clean up bilinear filter

make reference version of bilinear_filters short.
use reference versions of bilinear_filters and sub_pel_filters when
possible.

recognize that Width was being passed into
filter_block2d_bil_first_pass multiple times. ARM version had already
fixed this. propegate to C.

change references to src_pixels_per_line to src_pitch and standardize on
src/dst (instead of input/output).

recognize that first_pass is only run in the verticle and second_pass
only horizontal. ARM version had already fixed this. propegate to C

Change-Id: I292d376d239a9a7ca37ec2bf03cc0720606983e2

6 files changed, 163 insertions, 298 deletions

diff --git a/vp8/common/arm/armv6/bilinearfilter_v6.asm b/vp8/common/arm/armv6/bilinearfilter_v6.asm
index 09d7338d9..a86ed5d0a 100644
--- a/vp8/common/arm/armv6/bilinearfilter_v6.asm
+++ b/vp8/common/arm/armv6/bilinearfilter_v6.asm
@@ -15,19 +15,19 @@
     AREA    |.text|, CODE, READONLY  ; name this block of code
 
 ;-------------------------------------
-; r0    unsigned char *src_ptr,
-; r1    unsigned short *output_ptr,
-; r2    unsigned int src_pixels_per_line,
-; r3    unsigned int output_height,
-; stack    unsigned int output_width,
-; stack    const short *vp8_filter
+; r0    unsigned char  *src_ptr,
+; r1    unsigned short *dst_ptr,
+; r2    unsigned int    src_pitch,
+; r3    unsigned int    height,
+; stack unsigned int    width,
+; stack const short    *vp8_filter
 ;-------------------------------------
 ; The output is transposed stroed in output array to make it easy for second pass filtering.
 |vp8_filter_block2d_bil_first_pass_armv6| PROC
     stmdb   sp!, {r4 - r11, lr}
 
     ldr     r11, [sp, #40]                  ; vp8_filter address
-    ldr     r4, [sp, #36]                   ; output width
+    ldr     r4, [sp, #36]                   ; width
 
     mov     r12, r3                         ; outer-loop counter
     sub     r2, r2, r4                      ; src increment for height loop
@@ -38,10 +38,10 @@
 
     ldr     r5, [r11]                       ; load up filter coefficients
 
-    mov     r3, r3, lsl #1                  ; output_height*2
+    mov     r3, r3, lsl #1                  ; height*2
     add     r3, r3, #2                      ; plus 2 to make output buffer 4-bit aligned since height is actually (height+1)
 
-    mov     r11, r1                         ; save output_ptr for each row
+    mov     r11, r1                         ; save dst_ptr for each row
 
     cmp     r5, #128                        ; if filter coef = 128, then skip the filter
     beq     bil_null_1st_filter
@@ -140,17 +140,17 @@
 
 ;---------------------------------
 ; r0    unsigned short *src_ptr,
-; r1    unsigned char *output_ptr,
-; r2    int output_pitch,
-; r3    unsigned int  output_height,
-; stack unsigned int  output_width,
-; stack const short *vp8_filter
+; r1    unsigned char  *dst_ptr,
+; r2    int             dst_pitch,
+; r3    unsigned int    height,
+; stack unsigned int    width,
+; stack const short    *vp8_filter
 ;---------------------------------
 |vp8_filter_block2d_bil_second_pass_armv6| PROC
     stmdb   sp!, {r4 - r11, lr}
 
     ldr     r11, [sp, #40]                  ; vp8_filter address
-    ldr     r4, [sp, #36]                   ; output width
+    ldr     r4, [sp, #36]                   ; width
 
     ldr     r5, [r11]                       ; load up filter coefficients
     mov     r12, r4                         ; outer-loop counter = width, since we work on transposed data matrix
diff --git a/vp8/common/arm/bilinearfilter_arm.c b/vp8/common/arm/bilinearfilter_arm.c
index 65afb41a1..961d142c9 100644
--- a/vp8/common/arm/bilinearfilter_arm.c
+++ b/vp8/common/arm/bilinearfilter_arm.c
@@ -10,128 +10,48 @@
 
