v4l2_libs/libv4lconvert/bayer.c

/*
 * lib4lconvert, video4linux2 format conversion lib
 *             (C) 2008 Hans de Goede <hdegoede@redhat.com>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License, version 2.1, as published by the Free Software Foundation.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA  02110-1335  USA
 *
 * Note: original bayer_to_bgr24 code from :
 * 1394-Based Digital Camera Control Library
 *
 * Bayer pattern decoding functions
 *
 * Written by Damien Douxchamps and Frederic Devernay
 *
 * Note that the original bayer.c in libdc1394 supports many different
 * bayer decode algorithms, for lib4lconvert the one in this file has been
 * chosen (and optimized a bit) and the other algorithms have been removed,
 * see bayer.c from libdc1394 for all supported algorithms
 */

#include <string.h>
#include "libv4lconvert-priv.h"

/**************************************************************
 *     Color conversion functions for cameras that can        *
 * output raw-Bayer pattern images, such as some Basler and   *
 * Point Grey camera. Most of the algos presented here come   *
 * from http://www-ise.stanford.edu/~tingchen/ and have been  *
 * converted from Matlab to C and extended to all elementary  *
 * patterns.                                                  *
 **************************************************************/

/* inspired by OpenCV's Bayer decoding */
static void v4lconvert_border_bayer_line_to_bgr24(
		const unsigned char *bayer, const unsigned char *adjacent_bayer,
		unsigned char *bgr, int width, const int start_with_green, const int blue_line)
{
	int t0, t1;

	if (start_with_green) {
		/* First pixel */
		if (blue_line) {
			*bgr++ = bayer[1];
			*bgr++ = bayer[0];
			*bgr++ = adjacent_bayer[0];
		} else {
			*bgr++ = adjacent_bayer[0];
			*bgr++ = bayer[0];
			*bgr++ = bayer[1];
		}
		/* Second pixel */
		t0 = (bayer[0] + bayer[2] + adjacent_bayer[1] + 1) / 3;
		t1 = (adjacent_bayer[0] + adjacent_bayer[2] + 1) >> 1;
		if (blue_line) {
			*bgr++ = bayer[1];
			*bgr++ = t0;
			*bgr++ = t1;
		} else {
			*bgr++ = t1;
			*bgr++ = t0;
			*bgr++ = bayer[1];
		}
		bayer++;
		adjacent_bayer++;
		width -= 2;
	} else {
		/* First pixel */
		t0 = (bayer[1] + adjacent_bayer[0] + 1) >> 1;
		if (blue_line) {
			*bgr++ = bayer[0];
			*bgr++ = t0;
			*bgr++ = adjacent_bayer[1];
		} else {
			*bgr++ = adjacent_bayer[1];
			*bgr++ = t0;
			*bgr++ = bayer[0];
		}
		width--;
	}

	if (blue_line) {
		for ( ; width > 2; width -= 2) {
			t0 = (bayer[0] + bayer[2] + 1) >> 1;
			*bgr++ = t0;
			*bgr++ = bayer[1];
			*bgr++ = adjacent_bayer[1];
			bayer++;
			adjacent_bayer++;

			t0 = (bayer[0] + bayer[2] + adjacent_bayer[1] + 1) / 3;
			t1 = (adjacent_bayer[0] + adjacent_bayer[2] + 1) >> 1;
			*bgr++ = bayer[1];
			*bgr++ = t0;
			*bgr++ = t1;
			bayer++;
			adjacent_bayer++;
		}
	} else {
		for ( ; width > 2; width -= 2) {
			t0 = (bayer[0] + bayer[2] + 1) >> 1;
			*bgr++ = adjacent_bayer[1];
			*bgr++ = bayer[1];
			*bgr++ = t0;
			bayer++;
			adjacent_bayer++;

			t0 = (bayer[0] + bayer[2] + adjacent_bayer[1] + 1) / 3;
			t1 = (adjacent_bayer[0] + adjacent_bayer[2] + 1) >> 1;
			*bgr++ = t1;
			*bgr++ = t0;
			*bgr++ = bayer[1];
			bayer++;
			adjacent_bayer++;
		}
	}

