Update libvpx snapshot to v0.9.7-p1 (Cayuga).

source/libvpx/vpx_scale/generic/yv12config.c

Index: source/libvpx/vpx_scale/generic/yv12config.c
===================================================================
--- source/libvpx/vpx_scale/generic/yv12config.c	(revision 96967)
+++ source/libvpx/vpx_scale/generic/yv12config.c	(working copy)
@@ -24,9 +24,12 @@
 {
     if (ybf)
     {
-            duck_free(ybf->buffer_alloc);
+        vpx_free(ybf->buffer_alloc);
 
-        ybf->buffer_alloc = 0;
+        /* buffer_alloc isn't accessed by most functions.  Rather y_buffer,
+          u_buffer and v_buffer point to buffer_alloc and are used.  Clear out
+          all of this so that a freed pointer isn't inadvertently used */
+        vpx_memset (ybf, 0, sizeof (YV12_BUFFER_CONFIG));
     }
     else
     {
@@ -44,41 +47,48 @@
 {
 /*NOTE:*/
 
-    int yplane_size = (height + 2 * border) * (width + 2 * border);
-    int uvplane_size = ((1 + height) / 2 + border) * ((1 + width) / 2 + border);
-
     if (ybf)
     {
+        int y_stride = ((width + 2 * border) + 31) & ~31;
+        int yplane_size = (height + 2 * border) * y_stride;
+        int uv_width = width >> 1;
+        int uv_height = height >> 1;
+        /** There is currently a bunch of code which assumes
+          *  uv_stride == y_stride/2, so enforce this here. */
+        int uv_stride = y_stride >> 1;
+        int uvplane_size = (uv_height + border) * uv_stride;
+
         vp8_yv12_de_alloc_frame_buffer(ybf);
 
+        /** Only support allocating buffers that have a height and width that
+          *  are multiples of 16, and a border that's a multiple of 32.
+          * The border restriction is required to get 16-byte alignment of the
+          *  start of the chroma rows without intoducing an arbitrary gap
+          *  between planes, which would break the semantics of things like
+          *  vpx_img_set_rect(). */
+        if ((width & 0xf) | (height & 0xf) | (border & 0x1f))
+            return -3;
+
         ybf->y_width  = width;
         ybf->y_height = height;
-        ybf->y_stride = width + 2 * border;
+        ybf->y_stride = y_stride;
 
-        ybf->uv_width = (1 + width) / 2;
-        ybf->uv_height = (1 + height) / 2;
-        ybf->uv_stride = ybf->uv_width + border;
+        ybf->uv_width = uv_width;
+        ybf->uv_height = uv_height;
+        ybf->uv_stride = uv_stride;
 
         ybf->border = border;
         ybf->frame_size = yplane_size + 2 * uvplane_size;
 
-        /* Added 2 extra lines to framebuffer so that copy12x12 doesn't fail
-         * when we have a large motion vector in V on the last v block.
-         * Note : We never use these pixels anyway so this doesn't hurt.
-         */
-        ybf->buffer_alloc = (unsigned char *) duck_memalign(32,  ybf->frame_size + (ybf->y_stride * 2) + 32, 0);
+        ybf->buffer_alloc = (unsigned char *) vpx_memalign(32, ybf->frame_size);
 
         if (ybf->buffer_alloc == NULL)
             return -1;
 
-        ybf->y_buffer = ybf->buffer_alloc + (border * ybf->y_stride) + border;
+        ybf->y_buffer = ybf->buffer_alloc + (border * y_stride) + border;
+        ybf->u_buffer = ybf->buffer_alloc + yplane_size + (border / 2  * uv_stride) + border / 2;
+        ybf->v_buffer = ybf->buffer_alloc + yplane_size + uvplane_size + (border / 2  * uv_stride) + border / 2;
 
-        if (yplane_size & 0xf)
-            yplane_size += 16 - (yplane_size & 0xf);
-
-        ybf->u_buffer = ybf->buffer_alloc + yplane_size + (border / 2  * ybf->uv_stride) + border / 2;
-        ybf->v_buffer = ybf->buffer_alloc + yplane_size + uvplane_size + (border / 2  * ybf->uv_stride) + border / 2;
-
         ybf->corrupted = 0; /* assume not currupted by errors */
     }
     else