 
 #include <math.h>
+#include "filter.h"
 #include "subpixel.h"
 
-#define BLOCK_HEIGHT_WIDTH 4
-#define VP8_FILTER_WEIGHT 128
-#define VP8_FILTER_SHIFT  7
-
-static const short bilinear_filters[8][2] =
-{
-    { 128,   0 },
-    { 112,  16 },
-    {  96,  32 },
-    {  80,  48 },
-    {  64,  64 },
-    {  48,  80 },
-    {  32,  96 },
-    {  16, 112 }
-};
-
-
 extern void vp8_filter_block2d_bil_first_pass_armv6
 (
-    unsigned char *src_ptr,
-    unsigned short *output_ptr,
-    unsigned int src_pixels_per_line,
-    unsigned int output_height,
-    unsigned int output_width,
-    const short *vp8_filter
+    unsigned char  *src_ptr,
+    unsigned short *dst_ptr,
+    unsigned int    src_pitch,
+    unsigned int    height,
+    unsigned int    width,
+    const short    *vp8_filter
 );
 
 extern void vp8_filter_block2d_bil_second_pass_armv6
 (
     unsigned short *src_ptr,
-    unsigned char  *output_ptr,
-    int output_pitch,
-    unsigned int  output_height,
-    unsigned int  output_width,
-    const short *vp8_filter
+    unsigned char  *dst_ptr,
+    int             dst_pitch,
+    unsigned int    height,
+    unsigned int    width,
+    const short    *vp8_filter
 );
 
-#if 0
-void vp8_filter_block2d_bil_first_pass_6
-(
-    unsigned char *src_ptr,
-    unsigned short *output_ptr,
-    unsigned int src_pixels_per_line,
-    unsigned int output_height,
-    unsigned int output_width,
-    const short *vp8_filter
-)
-{
-    unsigned int i, j;
-
-    for ( i=0; i<output_height; i++ )
-    {
-        for ( j=0; j<output_width; j++ )
-        {
-            /* Apply bilinear filter */
-            output_ptr[j] = ( ( (int)src_ptr[0]          * vp8_filter[0]) +
-                               ((int)src_ptr[1] * vp8_filter[1]) +
-                                (VP8_FILTER_WEIGHT/2) ) >> VP8_FILTER_SHIFT;
-            src_ptr++;
-        }
-
-        /* Next row... */
-        src_ptr    += src_pixels_per_line - output_width;
-        output_ptr += output_width;
-    }
-}
-
-void vp8_filter_block2d_bil_second_pass_6
-(
-    unsigned short *src_ptr,
-    unsigned char  *output_ptr,
-    int output_pitch,
-    unsigned int  output_height,
-    unsigned int  output_width,
-    const short *vp8_filter
-)
-{
-    unsigned int  i,j;
-    int  Temp;
-
-    for ( i=0; i<output_height; i++ )
-    {
-        for ( j=0; j<output_width; j++ )
-        {
-            /* Apply filter */
-            Temp =  ((int)src_ptr[0]         * vp8_filter[0]) +
-                    ((int)src_ptr[output_width] * vp8_filter[1]) +
-                    (VP8_FILTER_WEIGHT/2);
-            output_ptr[j] = (unsigned int)(Temp >> VP8_FILTER_SHIFT);
-            src_ptr++;
-        }
-
-        /* Next row... */
-        /*src_ptr    += src_pixels_per_line - output_width;*/
-        output_ptr += output_pitch;
-    }
-}
-#endif
-
 void vp8_filter_block2d_bil_armv6
 (
     unsigned char *src_ptr,
-    unsigned char *output_ptr,
-    unsigned int   src_pixels_per_line,
+    unsigned char *dst_ptr,
+    unsigned int   src_pitch,
     unsigned int   dst_pitch,
-    const short      *HFilter,
-    const short      *VFilter,
+    const short   *HFilter,
+    const short   *VFilter,
     int            Width,
     int            Height
 )
 {
-
-    unsigned short FData[36*16]; /* Temp data bufffer used in filtering */
+    unsigned short FData[36*16]; /* Temp data buffer used in filtering */
 
