Script EMMC access

This example requires a device with onboard EMMC memory (e.g. OAK-1-POE).

To check whether your device has EMMC memory, run the bootloader version script at Bootloader Version and check whether the output contains Memory.EMMC.

This example shows how to use Script node to access EMMC memory of the device. Default location for EMMC memory is /media/mmcsd-0-0/. The first script in the pipeline works by writing an image to EMMC memory. The second script starts a webserver on :/media/mmcsd-0-0/ directory and serves the image from EMMC memory.

Setup

Please run the install script to download all required dependencies. Please note that this script must be ran from git context, so you have to download the depthai-python repository first and then run the script

Command Line

1git clone https://github.com/luxonis/depthai-python.git
2cd depthai-python/examples
3python3 install_requirements.py

For additional information, please follow the installation guide.

Prerequisites

We first need to enable the EMMC memory as storage on the device. To do so, we need to flash the device with an application that has EMMC enabled.Example application:

Command Line

1import depthai as dai
2
3    # Create pipeline
4    pipeline = dai.Pipeline()
5
6    # Set board config
7    board = dai.BoardConfig()
8    board.emmc = True
9    config = dai.Device.Config()
10    config.board = board
11    pipeline.setBoardConfig(board)
12
13    (f, bl) = dai.DeviceBootloader.getFirstAvailableDevice()
14    bootloader = dai.DeviceBootloader(bl)
15    progress = lambda p : print(f'Flashing progress: {p*100:.1f}%')
16    (r, errmsg) = bootloader.flash(progress, pipeline, memory=dai.DeviceBootloader.Memory.EMMC)
17    if r: print("Flash OK")

The above code will flash the device with the application that enables the script node to access EMMC memory. Now we should be able to access EMMC memory even when the device is in standard mode (connected to the host PC).

Source code

Python

GitHub

1#!/usr/bin/env python3
2
3import depthai as dai
4import cv2
5
6# Start defining a pipeline
7pipeline = dai.Pipeline()
8
9board = dai.BoardConfig()
10board.emmc = True
11pipeline.setBoardConfig(board)
12
13# Define source and output
14camRgb = pipeline.create(dai.node.ColorCamera)
15jpegEncoder = pipeline.create(dai.node.VideoEncoder)
16
17# Properties
18camRgb.setResolution(dai.ColorCameraProperties.SensorResolution.THE_4_K)
19jpegEncoder.setDefaultProfilePreset(1, dai.VideoEncoderProperties.Profile.MJPEG)
20
21#Set a write script
22script_write = pipeline.createScript()
23script_write.setProcessor(dai.ProcessorType.LEON_CSS)
24script_write.setScript("""
25
26    import os
27    index = 1000
28    import time
29    while True:
30        # Find an unused file name first
31        while True:
32            path = '/media/mmcsd-0-0/' + str(index) + '.jpg'
33            if not os.path.exists(path):
34                break
35            index += 1
36        frame = node.io['jpeg'].get()
37        node.warn(f'Saving to EMMC: {path}')
38        with open(path, 'wb') as f:
39            f.write(frame.getData())
40        index += 1
41        time.sleep(3)
42
43""")
44                      
45#Set a read script
46script_read = pipeline.createScript()
47script_read.setProcessor(dai.ProcessorType.LEON_CSS)
48script_read.setScript("""
49
50    import http.server
51    import socketserver
52    import socket
53    import fcntl
54    import struct
55    import os
56
57    def get_ip_address(ifname):
58        s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
59        return socket.inet_ntoa(fcntl.ioctl(
60            s.fileno(),
61            -1071617759,  # SIOCGIFADDR
62            struct.pack('256s', ifname[:15].encode())
63        )[20:24])
64
65    # Note: `chdir` here will prevent unmount, this should be improved!
66    os.chdir('/media/mmcsd-0-0')
67
68    PORT = 80
69    Handler = http.server.SimpleHTTPRequestHandler
70
71    with socketserver.TCPServer(("", PORT), Handler) as httpd:
72        ip = get_ip_address('re0')
73        node.warn(f'===== HTTP file server accessible at: http://{ip}')
74        httpd.serve_forever()
75
76""")
77                      
78# Linking
79
80camRgb.video.link(jpegEncoder.input)
81jpegEncoder.bitstream.link(script_write.inputs['jpeg'])
82script_write.inputs['jpeg'].setBlocking(False)
83xout = pipeline.create(dai.node.XLinkOut)
84xout.setStreamName("rgb")
85script_read.outputs['jpeg'].link(xout.input)
86
87
88# Pipeline defined, now the device is connected to
89with dai.Device(pipeline) as device:
90    # Output queue will be used to get the rgb frames from the output defined above
91    qRgb = device.getOutputQueue(name="rgb", maxSize=100, blocking=False)
92
93    while True:
94        inRgb = qRgb.tryGet() 
95        
96        if inRgb is not None:
97            cv2.imshow("rgb", inRgb.getCvFrame())
98            
99        if cv2.waitKey(1) == ord('q'):
100            break

Pipeline

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