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Joined: Sat Jul 13, 2019 8:05 pm

Possibly stupid GPU question

Sat Jul 13, 2019 8:20 pm

I understand that an amount of GPU processing is done when an image is captured using the official pi camera boards, and that in fact most of the image processing from the board is processed via the GPU e.g. when generating a jpg output from the sensor data.

I also understand that the GPU changes between RPi versions (correct me if I'm wrong here though), presumably getting better (whatever that might mean) each time.

My question is:

Does the GPU materially effect the quality of the image output in any way, and therefore do different GPUs lead to different capture results?
Or is it that the code for GPU processing remains constant and therefore the only improvement if any is speed of image generation?

As a case in point if I took an image with a v1.3 camera on an RPi 1 and an RPi 4 under exactly the same conditions, would I/should I notice a difference on any level?

I should make it clear that I have not seen any difference, it's purely a questions born out of not understanding how the GPU takes action on the data in hardware.

Thanks all

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Re: Possibly stupid GPU question

Sun Jul 14, 2019 8:35 am

Gpu is too vague a term.
The Pi uses the Videocore multimedia IP. That is made up of a 3d unit, h264 codecs, hdmi transmitter, display composition (hvs) , dsi transmitter, jpeg codec, csi2 receiver, isp, general purpose vector processor, gpio controller, and some other blocks I'm bound to have forgotten.

With pi 0-3, predominantly the arm cores were upgraded whilst the Videocore blocks remained the same.

With pi4, the 3d hardware, hdmi transmitter, and hvs have been upgraded, as well as the whole chip being made with a 28nm process which generally allows running everything at a slightly increased clock speed.
The isp hasn't changed, so it'll be the same except for the slight speed increase.
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