     /* First filter 1-D horizontally... */
-    /* pixel_step = 1; */
-    vp8_filter_block2d_bil_first_pass_armv6(src_ptr, FData, src_pixels_per_line, Height + 1, Width, HFilter);
+    vp8_filter_block2d_bil_first_pass_armv6(src_ptr, FData, src_pitch, Height + 1, Width, HFilter);
 
     /* then 1-D vertically... */
-    vp8_filter_block2d_bil_second_pass_armv6(FData, output_ptr, dst_pitch, Height, Width, VFilter);
+    vp8_filter_block2d_bil_second_pass_armv6(FData, dst_ptr, dst_pitch, Height, Width, VFilter);
 }
 
 
@@ -148,8 +68,8 @@ void vp8_bilinear_predict4x4_armv6
     const short  *HFilter;
     const short  *VFilter;
 
-    HFilter = bilinear_filters[xoffset];
-    VFilter = bilinear_filters[yoffset];
+    HFilter = vp8_bilinear_filters[xoffset];
+    VFilter = vp8_bilinear_filters[yoffset];
 
     vp8_filter_block2d_bil_armv6(src_ptr, dst_ptr, src_pixels_per_line, dst_pitch, HFilter, VFilter, 4, 4);
 }
@@ -167,8 +87,8 @@ void vp8_bilinear_predict8x8_armv6
     const short  *HFilter;
     const short  *VFilter;
 
-    HFilter = bilinear_filters[xoffset];
-    VFilter = bilinear_filters[yoffset];
+    HFilter = vp8_bilinear_filters[xoffset];
+    VFilter = vp8_bilinear_filters[yoffset];
 
     vp8_filter_block2d_bil_armv6(src_ptr, dst_ptr, src_pixels_per_line, dst_pitch, HFilter, VFilter, 8, 8);
 }
@@ -186,8 +106,8 @@ void vp8_bilinear_predict8x4_armv6
     const short  *HFilter;
     const short  *VFilter;
 
-    HFilter = bilinear_filters[xoffset];
-    VFilter = bilinear_filters[yoffset];
+    HFilter = vp8_bilinear_filters[xoffset];
+    VFilter = vp8_bilinear_filters[yoffset];
 
     vp8_filter_block2d_bil_armv6(src_ptr, dst_ptr, src_pixels_per_line, dst_pitch, HFilter, VFilter, 8, 4);
 }
@@ -205,8 +125,8 @@ void vp8_bilinear_predict16x16_armv6
     const short  *HFilter;
     const short  *VFilter;
 
-    HFilter = bilinear_filters[xoffset];
-    VFilter = bilinear_filters[yoffset];
+    HFilter = vp8_bilinear_filters[xoffset];
+    VFilter = vp8_bilinear_filters[yoffset];
 
     vp8_filter_block2d_bil_armv6(src_ptr, dst_ptr, src_pixels_per_line, dst_pitch, HFilter, VFilter, 16, 16);
 }
diff --git a/vp8/common/arm/filter_arm.c b/vp8/common/arm/filter_arm.c
index b4f2fe6ca..2612fc18a 100644
--- a/vp8/common/arm/filter_arm.c
+++ b/vp8/common/arm/filter_arm.c
@@ -11,26 +11,10 @@
 
 #include "vpx_ports/config.h"
 #include <math.h>
+#include "filter.h"
 #include "subpixel.h"
 #include "vpx_ports/mem.h"
 
