[BUG] ProcessLookupError: [Errno 3] No such process when Using maximal resolution and MJPEG Encoder

[Elaschatz]

Describe the bug
When I slightly change the capture_motion.py example I get an error: no such process.

To Reproduce
*changing only H264 to MJPEGEncoder works
*changing the resolution to maximum (4056,3040) I run out of memory, so added "buffer_count=2"
*then error occurs

Same with
*changing the resolution to 2028,1520 and buffer_count=1

Here is my code:
`
import time
from signal import pause

import numpy as np

from picamera2 import Picamera2
from picamera2.encoders import MJPEGEncoder
from picamera2.outputs import FileOutput

lsize = (320, 240)
picam2 = Picamera2()
video_config = picam2.create_video_configuration(main={"size": (2028, 1520), "format": "RGB888"},
lores={"size": lsize, "format": "YUV420"} )
picam2.configure(video_config)
encoder = MJPEGEncoder()
picam2.encoder = encoder
picam2.start()

w, h = lsize
prev = None
encoding = False
ltime = 0

while True:
cur = picam2.capture_buffer("lores")
cur = cur[:w*h].reshape(h, w)
if prev is not None:
# Measure pixels differences between current and
# previous frame
mse = np.square(np.subtract(cur, prev)).mean()
if mse > 7:
if not encoding:
encoder.output = FileOutput("{}.mjpeg".format(int(time.time())))
picam2.start_encoder()
encoding = True
print("New Motion", mse)
ltime = time.time()
else:
if encoding and time.time() - ltime > 2.0:
picam2.stop_encoder()
encoding = False
prev = cur`

Expected behaviour
Camera should capture the motion as in the capture_motion.py example but with MJPEG Encoder and maximal resolution

Console Output, Screenshots
0:10:44.267790118] [2280] INFO Camera camera_manager.cpp:293 libcamera v0.0.0+3866-0c55e522
[0:10:44.297385124] [2281] INFO RPI raspberrypi.cpp:1374 Registered camera /base/soc/i2c0mux/i2c@1/imx477@1a to Unicam device /dev/media4 and ISP device /dev/media1
[0:10:44.301472240] [2280] INFO Camera camera.cpp:1035 configuring streams: (0) 4056x3040-RGB888 (1) 320x240-YUV420
[0:10:44.301902062] [2281] INFO RPI raspberrypi.cpp:761 Sensor: /base/soc/i2c0mux/i2c@1/imx477@1a - Selected sensor format: 4056x3040-SBGGR12_1X12 - Selected unicam format: 4056x3040-pBCC
Traceback (most recent call last):
File "/home/raspbeequeen/raspbee_image/video/capture_motion.py", line 36, in
picam2.start_encoder()
File "/home/raspbeequeen/.local/lib/python3.9/site-packages/picamera2/picamera2.py", line 1483, in start_encoder
self.encoder._start()
File "/home/raspbeequeen/.local/lib/python3.9/site-packages/picamera2/encoders/v4l2_encoder.py", line 124, in _start
fcntl.ioctl(self.vd, VIDIOC_STREAMON, typev)
ProcessLookupError: [Errno 3] No such process

Hardware :
Pi 4b with 8GB Ram and bullseye

Additional context
Add any other context about the problem here.

[davidplowman]

Hi, thanks for the bug report.

It turns out that our MJPEG codec is enforcing the same overall resolution limits as our H264 encoder (namely 1920x1920), even though in the MJPEG case we could actually handle larger resolutions. We'll have to look into the kernel drivers to fix that. In the meantime you could try the software JPEG encoder (encoder = JpegEncoder()), though obviously that will use CPU and may result in a lower framerate.

[maxsitt]

Hi,

it seems like this problem still exists. Any resolution larger than 1920x1920 (multiple of 32) as input for the MJPEGEncoder leads to the previously mentioned ProcessLookupError: [Errno 3] No such process error.

Do you have any recent updates regarding potential workarounds or maybe a planned fix?

Thanks!

[davidplowman]

I'm sorry, but I have no news here. It's a feature of the Broadcom firmware which makes it more awkward to change. The only workaround I can suggest currently would be to use the software encoder.