Advanced users • Is the PISP a fake IP hidden by an over-complicated rpicam/libpisp/libcamera?

I'm using libcamera directly or via rpicam-hello. After the video is shown on the screen, I run media-ctl to print the topology:

So far, everything makes sense. The video goes from the sensor to the CSI2 module, to the PISP and is then reaching user-space.

But the color doesn't make any sense as the PISP is doing nothing. Same, there is no scaling done in hardware. All conversions are done in user-space software.

- The sensor is in SBGGR8_1X8
- The CSI module inputs in SBGGR8_1X8
- The CSI module outputs in SBGGR16_1X16 (waste here but let's assume that the PISP is 16 bit input only)
- The PISP module inputs in SBGGR16_1X16
- The PISP module outputs in SBGGR16_1X16 (doing absolutely nothing here. Plus, the resolution is the same as the sensor!)

I was expecting PISP to output in RGB or YUV420 and to rescale as needed. So what's the point of the PISP??? There are tons of line of code to manage hardware which doesn't nothing. It's better to output directly the sensor to /dev/video0

Statistics: Posted by gregoiregentil — Fri Nov 08, 2024 9:59 pm — Replies 3 — Views 53

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