-#define BLOCK_HEIGHT_WIDTH 4
-#define VP8_FILTER_WEIGHT 128
-#define VP8_FILTER_SHIFT  7
-
-DECLARE_ALIGNED(16, static const short, sub_pel_filters[8][6]) =
-{
-    { 0,  0,  128,    0,   0,  0 },         /* note that 1/8 pel positions are just as per alpha -0.5 bicubic */
-    { 0, -6,  123,   12,  -1,  0 },
-    { 2, -11, 108,   36,  -8,  1 },         /* New 1/4 pel 6 tap filter */
-    { 0, -9,   93,   50,  -6,  0 },
-    { 3, -16,  77,   77, -16,  3 },         /* New 1/2 pel 6 tap filter */
-    { 0, -6,   50,   93,  -9,  0 },
-    { 1, -8,   36,  108, -11,  2 },         /* New 1/4 pel 6 tap filter */
-    { 0, -1,   12,  123,  -6,  0 },
-};
-
-
 extern void vp8_filter_block2d_first_pass_armv6
 (
     unsigned char *src_ptr,
@@ -93,11 +77,11 @@ void vp8_sixtap_predict_armv6
 {
     const short  *HFilter;
     const short  *VFilter;
-    DECLARE_ALIGNED_ARRAY(4, short, FData, 12*4); /* Temp data bufffer used in filtering */
+    DECLARE_ALIGNED_ARRAY(4, short, FData, 12*4); /* Temp data buffer used in filtering */
 
 
-    HFilter = sub_pel_filters[xoffset];   /* 6 tap */
-    VFilter = sub_pel_filters[yoffset];       /* 6 tap */
+    HFilter = vp8_sub_pel_filters[xoffset];   /* 6 tap */
+    VFilter = vp8_sub_pel_filters[yoffset];   /* 6 tap */
 
     /* Vfilter is null. First pass only */
     if (xoffset && !yoffset)
@@ -129,47 +113,6 @@ void vp8_sixtap_predict_armv6
     }
 }
 
-#if 0
-void vp8_sixtap_predict8x4_armv6
-(
-    unsigned char  *src_ptr,
-    int  src_pixels_per_line,
-    int  xoffset,
-    int  yoffset,
-    unsigned char *dst_ptr,
-    int  dst_pitch
-)
-{
-    const short  *HFilter;
-    const short  *VFilter;
-    DECLARE_ALIGNED_ARRAY(4, short, FData, 16*8); /* Temp data bufffer used in filtering */
-
-    HFilter = sub_pel_filters[xoffset];   /* 6 tap */
-    VFilter = sub_pel_filters[yoffset];       /* 6 tap */
-
-
-    /*if (xoffset && !yoffset)
-    {
-        vp8_filter_block2d_first_pass_only_armv6 (  src_ptr, dst_ptr, src_pixels_per_line, 8, dst_pitch, HFilter );
-    }*/
-    /* Hfilter is null. Second pass only */
-    /*else if (!xoffset && yoffset)
-    {
-        vp8_filter_block2d_second_pass_only_armv6 ( src_ptr, dst_ptr, src_pixels_per_line, 8, dst_pitch, VFilter );
-    }
-    else
-    {
-        if (yoffset & 0x1)
-            vp8_filter_block2d_first_pass_armv6 ( src_ptr-src_pixels_per_line, FData+1, src_pixels_per_line, 8, 7, HFilter );
-        else*/
-
-        vp8_filter_block2d_first_pass_armv6 ( src_ptr-(2*src_pixels_per_line), FData, src_pixels_per_line, 8, 9, HFilter );
-
-        vp8_filter_block2d_second_pass_armv6 ( FData+2, dst_ptr, dst_pitch, 4, 8, VFilter );
-    /*}*/
-}
-#endif
-
 void vp8_sixtap_predict8x8_armv6
 (
     unsigned char  *src_ptr,
@@ -182,10 +125,10 @@ void vp8_sixtap_predict8x8_armv6
 {
     const short  *HFilter;
     const short  *VFilter;
-    DECLARE_ALIGNED_ARRAY(4, short, FData, 16*8); /* Temp data bufffer used in filtering */
+    DECLARE_ALIGNED_ARRAY(4, short, FData, 16*8); /* Temp data buffer used in filtering */
 
