libv4l: add support for converting to YV12 planar

From: Hans de Goede <hdegoede@redhat.com>

Add support for converting to YV12 planar (next to the already supported
YU12 / I420) and implement RGB/BGR24 -> YU/YV12 conversion

Priority: normal

Signed-off-by: Hans de Goede <hdegoede@redhat.com>

9 files changed, 260 insertions, 67 deletions

diff --git a/v4l2-apps/libv4l/ChangeLog b/v4l2-apps/libv4l/ChangeLog
index b6097fe41..49f1fd035 100644
--- a/v4l2-apps/libv4l/ChangeLog
+++ b/v4l2-apps/libv4l/ChangeLog
@@ -5,6 +5,9 @@ libv4l-0.5.4
 * Add support for downscaling to make apps which want low resolutions
   (skype, spcaview) happy when used with cams which can only do high
   resolutions (by Lukáš Karas <lukas.karas@centrum.cz>).
+* Add support for converting to YV12 planar (next to the already supported
+  YU12 / I420)
+* Implement RGB/BGR24 -> YU/YV12 conversion
 
 libv4l-0.5.3
 ------------
diff --git a/v4l2-apps/libv4l/TODO b/v4l2-apps/libv4l/TODO
index f3f9ff527..debb9c78c 100644
--- a/v4l2-apps/libv4l/TODO
+++ b/v4l2-apps/libv4l/TODO
@@ -7,6 +7,4 @@
  impossible for overlays) can be done, so that it will no longer be
  necessary to implement CGMBUF in the kernel for each driver.
 
--check v4l2_field during conversion
-
--add conversion from bgr24 to yuv420
+-take the possibility of pitch != width into account everywhere
diff --git a/v4l2-apps/libv4l/libv4lconvert/bayer.c b/v4l2-apps/libv4l/libv4lconvert/bayer.c
index ca7bb486f..033ee2724 100644
--- a/v4l2-apps/libv4l/libv4lconvert/bayer.c
+++ b/v4l2-apps/libv4l/libv4lconvert/bayer.c
@@ -433,16 +433,23 @@ static void v4lconvert_border_bayer_line_to_y(
   }
 }
 
-void v4lconvert_bayer_to_yuv420(const unsigned char *bayer,
-  unsigned char *yuv, int width, int height, unsigned int pixfmt)
+void v4lconvert_bayer_to_yuv420(const unsigned char *bayer, unsigned char *yuv,
+  int width, int height, unsigned int src_pixfmt, int yvu)
 {
   int blue_line = 0, start_with_green = 0, x, y;
   unsigned char *ydst = yuv;
-  unsigned char *udst = yuv + width * height;
-  unsigned char *vdst = udst + width * height / 4;
+  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 (pixfmt) {
+  switch (src_pixfmt) {
     case V4L2_PIX_FMT_SBGGR8:
       for (y = 0; y < height; y += 2) {
 	for (x = 0; x < width; x += 2) {
diff --git a/v4l2-apps/libv4l/libv4lconvert/crop.c b/v4l2-apps/libv4l/libv4lconvert/crop.c
index dcfa5152a..4294fbeaf 100644
--- a/v4l2-apps/libv4l/libv4lconvert/crop.c
+++ b/v4l2-apps/libv4l/libv4lconvert/crop.c
@@ -156,6 +156,7 @@ void v4lconvert_crop(unsigned char *src, unsigned char *dest,
 	v4lconvert_crop_rgbbgr24(src, dest, src_fmt, dest_fmt);
       break;
     case V4L2_PIX_FMT_YUV420:
+    case V4L2_PIX_FMT_YVU420:
       if (src_fmt->fmt.pix.width  >= 2 * dest_fmt->fmt.pix.width &&
 	  src_fmt->fmt.pix.height >= 2 * dest_fmt->fmt.pix.height)
 	v4lconvert_reduceandcrop_yuv420(src, dest, src_fmt, dest_fmt);
diff --git a/v4l2-apps/libv4l/libv4lconvert/flip.c b/v4l2-apps/libv4l/libv4lconvert/flip.c
index 5a108c8d9..f47afde72 100644
--- a/v4l2-apps/libv4l/libv4lconvert/flip.c
+++ b/v4l2-apps/libv4l/libv4lconvert/flip.c
@@ -119,6 +119,7 @@ void v4lconvert_rotate(unsigned char *src, unsigned char *dest,
 	v4lconvert_rotate90_rgbbgr24(src, dest, width, height);
 	break;
       case V4L2_PIX_FMT_YUV420:
+      case V4L2_PIX_FMT_YVU420:
 	v4lconvert_rotate90_yuv420(src, dest, width, height);
 	break;
     }
@@ -130,6 +131,7 @@ void v4lconvert_rotate(unsigned char *src, unsigned char *dest,
 	v4lconvert_rotate180_rgbbgr24(src, dest, width, height);
 	break;
       case V4L2_PIX_FMT_YUV420:
+      case V4L2_PIX_FMT_YVU420:
 	v4lconvert_rotate180_yuv420(src, dest, width, height);
 	break;
     }
diff --git a/v4l2-apps/libv4l/libv4lconvert/libv4lconvert-priv.h b/v4l2-apps/libv4l/libv4lconvert/libv4lconvert-priv.h
index 8473ba68f..a534ca321 100644
--- a/v4l2-apps/libv4l/libv4lconvert/libv4lconvert-priv.h
+++ b/v4l2-apps/libv4l/libv4lconvert/libv4lconvert-priv.h
@@ -104,11 +104,14 @@ struct v4lconvert_pixfmt {
   int flags;
 };
 
