# Webcam Logitech HD PRO C920 and Motion



## MsieurSVP (Jan 31, 2022)

Hello  from France !

Sorry for my english...

I own a Webcam Logitech HD PRO C920 for working with motion on FreeBSD 12.3.

But, when I launch motion, I got this error message :

*v4l2_mmap_set: Error querying buffer 0
VIDIOC_QUERYBUF: : Invalid argument*

You will find attached my motion.conf and the log.

Any Idea ?

Many Thanks !


----------



## sidetone (Feb 7, 2022)

Can you post out the text of those files on here?


----------



## MsieurSVP (Feb 7, 2022)

Hello !

motion.conf :

```
# Rename this distribution example file to motion.conf
#
# This config file was generated by motion 4.3.2
# Documentation:  /usr/local/share/doc/motion/motion_guide.html
#
# This file contains only the basic configuration options to get a
# system working.  There are many more options available.  Please
# consult the documentation for the complete list of all options.
#

############################################################
# System control configuration parameters
############################################################

# Start in daemon (background) mode and release terminal.
daemon off

# Start in Setup-Mode, daemon disabled.
setup_mode off

# File to store the process ID.
; pid_file value

# File to write logs messages into.  If not defined stderr and syslog is used.
; log_file value

# Level of log messages [1..9] (EMG, ALR, CRT, ERR, WRN, NTC, INF, DBG, ALL).
log_level 6

# Target directory for pictures, snapshots and movies
; target_dir value

# Video device (e.g. /dev/video0) to be used for capturing.
videodevice /dev/video0
v4l2_palette 15

# Parameters to control video device.  See motion_guide.html
; vid_control_params value

# The full URL of the network camera stream.
; netcam_url value


# Name of mmal camera (e.g. vc.ril.camera for pi camera).
; mmalcam_name value

# Camera control parameters (see raspivid/raspistill tool documentation)
; mmalcam_control_params value

############################################################
# Image Processing configuration parameters
############################################################

# Image width in pixels.
width 320

# Image height in pixels.
height 240

# Maximum number of frames to be captured per second.
framerate 15

# Text to be overlayed in the lower left corner of images
text_left CAMERA1

# Text to be overlayed in the lower right corner of images.
text_right %Y-%m-%d\n%T-%q

############################################################
# Motion detection configuration parameters
############################################################

# Always save pictures and movies even if there was no motion.
emulate_motion off

# Threshold for number of changed pixels that triggers motion.
threshold 1500

# Noise threshold for the motion detection.
; noise_level 32

# Despeckle the image using (E/e)rode or (D/d)ilate or (l)abel.
despeckle_filter EedDl

# Number of images that must contain motion to trigger an event.
minimum_motion_frames 1

# Gap in seconds of no motion detected that triggers the end of an event.
event_gap 60

# The number of pre-captured (buffered) pictures from before motion.
pre_capture 3

# Number of frames to capture after motion is no longer detected.
post_capture 0

############################################################
# Script execution configuration parameters
############################################################

# Command to be executed when an event starts.
; on_event_start value

# Command to be executed when an event ends.
; on_event_end value

# Command to be executed when a movie file is closed.
; on_movie_end value

############################################################
# Picture output configuration parameters
############################################################

# Output pictures when motion is detected
picture_output off

# File name(without extension) for pictures relative to target directory
picture_filename %Y%m%d%H%M%S-%q

############################################################
# Movie output configuration parameters
############################################################

# Create movies of motion events.
movie_output on

# Maximum length of movie in seconds.
movie_max_time 60

# The encoding quality of the movie. (0=use bitrate. 1=worst quality, 100=best)
movie_quality 45

# Container/Codec to used for the movie. See motion_guide.html
movie_codec mkv

# File name(without extension) for movies relative to target directory
movie_filename %t-%v-%Y%m%d%H%M%S

############################################################
# Webcontrol configuration parameters
############################################################

# Port number used for the webcontrol.
webcontrol_port 8082

# Restrict webcontrol connections to the localhost.
webcontrol_localhost on

# Type of configuration options to allow via the webcontrol.
webcontrol_parms 0

############################################################
# Live stream configuration parameters
############################################################

# The port number for the live stream.
stream_port 8081

# Restrict stream connections to the localhost.
stream_localhost on

##############################################################
# Camera config files - One for each camera.
##############################################################
; camera /usr/local/etc/motion/camera1.conf
; camera /usr/local/etc/motion/camera2.conf
; camera /usr/local/etc/motion/camera3.conf
; camera /usr/local/etc/motion/camera4.conf

##############################################################
# Directory to read '.conf' files for cameras.
##############################################################
; camera_dir /usr/local/etc/motion/conf.d
```