-    HFilter = sub_pel_filters[xoffset];   /* 6 tap */
-    VFilter = sub_pel_filters[yoffset];       /* 6 tap */
+    HFilter = vp8_sub_pel_filters[xoffset];   /* 6 tap */
+    VFilter = vp8_sub_pel_filters[yoffset];   /* 6 tap */
 
     if (xoffset && !yoffset)
     {
@@ -224,10 +167,10 @@ void vp8_sixtap_predict16x16_armv6
 {
     const short  *HFilter;
     const short  *VFilter;
-    DECLARE_ALIGNED_ARRAY(4, short, FData, 24*16);    /* Temp data bufffer used in filtering */
+    DECLARE_ALIGNED_ARRAY(4, short, FData, 24*16);    /* Temp data buffer used in filtering */
 
-    HFilter = sub_pel_filters[xoffset];   /* 6 tap */
-    VFilter = sub_pel_filters[yoffset];       /* 6 tap */
+    HFilter = vp8_sub_pel_filters[xoffset];   /* 6 tap */
+    VFilter = vp8_sub_pel_filters[yoffset];   /* 6 tap */
 
     if (xoffset && !yoffset)
     {
diff --git a/vp8/common/filter_c.c b/vp8/common/filter.c
index 399a847d5..6e364a94d 100644
--- a/vp8/common/filter_c.c
+++ b/vp8/common/filter.c
@@ -10,13 +10,10 @@
 
 
 #include <stdlib.h>
+#include "filter.h"
+#include "vpx_ports/mem.h"
 
-#define BLOCK_HEIGHT_WIDTH 4
-#define VP8_FILTER_WEIGHT 128
-#define VP8_FILTER_SHIFT  7
-
-
-static const int bilinear_filters[8][2] =
+DECLARE_ALIGNED(16, const short, vp8_bilinear_filters[8][2]) =
 {
     { 128,   0 },
     { 112,  16 },
@@ -28,8 +25,7 @@ static const int bilinear_filters[8][2] =
     {  16, 112 }
 };
 
-
-static const short sub_pel_filters[8][6] =
+DECLARE_ALIGNED(16, const short, vp8_sub_pel_filters[8][6]) =
 {
 
     { 0,  0,  128,    0,   0,  0 },         /* note that 1/8 pel positions are just as per alpha -0.5 bicubic */
@@ -40,9 +36,6 @@ static const short sub_pel_filters[8][6] =
     { 0, -6,   50,   93,  -9,  0 },
     { 1, -8,   36,  108, -11,  2 },         /* New 1/4 pel 6 tap filter */
     { 0, -1,   12,  123,  -6,  0 },
-
-
-
 };
 
 void vp8_filter_block2d_first_pass
@@ -146,7 +139,7 @@ void vp8_filter_block2d
     const short  *VFilter
 )
 {
-    int FData[9*4]; /* Temp data bufffer used in filtering */
+    int FData[9*4]; /* Temp data buffer used in filtering */
 
     /* First filter 1-D horizontally... */
     vp8_filter_block2d_first_pass(src_ptr - (2 * src_pixels_per_line), FData, src_pixels_per_line, 1, 9, 4, HFilter);
@@ -195,8 +188,8 @@ void vp8_sixtap_predict_c
     const short  *HFilter;
     const short  *VFilter;
 
-    HFilter = sub_pel_filters[xoffset];   /* 6 tap */
-    VFilter = sub_pel_filters[yoffset];   /* 6 tap */
+    HFilter = vp8_sub_pel_filters[xoffset];   /* 6 tap */
+    VFilter = vp8_sub_pel_filters[yoffset];   /* 6 tap */
 
     vp8_filter_block2d(src_ptr, dst_ptr, src_pixels_per_line, dst_pitch, HFilter, VFilter);
 }
@@ -212,10 +205,10 @@ void vp8_sixtap_predict8x8_c
 {
     const short  *HFilter;
     const short  *VFilter;
-    int FData[13*16];   /* Temp data bufffer used in filtering */
+    int FData[13*16];   /* Temp data buffer used in filtering */
 