+void v4lconvert_rgb24_to_yuv420(const unsigned char *src, unsigned char *dest,
+  const struct v4l2_format *src_fmt, int bgr, int yvu);
+
 void v4lconvert_yuv420_to_rgb24(const unsigned char *src, unsigned char *dst,
-  int width, int height);
+  int width, int height, int yvu);
 
 void v4lconvert_yuv420_to_bgr24(const unsigned char *src, unsigned char *dst,
-  int width, int height);
+  int width, int height, int yvu);
 
 void v4lconvert_yuyv_to_rgb24(const unsigned char *src, unsigned char *dst,
   int width, int height);
@@ -117,7 +120,7 @@ void v4lconvert_yuyv_to_bgr24(const unsigned char *src, unsigned char *dst,
   int width, int height);
 
 void v4lconvert_yuyv_to_yuv420(const unsigned char *src, unsigned char *dst,
-  int width, int height);
+  int width, int height, int yvu);
 
 void v4lconvert_yvyu_to_rgb24(const unsigned char *src, unsigned char *dst,
   int width, int height);
@@ -126,19 +129,22 @@ void v4lconvert_yvyu_to_bgr24(const unsigned char *src, unsigned char *dst,
   int width, int height);
 
 void v4lconvert_yvyu_to_yuv420(const unsigned char *src, unsigned char *dst,
-  int width, int height);
+  int width, int height, int yvu);
 
 void v4lconvert_swap_rgb(const unsigned char *src, unsigned char *dst,
   int width, int height);
 
+void v4lconvert_swap_uv(const unsigned char *src, unsigned char *dst,
+  const struct v4l2_format *src_fmt);
+
 void v4lconvert_spca501_to_yuv420(const unsigned char *src, unsigned char *dst,
-  int width, int height);
+  int width, int height, int yvu);
 
 void v4lconvert_spca505_to_yuv420(const unsigned char *src, unsigned char *dst,
-  int width, int height);
+  int width, int height, int yvu);
 
 void v4lconvert_spca508_to_yuv420(const unsigned char *src, unsigned char *dst,
-  int width, int height);
+  int width, int height, int yvu);
 
 void v4lconvert_decode_spca561(const unsigned char *src, unsigned char *dst,
   int width, int height);
@@ -155,8 +161,8 @@ void v4lconvert_bayer_to_rgb24(const unsigned char *bayer,
 void v4lconvert_bayer_to_bgr24(const unsigned char *bayer,
   unsigned char *rgb, int width, int height, unsigned int pixfmt);
 
-void v4lconvert_bayer_to_yuv420(const unsigned char *bayer,
-  unsigned char *yuv, int width, int height, unsigned int pixfmt);
+void v4lconvert_bayer_to_yuv420(const unsigned char *bayer, unsigned char *yuv,
+  int width, int height, unsigned int src_pixfmt, int yvu);
 
 void v4lconvert_rotate(unsigned char *src, unsigned char *dest,
   int width, int height, unsigned int pix_fmt, int rotate);
diff --git a/v4l2-apps/libv4l/libv4lconvert/libv4lconvert.c b/v4l2-apps/libv4l/libv4lconvert/libv4lconvert.c
index 536e5363d..c6c50c2e5 100644
--- a/v4l2-apps/libv4l/libv4lconvert/libv4lconvert.c
+++ b/v4l2-apps/libv4l/libv4lconvert/libv4lconvert.c
@@ -32,7 +32,8 @@
 #define SUPPORTED_DST_PIXFMTS \
   { V4L2_PIX_FMT_RGB24,  0 }, \
   { V4L2_PIX_FMT_BGR24,  0 }, \
-  { V4L2_PIX_FMT_YUV420, 0 }
+  { V4L2_PIX_FMT_YUV420, 0 }, \
+  { V4L2_PIX_FMT_YVU420, 0 }
 
