couldn't see! That is why we don't use them.

 

[CaptureYourAction]

Perfectly good place for it, I like going off topic!


It is true that the A139 Pro has PDAF (Phase Detection Array AutoFocus built into the sensor, but it is only the detection part of it - the PDAF sensor, there is no focusable lens. Since in a dashcam you want everything in focus all the time, a focusable lens would be useless! The sensor is there for cameras that do have autofocus.

I guess you could argue for a focusable lens to correct high temperature focus drift, but very often the temperature related problems can't actually be corrected by refocusing the lens since it is the individual elements within the lens that go out of focus rather than the whole lens.

The sensor does have lenses built in, the design of which is related to the PDAF, which may be causing some confusion, but these are not focusable lenses.

On the issue of the shroud, because of the very wide angle lens, the shroud would have to cover most of the windscreen to fully work, which would mean that the driver couldn't see! That is why we don't use them.

Are you familiar with any dash cameras that do use this feature and have auto focus?

 

[Nigel]

Are you familiar with any dash cameras that do use this feature and have auto focus?

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Autofocus on a dashcam is a silly idea, you always want everything in focus up to infinity - always. I think every dashcam advert that claims autofocus is going to be fake and there will be no autofocus inside the camera.

If you did have autofocus, what would you want it to focus on? The plate of the car in front, or the car approaching in the lane to your right, or the car further away in the lane to your left

This is the reason that we are limited in the size of the sensors that we can use, if we used a big full frame 35mm sensor then we could see great in the dark, but most of the plates in the image would be out of focus most of the time!

 

[CaptureYourAction]

If you did have autofocus, what would you want it to focus on? The plate of the car in front, or the car approaching in the lane to your right, or the car further away in the lane to your left

Good point! Thanks for the info.

 

[Nigel]

Good point! Thanks for the info.

Maybe somebody read this:

https://www.blackboxmycar.com/pages/viofo-a139-pros-sony-starvis2-and-super-night-vision-2-technology

How does the Super Night Vision 2.0 improve the VIOFO A139 Pro’s performance?​

Moreover, the Sony STARVIS 2 IMX678 image sensor features advanced noise reduction technology and supports an on-chip lens (OCL) and phase detection autofocus (PDAF) for better focus performance.

 

[CaptureYourAction]

Maybe somebody read this:

https://www.blackboxmycar.com/pages/viofo-a139-pros-sony-starvis2-and-super-night-vision-2-technology

That’s likely where they saw it.

 

[Cyker]

Not necessarily focus to infinity; Ideally you'd want as flat a focus as possible, so everything's in focus, but this requires a tiny pinhole-sized aperture (This is why pinhole cameras don't need lenses) - That's fine during day time, when there's loads of light, but when it's dark there's not enough light to get a useful image, especially for cameras that advertise good night performance, so a bigger aperture is required. Optimizing the aperture size between these two opposing things is the tricky bit.

 

[Nigel]

Not necessarily focus to infinity; Ideally you'd want as flat a focus as possible, so everything's in focus, but this requires a tiny pinhole-sized aperture (This is why pinhole cameras don't need lenses) - That's fine during day time, when there's loads of light, but when it's dark there's not enough light to get a useful image, especially for cameras that advertise good night performance, so a bigger aperture is required. Optimizing the aperture size between these two opposing things is the tricky bit.

The A139 Pro is fixed aperture as well as fixed focus, so the daytime and nighttime depth of field are exactly the same, and there is nothing mechanical to go wrong

Not stopping down the aperture during the day allows for very fast shutter speeds (not that it has a shutter either), which allows it to freeze sharp number plates at high speeds during daytime.