esp-idf/examples/peripherals/isp/dma_input/README.md

Supported Targets	ESP32-P4

ISP DMA Input Visual Test Example

Overview

This example generates a standard RAW8 Bayer color-bar pattern in software, writes it into a DMA-capable PSRAM input buffer, feeds it into the ISP through DW-GDMA, applies the ISP color adjustment module, and prints the RGB888 output as base64. The pytest script decodes the output into PPM images for inspection.

The data flow is:

1. A synthetic RAW8 Bayer color-bar pattern is generated in software into the ISP DMA input buffer.
2. The pattern is transferred into the ISP via DW-GDMA → ISP DMA input.
3. The ISP processes the data (demosaic, color adjustment) and outputs RGB888 (BGR24 byte layout).
4. The RGB888 frame is base64-encoded and printed with machine-parseable markers.
5. pytest decodes the payload, swaps BGR→RGB, and saves one PPM file per frame.

Hardware Required

• An ESP32-P4 devkit with PSRAM (this example allocates the ISP DMA input/output buffers from PSRAM).

If you replace the software-generated pattern with a RAW image embedded in flash, copy it into a DMA-capable buffer before feeding it to the ISP DMA input path.

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 reference.ppm for the standard reference color-bar image and isp_dma_input_frame00.ppm, ... for the decoded ISP output frames. The pytest script checks that the decoded frame contains the expected standard color-bar structure and verifies that the ISP color brightness adjustment brightens the black bar.

ISP feature-specific setup is kept under main/isp_features/<feature>/, and pytest feature checks are kept under pytest_features/<feature>.py. The current color brightness check lives in main/isp_features/color/ and pytest_features/color_brightness.py; new ISP feature checks can follow the same pattern while reusing the common DW-GDMA input/output and image parsing flow.

Example Output

Each frame uses the same standard vertical color-bar input pattern with positive color brightness enabled to validate the ISP color adjustment module.

Feeding 1 frames through ISP DMA input...
IMAGE_META frame=0 width=128 height=96 format=BGR24 encoding=base64 color_brightness=64
IMAGE_BASE64_BEGIN
IMAGE_BASE64 ...
IMAGE_BASE64_END
Frame 0 done
ISP DMA visual demo done.

Reference

• ESP-IDF: Image Signal Processor