-    HFilter = sub_pel_filters[xoffset];   /* 6 tap */
-    VFilter = sub_pel_filters[yoffset];   /* 6 tap */
+    HFilter = vp8_sub_pel_filters[xoffset];   /* 6 tap */
+    VFilter = vp8_sub_pel_filters[yoffset];   /* 6 tap */
 
     /* First filter 1-D horizontally... */
     vp8_filter_block2d_first_pass(src_ptr - (2 * src_pixels_per_line), FData, src_pixels_per_line, 1, 13, 8, HFilter);
@@ -238,10 +231,10 @@ void vp8_sixtap_predict8x4_c
 {
     const short  *HFilter;
     const short  *VFilter;
-    int FData[13*16];   /* Temp data bufffer used in filtering */
+    int FData[13*16];   /* Temp data buffer used in filtering */
 
-    HFilter = sub_pel_filters[xoffset];   /* 6 tap */
-    VFilter = sub_pel_filters[yoffset];   /* 6 tap */
+    HFilter = vp8_sub_pel_filters[xoffset];   /* 6 tap */
+    VFilter = vp8_sub_pel_filters[yoffset];   /* 6 tap */
 
     /* First filter 1-D horizontally... */
     vp8_filter_block2d_first_pass(src_ptr - (2 * src_pixels_per_line), FData, src_pixels_per_line, 1, 9, 8, HFilter);
@@ -264,11 +257,11 @@ void vp8_sixtap_predict16x16_c
 {
     const short  *HFilter;
     const short  *VFilter;
-    int FData[21*24];   /* Temp data bufffer used in filtering */
+    int FData[21*24];   /* Temp data buffer used in filtering */
 
 
-    HFilter = sub_pel_filters[xoffset];   /* 6 tap */
-    VFilter = sub_pel_filters[yoffset];   /* 6 tap */
+    HFilter = vp8_sub_pel_filters[xoffset];   /* 6 tap */
+    VFilter = vp8_sub_pel_filters[yoffset];   /* 6 tap */
 
     /* First filter 1-D horizontally... */
     vp8_filter_block2d_first_pass(src_ptr - (2 * src_pixels_per_line), FData, src_pixels_per_line, 1, 21, 16, HFilter);
@@ -283,57 +276,50 @@ void vp8_sixtap_predict16x16_c
  *
  *  ROUTINE       : filter_block2d_bil_first_pass
  *
- *  INPUTS        : UINT8  *src_ptr          : Pointer to source block.
- *                  UINT32 src_pixels_per_line : Stride of input block.
- *                  UINT32 pixel_step        : Offset between filter input samples (see notes).
- *                  UINT32 output_height     : Input block height.
- *                  UINT32 output_width      : Input block width.
- *                  INT32  *vp8_filter          : Array of 2 bi-linear filter taps.
+ *  INPUTS        : UINT8  *src_ptr    : Pointer to source block.
+ *                  UINT32  src_stride : Stride of source block.
+ *                  UINT32  height     : Block height.
+ *                  UINT32  width      : Block width.
+ *                  INT32  *vp8_filter : Array of 2 bi-linear filter taps.
  *
- *  OUTPUTS       : INT32 *output_ptr        : Pointer to filtered block.
+ *  OUTPUTS       : INT32  *dst_ptr    : Pointer to filtered block.
  *
  *  RETURNS       : void
  *
- *  FUNCTION      : Applies a 1-D 2-tap bi-linear filter to the source block in
- *                  either horizontal or vertical direction to produce the
- *                  filtered output block. Used to implement first-pass
- *                  of 2-D separable filter.
+ *  FUNCTION      : Applies a 1-D 2-tap bi-linear filter to the source block
+ *                  in the horizontal direction to produce the filtered output
+ *                  block. Used to implement first-pass of 2-D separable filter.
  *
  *  SPECIAL NOTES : Produces INT32 output to retain precision for next pass.
  *                  Two filter taps should sum to VP8_FILTER_WEIGHT.
- *                  pixel_step defines whether the filter is applied
- *                  horizontally (pixel_step=1) or vertically (pixel_step=stride).
- *                  It defines the offset required to move from one input
- *                  to the next.
  *
  ****************************************************************************/
 void vp8_filter_block2d_bil_first_pass
 (
-    unsigned char *src_ptr,
-    unsigned short *output_ptr,
-    unsigned int src_pixels_per_line,
-    int pixel_step,
-    unsigned int output_height,
-    unsigned int output_width,
-    const int *vp8_filter
+    unsigned char  *src_ptr,
+    unsigned short *dst_ptr,
+    unsigned int    src_stride,
+    unsigned int    height,
+    unsigned int    width,
+    const short    *vp8_filter
 )
 {
     unsigned int i, j;
 
