diff --git a/libmpcodecs/img_format.c b/libmpcodecs/img_format.c
index 2c83a643f7..d4f4d59f38 100644
--- a/libmpcodecs/img_format.c
+++ b/libmpcodecs/img_format.c
@@ -79,3 +79,40 @@ const char *vo_format_name(int format)
     snprintf(unknown_format,20,"Unknown 0x%04x",format);
     return unknown_format;
 }
+
+int mp_get_chroma_shift(int format, int *x_shift, int *y_shift)
+{
+    int xs = 0, ys = 0;
+    int err = 0;
+    switch (format) {
+    case IMGFMT_I420:
+    case IMGFMT_IYUV:
+    case IMGFMT_YV12:
+        xs = 1;
+        ys = 1;
+        break;
+    case IMGFMT_IF09:
+    case IMGFMT_YVU9:
+        xs = 2;
+        ys = 2;
+        break;
+    case IMGFMT_444P:
+        xs = 0;
+        ys = 0;
+        break;
+    case IMGFMT_422P:
+        xs = 1;
+        ys = 0;
+        break;
+    case IMGFMT_411P:
+        xs = 2;
+        ys = 0;
+        break;
+    default:
+        err = 1;
+        break;
+    }
+    if (x_shift) *x_shift = xs;
+    if (y_shift) *y_shift = ys;
+    return err ? 0 : 8 + (16 >> (xs + ys));
+}
diff --git a/libmpcodecs/img_format.h b/libmpcodecs/img_format.h
index 4c917b01e4..56d96c481a 100644
--- a/libmpcodecs/img_format.h
+++ b/libmpcodecs/img_format.h
@@ -133,4 +133,11 @@ typedef struct {
 
 const char *vo_format_name(int format);
 
+/**
+ * Calculates the scale shifts for the chroma planes for planar YUV
+ *
+ * \return bits-per-pixel for format if successful (i.e. format is 3 or 4-planes planar YUV), 0 otherwise
+ */
+int mp_get_chroma_shift(int format, int *x_shift, int *y_shift);
+
 #endif /* MPLAYER_IMG_FORMAT_H */
diff --git a/libmpcodecs/mp_image.h b/libmpcodecs/mp_image.h
index 9e02571380..cfc42f81e7 100644
--- a/libmpcodecs/mp_image.h
+++ b/libmpcodecs/mp_image.h
@@ -133,51 +133,24 @@ static inline void mp_image_setfmt(mp_image_t* mpi,unsigned int out_fmt){
     }
     mpi->flags|=MP_IMGFLAG_YUV;
     mpi->num_planes=3;
+    if (mp_get_chroma_shift(out_fmt, NULL, NULL)) {
+        mpi->flags|=MP_IMGFLAG_PLANAR;
+        mpi->bpp = mp_get_chroma_shift(out_fmt, &mpi->chroma_x_shift, &mpi->chroma_y_shift);
+        mpi->chroma_width  = mpi->width  >> mpi->chroma_x_shift;
+        mpi->chroma_height = mpi->height >> mpi->chroma_y_shift;
+    }
     switch(out_fmt){
     case IMGFMT_I420:
     case IMGFMT_IYUV:
 	mpi->flags|=MP_IMGFLAG_SWAPPED;
     case IMGFMT_YV12:
-	mpi->flags|=MP_IMGFLAG_PLANAR;
-	mpi->bpp=12;
-	mpi->chroma_width=(mpi->width>>1);
-	mpi->chroma_height=(mpi->height>>1);
-	mpi->chroma_x_shift=1;
-	mpi->chroma_y_shift=1;
 	return;
     case IMGFMT_IF09:
 	mpi->num_planes=4;
     case IMGFMT_YVU9:
-	mpi->flags|=MP_IMGFLAG_PLANAR;
-	mpi->bpp=9;
-	mpi->chroma_width=(mpi->width>>2);
-	mpi->chroma_height=(mpi->height>>2);
-	mpi->chroma_x_shift=2;
-	mpi->chroma_y_shift=2;
-	return;
     case IMGFMT_444P:
-	mpi->flags|=MP_IMGFLAG_PLANAR;
-	mpi->bpp=24;
-	mpi->chroma_width=(mpi->width);
-	mpi->chroma_height=(mpi->height);
-	mpi->chroma_x_shift=0;
-	mpi->chroma_y_shift=0;
-	return;
     case IMGFMT_422P:
-	mpi->flags|=MP_IMGFLAG_PLANAR;
-	mpi->bpp=16;
-	mpi->chroma_width=(mpi->width>>1);
-	mpi->chroma_height=(mpi->height);
-	mpi->chroma_x_shift=1;
-	mpi->chroma_y_shift=0;
-	return;
     case IMGFMT_411P:
-	mpi->flags|=MP_IMGFLAG_PLANAR;
-	mpi->bpp=12;
-	mpi->chroma_width=(mpi->width>>2);
-	mpi->chroma_height=(mpi->height);
-	mpi->chroma_x_shift=2;
-	mpi->chroma_y_shift=0;
 	return;
     case IMGFMT_Y800:
     case IMGFMT_Y8: