Unable to open camera(): Cannot allocate memory

[sobchek]

I’m using motion built from current master, running on a Raspberry Pi Zero 2 W, using the Pi Camera module (OV5647) and the libcamera stack on Raspberry Pi OS Bookworm. Im having issue with memory allocation:

testnet@birdhaus:~ $ LIBCAMERA_V4L2_BUFFERS=16 libcamerify motion -c ~/motion.conf -n -d 6
[NTC][ALL][mo00] process: Processing config file /home/testnet/motion.conf
[NTC][ALL][mo00] process: Processing config file camera1.conf
[CRT][NET][mo00] edit_height: Image height (540) requested is not modulo 8.
[CRT][NET][mo00] edit_height: Adjusting height to next higher multiple of 8 (544).
[NTC][ALL][mo00] set_log_file: Logging to syslog
[NTC][ALL][mo00] mytranslate_init: Language: English
[NTC][ALL][mo00] mycreate_path: Creating /var/run/motion/
[ERR][ALL][mo00] mycreate_path: Problem creating directory /var/run/motion/: Permission denied
[EMG][ALL][mo00] pid_write: Cannot create process id file (pid file) /var/run/motion/motion.pid: Permission denied
[NTC][ALL][mo00] pid_write: Motion pid: 584
[NTC][ENC][mo00] av_init: libavcodec  version 59.37.100
[NTC][ENC][mo00] av_init: libavformat version 59.27.100

Broadcast message from systemd-journald@birdhaus (Fri 2025-07-11 13:48:46 EDT):

motion[584]: [EMG][ALL][mo00] pid_write: Cannot create process id file (pid file) /var/run/motion/motion.pid: Permission denied

[NTC][STR][mo00] startup: Starting webcontrol on port 8081
[NTC][STR][mo00] start_daemon_port1: Started webcontrol on port 8081
[NTC][VID][cl01] netcam_start: Norm: Opening Netcam
[0:09:03.682965919] [593] ERROR IPAModule ipa_module.cpp:171 Symbol ipaModuleInfo not found
[0:09:03.683210656] [593] ERROR IPAModule ipa_module.cpp:291 v4l2-compat.so: IPA module has no valid info
[0:09:03.683332685] [593]  INFO Camera camera_manager.cpp:326 libcamera v0.5.0+59-d83ff0a4
[0:09:03.904135996] [594]  WARN RPiSdn sdn.cpp:40 Using legacy SDN tuning - please consider moving SDN inside rpi.denoise
[0:09:03.917207204] [594]  INFO RPI vc4.cpp:447 Registered camera /base/soc/i2c0mux/i2c@1/ov5647@36 to Unicam device /dev/media0 and ISP device /dev/media1
[0:09:03.919171505] [593]  INFO Camera camera.cpp:1205 configuring streams: (0) 960x544-YUV420
[0:09:03.920185191] [594]  INFO RPI vc4.cpp:622 Sensor: /base/soc/i2c0mux/i2c@1/ov5647@36 - Selected sensor format: 1920x1080-SGBRG10_1X10 - Selected unicam format: 1920x1080-pGAA
[0:09:03.923513071] [593]  INFO Camera camera.cpp:1205 configuring streams: (0) 960x544-YUV420
[0:09:03.924471497] [594]  INFO RPI vc4.cpp:622 Sensor: /base/soc/i2c0mux/i2c@1/ov5647@36 - Selected sensor format: 1920x1080-SGBRG10_1X10 - Selected unicam format: 1920x1080-pGAA
[0:09:03.954293612] [594] ERROR V4L2 v4l2_videodevice.cpp:1328 /dev/video14[18:cap]: Not enough buffers provided by V4L2VideoDevice
[NTC][NET][cl01] open_context: Norm:Unable to open camera():Cannot allocate memory
[NTC][NET][cl01] handler_shutdown: Norm:Shut down complete.
[ERR][ALL][cl01] init_cam_start: Failed to start camera.
[NTC][ALL][cl01] ring_resize: Resizing buffer to 1 items
[ERR][ALL][cl01] init_firstimage: Unable to open camera
[NTC][NET][cl01] noimage: Camera did not reconnect.
[NTC][NET][cl01] noimage: Checking for camera every 30 seconds.
[NTC][NET][cl01] handler_shutdown: Norm:Shut down complete.

