capture returns None while camera is initialised and crashes on next init

[FredrikMorstad]

Describe the bug
Camera becomes None or cannot init properly after multiple attempt to capture image

I have this endpoint using microdot

@app.route('/picture')
async def picture(request):
    # try:
    start_time = time.time()
    cam.init()
    # print(dir(cam))
    buff = None
    if cam is not None:
        while buff is None:
            buff = cam.capture()
            print(buff)
            cam.free_buffer()
    else:
        return 500

    cam.deinit()
    if buff is None:
        return 500

    end_time = time.time()

    elapsed = end_time-start_time
    print(f"capture time: {elapsed:.3f}")
    return buff, 200, {'Content-Type': 'image/jpeg', 'Content-Length': len(buff)}

and every time I run the server the capture method randomly returns None from the capture method. I used
this driver and had no problems where the capture method could not capture an image. Generally the capture method returns an image but randomly it returns none. After retrying for about 8 seconds it returns an image but the next request always fails with this exception

Traceback (most recent call last):
  File "microdot/microdot.py", line 1394, in dispatch_request
  File "microdot/microdot.py", line 45, in invoke_handler
  File "<stdin>", line 50, in picture
OSError: (-261, 'ESP_ERR_NOT_FOUND')

To Reproduce
Code to reproduce

from microdot import Microdot
from camera import Camera, PixelFormat, Version

app = Microdot()

cam = Camera(
    pixel_format=PixelFormat.JPEG,
    data_pins=[5,18,19,21,36,39,34,35],
    vsync_pin=25,
    href_pin=23,
    sda_pin=26,
    scl_pin=27,
    pclk_pin=22,
    xclk_pin=0,
    xclk_freq=20000000,
    powerdown_pin=32,
    reset_pin=-1,
)

@app.route('/picture')
async def picture(request):
    cam.init()
    buff = None
    if cam is not None:
        while buff is None:
            buff = cam.capture()
            cam.free_buffer()
    else:
        return 500

    cam.deinit()
    if buff is None:
        return 500
    return buff, 200, {'Content-Type': 'image/jpeg', 'Content-Length': len(buff)}

app.run(debug=True)

Expected behavior
A clear and concise description of what you expected to happen.
capture method should be consistent when camera is initialised

Environment:

• Board: e.g. ESP32-CAM
• Camera drivers version: 28035e0

Additional context
Add any other context about the problem here.

[cnadler86]

first of all, please read the documentation and take a look at the examples.

You don't need to init the camera (only if you pass the init flag = false at construction)
Second, you don't need to free the buffer.

[cnadler86]

If you want to stay with your impelemation, pass init flag with false and convert you buffer to bytes before freeing the Buffer

[FredrikMorstad]

I have updated the code and it still has the same issues. I originally initialised the camera at startup and then used a global cam variable but this resulted in the same problem. So I tried an approach more similar to the example but this also results in the same error. Also the can get 5 or 6 captures resulting in none which is very strange

[FredrikMorstad]

Update:
I moved back to having a global camera instance and it seems to be working now. The only problem is that sometimes the capture method can sometimes use 1-10 tries to get an image from the capture method. But that is probably not the responsibility of this lib to find out why