Micropython MemoryError when trying to get image from URL

Question

Hi I’ve bought the dispay pack2 (https://shop.pimoroni.com/products/pico-display-pack-2-0?variant=39374122582099) and am trying to display an image. If I download the image and put it on the pi pico w then the image displays OK. I’m trying to get the image to be downloaded from a URL and displayed but am getting

MemoryError: memory allocation failed, allocating 21760 bytes

I’m new to this sort of coding and am struggling to see what I’m doing wrong. here is my full py code

`

import network
import urequests
import time
import picographics
import jpegdec
from pimoroni import Button



wlan = network.WLAN(network.STA_IF)
wlan.active(True)
wlan.connect("SSID","password")
time.sleep(5)
print(wlan.isconnected())


display = picographics.PicoGraphics(display=picographics.DISPLAY_PICO_DISPLAY_2, rotate=0)
display.set_backlight(0.8)

# Create a new JPEG decoder for our PicoGraphics
j = jpegdec.JPEG(display)

# Open the JPEG file
#j.open_file("squid.jpg")

# Decode the JPEG
#j.decode(0, 0, jpegdec.JPEG_SCALE_FULL)

if wlan.isconnected():
    
    res = urequests.get(url='https://squirrel365.io/tmp/squid.jpg')
   
    j.open_RAM(memoryview(res.content))

    # Decode the JPEG
    j.decode(0, 0, jpegdec.JPEG_SCALE_FULL)

    # Display the result
    display.update()

` Any ideas?

Kedge

I've tested and can get plain text back from the URL, as soon as I try and get an image I get the memory error

The exact error is: Traceback (most recent call last): File "", line 35, in File "urequests.py", line 20, in content MemoryError: memory allocation failed, allocating 22528 bytes line 35 is the line with j.open_RAM(memoryview(res.content)) on it. doing some debugging it's the res.content that is causing the error, because if I add print(res.content) I get the same erroro — Rich Harvey, Dec 09 '22 at 11:33

score 0 · Accepted Answer · answered Dec 09 '22 at 13:22

You're not doing anything "wrong"; you're just working with a device that has very limited resources. What if you re-arrange your code to perform the fetch before initializing any graphics resources, write the data to a file, and then have the jpeg module read it from disk? Something like:

import jpegdec
import network
import picographics
import time
import urequests

wlan = network.WLAN(network.STA_IF)
wlan.active(True)
wlan.connect("SSID","password")

while not wlan.isconnected():
    print('waiting for network')
    time.sleep(1)

res = urequests.get(url='https://squirrel365.io/tmp/squid.jpg')
with open('squid.jpg', 'wb') as fd:
    fd.write(res.content)

display = picographics.PicoGraphics(display=picographics.DISPLAY_PICO_DISPLAY_2, rotate=0)
display.set_backlight(0.8)

# Create a new JPEG decoder for our PicoGraphics
j = jpegdec.JPEG(display)

# Open the JPEG file
j.open_file("squid.jpg")

# Decode the JPEG
j.decode(0, 0, jpegdec.JPEG_SCALE_FULL)

# Display the result
display.update()

You can sometimes free up additional memory by adding an explicit garbage collection to your code:

import gc

.
.
.

with open('squid.jpg', 'wb') as fd:
    fd.write(res.content)

gc.collect()

thank you! I've been stuck on this for ages. It's got further. I'm still getting the memory error, but now it's after the file has been downloaded and it's when it's setting the display. I'll have a play to see if I can see a way to release memory now that I've got the file as physical jpg. — Rich Harvey, Dec 09 '22 at 13:42

Micropython MemoryError when trying to get image from URL

1 Answers1