	if (width == 2) {
		/* Second to last pixel */
		t0 = (bayer[0] + bayer[2] + 1) >> 1;
		if (blue_line) {
			*bgr++ = t0;
			*bgr++ = bayer[1];
			*bgr++ = adjacent_bayer[1];
		} else {
			*bgr++ = adjacent_bayer[1];
			*bgr++ = bayer[1];
			*bgr++ = t0;
		}
		/* Last pixel */
		t0 = (bayer[1] + adjacent_bayer[2] + 1) >> 1;
		if (blue_line) {
			*bgr++ = bayer[2];
			*bgr++ = t0;
			*bgr++ = adjacent_bayer[1];
		} else {
			*bgr++ = adjacent_bayer[1];
			*bgr++ = t0;
			*bgr++ = bayer[2];
		}
	} else {
		/* Last pixel */
		if (blue_line) {
			*bgr++ = bayer[0];
			*bgr++ = bayer[1];
			*bgr++ = adjacent_bayer[1];
		} else {
			*bgr++ = adjacent_bayer[1];
			*bgr++ = bayer[1];
			*bgr++ = bayer[0];
		}
	}
}

/* From libdc1394, which on turn was based on OpenCV's Bayer decoding */
static void bayer_to_rgbbgr24(const unsigned char *bayer,
		unsigned char *bgr, int width, int height, const unsigned int stride, unsigned int pixfmt,
		int start_with_green, int blue_line)
{
	/* render the first line */
	v4lconvert_border_bayer_line_to_bgr24(bayer, bayer + stride, bgr, width,
			start_with_green, blue_line);
	bgr += width * 3;

	/* reduce height by 2 because of the special case top/bottom line */
	for (height -= 2; height; height--) {
		int t0, t1;
		/* (width - 2) because of the border */
		const unsigned char *bayer_end = bayer + (width - 2);

		if (start_with_green) {

			t0 = (bayer[1] + bayer[stride * 2 + 1] + 1) >> 1;
			/* Write first pixel */
			t1 = (bayer[0] + bayer[stride * 2] + bayer[stride + 1] + 1) / 3;
			if (blue_line) {
				*bgr++ = t0;
				*bgr++ = t1;
				*bgr++ = bayer[stride];
			} else {
				*bgr++ = bayer[stride];
				*bgr++ = t1;
				*bgr++ = t0;
			}

			/* Write second pixel */
			t1 = (bayer[stride] + bayer[stride + 2] + 1) >> 1;
			if (blue_line) {
				*bgr++ = t0;
				*bgr++ = bayer[stride + 1];
				*bgr++ = t1;
			} else {
				*bgr++ = t1;
				*bgr++ = bayer[stride + 1];
				*bgr++ = t0;
			}
			bayer++;
		} else {
			/* Write first pixel */
			t0 = (bayer[0] + bayer[stride * 2] + 1) >> 1;
			if (blue_line) {
				*bgr++ = t0;
				*bgr++ = bayer[stride];
				*bgr++ = bayer[stride + 1];
			} else {
				*bgr++ = bayer[stride + 1];
				*bgr++ = bayer[stride];
				*bgr++ = t0;
			}
		}

		if (blue_line) {
			for (; bayer <= bayer_end - 2; bayer += 2) {
				t0 = (bayer[0] + bayer[2] + bayer[stride * 2] +
					bayer[stride * 2 + 2] + 2) >> 2;
				t1 = (bayer[1] + bayer[stride] + bayer[stride + 2] +
					bayer[stride * 2 + 1] + 2) >> 2;
				*bgr++ = t0;
				*bgr++ = t1;
				*bgr++ = bayer[stride + 1];

