topic Re: PXP to only resize a buffer in i.MX RT Crossover MCUs

PXP to only resize a buffer

jose_au_zone — Mon, 23 Aug 2021 22:48:49 GMT

Hello!

Is it possible to use PXP to only resize an image? Without any color conversion?

Right now I'm using PXP to get data from a 10626 sensor (YUV to RGB888). That part is fine.

But I need access to that RGB888 image buffer, so I am using that buffer and then trying to configure PXP again just to do a resize, but I'm getting wrong results

The output buffer config of the first step (from camera to RGB888) is configured like this:

/* PS configure. */ const pxp_output_buffer_config_t outputBufferConfig = { .pixelFormat = kPXP_OutputPixelFormatRGB888P, .interlacedMode = kPXP_OutputProgressive, .buffer0Addr = (uint32_t) camera_buffer_rgb24, .buffer1Addr = 0U, .pitchBytes = cameraWidth * 3, .width = cameraWidth, .height = cameraHeight, };

This works fine! Now I want to just resize that buffer, so the second stage is configured like this:

Output buffer config:

/* PS configure. */ const pxp_output_buffer_config_t outputBufferConfig = { .pixelFormat = kPXP_OutputPixelFormatRGB888P, .interlacedMode = kPXP_OutputProgressive, .buffer0Addr = (uint32_t) input_buffer, .buffer1Addr = 0U, .pitchBytes = output_size * 3, .width = output_size, .height = output_size, };

Input buffer config (from the output of the first stage [YUV to RGB888]):

/* PS config. */ inputBufferConfig.pixelFormat = kPXP_PsPixelFormatRGB888; inputBufferConfig.bufferAddrU = 0U; inputBufferConfig.bufferAddrV = 0U; inputBufferConfig.bufferAddr = (uint32_t) camera_buffer_rgb24; inputBufferConfig.pitchBytes = cameraWidth * 3; inputBufferConfig.swapByte = false;

But the output image is in greyscale (should be colored) and its shifted like in the following picture:

One thing that I noticed is that the enum _pxp_ps_pixel_format doesn't have the an RGB888 packed format, it only has the kPXP_PsPixelFormatRGB888 format which is unpacked (opposed to the enum _pxp_output_pixel_format which has the format kPXP_OutputPixelFormatRGB888P which is packed)

Any input will be greatly appreciated!

Thanks!

Re: PXP to only resize a buffer

jeremyzhou — Tue, 24 Aug 2021 03:46:34 GMT

Hi,
Thank you for your interest in NXP Semiconductor products and for the opportunity to serve you.
I'd like to suggest you configure the sensor to output an RGB8888 format or use an algorithm code to convert RGB888 into RGB8888 prior to outputting the buffer data to the PXP engine
Have a great day,
TIC

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Re: PXP to only resize a buffer

jose_au_zone — Tue, 24 Aug 2021 22:46:16 GMT

Thank you for the reply. My goal was to not use use any software conversion, and let PXP do everything due to time constraints. Is it possible to do just a resizing without color conversion on PXP?

Thank you!

Re: PXP to only resize a buffer

jeremyzhou — Wed, 25 Aug 2021 08:16:30 GMT

Hi,
Thanks for your reply.
1) Is it possible to do just a resizing without color conversion on PXP?
-- No, I'm afraid not, as scaling, color space conversion, rotation is integrated into a single processing engine.
Have a great day,
TIC

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Re: PXP to only resize a buffer

jose_au_zone — Wed, 25 Aug 2021 19:17:06 GMT

Ok thanks