- Joined
- Jan 27, 2013
- Messages
- 52,458
- Reaction score
- 30,349
- Location
- Sydney, Australia ~ Shenzhen, China
- Country
- Australia
- Dash Cam
- Too many ¯\_(ツ)_/¯
But if not mine, get a brick ??
yes, start with the correct firmware first
But if not mine, get a brick ??
Started to modify my JOOY A1 firmware. Bitrates are changing without any question so video quality is really good now.
But when I increase framerates that Novatek 96558 can handle according to its datasheet (720p at 60 FPS and 480p at 120FPS) I am facing the following problem:
The video framerate for 480p is really 120 FPS (I see it in mediainfo and in videoplayers) but frames on video are changing only at 30 FPS.
So every frame is displayed 4 times, then I see some movement in video and then again the picture stays still for the next 4 frames. Video compression artefacts are changing EVERY frame so it's not a Novatek lack of processing power, I guess. Maybe it's a SONY IMX 322 sensor that cannot capture at these frame rates?
And 720p at 60 FPS is more mysterious. Sometimes there are videos that really are at 60 fps and sometimes not (each frame is displayed twice).
Can this be related to video sensor or is it a firmware problem related to video preview modes? I heard they are somehow connected with main recording modes.
Thanks! Will try again tomorrow during bright sunlight.Frame skipping for 60 fps and greater is enabled by default for modern Novatek SoCs
Well, I used 20 Mbit/s instead of 11 Mbit/s without any problem. Going to test even higher bitrate. Will post results later.Have you tried to find out the max bitrate for 96558 chip?
I didn't find these values yet. If you want to modify video bitrate/fps, check this thread: https://dashcamtalk.com/forum/threads/reverse-engineering-web-api-live-feed-etc.21057/Prompt where to look for increase in bitrate audio and a possibility of disable HDR?
Nice script, makes things a lot easierThanks! Will try again tomorrow during bright sunlight.
Well, I used 20 Mbit/s instead of 11 Mbit/s without any problem. Going to test even higher bitrate. Will post results later.
========
CMD Script that is using ntkcalc and bfc utilities by Tobi@s to automate compression, decompression and CRC calculation of firmware files. Just drag and drop FW file onto this cmd and select a mode.
https://yadi.sk/d/Uov8WibY3F663H
Thanks! I increased bitrate of video for YI DashCAM, but there is a wish to increase audio frequency since in a firmware it is set 16KHzI didn't find these values yet. If you want to modify video bitrate/fps, check this thread: https://dashcamtalk.com/forum/threads/reverse-engineering-web-api-live-feed-etc.21057/
OK!Please upload these two firmware files so that we can have a better look at it
It's not crc32 but a novatek proprietary algorithm (fyi)Colleagues, explain !!
Here is the screen:
Comparing the contents of files
The difference in the files is two.
I understand that in the offset 68 - CRC32
And in the offset 58A190 - bitrate.
But h_0028 - 2800 = 10240_d
And where is 20 000 ???
This is also in the original file.
What's wrong here?
Thank you.
Using this modification for a month daily and it seems to be stable.I'm not sure how useful this is, but I just found out that Novatek NT96655 is able to record 1600x900 @ 50 fps.
60 fps is too much, but 50 works.
View attachment 28921
Yes, that's exactly what we're doing.So if you want to modify the bitrate, modify the word @0x0058a195
maybe the bitrate is too high for wireless transmission
It turns out that way.maybe the bitrate is too high for wireless transmission
It turns out that way.
If the bitrate is <20, then everything is OK