RPI_333333
Posts: 15
Joined: Wed Nov 14, 2018 8:53 am

Jpeg compression On board or on RPI

Sun Mar 17, 2019 9:48 am

Hello,
I would like to know if the camera compression (to Jpeg) is done on the camera board itself or on the Raspberry Pi.
More detailed, I would like to know if the raw image is transfers to the Raspberry pi (Via the CSI interface) or the compressed image in order to understand better the data rate between the camera board to the Raspberry Pi.

Is there any documentation about camera hardware?

Thanks for the help!


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Gavinmc42
Posts: 2621
Joined: Wed Aug 28, 2013 3:31 am

Re: Jpeg compression On board or on RPI

Sun Mar 17, 2019 10:11 am

The data from the camera sensor goes via an image processing system.
Most of it (all?) is done by the VC4 including the JPEG and H.264.
But there is a way to get the raw data so you can process everything yourself.
A search will find that way.

There is also info on the CSI in the forums.
The sensors can do some processing, white balance etc but I think that is turned off and all done by the VC4.
The VC4 does the lens correction and colour correction for both cameras as well.
The code for this is embedded in the start_x.elf file.

Some guys have messed around with the cameras and got 1000fps sub sampling part of the image sensor.
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HermannSW
Posts: 1026
Joined: Fri Jul 22, 2016 9:09 pm

Re: Jpeg compression On board or on RPI

Sun Mar 17, 2019 11:10 am

Gavinmc42 wrote:
Sun Mar 17, 2019 10:11 am
But there is a way to get the raw data so you can process everything yourself.
A search will find that way.
raspiraw:
viewtopic.php?f=43&t=109137

Gavinmc42 wrote:
Sun Mar 17, 2019 10:11 am
Some guys have messed around with the cameras and got 1000fps sub sampling part of the image sensor.
viewtopic.php?f=43&t=212518&p=1310445#p1319675
Image
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RPI_333333
Posts: 15
Joined: Wed Nov 14, 2018 8:53 am

Re: Jpeg compression On board or on RPI

Tue Mar 19, 2019 6:57 am

Thanks for the answers- I'ts all clear now :)

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