| Supported Targets | ESP32-P4 |
|---|
ISP DMA Input Visual Test Example
Overview
This example embeds a 240 x 280 RAW8 Bayer image of a real scene in flash, feeds it directly into the ISP through DW-GDMA, and prints the RGB888 output as base64. The ISP driver synchronizes the DMA buffers' cache automatically. The pytest script decodes the output into a PPM image and compares it with the checked-in golden image.
The data flow is:
- The embedded 16-byte-aligned BGGR RAW8 image is transferred from mapped flash into the ISP via
DW-GDMA → ISP DMA input. - The ISP processes the data (demosaic, color adjustment) and outputs RGB888 (BGR24 byte layout).
- The RGB888 frame is base64-encoded and printed with machine-parseable markers.
- pytest decodes the payload, swaps BGR→RGB, saves one PPM file per frame, and compares it with the golden image.
Hardware Required
- An ESP32-P4 devkit with PSRAM (this example allocates the ISP output buffer from PSRAM).
How to Use
Run the test locally. It builds and flashes the example, captures the serial output, and saves one PPM artifact per frame:
cd examples/peripherals/isp/dma_input
pytest pytest_isp_dma_input.py --target esp32p4 --port PORT
The pytest log directory (dut.logdir) contains isp_dma_input_frame00.ppm, the decoded RGB888 ISP output from the current hardware run. The repository includes golden/golden.ppm, the checked-in reference image. The test compares the decoded RGB888 pixels with this reference image, making image-quality regressions visible in review and detectable in CI.
Example Output
The example processes one embedded 240 x 280 BGGR RAW8 frame.
Feeding 1 frames through ISP DMA input...
IMAGE_META frame=0 width=240 height=280 format=BGR24 encoding=base64
IMAGE_BASE64_BEGIN
IMAGE_BASE64 ...
IMAGE_BASE64_END
Frame 0 done
ISP DMA visual demo done.