 static void v4lconvert_get_framesizes(struct v4lconvert_data *data,
   unsigned int pixelformat);
@@ -243,6 +244,7 @@ static void v4lconvert_fixup_fmt(struct v4l2_format *fmt)
     fmt->fmt.pix.sizeimage = fmt->fmt.pix.width * fmt->fmt.pix.height * 3;
     break;
   case V4L2_PIX_FMT_YUV420:
+  case V4L2_PIX_FMT_YVU420:
     fmt->fmt.pix.bytesperline = fmt->fmt.pix.width;
     fmt->fmt.pix.sizeimage = fmt->fmt.pix.width * fmt->fmt.pix.height * 3 / 2;
     break;
@@ -354,13 +356,15 @@ static unsigned char *v4lconvert_alloc_buffer(struct v4lconvert_data *data,
 }
 
 static int v4lconvert_convert_pixfmt(struct v4lconvert_data *data,
-  unsigned int src_pix_fmt, unsigned int dest_pix_fmt,
-  unsigned int width, unsigned int height,
-  unsigned char *src, int src_size, unsigned char *dest)
+  unsigned char *src, int src_size, unsigned char *dest,
+  const struct v4l2_format *src_fmt, unsigned int dest_pix_fmt)
 {
   unsigned int header_width, header_height;
   int result = 0, jpeg_flags = TINYJPEG_FLAGS_MJPEG_TABLE;
   unsigned char *components[3];
+  unsigned int src_pix_fmt = src_fmt->fmt.pix.pixelformat;
+  unsigned int width  = src_fmt->fmt.pix.width;
+  unsigned int height = src_fmt->fmt.pix.height;
 
   switch (src_pix_fmt) {
     case V4L2_PIX_FMT_PJPG:
@@ -404,8 +408,6 @@ static int v4lconvert_convert_pixfmt(struct v4lconvert_data *data,
       }
 
       components[0] = dest;
-      components[1] = components[0] + width * height;
-      components[2] = components[1] + width * height / 4;
 
       switch (dest_pix_fmt) {
       case V4L2_PIX_FMT_RGB24:
@@ -417,6 +419,14 @@ static int v4lconvert_convert_pixfmt(struct v4lconvert_data *data,
 	result = tinyjpeg_decode(data->jdec, TINYJPEG_FMT_BGR24);
 	break;
       case V4L2_PIX_FMT_YUV420:
+	components[1] = components[0] + width * height;
+	components[2] = components[1] + width * height / 4;
+	tinyjpeg_set_components(data->jdec, components, 3);
+	result = tinyjpeg_decode(data->jdec, TINYJPEG_FMT_YUV420P);
+	break;
+      case V4L2_PIX_FMT_YVU420:
+	components[2] = components[0] + width * height;
+	components[1] = components[2] + width * height / 4;
 	tinyjpeg_set_components(data->jdec, components, 3);
 	result = tinyjpeg_decode(data->jdec, TINYJPEG_FMT_YUV420P);
 	break;
@@ -454,7 +464,10 @@ static int v4lconvert_convert_pixfmt(struct v4lconvert_data *data,
 	v4lconvert_bayer_to_bgr24(src, dest, width, height, src_pix_fmt);
 	break;
       case V4L2_PIX_FMT_YUV420:
-	v4lconvert_bayer_to_yuv420(src, dest, width, height, src_pix_fmt);
+	v4lconvert_bayer_to_yuv420(src, dest, width, height, src_pix_fmt, 0);
+	break;
+      case V4L2_PIX_FMT_YVU420:
+	v4lconvert_bayer_to_yuv420(src, dest, width, height, src_pix_fmt, 1);
 	break;
       }
       break;
@@ -465,8 +478,10 @@ static int v4lconvert_convert_pixfmt(struct v4lconvert_data *data,
     case V4L2_PIX_FMT_SPCA508:
     {
       unsigned char *d;
+      int yvu = 0;
 
