libv4lconvert: Add support for V4L2_PIX_FMT_NV12

NV12 is a two-plane version YUV 4:2:0, where the U and V components
are subsampled 2x2.

Signed-off-by: Ricardo Ribalda Delgado <ricardo@ribalda.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

3 files changed, 81 insertions, 0 deletions

diff --git a/lib/libv4lconvert/libv4lconvert-priv.h b/lib/libv4lconvert/libv4lconvert-priv.h
index 5286a9b1..ce5970c9 100644
--- a/lib/libv4lconvert/libv4lconvert-priv.h
+++ b/lib/libv4lconvert/libv4lconvert-priv.h
@@ -286,6 +286,12 @@ void v4lconvert_hm12_to_yuv420(const unsigned char *src,
 void v4lconvert_hsv_to_rgb24(const unsigned char *src, unsigned char *dest,
 		int width, int height, int bgr, int Xin, unsigned char hsv_enc);
 
+void v4lconvert_nv12_to_rgb24(const unsigned char *src, unsigned char *dest,
+		int width, int height, int bgr);
+
+void v4lconvert_nv12_to_yuv420(const unsigned char *src, unsigned char *dest,
+		int width, int height, int yvu);
+
 void v4lconvert_rotate90(unsigned char *src, unsigned char *dest,
 		struct v4l2_format *fmt);
 
diff --git a/lib/libv4lconvert/libv4lconvert.c b/lib/libv4lconvert/libv4lconvert.c
index 379e5087..5945be43 100644
--- a/lib/libv4lconvert/libv4lconvert.c
+++ b/lib/libv4lconvert/libv4lconvert.c
@@ -139,6 +139,7 @@ static const struct v4lconvert_pixfmt supported_src_pixfmts[] = {
 	{ V4L2_PIX_FMT_SN9C20X_I420,	12,	 6,	 3,	1 },
 	{ V4L2_PIX_FMT_M420,		12,	 6,	 3,	1 },
 	{ V4L2_PIX_FMT_HM12,		12,	 6,	 3,	1 },
+	{ V4L2_PIX_FMT_NV12,		12,	 6,	 3,	1 },
 	{ V4L2_PIX_FMT_CPIA1,		 0,	 6,	 3,	1 },
 	/* JPEG and variants */
 	{ V4L2_PIX_FMT_MJPEG,		 0,	 7,	 7,	0 },
@@ -932,6 +933,24 @@ static int v4lconvert_convert_pixfmt(struct v4lconvert_data *data,
 		}
 		break;
 
+		/* NV12 formats */
+	case V4L2_PIX_FMT_NV12:
+		switch (dest_pix_fmt) {
+		case V4L2_PIX_FMT_RGB24:
+			v4lconvert_nv12_to_rgb24(src, dest, width, height, 0);
+			break;
+		case V4L2_PIX_FMT_BGR24:
+			v4lconvert_nv12_to_rgb24(src, dest, width, height, 1);
+			break;
+		case V4L2_PIX_FMT_YUV420:
+			v4lconvert_nv12_to_yuv420(src, dest, width, height, 0);
+			break;
+		case V4L2_PIX_FMT_YVU420:
+			v4lconvert_nv12_to_yuv420(src, dest, width, height, 1);
+			break;
+		}
+		break;
+
 		/* compressed bayer formats */
 	case V4L2_PIX_FMT_SPCA561:
 	case V4L2_PIX_FMT_SN9C10X:
diff --git a/lib/libv4lconvert/rgbyuv.c b/lib/libv4lconvert/rgbyuv.c
index 02c8cb5b..79bc0bdb 100644
--- a/lib/libv4lconvert/rgbyuv.c
+++ b/lib/libv4lconvert/rgbyuv.c
@@ -845,3 +845,59 @@ void v4lconvert_hsv_to_rgb24(const unsigned char *src, unsigned char *dest,
 			src += bppIN;
 		}
 }
+
+void v4lconvert_nv12_to_rgb24(const unsigned char *src, unsigned char *dest,
+		int width, int height, int bgr)
+{
+	int i, j;
+	const unsigned char *ysrc = src;
+	const unsigned char *uvsrc = src + width * height;
+
+	for (i = 0; i < height; i++) {
+		for (j = 0; j < width; j ++) {
+			if (bgr) {
+				*dest++ = YUV2B(*ysrc, *uvsrc, *(uvsrc + 1));
+				*dest++ = YUV2G(*ysrc, *uvsrc, *(uvsrc + 1));
+				*dest++ = YUV2R(*ysrc, *uvsrc, *(uvsrc + 1));
+			} else {
+				*dest++ = YUV2R(*ysrc, *uvsrc, *(uvsrc + 1));
+				*dest++ = YUV2G(*ysrc, *uvsrc, *(uvsrc + 1));
+				*dest++ = YUV2B(*ysrc, *uvsrc, *(uvsrc + 1));
+			}
+			ysrc++;
+			if (j&1)
+				uvsrc += 2;
+		}
+
+		/* Rewind u and v for next line */
+		if (!(i&1))
+			uvsrc -= width;
+	}
+}
+
+void v4lconvert_nv12_to_yuv420(const unsigned char *src, unsigned char *dest,
+		int width, int height, int yvu)
+{
+	int i, j;
+	const unsigned char *ysrc = src;
+	const unsigned char *uvsrc = src + width * height;
+	unsigned char *ydst = dest;
+	unsigned char *udst, *vdst;
+
+	if (yvu) {
+		vdst = ydst + width * height;
+		udst = vdst + ((width / 2) * (height / 2));
+	} else {
+		udst = ydst + width * height;
+		vdst = udst + ((width / 2) * (height / 2));
+	}
+
+	for (i = 0; i < height; i++)
+		for (j = 0; i < width; j++) {
+			*ydst++ = *ysrc++;
+			if (((i % 2) == 0) && ((j % 2) == 0)) {
+				*udst++ = *uvsrc++;
+				*vdst++ = *uvsrc++;
+			}
+		}
+}