Re: Question about BTTV-video controls whitecrush upper/lower
Andy Walls schrieb: On Tue, 2010-07-06 at 13:27 +0200, Frank Schaefer wrote: Hi, there are two video controls in the Bttv-driver called whitecrush upper and whitecrush lower. But what does whitecrush mean ? Is it the same as white noise ? The german KDE translators are currently trying to translate these strings... White Crush is Conexant's term for adapting to nonstandard or varying Sync to White level voltage differences of the incoming video signal. It's basically an adaptive AGC to prevent blooming of the video signal due to very high Luminance levels. The public BT878A datasheet has terse descriptions of what the registers settings do: they are basically upper and lower thresholds to determine when to adapt the automatic gain control. The public CX25840 datasheet gives a better written description of white crush in section 3.4.9: http://dl.ivtvdriver.org/datasheets/video/cx25840.pdf I'm actually surprised the bttv driver has those presented as user controls at all. Regards, Andy Thank you Andy, that really helps a lot ! Regards, Frank -- 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: Question about BTTV-video controls whitecrush upper/lower
On Tue, 2010-07-06 at 13:27 +0200, Frank Schaefer wrote: Hi, there are two video controls in the Bttv-driver called whitecrush upper and whitecrush lower. But what does whitecrush mean ? Is it the same as white noise ? The german KDE translators are currently trying to translate these strings... White Crush is Conexant's term for adapting to nonstandard or varying Sync to White level voltage differences of the incoming video signal. It's basically an adaptive AGC to prevent blooming of the video signal due to very high Luminance levels. The public BT878A datasheet has terse descriptions of what the registers settings do: they are basically upper and lower thresholds to determine when to adapt the automatic gain control. The public CX25840 datasheet gives a better written description of white crush in section 3.4.9: http://dl.ivtvdriver.org/datasheets/video/cx25840.pdf I'm actually surprised the bttv driver has those presented as user controls at all. Regards, Andy Thanks, Frank -- 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
Question about BTTV-video controls whitecrush upper/lower
Hi, there are two video controls in the Bttv-driver called whitecrush upper and whitecrush lower. But what does whitecrush mean ? Is it the same as white noise ? The german KDE translators are currently trying to translate these strings... Thanks, Frank -- 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