-      if (dest_pix_fmt != V4L2_PIX_FMT_YUV420) {
+      if (dest_pix_fmt != V4L2_PIX_FMT_YUV420 &&
+	  dest_pix_fmt != V4L2_PIX_FMT_YVU420) {
 	d = v4lconvert_alloc_buffer(data, width * height * 3 / 2,
 	      &data->convert_pixfmt_buf, &data->convert_pixfmt_buf_size);
 	if (!d)
@@ -474,26 +489,29 @@ static int v4lconvert_convert_pixfmt(struct v4lconvert_data *data,
       } else
 	d = dest;
 
+      if (dest_pix_fmt == V4L2_PIX_FMT_YVU420)
+	yvu = 1;
+
       switch (src_pix_fmt) {
 	case V4L2_PIX_FMT_SPCA501:
-	  v4lconvert_spca501_to_yuv420(src, d, width, height);
+	  v4lconvert_spca501_to_yuv420(src, d, width, height, yvu);
 	  break;
 	case V4L2_PIX_FMT_SPCA505:
-	  v4lconvert_spca505_to_yuv420(src, d, width, height);
+	  v4lconvert_spca505_to_yuv420(src, d, width, height, yvu);
 	  break;
 	case V4L2_PIX_FMT_SPCA508:
-	  v4lconvert_spca508_to_yuv420(src, d, width, height);
+	  v4lconvert_spca508_to_yuv420(src, d, width, height, yvu);
 	  break;
       }
 
       switch (dest_pix_fmt) {
       case V4L2_PIX_FMT_RGB24:
 	v4lconvert_yuv420_to_rgb24(data->convert_pixfmt_buf, dest, width,
-				   height);
+				   height, yvu);
 	break;
       case V4L2_PIX_FMT_BGR24:
 	v4lconvert_yuv420_to_bgr24(data->convert_pixfmt_buf, dest, width,
-				   height);
+				   height, yvu);
 	break;
       }
       break;
@@ -535,7 +553,10 @@ static int v4lconvert_convert_pixfmt(struct v4lconvert_data *data,
 	v4lconvert_bayer_to_bgr24(tmpbuf, dest, width, height, bayer_fmt);
 	break;
       case V4L2_PIX_FMT_YUV420:
-	v4lconvert_bayer_to_yuv420(tmpbuf, dest, width, height, bayer_fmt);
+	v4lconvert_bayer_to_yuv420(tmpbuf, dest, width, height, bayer_fmt, 0);
+	break;
+      case V4L2_PIX_FMT_YVU420:
+	v4lconvert_bayer_to_yuv420(tmpbuf, dest, width, height, bayer_fmt, 1);
 	break;
       }
       break;
@@ -547,7 +568,10 @@ static int v4lconvert_convert_pixfmt(struct v4lconvert_data *data,
 	v4lconvert_swap_rgb(src, dest, width, height);
 	break;
       case V4L2_PIX_FMT_YUV420:
-	printf("FIXME add rgb24 -> yuv420 conversion\n");
+	v4lconvert_rgb24_to_yuv420(src, dest, src_fmt, 0, 0);
+	break;
+      case V4L2_PIX_FMT_YVU420:
+	v4lconvert_rgb24_to_yuv420(src, dest, src_fmt, 0, 1);
 	break;
       }
       break;
@@ -558,7 +582,10 @@ static int v4lconvert_convert_pixfmt(struct v4lconvert_data *data,
 	v4lconvert_swap_rgb(src, dest, width, height);
 	break;
       case V4L2_PIX_FMT_YUV420:
-	printf("FIXME add bgr24 -> yuv420 conversion\n");
+	v4lconvert_rgb24_to_yuv420(src, dest, src_fmt, 1, 0);
+	break;
+      case V4L2_PIX_FMT_YVU420:
+	v4lconvert_rgb24_to_yuv420(src, dest, src_fmt, 1, 1);
 	break;
       }
       break;
@@ -567,11 +594,30 @@ static int v4lconvert_convert_pixfmt(struct v4lconvert_data *data,
       switch (dest_pix_fmt) {
       case V4L2_PIX_FMT_RGB24:
 	v4lconvert_yuv420_to_rgb24(src, dest, width,
-				   height);
+				   height, 0);
 	break;
       case V4L2_PIX_FMT_BGR24:
 	v4lconvert_yuv420_to_bgr24(src, dest, width,
-				   height);
+				   height, 0);
+	break;
+      case V4L2_PIX_FMT_YVU420:
+	v4lconvert_swap_uv(src, dest, src_fmt);
+	break;
+      }
+      break;
+
+    case V4L2_PIX_FMT_YVU420:
+      switch (dest_pix_fmt) {
+      case V4L2_PIX_FMT_RGB24:
+	v4lconvert_yuv420_to_rgb24(src, dest, width,
+				   height, 1);
+	break;
+      case V4L2_PIX_FMT_BGR24:
+	v4lconvert_yuv420_to_bgr24(src, dest, width,
+				   height, 1);
+	break;
+      case V4L2_PIX_FMT_YUV420:
+	v4lconvert_swap_uv(src, dest, src_fmt);
 	break;
       }
       break;
@@ -585,7 +631,10 @@ static int v4lconvert_convert_pixfmt(struct v4lconvert_data *data,
 	v4lconvert_yuyv_to_bgr24(src, dest, width, height);
 	break;
       case V4L2_PIX_FMT_YUV420:
-	v4lconvert_yuyv_to_yuv420(src, dest, width, height);
+	v4lconvert_yuyv_to_yuv420(src, dest, width, height, 0);
+	break;
+      case V4L2_PIX_FMT_YVU420:
+	v4lconvert_yuyv_to_yuv420(src, dest, width, height, 1);
 	break;
       }
       break;
@@ -599,7 +648,10 @@ static int v4lconvert_convert_pixfmt(struct v4lconvert_data *data,
 	v4lconvert_yvyu_to_bgr24(src, dest, width, height);
 	break;
       case V4L2_PIX_FMT_YUV420:
-	v4lconvert_yvyu_to_yuv420(src, dest, width, height);
+	v4lconvert_yvyu_to_yuv420(src, dest, width, height, 0);
+	break;
+      case V4L2_PIX_FMT_YVU420:
+	v4lconvert_yvyu_to_yuv420(src, dest, width, height, 1);
 	break;
       }
       break;
@@ -645,6 +697,7 @@ int v4lconvert_convert(struct v4lconvert_data *data,
       temp_needed = my_src_fmt.fmt.pix.width * my_src_fmt.fmt.pix.height * 3;
       break;
     case V4L2_PIX_FMT_YUV420:
+    case V4L2_PIX_FMT_YVU420:
       dest_needed =
 	my_dest_fmt.fmt.pix.width * my_dest_fmt.fmt.pix.height * 3 / 2;
       temp_needed =
@@ -694,11 +747,9 @@ int v4lconvert_convert(struct v4lconvert_data *data,
   }
 