-    for (i = 0; i < output_height; i++)
+    for (i = 0; i < height; i++)
     {
-        for (j = 0; j < output_width; j++)
+        for (j = 0; j < width; j++)
         {
             /* Apply bilinear filter */
-            output_ptr[j] = (((int)src_ptr[0]          * vp8_filter[0]) +
-                             ((int)src_ptr[pixel_step] * vp8_filter[1]) +
-                             (VP8_FILTER_WEIGHT / 2)) >> VP8_FILTER_SHIFT;
+            dst_ptr[j] = (((int)src_ptr[0] * vp8_filter[0]) +
+                          ((int)src_ptr[1] * vp8_filter[1]) +
+                          (VP8_FILTER_WEIGHT / 2)) >> VP8_FILTER_SHIFT;
             src_ptr++;
         }
 
         /* Next row... */
-        src_ptr    += src_pixels_per_line - output_width;
-        output_ptr += output_width;
+        src_ptr += src_stride - width;
+        dst_ptr += width;
     }
 }
 
@@ -341,60 +327,51 @@ void vp8_filter_block2d_bil_first_pass
  *
  *  ROUTINE       : filter_block2d_bil_second_pass
  *
- *  INPUTS        : INT32  *src_ptr          : Pointer to source block.
- *                  UINT32 src_pixels_per_line : Stride of input block.
- *                  UINT32 pixel_step        : Offset between filter input samples (see notes).
- *                  UINT32 output_height     : Input block height.
- *                  UINT32 output_width      : Input block width.
- *                  INT32  *vp8_filter          : Array of 2 bi-linear filter taps.
+ *  INPUTS        : INT32  *src_ptr    : Pointer to source block.
+ *                  UINT32  dst_pitch  : Destination block pitch.
+ *                  UINT32  height     : Block height.
+ *                  UINT32  width      : Block width.
+ *                  INT32  *vp8_filter : Array of 2 bi-linear filter taps.
  *
- *  OUTPUTS       : UINT16 *output_ptr       : Pointer to filtered block.
+ *  OUTPUTS       : UINT16 *dst_ptr    : Pointer to filtered block.
  *
  *  RETURNS       : void
  *
- *  FUNCTION      : Applies a 1-D 2-tap bi-linear filter to the source block in
- *                  either horizontal or vertical direction to produce the
- *                  filtered output block. Used to implement second-pass
- *                  of 2-D separable filter.
+ *  FUNCTION      : Applies a 1-D 2-tap bi-linear filter to the source block
+ *                  in the vertical direction to produce the filtered output
+ *                  block. Used to implement second-pass of 2-D separable filter.
  *
  *  SPECIAL NOTES : Requires 32-bit input as produced by filter_block2d_bil_first_pass.
  *                  Two filter taps should sum to VP8_FILTER_WEIGHT.
- *                  pixel_step defines whether the filter is applied
- *                  horizontally (pixel_step=1) or vertically (pixel_step=stride).
- *                  It defines the offset required to move from one input
- *                  to the next.
  *
  ****************************************************************************/
 void vp8_filter_block2d_bil_second_pass
 (
     unsigned short *src_ptr,
-    unsigned char  *output_ptr,
-    int output_pitch,
-    unsigned int  src_pixels_per_line,
-    unsigned int  pixel_step,
-    unsigned int  output_height,
-    unsigned int  output_width,
-    const int *vp8_filter
+    unsigned char  *dst_ptr,
+    int             dst_pitch,
+    unsigned int    height,
+    unsigned int    width,
+    const short    *vp8_filter
 )
 {
     unsigned int  i, j;
     int  Temp;
 
