Bitrate & resolution

[thancam]

what is diffirent between bitrate and resolution when judge a dashcam ?
A dashcam has 1080p and bitrate about 20 Mbps and B dashcam has 1296p and bitrate about 20 Mbps. In daytime, which dashcam have a better image quality ? ( same sensor, same len, same chipset).

 

[jokiin]

there's no one answer as it can vary a bit, generally speaking though if you were looking at Ambarella for example (using Ambarella as the example as most of the 1296p models are using their solution) in this case the 1080p result would be better as you need a higher bitrate for 1296p to capture the same level of detail

 

[Nigel]

what is diffirent between bitrate and resolution when judge a dashcam ?
A dashcam has 1080p and bitrate about 20 Mbps and B dashcam has 1296p and bitrate about 20 Mbps. In daytime, which dashcam have a better image quality ? ( same sensor, same len, same chipset).

Simplifying things a little:

The resolution is how big the image is. With a larger resolution you can zoom in more before the image starts to look blurred.

The bitrate is maximum amount of detail that can be stored every second. With a higher bitrate you can drive faster before the image starts to look blurred, but also a higher resolution requires extra bitrate for a given speed so starts to look blurred at a lower speed.

"which dashcam have a better image quality ?"

Comparing your two cameras, the real difference is that with A you can drive faster before the image starts to look blurred. With B you can zoom in more before the image starts to look blurred, but only if you are driving slow enough.

So which is better depends on how fast you are driving, and also how closely you look at the video. If you only ever view the video full screen on an HD display then there is no point having higher than HD resolution and A will always be as good or better. If you view on a 4K display and never drive more than 30kph then B will always be as good or better.

 

[thancam]

example: when compare between my canon EOS600D and the mini 0805, mini 0806.
The video which made by EOS600D has resolution is 1080p. The bitrate of this video is 45 Mbps. And this video is much better in anyway than 1296p video made by mini 0806 or 0805.
And compare between 0805 and 0806: video made by 0805 has bitrate about 15 Mbps. 0806's is 20 Mbps. And 0806's is better than 0805's in the highest resolution.
So I am started to think: resolution can be set by any camera. The camera will set resolution for every video. But it's doesn't fill full everybit of colour in it. Even with 45 Mbps of bitrate is sill fit with 1080p in my canon EOS600D. So everything we see in ads of 1296p video are all lies.
And then I started to do some search. I find a bit depth which can change bitrate of a video alot. Bit depth is the amount of bit define colour of video. The more bit depth video have, the size of video is bigger. And quality of video is also better.
Then I enlarge a video make by my canon and I realize: the detail of this video is better than a video made by mini 0806. Not just about colour but the amount of pixels for detail are much more in the same resolution 1080p.
My english is such. Hope you all can understand what I trying to say.

 

[Nigel]

If you use 2560 resolution on the 0806 and the 24mbps firmware then it should do better on license plates than the Canon would, but only if there is not too much movement and the lighting is good and they have the same FOV. However the Canon will have a much narrower FOV giving it a big advantage for any plates it can see and making it useless for the ones it can't!

The sensor on the Canon is 20x bigger than the sensor on the mini 0806, it has a huge advantage in low light.

 

[thancam]

If you use 2560 resolution on the 0806 and the 24mbps firmware then it should do better on license plates than the Canon would, but only if there is not too much movement and the lighting is good and they have the same FOV. However the Canon will have a much narrower FOV giving it a big advantage for any plates it can see and making it useless for the ones it can't!

The sensor on the Canon is 20x bigger than the sensor on the mini 0806, it has a huge advantage in low light.

I will do a test tomorrow. In close distance, FOV is not so affect to result. With lighting is good and static sence, everything will be like you said. Is that ok ?

 

[Nigel]

I will do a test tomorrow. In close distance, FOV is not so affect to result. With lighting is good and static sence, everything will be like you said. Is that ok ?

Post some high quality frame grabs from both cameras so we can have a look. I don't know how you will get the FOV similar but I am interested to see the result and we will be able to see the quality even if the FOV is different. (I don't want to download 45mbps video - too much data.)