   if (convert) {
-    res = v4lconvert_convert_pixfmt(data, my_src_fmt.fmt.pix.pixelformat,
-			      my_dest_fmt.fmt.pix.pixelformat,
-			      my_src_fmt.fmt.pix.width,
-			      my_src_fmt.fmt.pix.height,
-			      src, src_size, convert_dest);
+    res = v4lconvert_convert_pixfmt(data, src, src_size, convert_dest,
+				    &my_src_fmt,
+				    my_dest_fmt.fmt.pix.pixelformat);
     if (res)
       return res;
 
diff --git a/v4l2-apps/libv4l/libv4lconvert/rgbyuv.c b/v4l2-apps/libv4l/libv4lconvert/rgbyuv.c
index 0f26b227a..d5feb457e 100644
--- a/v4l2-apps/libv4l/libv4lconvert/rgbyuv.c
+++ b/v4l2-apps/libv4l/libv4lconvert/rgbyuv.c
@@ -20,13 +20,65 @@
 
 */
 
+#include <string.h>
 #include "libv4lconvert-priv.h"
 
-#define RGB2YUV(r,g,b,y,u,v) \
-    (y) = ((  8453*(r) + 16594*(g) +  3223*(b) +  524288) >> 15); \
+#define RGB2Y(r,g,b,y) \
+    (y) = ((  8453*(r) + 16594*(g) +  3223*(b) +  524288) >> 15)
+
+#define RGB2UV(r,g,b,u,v) \
     (u) = (( -4878*(r) -  9578*(g) + 14456*(b) + 4210688) >> 15); \
     (v) = (( 14456*(r) - 12105*(g) -  2351*(b) + 4210688) >> 15)
 