				t0 = (bayer[2] + bayer[stride * 2 + 2] + 1) >> 1;
				t1 = (bayer[stride + 1] + bayer[stride + 3] + 1) >> 1;
				*bgr++ = t0;
				*bgr++ = bayer[stride + 2];
				*bgr++ = t1;
			}
		} else {
			for (; bayer <= bayer_end - 2; bayer += 2) {
				t0 = (bayer[0] + bayer[2] + bayer[stride * 2] +
					bayer[stride * 2 + 2] + 2) >> 2;
				t1 = (bayer[1] + bayer[stride] + bayer[stride + 2] +
					bayer[stride * 2 + 1] + 2) >> 2;
				*bgr++ = bayer[stride + 1];
				*bgr++ = t1;
				*bgr++ = t0;

				t0 = (bayer[2] + bayer[stride * 2 + 2] + 1) >> 1;
				t1 = (bayer[stride + 1] + bayer[stride + 3] + 1) >> 1;
				*bgr++ = t1;
				*bgr++ = bayer[stride + 2];
				*bgr++ = t0;
			}
		}

		if (bayer < bayer_end) {
			/* write second to last pixel */
			t0 = (bayer[0] + bayer[2] + bayer[stride * 2] +
				bayer[stride * 2 + 2] + 2) >> 2;
			t1 = (bayer[1] + bayer[stride] + bayer[stride + 2] +
				bayer[stride * 2 + 1] + 2) >> 2;
			if (blue_line) {
				*bgr++ = t0;
				*bgr++ = t1;
				*bgr++ = bayer[stride + 1];
			} else {
				*bgr++ = bayer[stride + 1];
				*bgr++ = t1;
				*bgr++ = t0;
			}
			/* write last pixel */
			t0 = (bayer[2] + bayer[stride * 2 + 2] + 1) >> 1;
			if (blue_line) {
				*bgr++ = t0;
				*bgr++ = bayer[stride + 2];
				*bgr++ = bayer[stride + 1];
			} else {
				*bgr++ = bayer[stride + 1];
				*bgr++ = bayer[stride + 2];
				*bgr++ = t0;
			}

			bayer++;

		} else {
			/* write last pixel */
			t0 = (bayer[0] + bayer[stride * 2] + 1) >> 1;
			t1 = (bayer[1] + bayer[stride * 2 + 1] + bayer[stride] + 1) / 3;
			if (blue_line) {
				*bgr++ = t0;
				*bgr++ = t1;
				*bgr++ = bayer[stride + 1];
			} else {
				*bgr++ = bayer[stride + 1];
				*bgr++ = t1;
				*bgr++ = t0;
			}

		}

		/* skip 2 border pixels and padding */
		bayer += (stride - width) + 2;

		blue_line = !blue_line;
		start_with_green = !start_with_green;
	}

	/* render the last line */
	v4lconvert_border_bayer_line_to_bgr24(bayer + stride, bayer, bgr, width,
			!start_with_green, !blue_line);
}

void v4lconvert_bayer_to_rgb24(const unsigned char *bayer,
		unsigned char *bgr, int width, int height, const unsigned int stride, unsigned int pixfmt)
{
	bayer_to_rgbbgr24(bayer, bgr, width, height, stride, pixfmt,
			pixfmt == V4L2_PIX_FMT_SGBRG8		/* start with green */
			|| pixfmt == V4L2_PIX_FMT_SGRBG8,
			pixfmt != V4L2_PIX_FMT_SBGGR8		/* blue line */
			&& pixfmt != V4L2_PIX_FMT_SGBRG8);
}

void v4lconvert_bayer_to_bgr24(const unsigned char *bayer,
		unsigned char *bgr, int width, int height, const unsigned int stride, unsigned int pixfmt)
{
	bayer_to_rgbbgr24(bayer, bgr, width, height, stride, pixfmt,
			pixfmt == V4L2_PIX_FMT_SGBRG8		/* start with green */
			|| pixfmt == V4L2_PIX_FMT_SGRBG8,
			pixfmt == V4L2_PIX_FMT_SBGGR8		/* blue line */
			|| pixfmt == V4L2_PIX_FMT_SGBRG8);
}

