3.13 NONAI2D CSC API Manual

1. Overview

The K230 chip has 24 built-in hardware Color Space Conversion (CSC) channels, which can efficiently perform image color space conversions. This module supports various image format conversions including common formats such as RGB/YUV, making it suitable for video processing, image display, and similar applications.

2. API Reference

2.1 Constructor

Function
Initialize a CSC conversion channel

Syntax

from nonai2d import CSC
csc = CSC(chn, fmt, max_width=1920, max_height=1080, buf_num=2)

Parameter Description

Parameter	Type	Description	Default
chn	int	CSC channel number, range: 0–23	Required
fmt	int	Target image format (see constant definitions)	Required
max_width	int	Maximum image width supported (in pixels)	1920
max_height	int	Maximum image height supported (in pixels)	1080
buf_num	int	Number of VB buffers allocated, affects processing performance	2

Return Value
Returns a CSC object on success, raises an exception on failure.

Important Notes

1. The CSC object must be initialized before calling MediaManager.init()

2. Channel numbers 0–23 must not be reused

3. It’s recommended to set max_width/max_height according to actual image size to save memory

2.2 convert Method

Function
Perform image color space conversion

Syntax

result = csc.convert(frame, timeout_ms=1000, cvt=True)

Parameter Description

Parameter	Type	Description	Default
frame	py_video_frame_info	Input image frame (from Sensor.snapshot)	Required
timeout_ms	int	Conversion timeout in milliseconds	1000
cvt	bool	True returns an Image object, False returns py_video_frame_info	True

Return Value
Returns a converted Image object or py_video_frame_info, depending on the cvt parameter.

2.3 destroy Method

Function
Release CSC channel resources

Syntax

csc.destroy()

Description
After calling this method, all resources used by the CSC channel will be released, and the object can no longer be used.

3. Constant Definitions

Image Format Constants

Constant Name	Description	Typical Use Case
PIXEL_FORMAT_GRAYSCALE	Grayscale image format	Black-and-white image processing
PIXEL_FORMAT_RGB_565	RGB565 format (big-endian)	LCD display
PIXEL_FORMAT_RGB_565_LE	RGB565 format (little-endian)	Special display devices
PIXEL_FORMAT_BGR_565	BGR565 format (big-endian)	OpenCV compatibility
PIXEL_FORMAT_BGR_565_LE	BGR565 format (little-endian)	Special display devices
PIXEL_FORMAT_RGB_888	RGB888 format	High-quality image processing
PIXEL_FORMAT_BGR_888	BGR888 format	OpenCV compatibility
PIXEL_FORMAT_ARGB_8888	ARGB8888 format (with transparency)	GUI composition
PIXEL_FORMAT_YVU_PLANAR_420	YVU420 planar format	Video decoding output
PIXEL_FORMAT_YUV_SEMIPLANAR_420	YUV420 semi-planar format	Video encoding input

4. Best Practice Example

import time, os, urandom, sys

from media.display import *
from media.media import *
from media.uvc import *

from nonai2d import CSC

DISPLAY_WIDTH = ALIGN_UP(800, 16)
DISPLAY_HEIGHT = 480

# hardware Color Space Converter
csc = CSC(0, CSC.PIXEL_FORMAT_RGB_565)

# use lcd as display output
Display.init(Display.ST7701, width = DISPLAY_WIDTH, height = DISPLAY_HEIGHT, to_ide = True)
# init media manager
MediaManager.init()

while True:
    plugin, dev = UVC.probe()
    if plugin:
        print(f"detect USB Camera {dev}")
        break
    time.sleep_ms(100)

mode = UVC.video_mode(640, 480, UVC.FORMAT_MJPEG, 30)

succ, mode = UVC.select_video_mode(mode)
print(f"select mode success: {succ}, mode: {mode}")

UVC.start(cvt = True)

clock = time.clock()

while True:
    clock.tick()

    img = UVC.snapshot()
    if img is not None:
        img = csc.convert(img)
        Display.show_image(img)

    print(clock.fps())

# deinit display
Display.deinit()
csc.destroy()
UVC.stop()

time.sleep_ms(100)
# release media buffer
MediaManager.deinit()