+void v4lconvert_rgb24_to_yuv420(const unsigned char *src, unsigned char *dest,
+  const struct v4l2_format *src_fmt, int bgr, int yvu)
+{
+  int x, y;
+  unsigned char *udest, *vdest;
+
+  /* Y */
+  for (y = 0; y < src_fmt->fmt.pix.height; y++) {
+    for (x = 0; x < src_fmt->fmt.pix.width; x++) {
+      if (bgr) {
+	RGB2Y(src[2], src[1], src[0], *dest++);
+      } else {
+	RGB2Y(src[0], src[1], src[2], *dest++);
+      }
+      src += 3;
+    }
+    src += src_fmt->fmt.pix.bytesperline - 3 * src_fmt->fmt.pix.width;
+  }
+  src -= src_fmt->fmt.pix.height * src_fmt->fmt.pix.bytesperline;
+
+  /* U + V */
+  if (yvu) {
+    vdest = dest;
+    udest = dest + src_fmt->fmt.pix.width * src_fmt->fmt.pix.height / 4;
+  } else {
+    udest = dest;
+    vdest = dest + src_fmt->fmt.pix.width * src_fmt->fmt.pix.height / 4;
+  }
+
+  for (y = 0; y < src_fmt->fmt.pix.height / 2; y++) {
+    for (x = 0; x < src_fmt->fmt.pix.width / 2; x++) {
+      int avg_src[3];
+      avg_src[0] = (src[0] + src[3] + src[src_fmt->fmt.pix.bytesperline] +
+		    src[src_fmt->fmt.pix.bytesperline + 3]) / 4;
+      avg_src[1] = (src[1] + src[4] + src[src_fmt->fmt.pix.bytesperline + 1] +
+		    src[src_fmt->fmt.pix.bytesperline + 4]) / 4;
+      avg_src[2] = (src[2] + src[5] + src[src_fmt->fmt.pix.bytesperline + 2] +
+		    src[src_fmt->fmt.pix.bytesperline + 5]) / 4;
+      if (bgr) {
+	RGB2UV(avg_src[2], avg_src[1], avg_src[0], *udest++, *vdest++);
+      } else {
+	RGB2UV(avg_src[0], avg_src[1], avg_src[2], *udest++, *vdest++);
+      }
+      src += 6;
+    }
+    src += 2 * src_fmt->fmt.pix.bytesperline - 3 * src_fmt->fmt.pix.width;
+  }
+}
+
 #define YUV2R(y, u, v) ({ \
   int r = (y) + ((((v)-128)*1436) >> 10); r > 255 ? 255 : r < 0 ? 0 : r; })
 #define YUV2G(y, u, v) ({ \
@@ -37,13 +89,20 @@
 #define CLIP(color) (unsigned char)(((color)>0xFF)?0xff:(((color)<0)?0:(color)))
 
 void v4lconvert_yuv420_to_bgr24(const unsigned char *src, unsigned char *dest,
-  int width, int height)
+  int width, int height, int yvu)
 {
   int i,j;
 
   const unsigned char *ysrc = src;
-  const unsigned char *usrc = src + width * height;
-  const unsigned char *vsrc = usrc + (width * height) / 4;
+  const unsigned char *usrc, *vsrc;
+
+  if (yvu) {
+    vsrc = src + width * height;
+    usrc = vsrc + (width * height) / 4;
+  } else {
+    usrc = src + width * height;
+    vsrc = usrc + (width * height) / 4;
+  }
 
   for (i = 0; i < height; i++) {
     for (j = 0; j < width; j += 2) {
@@ -84,13 +143,20 @@ void v4lconvert_yuv420_to_bgr24(const unsigned char *src, unsigned char *dest,
 }
 
 void v4lconvert_yuv420_to_rgb24(const unsigned char *src, unsigned char *dest,
-  int width, int height)
+  int width, int height, int yvu)
 {
   int i,j;
 
   const unsigned char *ysrc = src;
-  const unsigned char *usrc = src + width * height;
-  const unsigned char *vsrc = usrc + (width * height) / 4;
+  const unsigned char *usrc, *vsrc;
+
+  if (yvu) {
+    vsrc = src + width * height;
+    usrc = vsrc + (width * height) / 4;
+  } else {
+    usrc = src + width * height;
+    vsrc = usrc + (width * height) / 4;
+  }
 
   for (i = 0; i < height; i++) {
     for (j = 0; j < width; j += 2) {
@@ -183,11 +249,11 @@ void v4lconvert_yuyv_to_rgb24(const unsigned char *src, unsigned char *dest,
 }
 
 void v4lconvert_yuyv_to_yuv420(const unsigned char *src, unsigned char *dest,
-  int width, int height)
+  int width, int height, int yvu)
 {
   int i, j;
   const unsigned char *src1;
-  unsigned char *vdest;
+  unsigned char *udest, *vdest;
 