static void v4lconvert_border_bayer_line_to_y(
		const unsigned char *bayer, const unsigned char *adjacent_bayer,
		unsigned char *y, int width, int start_with_green, int blue_line)
{
	int t0, t1;

	if (start_with_green) {
		/* First pixel */
		if (blue_line) {
			*y++ = (8453 * adjacent_bayer[0] + 16594 * bayer[0] +
					3223 * bayer[1] + 524288) >> 15;
		} else {
			*y++ = (8453 * bayer[1] + 16594 * bayer[0] +
					3223 * adjacent_bayer[0] + 524288) >> 15;
		}
		/* Second pixel */
		t0 = bayer[0] + bayer[2] + adjacent_bayer[1];
		t1 = adjacent_bayer[0] + adjacent_bayer[2];
		if (blue_line)
			*y++ = (4226 * t1 + 5531 * t0 + 3223 * bayer[1] + 524288) >> 15;
		else
			*y++ = (8453 * bayer[1] + 5531 * t0 + 1611 * t1 + 524288) >> 15;
		bayer++;
		adjacent_bayer++;
		width -= 2;
	} else {
		/* First pixel */
		t0 = bayer[1] + adjacent_bayer[0];
		if (blue_line) {
			*y++ = (8453 * adjacent_bayer[1] + 8297 * t0 +
					3223 * bayer[0] + 524288) >> 15;
		} else {
			*y++ = (8453 * bayer[0] + 8297 * t0 +
					3223 * adjacent_bayer[1] + 524288) >> 15;
		}
		width--;
	}

	if (blue_line) {
		for ( ; width > 2; width -= 2) {
			t0 = bayer[0] + bayer[2];
			*y++ = (8453 * adjacent_bayer[1] + 16594 * bayer[1] +
					1611 * t0 + 524288) >> 15;
			bayer++;
			adjacent_bayer++;

			t0 = bayer[0] + bayer[2] + adjacent_bayer[1];
			t1 = adjacent_bayer[0] + adjacent_bayer[2];
			*y++ = (4226 * t1 + 5531 * t0 + 3223 * bayer[1] + 524288) >> 15;
			bayer++;
			adjacent_bayer++;
		}
	} else {
		for ( ; width > 2; width -= 2) {
			t0 = bayer[0] + bayer[2];
			*y++ = (4226 * t0 + 16594 * bayer[1] +
					3223 * adjacent_bayer[1] + 524288) >> 15;
			bayer++;
			adjacent_bayer++;

			t0 = bayer[0] + bayer[2] + adjacent_bayer[1];
			t1 = adjacent_bayer[0] + adjacent_bayer[2];
			*y++ = (8453 * bayer[1] + 5531 * t0 + 1611 * t1 + 524288) >> 15;
			bayer++;
			adjacent_bayer++;
		}
	}

	if (width == 2) {
		/* Second to last pixel */
		t0 = bayer[0] + bayer[2];
		if (blue_line) {
			*y++ = (8453 * adjacent_bayer[1] + 16594 * bayer[1] +
					1611 * t0 + 524288) >> 15;
		} else {
			*y++ = (4226 * t0 + 16594 * bayer[1] +
					3223 * adjacent_bayer[1] + 524288) >> 15;
		}
		/* Last pixel */
		t0 = bayer[1] + adjacent_bayer[2];
		if (blue_line) {
			*y++ = (8453 * adjacent_bayer[1] + 8297 * t0 +
					3223 * bayer[2] + 524288) >> 15;
		} else {
			*y++ = (8453 * bayer[2] + 8297 * t0 +
					3223 * adjacent_bayer[1] + 524288) >> 15;
		}
	} else {
		/* Last pixel */
		if (blue_line) {
			*y++ = (8453 * adjacent_bayer[1] + 16594 * bayer[1] +
					3223 * bayer[0] + 524288) >> 15;
		} else {
			*y++ = (8453 * bayer[0] + 16594 * bayer[1] +
					3223 * adjacent_bayer[1] + 524288) >> 15;
		}
	}
}

void v4lconvert_bayer_to_yuv420(const unsigned char *bayer, unsigned char *yuv,
		int width, int height, const unsigned int stride, unsigned int src_pixfmt, int yvu)
{
	int blue_line = 0, start_with_green = 0, x, y;
	unsigned char *ydst = yuv;
	unsigned char *udst, *vdst;

	if (yvu) {
		vdst = yuv + width * height;
		udst = vdst + width * height / 4;
	} else {
		udst = yuv + width * height;
		vdst = udst + width * height / 4;
	}

