Re: About white balance control.
Hi Bill, Thank you for your explanation. I think this one-shot white balance cal feature should be supported by H/W, or we should implement this with AWB activation for short period and lock immediately. That should be hard to tune properly to make it work in every circumstances. I'll do some research on it to make it work properly with my mobile camera module devices. Any technical advise appreciated. Cheers, Nate 2009/3/20 Bill Dirks b...@thedirks.org: DO_WHITE_BALANCE is intended to do a one-shot white balance calibration and then hold it. So you would hold up, for example, a white piece of paper in front of the camera and click the do white balance. Then the white balance should be correct as long as the lighting doesn't change. This can work better than auto white balance which can be fooled by colored walls, etc. Some video cameras used to have a button like this. Bill. Dongsoo, Nathaniel Kim wrote: Thank you Pingchart. So, V4L2_CID_DO_WHITE_BALANCE acts WB adjustment at every single time it has issued when device is in manual WB mode like V4L2_CID_WHITE_BALANCE_TEMPERATURE? Now I get it. But CID still missing for white balance presets like cloudy, sunny, fluorescentand so on. I think some sort of menu type CID could be useful to handle them, because WB presets differ for each devices. Cheers, Nate 2009/3/18 Laurent Pinchart laurent.pinch...@skynet.be: Hi Kim, On Wednesday 18 March 2009 05:32:08 Dongsoo, Nathaniel Kim wrote: Hello, I accidently realized today that I was using white balance control in wrong way. As far as I understand we've got V4L2_CID_AUTO_WHITE_BALANCE which activate auto white balance adjustment in runtime, V4L2_CID_DO_WHITE_BALANCE_TEMPERATURE specifying absolute kelvin value I suppose you mean V4L2_CID_WHITE_BALANCE_TEMPERATURE here. but can't get what V4L2_CID_DO_WHITE_BALANCE is for. I think after issuing V4L2_CID_AUTO_WHITE_BALANCE and V4L2_CID_WHITE_BALANCE_TEMPERATURE, the white balance functionality works immediately. Isn't it right? What exactly is the button type V4L2_CID_DO_WHITE_BALANCE for? Because the V4L2 API document says that (the value is ignored). Does that mean that even we have issued V4L2_CID_AUTO_WHITE_BALANCE and V4L2_CID_WHITE_BALANCE_TEMPERATURE, we can't see the white balance working at that moment? V4L2_CID_AUTO_WHITE_BALANCE to enables or disables automatic white balance adjustment. When automatic white balance is enabled the device adjusts the white balance continuously. V4L2_CID_WHITE_BALANCE_TEMPERATURE controls the white balance adjustment manually. The control is only effective when automatic white balance is disabled. V4L2_CID_DO_WHITE_BALANCE instructs the device to run the automatic white balance adjustment algorithm once and use the results for white balance correction. It only makes sense when automatic white balance is disabled. And one more thing. If I want to serve several white balance presets, like cloudy, dawn, sunny and so on, what should I do? I think it should be supported as menu type, but most of drivers are using white balance CID with integer type...then what should I do? Define preset names with kelvin number like this? #define WB_CLOUDY 8000 Pretty confusing... anyone knows what should I do? Best regards, Laurent Pinchart -- DongSoo, Nathaniel Kim Engineer Mobile S/W Platform Lab. Digital Media Communications RD Centre Samsung Electronics CO., LTD. e-mail : dongsoo@gmail.com dongsoo45@samsung.com -- To unsubscribe from this list: send the line unsubscribe linux-media in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: About white balance control.
Hi Kim, On Wed, 2009-03-18 at 13:32 +0900, Dongsoo, Nathaniel Kim wrote: Hello, I accidently realized today that I was using white balance control in wrong way. As far as I understand we've got V4L2_CID_AUTO_WHITE_BALANCE which activate auto white balance adjustment in runtime, V4L2_CID_DO_WHITE_BALANCE_TEMPERATURE specifying absolute kelvin value but can't get what V4L2_CID_DO_WHITE_BALANCE is for. My understanding is that V4L2_CID_DO_WHITE_BALANCE enable/disable white balance processing, while with V4L2_CID_DO_WHITE_BALANCE_TEMPERATURE you can specify explicitly ambient temperature. I think after issuing V4L2_CID_AUTO_WHITE_BALANCE and V4L2_CID_WHITE_BALANCE_TEMPERATURE, the white balance functionality works immediately. Isn't it right? What exactly is the button type V4L2_CID_DO_WHITE_BALANCE for? Because the V4L2 API document says that (the value is ignored). Does that mean that even we have issued V4L2_CID_AUTO_WHITE_BALANCE and V4L2_CID_WHITE_BALANCE_TEMPERATURE, we can't see the white balance working at that moment? And one more thing. If I want to serve several white balance presets, like cloudy, dawn, sunny and so on, what should I do? I think it should be supported as menu type, but most of drivers are using white balance CID with integer type...then what should I do? Define preset names with kelvin number like this? I also will like to see controls which specify different kind of white balance mode (cloudy, sunny, tungsten...). in this case we can thing about V4L2_CID_WHITE_BALANCE_TEMPERATURE as 'manual' mode, and let other modes to be handled by some clever algorithms ;). IIvanov #define WB_CLOUDY 8000 Pretty confusing... anyone knows what should I do? Nate -- To unsubscribe from this list: send the line unsubscribe linux-media in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line unsubscribe linux-media in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: About white balance control.
