Hi Moreno, On Sunday 22 June 2008, Moreno Marzolla wrote: > Hi all, > > I recently bought a Creative Live! Cam Optia (the cheap, non-PRO, non-AF > version) with USB id 041e:4057. I'm trying to get the camera to work > with linux to capture outdoor images. > I succesfully compiled the uvcvideo module (r217) both on Ubuntu 6.06LTS > (AMD64 flavour) and under debian 4.0 (i686) without any trouble. > luvcview-20070512 also works great on both platforms. The camera is > recognized and I'm able to get the video with luvcview. > However, while the quality of indoor pictures is in my opinion very > good, even in dark environments, outdoor pictures are severely > overexposed and so far I have been unable to get around that. > I'm currently working on the debian machine (debian kernel 2.6.18-6-686, > uvcvideo r217). Just to have an idea, this is what I get with the > default settings of the Live! Cam Optia at 640x480: > > http://www.dsi.unive.it/~marzolla/snapshot_optia.jpg > > This is the same panorama taken with my digital photo camera: > > http://www.dsi.unive.it/~marzolla/snapshot_ok.jpg > > Of course I tried to tweak the picture parameters with luvcview, but > changing contrast and luminosity does not help, and I'm unable to set > manual exposure (luvcview says "Set Auto Exposure off error"). > unsure whether exposure can be controlled at all with this webcam, > because if I do: > > [EMAIL PROTECTED]:~/src/linux-uvc$ v4lctl -c /dev/video0 list > ioctl: VIDIOC_G_STD(std=0xb7ce44c0b7c1d9ef > [PAL_B,PAL_B1,PAL_G,PAL_H,PAL_D,PAL_D1,PAL_K,PAL_M,PAL_60,NTSC_M,?,?,SECAM_ >B,SECAM_L,?ATSC_8_VSB,ATSC_16_VSB,(null),(null),(null),(null),(null),(null), >(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null) >,(null),(null),(null)]): Invalid argument > attribute | type | current | default | comment > -----------+--------+---------+---------+---------------------------------- >--- norm | choice | (null) | (null) | > input | choice | Camera | Camera | Camera 1 > bright | int | 30 | 30 | range is 0 => 100 > contrast | int | 2 | 2 | range is 0 => 6 > color | int | 3 | 3 | range is 0 => 8 > hue | int | 0 | 0 | range is -4 => 4 > Gamma | int | 3 | 3 | range is 0 => 7 > Power Line | choice | 50 Hz | Disable | Disabled 50 Hz 60 Hz > Sharpness | int | 39 | 40 | range is 0 => 96 > > I see no mention of exposure. The same happens even using luvcview: > > [EMAIL PROTECTED]:~/src/luvcview-20070512$ ./luvcview -d /dev/video0 -l > luvcview version 0.2.1 > Video driver: x11 > A window manager is available > video /dev/video0 > Available controls of device 'Camera 1' (Type 1=Integer 2=Boolean 3=Menu > 4=Button) > V4L2_CID_BASE (predefined controls): > index:9963776 name:Brightness type:1 min:0 > max:100 step:1 def:30 now:30 > index:9963777 name:Contrast type:1 min:0 > max:6 step:1 def:2 now:2 > index:9963778 name:Saturation type:1 min:0 > max:8 step:1 def:3 now:3 > index:9963779 name:Hue type:1 min:-4 > max:4 step:1 def:0 now:0 > index:9963792 name:Gamma type:1 min:0 > max:7 step:1 def:3 now:3 > V4L2_CID_PRIVATE_BASE (driver specific controls): > find DRI > find DRI > find DRI > > Before going into deeper details, I would like to ask whether anybody > has been able to get good outdoor pictures with the Creative Live! Cam > Optia, and/or whether anybody has been able to manually set the exposure > with the same camera.
I haven't tried the Creative Live! Cam Optia outdoor, but exposure time is definitely the way to go. In theory any v4l2 application should be able to set the exposure-related controls. In practise very few of them can, because the involved API has evolved quite a lot lately. Please install uvcdynctrl (part of the libwebcam package) from http://www.quickcamteam.net/software/libwebcam/. Get the SVN version, as the latest released package is outdated. You should then be able to use that command line tool to set the exposure mode and exposure time controls. Best regards, Laurent Pinchart _______________________________________________ Linux-uvc-devel mailing list [email protected] https://lists.berlios.de/mailman/listinfo/linux-uvc-devel