	/* First calculate the u and v planes 2x2 pixels at a time */
	switch (src_pixfmt) {
	case V4L2_PIX_FMT_SBGGR8:
		for (y = 0; y < height; y += 2) {
			for (x = 0; x < width; x += 2) {
				int b, g, r;

				b  = bayer[x];
				g  = bayer[x + 1];
				g += bayer[x + stride];
				r  = bayer[x + stride + 1];
				*udst++ = (-4878 * r - 4789 * g + 14456 * b + 4210688) >> 15;
				*vdst++ = (14456 * r - 6052 * g -  2351 * b + 4210688) >> 15;
			}
			bayer += 2 * stride;
		}
		blue_line = 1;
		break;

	case V4L2_PIX_FMT_SRGGB8:
		for (y = 0; y < height; y += 2) {
			for (x = 0; x < width; x += 2) {
				int b, g, r;

				r  = bayer[x];
				g  = bayer[x + 1];
				g += bayer[x + stride];
				b  = bayer[x + stride + 1];
				*udst++ = (-4878 * r - 4789 * g + 14456 * b + 4210688) >> 15;
				*vdst++ = (14456 * r - 6052 * g -  2351 * b + 4210688) >> 15;
			}
			bayer += 2 * stride;
		}
		break;

	case V4L2_PIX_FMT_SGBRG8:
		for (y = 0; y < height; y += 2) {
			for (x = 0; x < width; x += 2) {
				int b, g, r;

				g  = bayer[x];
				b  = bayer[x + 1];
				r  = bayer[x + stride];
				g += bayer[x + stride + 1];
				*udst++ = (-4878 * r - 4789 * g + 14456 * b + 4210688) >> 15;
				*vdst++ = (14456 * r - 6052 * g -  2351 * b + 4210688) >> 15;
			}
			bayer += 2 * stride;
		}
		blue_line = 1;
		start_with_green = 1;
		break;

	case V4L2_PIX_FMT_SGRBG8:
		for (y = 0; y < height; y += 2) {
			for (x = 0; x < width; x += 2) {
				int b, g, r;

				g  = bayer[x];
				r  = bayer[x + 1];
				b  = bayer[x + stride];
				g += bayer[x + stride + 1];
				*udst++ = (-4878 * r - 4789 * g + 14456 * b + 4210688) >> 15;
				*vdst++ = (14456 * r - 6052 * g -  2351 * b + 4210688) >> 15;
			}
			bayer += 2 * stride;
		}
		start_with_green = 1;
		break;
	}

	/* Point bayer back to start of frame */
	bayer -= stride * height;

	/* render the first line */
	v4lconvert_border_bayer_line_to_y(bayer, bayer + stride, ydst, width,
			start_with_green, blue_line);
	ydst += width;

	/* reduce height by 2 because of the border */
	for (height -= 2; height; height--) {
		int t0, t1;
		/* (width - 2) because of the border */
		const unsigned char *bayer_end = bayer + (width - 2);

		if (start_with_green) {
			t0 = bayer[1] + bayer[stride * 2 + 1];
			/* Write first pixel */
			t1 = bayer[0] + bayer[stride * 2] + bayer[stride + 1];
			if (blue_line)
				*ydst++ = (8453 * bayer[stride] + 5516 * t1 +
						1661 * t0 + 524288) >> 15;
			else
				*ydst++ = (4226 * t0 + 5516 * t1 +
						3223 * bayer[stride] + 524288) >> 15;