 

[kamkar]

Slap a fisheye lens on that canon, and you will be like "where the hell is the licenceplates"

 

[Module 79L]

And then I started to do some search. I find a bit depth which can change bitrate of a video alot. Bit depth is the amount of bit define colour of video. The more bit depth video have, the size of video is bigger. And quality of video is also better.
Then I enlarge a video make by my canon and I realize: the detail of this video is better than a video made by mini 0806. Not just about colour but the amount of pixels for detail are much more in the same resolution 1080p.

Ever since I started making videos (with Windows Movie Maker) I chose to render them in .wmv format at 24Mbps rather than in .mp4, because even though its bitrate is also set to 24Mbps, the final file's bitrate is never fixed and the video quality is worse. What surprised me was that the clips, which were originally in .mov format at 12Mbps (G1W), 15Mbps (G1W-H) and 13Mbps (AT11DA), have much better quality after being rendered in .wmv format at 24Mbps than the original ones!
I can't explain this but sure would like if someone could.

 

[thancam]

In my city, it's raining all day today.

 

[thancam]

Ever since I started making videos (with Windows Movie Maker) I chose to render them in .wmv format at 24Mbps rather than in .mp4, because even though its bitrate is also set to 24Mbps, the final file's bitrate is never fixed and the video quality is worse. What surprised me was that the clips, which were originally in .mov format at 12Mbps (G1W), 15Mbps (G1W-H) and 13Mbps (AT11DA), have much better quality after being rendered in .wmv format at 24Mbps than the original ones!
I can't explain this but sure would like if someone could.

I have to try this too. How can quality of video become better because of render ? I can't believe.

 

[Deleted member 37895]

Ever since I started making videos (with Windows Movie Maker) I chose to render them in .wmv format at 24Mbps rather than in .mp4, because even though its bitrate is also set to 24Mbps, the final file's bitrate is never fixed and the video quality is worse. What surprised me was that the clips, which were originally in .mov format at 12Mbps (G1W), 15Mbps (G1W-H) and 13Mbps (AT11DA), have much better quality after being rendered in .wmv format at 24Mbps than the original ones!
I can't explain this but sure would like if someone could.

You always lose quality when you recompress because you're taking the original video and applying another compression to it after your edits.

To combine or split videos, or remove audio, use AVIDEMUX. It just copies the data

 

[Falsificator]

what is diffirent between bitrate and resolution when judge a dashcam ?

8Mbits vs 22Mbits...

 

[Module 79L]

You always lose quality when you recompress because you're taking the original video and applying another compression to it after your edits.

Well, that's not what my eyes tell me when I play the original MP4 clip and the same clip in the WMV-converted video back to back on VLC.

To combine or split videos, or remove audio, use AVIDEMUX. It just copies the data

And why would I do that when I have Registrator Viewer?
Also, I don't convert loose clips to WMV (what's the point of that?), just whole videos, as in "compilation of several clips", in case you haven't understood.

 

[Deleted member 37895]

Well, that's not what my eyes tell me when I play the original MP4 clip and the same clip in the WMV-converted video back to back on VLC.


And why would I do that when I have Registrator Viewer?
Also, I don't convert loose clips to WMV (what's the point of that?), just whole videos, as in "compilation of several clips", in case you haven't understood.

Maybe the image just looks better because you're applying processing? But no new information is there

Compilation is what I'm talking about, combining clips into long videos. AVIDEMUX and some other similar programs will combine them without recompressing them so the original information is retained. It can also cut parts off clips and remove sound. It's virtually instant and doesn't require much CPU power because there's no compression that has to take place when you save to the new file

 

[Module 79L]

Maybe the image just looks better because you're applying processing? But no new information is there

I know that increasing the bitrate when converting doesn't add information but isn't "looking better" what counts?

Compilation is what I'm talking about, combining clips into long videos. AVIDEMUX and some other similar programs will combine them without recompressing them so the original information is retained. It can also cut parts off clips and remove sound. It's virtually instant and doesn't require much CPU power because there's no compression that has to take place when you save to the new file

Registrator Viewer also does all that and I would use it if my goal was simply to combine clips into long videos but what I do requires tools that neither RV or Avidemux have: inserting text or symbols, still images, zooming, transitions, effects, add audio, etc. Plus, the main reason why I'm using the WMV format it's because Youtube has some kind of problem with MP4 files.

Before I started making videos I tried lots of editors, including Avidemux. I ended up choosing MM because it had all the tools I needed and it was the least demanding on my current hardware.