libv4l: add hm12 support for the cx2341x MPEG encoder devices.

From: Hans Verkuil <hverkuil@xs4all.nl>

Priority: normal

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

1 files changed, 159 insertions, 0 deletions

diff --git a/v4l2-apps/libv4l/libv4lconvert/hm12.c b/v4l2-apps/libv4l/libv4lconvert/hm12.c
new file mode 100644
index 000000000..f711627b4
--- /dev/null
+++ b/v4l2-apps/libv4l/libv4lconvert/hm12.c
@@ -0,0 +1,159 @@
+/*
+
+cx2341x HM12 conversion routines
+
+(C) 2009 Hans Verkuil <hverkuil@xs4all.nl>
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation; either version 2.1 of the License, or
+(at your option) any later version.
+
+This program 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 program; if not, write to the Free Software
+Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+ */
+
+#include "libv4lconvert-priv.h"
+#include <string.h>
+
+/* The HM12 format is used in the Conexant cx23415/6/8 MPEG encoder devices.
+   It is a macroblock format with separate Y and UV planes, each plane
+   consisting of 16x16 values. All lines are always 720 bytes long. If the
+   width of the image is less than 720, then the remainder is padding.
+
+   The height has to be a multiple of 32 in order to get correct chroma
+   values.
+
+   It is basically a by-product of the MPEG encoding inside the device,
+   which is available for raw video as a 'bonus feature'.
+ */
+
+#define CLIP(color) \
+	(unsigned char)(((color) > 0xff) ? 0xff : (((color) < 0) ? 0 : (color)))
+
+static const int stride = 720;
+
+static void v4lconvert_hm12_to_rgb(const unsigned char *src, unsigned char *dest,
+		int width, int height, int rgb)
+{
+	unsigned int y, x, i, j;
+	const unsigned char *y_base = src;
+	const unsigned char *uv_base = src + stride * height;
+	const unsigned char *src_y;
+	const unsigned char *src_uv;
+	int mb_size = 256;
+	int r = rgb ? 0 : 2;
+	int b = 2 - r;
+
+	for (y = 0; y < height; y += 16) {
+		int mb_y = (y / 16) * (stride / 16);
+		int mb_uv = (y / 32) * (stride / 16);
+		int maxy = (height - y < 16 ? height - y : 16);
+
+		for (x = 0; x < width; x += 16, mb_y++, mb_uv++) {
+			int maxx = (width - x < 16 ? width - x : 16);
+
+			src_y = y_base + mb_y * mb_size;
+			src_uv = uv_base + mb_uv * mb_size;
+
+			if (y & 0x10)
+				src_uv += mb_size / 2;
+
+			for (i = 0; i < maxy; i++) {
+				int idx = (x + (y + i) * width) * 3;
+
+				for (j = 0; j < maxx; j++) {
+					int y = src_y[j];
+					int u = src_uv[j & ~1];
+					int v = src_uv[j | 1];
+					int u1 = (((u - 128) << 7) + (u - 128)) >> 6;
+					int rg = (((u - 128) << 1) + (u - 128) +
+						((v - 128) << 2) + ((v - 128) << 1)) >> 3;
+					int v1 = (((v - 128) << 1) + (v - 128)) >> 1;
+
+					dest[idx+r] = CLIP(y + v1);
+					dest[idx+1] = CLIP(y - rg);
+					dest[idx+b] = CLIP(y + u1);
+					idx += 3;
+				}
+				src_y += 16;
+				if (i & 1)
+					src_uv += 16;
+			}
+		}
+	}
+}
+
+void v4lconvert_hm12_to_rgb24(const unsigned char *src, unsigned char *dest,
+		int width, int height)
+{
+	v4lconvert_hm12_to_rgb(src, dest, width, height, 1);
+}
+
+void v4lconvert_hm12_to_bgr24(const unsigned char *src, unsigned char *dest,
+		int width, int height)
+{
+	v4lconvert_hm12_to_rgb(src, dest, width, height, 0);
+}
+
+static void de_macro_uv(unsigned char *dstu, unsigned char *dstv,
+		const unsigned char *src, int w, int h)
+{
+	unsigned int y, x, i, j;
+
+	for (y = 0; y < h; y += 16) {
+		for (x = 0; x < w; x += 8) {
+			const unsigned char *src_uv = src + y * stride + x * 32;
+			int maxy = (h - y < 16 ? h - y : 16);
+			int maxx = (w - x < 8 ? w - x : 8);
+
+			for (i = 0; i < maxy; i++) {
+				int idx = x + (y + i) * w;
+
+				for (j = 0; j < maxx; j++) {
+					dstu[idx+j] = src_uv[2 * j];
+					dstv[idx+j] = src_uv[2 * j + 1];
+				}
+				src_uv += 16;
+			}
+		}
+	}
+}
+
+static void de_macro_y(unsigned char *dst, const unsigned char *src,
+		int w, int h)
+{
+	unsigned int y, x, i;
+
+	for (y = 0; y < h; y += 16) {
+		for (x = 0; x < w; x += 16) {
+			const unsigned char *src_y = src + y * stride + x * 16;
+			int maxy = (h - y < 16 ? h - y : 16);
+			int maxx = (w - x < 16 ? w - x : 16);
+
+			for (i = 0; i < maxy; i++) {
+				memcpy(dst + x + (y + i) * w, src_y, maxx);
+				src_y += 16;
+			}
+		}
+	}
+}
+
+void v4lconvert_hm12_to_yuv420(const unsigned char *src, unsigned char *dest,
+		int width, int height, int yvu)
+{
+	de_macro_y(dest, src, width, height);
+	dest += width * height;
+	src += stride * height;
+	if (yvu)
+		de_macro_uv(dest + width * height / 4, dest, src, width / 2, height / 2);
+	else
+		de_macro_uv(dest, dest + width * height / 4, src, width / 2, height / 2);
+}