			/* Write second pixel */
			t1 = bayer[stride] + bayer[stride + 2];
			if (blue_line)
				*ydst++ = (4226 * t1 + 16594 * bayer[stride + 1] +
						1611 * t0 + 524288) >> 15;
			else
				*ydst++ = (4226 * t0 + 16594 * bayer[stride + 1] +
						1611 * t1 + 524288) >> 15;
			bayer++;
		} else {
			/* Write first pixel */
			t0 = bayer[0] + bayer[stride * 2];
			if (blue_line) {
				*ydst++ = (8453 * bayer[stride + 1] + 16594 * bayer[stride] +
						1661 * t0 + 524288) >> 15;
			} else {
				*ydst++ = (4226 * t0 + 16594 * bayer[stride] +
						3223 * bayer[stride + 1] + 524288) >> 15;
			}
		}

		if (blue_line) {
			for (; bayer <= bayer_end - 2; bayer += 2) {
				t0 = bayer[0] + bayer[2] + bayer[stride * 2] + bayer[stride * 2 + 2];
				t1 = bayer[1] + bayer[stride] + bayer[stride + 2] + bayer[stride * 2 + 1];
				*ydst++ = (8453 * bayer[stride + 1] + 4148 * t1 +
						806 * t0 + 524288) >> 15;

				t0 = bayer[2] + bayer[stride * 2 + 2];
				t1 = bayer[stride + 1] + bayer[stride + 3];
				*ydst++ = (4226 * t1 + 16594 * bayer[stride + 2] +
						1611 * t0 + 524288) >> 15;
			}
		} else {
			for (; bayer <= bayer_end - 2; bayer += 2) {
				t0 = bayer[0] + bayer[2] + bayer[stride * 2] + bayer[stride * 2 + 2];
				t1 = bayer[1] + bayer[stride] + bayer[stride + 2] + bayer[stride * 2 + 1];
				*ydst++ = (2113 * t0 + 4148 * t1 +
						3223 * bayer[stride + 1] + 524288) >> 15;

				t0 = bayer[2] + bayer[stride * 2 + 2];
				t1 = bayer[stride + 1] + bayer[stride + 3];
				*ydst++ = (4226 * t0 + 16594 * bayer[stride + 2] +
						1611 * t1 + 524288) >> 15;
			}
		}

		if (bayer < bayer_end) {
			/* Write second to last pixel */
			t0 = bayer[0] + bayer[2] + bayer[stride * 2] + bayer[stride * 2 + 2];
			t1 = bayer[1] + bayer[stride] + bayer[stride + 2] + bayer[stride * 2 + 1];
			if (blue_line)
				*ydst++ = (8453 * bayer[stride + 1] + 4148 * t1 +
						806 * t0 + 524288) >> 15;
			else
				*ydst++ = (2113 * t0 + 4148 * t1 +
						3223 * bayer[stride + 1] + 524288) >> 15;

			/* write last pixel */
			t0 = bayer[2] + bayer[stride * 2 + 2];
			if (blue_line) {
				*ydst++ = (8453 * bayer[stride + 1] + 16594 * bayer[stride + 2] +
						1661 * t0 + 524288) >> 15;
			} else {
				*ydst++ = (4226 * t0 + 16594 * bayer[stride + 2] +
						3223 * bayer[stride + 1] + 524288) >> 15;
			}
			bayer++;
		} else {
			/* write last pixel */
			t0 = bayer[0] + bayer[stride * 2];
			t1 = bayer[1] + bayer[stride * 2 + 1] + bayer[stride];
			if (blue_line)
				*ydst++ = (8453 * bayer[stride + 1] + 5516 * t1 +
						1661 * t0 + 524288) >> 15;
			else
				*ydst++ = (4226 * t0 + 5516 * t1 +
						3223 * bayer[stride + 1] + 524288) >> 15;
		}

		/* skip 2 border pixels and padding */
		bayer += (stride - width) + 2;

		blue_line = !blue_line;
		start_with_green = !start_with_green;
	}

	/* render the last line */
	v4lconvert_border_bayer_line_to_y(bayer + stride, bayer, ydst, width,
			!start_with_green, !blue_line);
}