video0: Invalid argument

(http://stream-recorder.com/forum/showthread.php?t=6516)

zmu -d /dev/video0 -q -v: Error, failed to query crop /dev/video0: Invalid argument

When I launch

Code:

zmu -d /dev/video0 -q -v

I get the following error:

Code:

Error, failed to query crop /dev/video0: Invalid argument

I've tried to chmod 777 my web cam:

Code:

sudo chmod 777 /dev/video0

but the I was getting the same error.

However

Code:

zmu -d /dev/video0 -V 1 -q -v

is working fine in Ubuntu 10.04 Lucid:

Code:

Video Device: /dev/video0

Video Capabilities

  Name: Slim 1322 AF

  Type: 1

    Can capture

  Video Channels: 1

  Audio Channels: 0

  Maximum Width: 1280

  Maximum Height: 1024

  Minimum Width: 48

  Minimum Height: 32

Window Attributes

  X Offset: 0

  Y Offset: 0

  Width: 640

  Height: 480

Picture Attributes

  Palette: 8 - YUYV

  Colour Depth: 16

  Brightness: 21959

  Hue: 32768

  Colour :44127

  Contrast: 0

  Whiteness: 0

Channel 0 Attributes

  Name: Camera 1

  Channel: 0

  Flags: 0

  Type: 2 - Camera

  Format: 0 - PAL

Re: zmu -d /dev/video0 -q -v: Error, failed to query crop /dev/video0: Invalid argume

A USB camera that doesn't support cropping will produce an error message

Code:

Error, failed to query crop: /dev/video0: Invalid argument

from

Code:

zmu -d /dev/video0 -q -v

Fix for the problem:

Quote:

Originally Posted by [FIX] ZM 1.24.2: Error, failed to query crop

Failures are exhibited in zmu, and other places that rely on LocalCamera::GetCurrentSettings.

The fault is in LocalCamera::GetCurrentSettings.

The error arises from the fact that ioctl VIDIOC_G_CROP returns -1 and errno = EINVAL to indicate that cropping is not supported. LocalCamera::GetCurrentSettings treats any negative rc from ioctl VIDIOC_G_CROP as grounds for abnormal termination.

The fix is straightforward and short. All changes are in zm_local_camera.cpp as follows:

Code:

911,912c911 

<        int crop_rc = vidioctl( vid_fd, VIDIOC_G_CROP, &crop ); 

<             if ((crop_rc  < 0 ) && (errno != EINVAL)) 

--- 

>             if ( vidioctl( vid_fd, VIDIOC_G_CROP, &crop ) < 0 ) 

921,928c920,921 

<             if ( verbose ) { 

<       if (crop_rc >= 0) { 

<                    sprintf( output+strlen(output), "  Current: %d x %d\n", crop.c.width, crop.c.height ); 

<       } 

<       else { 

<          sprintf( output+strlen(output), "  Current: Cropping is not supported\n"); 

<       } 

<        } 

--- 

>             if ( verbose ) 

>                 sprintf( output+strlen(output), "  Current: %d x %d\n", crop.c.width, crop.c.height );