   /* copy the Y values */
   src1 = src;
@@ -202,10 +268,16 @@ void v4lconvert_yuyv_to_yuv420(const unsigned char *src, unsigned char *dest,
   /* copy the U and V values */
   src++;				/* point to V */
   src1 = src + width * 2;		/* next line */
-  vdest = dest + width * height / 4;
+  if (yvu) {
+    vdest = dest;
+    udest = dest + width * height / 4;
+  } else {
+    udest = dest;
+    vdest = dest + width * height / 4;
+  }
   for (i = 0; i < height; i += 2) {
     for (j = 0; j < width; j += 2) {
-      *dest++  = ((int) src[0] + src1[0]) / 2;	/* U */
+      *udest++ = ((int) src[0] + src1[0]) / 2;	/* U */
       *vdest++ = ((int) src[2] + src1[2]) / 2;	/* V */
       src += 4;
       src1 += 4;
@@ -268,11 +340,11 @@ void v4lconvert_yvyu_to_rgb24(const unsigned char *src, unsigned char *dest,
 }
 
 void v4lconvert_yvyu_to_yuv420(const unsigned char *src, unsigned char *dest,
-  int width, int height)
+  int width, int height, int yvu)
 {
   int i, j;
   const unsigned char *src1;
-  unsigned char *vdest;
+  unsigned char *udest, *vdest;
 
   /* copy the Y values */
   src1 = src;
@@ -287,10 +359,16 @@ void v4lconvert_yvyu_to_yuv420(const unsigned char *src, unsigned char *dest,
   /* copy the U and V values */
   src++;				/* point to V */
   src1 = src + width * 2;		/* next line */
-  vdest = dest + width * height / 4;
+  if (yvu) {
+    vdest = dest;
+    udest = dest + width * height / 4;
+  } else {
+    udest = dest;
+    vdest = dest + width * height / 4;
+  }
   for (i = 0; i < height; i += 2) {
     for (j = 0; j < width; j += 2) {
-      *dest++  = ((int) src[2] + src1[2]) / 2;	/* U */
+      *udest++ = ((int) src[2] + src1[2]) / 2;	/* U */
       *vdest++ = ((int) src[0] + src1[0]) / 2;	/* V */
       src += 4;
       src1 += 4;
@@ -314,3 +392,32 @@ void v4lconvert_swap_rgb(const unsigned char *src, unsigned char *dst,
     *dst++ = tmp0;
   }
 }
+
+void v4lconvert_swap_uv(const unsigned char *src, unsigned char *dest,
+  const struct v4l2_format *src_fmt)
+{
+  int y;
+
+  /* Copy Y */
+  for (y = 0; y < src_fmt->fmt.pix.height; y++) {
+    memcpy(dest, src, src_fmt->fmt.pix.width);
+    dest += src_fmt->fmt.pix.width;
+    src += src_fmt->fmt.pix.bytesperline;
+  }
+
+  /* Copy component 2 */
+  src += src_fmt->fmt.pix.height * src_fmt->fmt.pix.bytesperline / 4;
+  for (y = 0; y < src_fmt->fmt.pix.height / 2; y++) {
+    memcpy(dest, src, src_fmt->fmt.pix.width / 2);
+    dest += src_fmt->fmt.pix.width / 2;
+    src += src_fmt->fmt.pix.bytesperline / 2;
+  }
+
+  /* Copy component 1 */
+  src -= src_fmt->fmt.pix.height * src_fmt->fmt.pix.bytesperline / 2;
+  for (y = 0; y < src_fmt->fmt.pix.height / 2; y++) {
+    memcpy(dest, src, src_fmt->fmt.pix.width / 2);
+    dest += src_fmt->fmt.pix.width / 2;
+    src += src_fmt->fmt.pix.bytesperline / 2;
+  }
+}
diff --git a/v4l2-apps/libv4l/libv4lconvert/spca501.c b/v4l2-apps/libv4l/libv4lconvert/spca501.c
index 9157629e3..f491512e3 100644
--- a/v4l2-apps/libv4l/libv4lconvert/spca501.c
+++ b/v4l2-apps/libv4l/libv4lconvert/spca501.c
@@ -20,7 +20,7 @@
 
 /* YUYV per line */
 void v4lconvert_spca501_to_yuv420(const unsigned char *src, unsigned char *dst,
-  int width, int height)
+  int width, int height, int yvu)
 {
   int i,j;
   unsigned long *lsrc = (unsigned long *)src;
@@ -34,7 +34,10 @@ void v4lconvert_spca501_to_yuv420(const unsigned char *src, unsigned char *dst,
     }
 
