Motion with Logitech cam works for the first time, the second always fails

Question

If I run Motion with Logitech cam for the first time - it works fine. If I kill Motion, wait 5 sec and start it again - it begins to fail in a loop. To make it working again I need to to either:

* disconnect and reconnect the camera, or

* run vlc

There is something that vlc can do with the camera that Motion can't do. Also, I noticed, mplayer fails as well as Motion until you fix it by disconnecting or running vlc

See Verbatim text for full log details

Full log is available here: http://pastebin.com/9dmfJ6fE

1. Start Motion for the first time - it's OK
2. Kill it and start again - it fails:

1] VIDIOC_TRY_FMT failed for format YUYV:
[1] Unable to find a compatible palette format.
[1] ioctl(VIDIOCGMBUF) - Error device does not support memory map
[1] V4L capturing using read is deprecated!
[1] Motion only supports mmap.
[1] Could not fetch initial image from camera
[1] Motion continues using width and height from config file(s)
[1] Resizing pre_capture buffer to 1 items

3. run vlc:

vlc v4l2:///dev/video1

4. now try Motion - it works again

So why Motion fails for the second time? And what vlc can do with the camera so it works again?

Reproducible: always with Logitech cameras 046d:08c1 and 046d:0991
Not reproducible with HP laptop integrated webcamera 5986:0137


Thanks

UPDATE. Latest trunk version on ARM device behaves same way with the same camera:

[1] [NTC] [VID] v4l2_get_capability:
------------------------
cap.driver: "uvcvideo"
cap.card: "UVC Camera (046d:080a)"
cap.bus_info: "usb-fsl-ehci.0-1.4"
cap.capabilities=0x04000001
------------------------
[1] [NTC] [VID] v4l2_get_capability: - VIDEO_CAPTURE
[1] [NTC] [VID] v4l2_get_capability: - STREAMING
[1] [NTC] [VID] v4l2_select_input: name = "Camera 1", type 0x00000002, status 00000000
[1] [NTC] [VID] v4l2_select_input: - CAMERA
[1] [WRN] [VID] v4l2_select_input: Device doesn't support VIDIOC_G_STD
[0] [NTC] [STR] httpd_run: motion-httpd testing : IPV4 addr: 127.0.0.1 port: 8080
[0] [NTC] [STR] httpd_run: motion-httpd Bound : IPV4 addr: 127.0.0.1 port: 8080
[0] [NTC] [STR] httpd_run: motion-httpd/Git-8619d7c17ce112e7196975905c6e840f345141ba running, accepting connections
[0] [NTC] [STR] httpd_run: motion-httpd: waiting for data on 127.0.0.1 port TCP 8080
[1] [NTC] [VID] v4l2_set_pix_format: Config palette index 8 (MJPG) doesn't work.
[1] [NTC] [VID] v4l2_set_pix_format: Supported palettes:
[1] [NTC] [VID] v4l2_set_pix_format: (0) YUYV (YUV 4:2:2 (YUYV))
[1] [NTC] [VID] v4l2_set_pix_format: 0 - YUV 4:2:2 (YUYV) (compressed : 0) (0x56595559)
[1] [NTC] [VID] v4l2_set_pix_format: (1) MJPG (MJPEG)
[1] [NTC] [VID] v4l2_set_pix_format: 1 - MJPEG (compressed : 1) (0x47504a4d)
[1] [NTC] [VID] v4l2_set_pix_format Selected palette YUYV
[1] [ERR] [VID] VIDIOC_TRY_FMT failed for format v4l2_set_pix_format:
[1] [ERR] [VID] v4l2_set_pix_format: Unable to find a compatible palette format.
[1] [NTC] [VID] vid_v4lx_start: Using V4L1
[1] [NTC] [ALL] image_ring_resize: Resizing pre_capture buffer to 1 items
[1] [ERR] [ALL] motion_init: Error capturing first image
[1] [NTC] [STR] http_bindsock: motion-stream testing : IPV4 addr: 0.0.0.0 port: 8081
[1] [NTC] [STR] http_bindsock: motion-stream Bound : IPV4 addr: 0.0.0.0 port: 8081
[1] [NTC] [ALL] motion_init: Started motion-stream server in port 8081 auth Disabled
[1] [ERR] [ALL] motion_loop: Video device fatal error - Closing video device

Workaround

As for now I'm using a workaround:

1. stop motion
2. run script: su - linaro -c "cvlc -I dummy v4l2:///dev/video0 --run-time=1 vlc://quit -vvv"
3. start motion

Environment

Motion version:	3.2.12
ffmpeg version:	SVN "motion compatible"
Libraries:	ffmpeg, v4l, v4l2
Server OS:	openSUSE 11.4 32bit kernel 2.6.37.6-0.11-desktop

-- TosiaraT - 28 Jan 2012

Answer