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/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* Copyright (C) 2019, Google Inc.
*
* format_convert.cpp - qcam - Convert buffer to RGB
*/
#include <errno.h>
#include <linux/videodev2.h>
#include <QImage>
#include "format_converter.h"
#define RGBSHIFT 8
#ifndef MAX
#define MAX(a,b) ((a)>(b)?(a):(b))
#endif
#ifndef MIN
#define MIN(a,b) ((a)<(b)?(a):(b))
#endif
#ifndef CLAMP
#define CLAMP(a,low,high) MAX((low),MIN((high),(a)))
#endif
#ifndef CLIP
#define CLIP(x) CLAMP(x,0,255)
#endif
int FormatConverter::configure(unsigned int format, unsigned int width,
unsigned int height)
{
switch (format) {
case V4L2_PIX_FMT_VYUY:
y_pos_ = 1;
cb_pos_ = 2;
break;
case V4L2_PIX_FMT_YVYU:
y_pos_ = 0;
cb_pos_ = 3;
break;
case V4L2_PIX_FMT_UYVY:
y_pos_ = 1;
cb_pos_ = 0;
break;
case V4L2_PIX_FMT_YUYV:
y_pos_ = 0;
cb_pos_ = 1;
break;
case V4L2_PIX_FMT_MJPEG:
break;
default:
return -EINVAL;
};
format_ = format;
width_ = width;
height_ = height;
return 0;
}
void FormatConverter::convert(const unsigned char *src, size_t size,
QImage *dst)
{
if (format_ == V4L2_PIX_FMT_MJPEG)
dst->loadFromData(src, size, "JPEG");
else
convertYUV(src, dst->bits());
}
static void yuv_to_rgb(int y, int u, int v, int *r, int *g, int *b)
{
int c = y - 16;
int d = u - 128;
int e = v - 128;
*r = CLIP(( 298 * c + 409 * e + 128) >> RGBSHIFT);
*g = CLIP(( 298 * c - 100 * d - 208 * e + 128) >> RGBSHIFT);
*b = CLIP(( 298 * c + 516 * d + 128) >> RGBSHIFT);
}
void FormatConverter::convertYUV(const unsigned char *src, unsigned char *dst)
{
unsigned int src_x, src_y, dst_x, dst_y;
unsigned int src_stride;
unsigned int dst_stride;
unsigned int cr_pos;
int r, g, b, y, cr, cb;
cr_pos = (cb_pos_ + 2) % 4;
src_stride = width_ * 2;
dst_stride = width_ * 4;
for (src_y = 0, dst_y = 0; dst_y < height_; src_y++, dst_y++) {
for (src_x = 0, dst_x = 0; dst_x < width_; ) {
cb = src[src_y * src_stride + src_x * 4 + cb_pos_];
cr = src[src_y * src_stride + src_x * 4 + cr_pos];
y = src[src_y * src_stride + src_x * 4 + y_pos_];
yuv_to_rgb(y, cb, cr, &r, &g, &b);
dst[dst_y * dst_stride + 4 * dst_x + 0] = b;
dst[dst_y * dst_stride + 4 * dst_x + 1] = g;
dst[dst_y * dst_stride + 4 * dst_x + 2] = r;
dst[dst_y * dst_stride + 4 * dst_x + 3] = 0xff;
dst_x++;
y = src[src_y * src_stride + src_x * 4 + y_pos_ + 2];
yuv_to_rgb(y, cb, cr, &r, &g, &b);
dst[dst_y * dst_stride + 4 * dst_x + 0] = b;
dst[dst_y * dst_stride + 4 * dst_x + 1] = g;
dst[dst_y * dst_stride + 4 * dst_x + 2] = r;
dst[dst_y * dst_stride + 4 * dst_x + 3] = 0xff;
dst_x++;
src_x++;
}
}
}
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