Video bitrate for chinese 1080p@60fps acion cams

[grg666]

Hi Guys,

First I will introduce myself because this is my first post, my name is Rafal, i'm from Poland and I'm a ISF(Imaging Science Foundation) video engineer. I know exactly what makes for the best picture and I'm pretty frustrated about the marketing (in general) of chinese action cam manufacturers, because they do not provide us with one of the most important factors regarding the video quality(which should be obvious) as video bitrate. Now, we have the Xiaomi which is in the market for some time a gathered a big group of owners, some of whom tranformed into modders, providing excellent custom firmwares as well as scripts for tuning the quality of the picture. Other brands have probably less support from "us" the customers, so it makes hard to jugde what can you expect from certain camera. You are basically relying of the manufacturer itself to produce a good software. There are, and there always will be some drawbacks regaring each manufacturers software, so either you choose to buy a camera for modding or just to leave it "as is". I'm really tired of neverending reading about the specs and reviews of each cam, uploading the recordings to youtube which is totally wrong beacuse of the compression and image processing always occuring, which makes it nearly impossible to judge. You NEED TO HAVE a RAW unedited file to make correct judgments. And very often that is very hard to find. So I decided to start a new thread here, to ask you guys about the VIDEO BITRATE for gopro4 black(bitrate 40-60mbps@1080p) chinese alternatives. I'm especially interested in new cams with image stabilization(as well as the quality of that stabilization) such as e.g Firefly 6S, SJ5000x ELITE and so on... perhaps there is something interesting which I missed?
Please write down the highest bitrates for gopro alternatives, I think this would help the community a lot!

Cheers,
Rafal

 

[Nigel]

Bitrate is not a good measure of quality as it depends hugely on the codec used to compress the video. Any camera, like the GoPro using the Ambarella processor needs a far higher bitrate than those using Novatek processors and codecs. The different codecs also do better or worse at different things, for example Novatek codecs do a good job at encoding smooth motion at only 30fps while to get the same smoothness from Ambarella codecs you will need 60fps and the higher bitrate that comes with it.

I recorded some video last night using my GitUp Git1 which used 17Mbps and my GitUp Git2 which used 28Mbps, I think theGit1 video is the better, but maybe only because it was dark at the time!

 

[JooVuu]

Bitrate is not a good measure of quality as it depends hugely on the codec used to compress the video. Any camera, like the GoPro using the Ambarella processor needs a far higher bitrate than those using Novatek processors and codecs. The different codecs also do better or worse at different things, for example Novatek codecs do a good job at encoding smooth motion at only 30fps while to get the same smoothness from Ambarella codecs you will need 60fps and the higher bitrate that comes with it.

I recorded some video last night using my GitUp Git1 which used 17Mbps and my GitUp Git2 which used 28Mbps, I think theGit1 video is the better, but maybe only because it was dark at the time!

Hi Nigel,
That's a very interesting assertion...could you show us how Ambarella devices need 60fps for the same smoothness as NVT devices? I've never come across that at all really.

Cheers,

Dan

 

[Nigel]

Hi Nigel,
That's a very interesting assertion...could you show us how Ambarella devices need 60fps for the same smoothness as NVT devices? I've never come across that at all really.

Cheers,

Dan

Try panning the camera, and see how fast you can pan before you start to see the individual frames instead of smooth motion.

One place I really notice this is when I take some 30fps video from my GitUp Git1 containing smooth panning and edit it, if I use Microsoft Movie Maker it stays smooth just like the original, if I use VSDC it ends up with individual frames visible even with really slow panning even though the original was smooth and it is still 30fps, I'm sure it is because it is using a different codec. I think it also depends a bit on the playback device and how it decodes the motion information.

I think for a dashcam there is a bit of a disadvantage to encoding the smoothness since if you pause the video, Ambarella encoded video tends to give a sharper freeze frame making it easier to read license plates, but it is not as good to watch at normal speed.

TV is normally recorded at only 24fps and yet I rarely notice any issue with low frame rate, but they put a lot more effort into encoding the motion information so that when played you don't notice the low frame rate.

 

[jokiin]

bitrate isn't everything, if it's Ambarella though it does generally benefit from higher bitrates