Hi Ivan, 2009/3/18 Ivan T. Ivanov iiva...@mm-sol.com: Hi Kim, On Wed, 2009-03-18 at 13:32 +0900, Dongsoo, Nathaniel Kim wrote: Hello, I accidently realized today that I was using white balance control in wrong way. As far as I understand we've got V4L2_CID_AUTO_WHITE_BALANCE which activate auto white balance adjustment in runtime, V4L2_CID_DO_WHITE_BALANCE_TEMPERATURE specifying absolute kelvin value but can't get what V4L2_CID_DO_WHITE_BALANCE is for. My understanding is that V4L2_CID_DO_WHITE_BALANCE enable/disable white balance processing, while with V4L2_CID_DO_WHITE_BALANCE_TEMPERATURE you can specify explicitly ambient temperature. OK, then according to your explanation DO_WHITE_BALANCE is only for AUTO_WHITE_BALANCE. Am I following? Because only auto white balance mode does processing and make changes in color temperature while preview is working. I think after issuing V4L2_CID_AUTO_WHITE_BALANCE and V4L2_CID_WHITE_BALANCE_TEMPERATURE, the white balance functionality works immediately. Isn't it right? What exactly is the button type V4L2_CID_DO_WHITE_BALANCE for? Because the V4L2 API document says that (the value is ignored). Does that mean that even we have issued V4L2_CID_AUTO_WHITE_BALANCE and V4L2_CID_WHITE_BALANCE_TEMPERATURE, we can't see the white balance working at that moment? And one more thing. If I want to serve several white balance presets, like cloudy, dawn, sunny and so on, what should I do? I think it should be supported as menu type, but most of drivers are using white balance CID with integer type...then what should I do? Define preset names with kelvin number like this? I also will like to see controls which specify different kind of white balance mode (cloudy, sunny, tungsten...). in this case we can thing about V4L2_CID_WHITE_BALANCE_TEMPERATURE as 'manual' mode, and let other modes to be handled by some clever algorithms ;). If there isn't any driver which is driving white balance with menu type, there should be some reason for that. I want to make it clear if I could. I hope Hans or other maintainer could answer this. Cheers, Nate IIvanov #define WB_CLOUDY 8000 Pretty confusing... anyone knows what should I do? Nate -- To unsubscribe from this list: send the line unsubscribe linux-media in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html -- DongSoo, Nathaniel Kim Engineer Mobile S/W Platform Lab. Digital Media Communications RD Centre Samsung Electronics CO., LTD. e-mail : dongsoo@gmail.com dongsoo45@samsung.com -- To unsubscribe from this list: send the line unsubscribe linux-media in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: About white balance control.
Thank you Pingchart. So, V4L2_CID_DO_WHITE_BALANCE acts WB adjustment at every single time it has issued when device is in manual WB mode like V4L2_CID_WHITE_BALANCE_TEMPERATURE? Now I get it. But CID still missing for white balance presets like cloudy, sunny, fluorescentand so on. I think some sort of menu type CID could be useful to handle them, because WB presets differ for each devices. Cheers, Nate 2009/3/18 Laurent Pinchart laurent.pinch...@skynet.be: Hi Kim, On Wednesday 18 March 2009 05:32:08 Dongsoo, Nathaniel Kim wrote: Hello, I accidently realized today that I was using white balance control in wrong way. As far as I understand we've got V4L2_CID_AUTO_WHITE_BALANCE which activate auto white balance adjustment in runtime, V4L2_CID_DO_WHITE_BALANCE_TEMPERATURE specifying absolute kelvin value I suppose you mean V4L2_CID_WHITE_BALANCE_TEMPERATURE here. but can't get what V4L2_CID_DO_WHITE_BALANCE is for. I think after issuing V4L2_CID_AUTO_WHITE_BALANCE and V4L2_CID_WHITE_BALANCE_TEMPERATURE, the white balance functionality works immediately. Isn't it right? What exactly is the button type V4L2_CID_DO_WHITE_BALANCE for? Because the V4L2 API document says that (the value is ignored). Does that mean that even we have issued V4L2_CID_AUTO_WHITE_BALANCE and V4L2_CID_WHITE_BALANCE_TEMPERATURE, we can't see the white balance working at that moment? V4L2_CID_AUTO_WHITE_BALANCE to enables or disables automatic white balance adjustment. When automatic white balance is enabled the device adjusts the white balance continuously. V4L2_CID_WHITE_BALANCE_TEMPERATURE controls the white balance adjustment manually. The control is only effective when automatic white balance is disabled. V4L2_CID_DO_WHITE_BALANCE instructs the device to run the automatic white balance adjustment algorithm once and use the results for white balance correction. It only makes sense when automatic white balance is disabled. And one more thing. If I want to serve several white balance presets, like cloudy, dawn, sunny and so on, what should I do? I think it should be supported as menu type, but most of drivers are using white balance CID with integer type...then what should I do? Define preset names with kelvin number like this? #define WB_CLOUDY 8000 Pretty confusing... anyone knows what should I do? Best regards, Laurent Pinchart -- DongSoo, Nathaniel Kim Engineer Mobile S/W Platform Lab. Digital Media Communications RD Centre Samsung Electronics CO., LTD. e-mail : dongsoo@gmail.com dongsoo45@samsung.com -- To unsubscribe from this list: send the line unsubscribe linux-media in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
