This example embeds a 240 x 280 RAW8 Bayer image of a real scene in flash, copies it into a DMA-capable PSRAM input buffer, feeds it into the ISP through DW-GDMA, and prints the RGB888 output as base64. 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 BGGR RAW8 image is copied from flash into the ISP DMA input buffer.
The image is transferred 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 DMA input/output buffers 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.

Reference

ESP-IDF: Image Signal Processor