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Is it possible to convert YCbCr 4:2:2 received on DCMI to RGB for Display in real time with STM32F746 MCU?

SLavi
Associate II

Hello Everyone,

Similar questions have been asked and I have followed up all threads related to my problem and have not found a solution that works. A somewhat near to solution is provided in this thread (https://community.st.com/s/question/0D50X00009cgJErSAM/is-using-dma2d-to-convert-ycbcr-422-to-argb8888-with-stm32h7-and-dcmi-as-input-possible-) but it still is not satisfactory and it is for the STM32H7 series which has JPEG Codec. The MCU series I am using does not have that feature (STM32F746G-DISCO board)

Quoted from AN5020 (DCMI for STM32 MCUs) "This example implementation aims to receive the YCbCr data from the camera module and to transfer it into the SDRAM.

Displaying the YCbCr received data on the LCD (configured to display RGB565 data in the previous configuration) is not correct but can be used for verification.

To display images correctly, the YCbCr data must be converted into RGB565 data (or RGB888 or ARGB8888, depending on the application needs)."

All the examples except the one of JPEG is shown using the STM32F746G-DISCO board. The example shows how to capture the YCbCr but there is no mention of how to convert that data for display or whether it is even possible to do so.

So my requirement is YCbCr -> DCMI -> (conversion process in real time) -> RGB -> Display.

So do I have to upgrade my MCU to one which has JPEG CODEC (eventually YCbCr -> RGB) and what guarantee do I have that it will work smoothly? Or is it somehow possible to get it done with the STM32F746 MCU?

Any help would really be appreciated as I have made so much investment into STM32 and just this part is letting me down and probably a reason for me to look for other options.

Thanks in Advance

Salman

1 REPLY 1

In the thread you pointed to we discussed that's it's unlikely that the jpeg decoder would help with progressive YCbCr input from a camera (DCMI).

Even if for some smaller resolution/framerate software conversion would be possible, the processor would not be able to do anything else, so you probably want to move away from either STM32 or YCbCr anyway.

JW