61 lines
		
	
	
		
			2.0 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			61 lines
		
	
	
		
			2.0 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/*
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 * Pixart PAC207BCA / PAC73xx common functions
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 *
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 * Copyright (C) 2008 Hans de Goede <j.w.r.degoede@hhs.nl>
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 * Copyright (C) 2005 Thomas Kaiser thomas@kaiser-linux.li
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 * Copyleft (C) 2005 Michel Xhaard mxhaard@magic.fr
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 *
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 * V4L2 by Jean-Francois Moine <http://moinejf.free.fr>
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 *
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 * This program is free software; you can redistribute it and/or modify
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 * it under the terms of the GNU General Public License as published by
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 * the Free Software Foundation; either version 2 of the License, or
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 * (at your option) any later version.
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 *
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 * This program is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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 * GNU General Public License for more details.
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 *
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 * You should have received a copy of the GNU General Public License
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 * along with this program; if not, write to the Free Software
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 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
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 *
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 */
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/* We calculate the autogain at the end of the transfer of a frame, at this
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   moment a frame with the old settings is being transmitted, and a frame is
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   being captured with the old settings. So if we adjust the autogain we must
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   ignore atleast the 2 next frames for the new settings to come into effect
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   before doing any other adjustments */
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#define PAC_AUTOGAIN_IGNORE_FRAMES	3
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static const unsigned char pac_sof_marker[5] =
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		{ 0xff, 0xff, 0x00, 0xff, 0x96 };
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static unsigned char *pac_find_sof(struct gspca_dev *gspca_dev,
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					unsigned char *m, int len)
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{
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	struct sd *sd = (struct sd *) gspca_dev;
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	int i;
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	/* Search for the SOF marker (fixed part) in the header */
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	for (i = 0; i < len; i++) {
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		if (m[i] == pac_sof_marker[sd->sof_read]) {
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			sd->sof_read++;
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			if (sd->sof_read == sizeof(pac_sof_marker)) {
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				PDEBUG(D_FRAM,
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					"SOF found, bytes to analyze: %u."
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					" Frame starts at byte #%u",
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					len, i + 1);
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				sd->sof_read = 0;
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				return m + i + 1;
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			}
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		} else {
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			sd->sof_read = 0;
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		}
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	}
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	return NULL;
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}
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