     /* -128 - 127 --> 0 - 255 and copy 1 line U */
-    ldst = (unsigned long *)(dst + width * height + i * width / 4);
+    if (yvu)
+      ldst = (unsigned long *)(dst + (width * height * 5) / 4 + i * width / 4);
+    else
+      ldst = (unsigned long *)(dst + width * height + i * width / 4);
     for (j = 0; j < width/2; j += sizeof(long)) {
       *ldst = *lsrc++;
       *ldst++ ^= 0x8080808080808080ULL;
@@ -48,7 +51,10 @@ void v4lconvert_spca501_to_yuv420(const unsigned char *src, unsigned char *dst,
     }
 
     /* -128 - 127 --> 0 - 255 and copy 1 line V */
-    ldst = (unsigned long *)(dst + (width * height * 5) / 4 + i * width / 4);
+    if (yvu)
+      ldst = (unsigned long *)(dst + width * height + i * width / 4);
+    else
+      ldst = (unsigned long *)(dst + (width * height * 5) / 4 + i * width / 4);
     for (j = 0; j < width/2; j += sizeof(long)) {
       *ldst = *lsrc++;
       *ldst++ ^= 0x8080808080808080ULL;
@@ -58,7 +64,7 @@ void v4lconvert_spca501_to_yuv420(const unsigned char *src, unsigned char *dst,
 
 /* YYUV per line */
 void v4lconvert_spca505_to_yuv420(const unsigned char *src, unsigned char *dst,
-  int width, int height)
+  int width, int height, int yvu)
 {
   int i,j;
   unsigned long *lsrc = (unsigned long *)src;
@@ -72,14 +78,20 @@ void v4lconvert_spca505_to_yuv420(const unsigned char *src, unsigned char *dst,
     }
 
     /* -128 - 127 --> 0 - 255 and copy 1 line U */
-    ldst = (unsigned long *)(dst + width * height + i * width / 4);
+    if (yvu)
+      ldst = (unsigned long *)(dst + (width * height * 5) / 4 + i * width / 4);
+    else
+      ldst = (unsigned long *)(dst + width * height + i * width / 4);
     for (j = 0; j < width/2; j += sizeof(long)) {
       *ldst = *lsrc++;
       *ldst++ ^= 0x8080808080808080ULL;
     }
 
     /* -128 - 127 --> 0 - 255 and copy 1 line V */
-    ldst = (unsigned long *)(dst + (width * height * 5) / 4 + i * width / 4);
+    if (yvu)
+      ldst = (unsigned long *)(dst + width * height + i * width / 4);
+    else
+      ldst = (unsigned long *)(dst + (width * height * 5) / 4 + i * width / 4);
     for (j = 0; j < width/2; j += sizeof(long)) {
       *ldst = *lsrc++;
       *ldst++ ^= 0x8080808080808080ULL;
@@ -89,7 +101,7 @@ void v4lconvert_spca505_to_yuv420(const unsigned char *src, unsigned char *dst,
 
 /* YUVY per line */
 void v4lconvert_spca508_to_yuv420(const unsigned char *src, unsigned char *dst,
-  int width, int height)
+  int width, int height, int yvu)
 {
   int i,j;
   unsigned long *lsrc = (unsigned long *)src;
@@ -103,14 +115,20 @@ void v4lconvert_spca508_to_yuv420(const unsigned char *src, unsigned char *dst,
     }
 
     /* -128 - 127 --> 0 - 255 and copy 1 line U */
-    ldst = (unsigned long *)(dst + width * height + i * width / 4);
+    if (yvu)
+      ldst = (unsigned long *)(dst + (width * height * 5) / 4 + i * width / 4);
+    else
+      ldst = (unsigned long *)(dst + width * height + i * width / 4);
     for (j = 0; j < width/2; j += sizeof(long)) {
       *ldst = *lsrc++;
       *ldst++ ^= 0x8080808080808080ULL;
     }
 
     /* -128 - 127 --> 0 - 255 and copy 1 line V */
-    ldst = (unsigned long *)(dst + (width * height * 5) / 4 + i * width / 4);
+    if (yvu)
+      ldst = (unsigned long *)(dst + width * height + i * width / 4);
+    else
+      ldst = (unsigned long *)(dst + (width * height * 5) / 4 + i * width / 4);
     for (j = 0; j < width/2; j += sizeof(long)) {
       *ldst = *lsrc++;
       *ldst++ ^= 0x8080808080808080ULL;