log-motion.txt :

```
[0:Unknown] [NTC] [ALL] conf_load: Processing thread 0 - config file /usr/local/etc/motion/motion.conf
[0:Unknown] [NTC] [ALL] motion_startup: Logging to syslog
[0:Unknown] [NTC] [ALL] motion_startup: Motion 4.3.2 Started
[0:Unknown] [NTC] [ALL] motion_startup: Using default log type (ALL)
[0:Unknown] [NTC] [ALL] motion_startup: Using log type (ALL) log level (NTC)
[0:Unknown] [NTC] [STR] webu_start_strm: Starting all camera streams on port 8081
[0:Unknown] [NTC] [STR] webu_strm_ntc: Started camera 0 stream on port 8081
[0:Unknown] [NTC] [STR] webu_start_ctrl: Starting webcontrol on port 8082
[0:Unknown] [NTC] [STR] webu_start_ctrl: Started webcontrol on port 8082
[0:Unknown] [NTC] [ENC] ffmpeg_global_init: ffmpeg libavcodec version 58.134.100 libavformat version 58.76.100
[0:Unknown] [NTC] [ALL] translate_init: Language: English
[0:Unknown] [NTC] [ALL] motion_start_thread: Camera ID: 0 is from /usr/local/etc/motion/motion.conf
[0:Unknown] [NTC] [ALL] motion_start_thread: Camera ID: 0 Camera Name: (null) Device: /dev/video0
[0:Unknown] [NTC] [ALL] main: Waiting for threads to finish, pid: 48682
[1:Unknown] [NTC] [ALL] motion_init: Camera 0 started: motion detection Enabled
[1:Unknown] [NTC] [VID] vid_start: Opening V4L2 device
[1:Unknown] [NTC] [VID] v4l2_device_open: Using videodevice /dev/video0 and input -1
[1:Unknown] [NTC] [VID] v4l2_device_capability: - VIDEO_CAPTURE
[1:Unknown] [NTC] [VID] v4l2_device_capability: - STREAMING
[1:Unknown] [NTC] [VID] v4l2_input_select: Name = "Camera 1"- CAMERA
[1:Unknown] [NTC] [VID] v4l2_norm_select: Device does not support specifying PAL/NTSC norm
[1:Unknown] [NTC] [VID] v4l2_pixfmt_set: Testing palette YUYV (320x240)
[1:Unknown] [NTC] [VID] v4l2_pixfmt_set: Using palette YUYV (320x240)
[1:Unknown] [ERR] [VID] v4l2_mmap_set: Error querying buffer 0
VIDIOC_QUERYBUF: : Invalid argument
[1:Unknown] [ERR] [VID] vid_start: V4L2 device failed to open
[1:Unknown] [WRN] [ALL] motion_init: Could not fetch initial image from camera
[1:Unknown] [WRN] [ALL] motion_init: Motion continues using width and height from config file(s)
[1:Unknown] [NTC] [ALL] image_ring_resize: Resizing pre_capture buffer to 1 items
[1:Unknown] [NTC] [ALL] image_ring_resize: Resizing pre_capture buffer to 4 items
[1:Unknown] [WRN] [ALL] mlp_retry: Retrying until successful connection with camera
[1:Unknown] [NTC] [VID] vid_start: Opening V4L2 device
[1:Unknown] [NTC] [VID] v4l2_device_open: Using videodevice /dev/video0 and input -1
[1:Unknown] [NTC] [VID] v4l2_device_capability: - VIDEO_CAPTURE
[1:Unknown] [NTC] [VID] v4l2_device_capability: - STREAMING
[1:Unknown] [NTC] [VID] v4l2_input_select: Name = "Camera 1"- CAMERA
[1:Unknown] [NTC] [VID] v4l2_norm_select: Device does not support specifying PAL/NTSC norm
[1:Unknown] [NTC] [VID] v4l2_pixfmt_set: Testing palette YUYV (320x240)
[1:Unknown] [NTC] [VID] v4l2_pixfmt_set: Using palette YUYV (320x240)
[1:Unknown] [ERR] [VID] v4l2_mmap_set: Error querying buffer 0
VIDIOC_QUERYBUF: : Invalid argument
[1:Unknown] [ERR] [VID] vid_start: V4L2 device failed to open
[1:Unknown] [NTC] [ALL] motion_loop: Thread exiting
^C[0:Unknown] [NTC] [ALL] main: Threads finished
[0:Unknown] [NTC] [ALL] main: Motion terminating
```


----------