I’m launching motion wrapped in libcamerify so it gets /dev/video0 as a V4L2 source from libcamera.
I’ve also tried setting LIBCAMERA_V4L2_BUFFERS=16 when launching libcamerify to bump the buffer count.

LIBCAMERA_V4L2_BUFFERS=16 libcamerify motion -c ~/motion.conf -n -d 6

motion.conf:

camera camera1.conf

camera1.conf:

netcam_url v4l2:///dev/video0
width 960
height 540
framerate 15

I’ve tried gpu_mem from 128 up to 320.

libcamera-hello works perfectly at full 1080p.

Using libcamera-vid with v4l2loopback works — so the hardware is fine.

Dropping to 720p helps but doesn’t always fix the buffer issue when using libcamerify.

When I run:

LIBCAMERA_V4L2_BUFFERS=16 libcamerify motion -c ~/motion.conf -n -d 6

I consistently get:

ERROR V4L2 v4l2_videodevice.cpp:1328 /dev/videoX[cap]: Not enough buffers provided by V4L2VideoDevice
open_context: Norm:Unable to open camera():Cannot allocate memory

And logs confirm:

configuring streams: (0) 960x544-YUV420
Sensor: ... Selected sensor format: 1920x1080-SGBRG10_1X10

So even though I’m asking for ~960×540 output, the sensor is always running in 1080p mode, so the DMA ring wants enough buffers for full 1080p RAW frames, then downscales.

Is there any official or recommended way to tune the buffer_count when using libcamerify?

Or should I always prefer libcamera-vid → v4l2loopback when I need to lock sensor resolution and keep the buffer pool small?

Is there a libcamerify env var or option I’m missing?

Are there known best practices for getting around the fact that the sensor mode doesn’t shrink when you downscale?

Thanks

[axeljerabek]

I also run rpicam-vid on a Zero 2W, but not motion itself. My stream runs 1920x1080 with only 4 buffers. Motion is on a different server and i stream from the Pi zero 2W to this server. I have a setup of this somewhere with my rpicam-vid scripts in detail:
https://www.wetransco.de/
Maybe you find some help there.

[sobchek]

Thanks.

I had not considered this approach, as this is a gift for a bird-watcher - was hoping it could be all-in-one. Even if I get it running on the Pi Zero, its not going to be stable.

I will try this approach. The server needs to run on a PC, so I'll try https://www.ispyconnect.com and see how it goes.

[sobchek]

Wanted to thank you for the link to your project. Setting up the cam and feed is simple enough, but using your config made the stream much more stable. Appreciate it.

[JChristensen]

Looks like there might be other issues going on there, permissions, etc.?
Using Zero 2W here with Raspberry Pi Camera v2 and Motion 5.0.0-git-20250515-462b701 built from source, bookworm, no libcamerify. Works well at 1600x1200, 4fps. 15-minute CPU load average does not get much over 1.00, so with four processors, the machine is not working too hard. Available memory is ~200MB.

$ free -h
               total        used        free      shared  buff/cache   available
Mem:           416Mi       208Mi       123Mi        24Ki       138Mi       207Mi
Swap:          511Mi        57Mi       454Mi

[sobchek]

Might be the camera module. Could only get this far using libcamerify and the split conf files. @axeljerabek suggestion of offloading the hard work to server is working out well.

Dropped motion from the Pi and just running RTSP stream. 1080@15fps has been stable thus far, and I can get all the features I was looking for with DVR Agent.