-    for (i = 0; i < output_height; i++)
+    for (i = 0; i < height; i++)
     {
-        for (j = 0; j < output_width; j++)
+        for (j = 0; j < width; j++)
         {
             /* Apply filter */
-            Temp = ((int)src_ptr[0]         * vp8_filter[0]) +
-                   ((int)src_ptr[pixel_step] * vp8_filter[1]) +
+            Temp = ((int)src_ptr[0]     * vp8_filter[0]) +
+                   ((int)src_ptr[width] * vp8_filter[1]) +
                    (VP8_FILTER_WEIGHT / 2);
-            output_ptr[j] = (unsigned int)(Temp >> VP8_FILTER_SHIFT);
+            dst_ptr[j] = (unsigned int)(Temp >> VP8_FILTER_SHIFT);
             src_ptr++;
         }
 
         /* Next row... */
-        src_ptr    += src_pixels_per_line - output_width;
-        output_ptr += output_pitch;
+        dst_ptr += dst_pitch;
     }
 }
 
@@ -404,11 +381,14 @@ void vp8_filter_block2d_bil_second_pass
  *  ROUTINE       : filter_block2d_bil
  *
  *  INPUTS        : UINT8  *src_ptr          : Pointer to source block.
- *                  UINT32 src_pixels_per_line : Stride of input block.
- *                  INT32  *HFilter         : Array of 2 horizontal filter taps.
- *                  INT32  *VFilter         : Array of 2 vertical filter taps.
+ *                  UINT32  src_pitch        : Stride of source block.
+ *                  UINT32  dst_pitch        : Stride of destination block.
+ *                  INT32  *HFilter          : Array of 2 horizontal filter taps.
+ *                  INT32  *VFilter          : Array of 2 vertical filter taps.
+ *                  INT32  Width             : Block width
+ *                  INT32  Height            : Block height
  *
- *  OUTPUTS       : UINT16 *output_ptr       : Pointer to filtered block.
+ *  OUTPUTS       : UINT16 *dst_ptr       : Pointer to filtered block.
  *
  *  RETURNS       : void
  *
@@ -422,23 +402,23 @@ void vp8_filter_block2d_bil_second_pass
 void vp8_filter_block2d_bil
 (
     unsigned char *src_ptr,
-    unsigned char *output_ptr,
-    unsigned int   src_pixels_per_line,
+    unsigned char *dst_ptr,
+    unsigned int   src_pitch,
     unsigned int   dst_pitch,
-    const int      *HFilter,
-    const int      *VFilter,
+    const short   *HFilter,
+    const short   *VFilter,
     int            Width,
     int            Height
 )
 {
 
-    unsigned short FData[17*16];    /* Temp data bufffer used in filtering */
+    unsigned short FData[17*16];    /* Temp data buffer used in filtering */
 
     /* First filter 1-D horizontally... */
-    vp8_filter_block2d_bil_first_pass(src_ptr, FData, src_pixels_per_line, 1, Height + 1, Width, HFilter);
+    vp8_filter_block2d_bil_first_pass(src_ptr, FData, src_pitch, Height + 1, Width, HFilter);
 
     /* then 1-D vertically... */
-    vp8_filter_block2d_bil_second_pass(FData, output_ptr, dst_pitch, Width, Width, Height, Width, VFilter);
+    vp8_filter_block2d_bil_second_pass(FData, dst_ptr, dst_pitch, Height, Width, VFilter);
 }
 
 
@@ -452,11 +432,11 @@ void vp8_bilinear_predict4x4_c
     int dst_pitch
 )
 {
-    const int  *HFilter;
-    const int  *VFilter;
+    const short *HFilter;
+    const short *VFilter;
 
-    HFilter = bilinear_filters[xoffset];
-    VFilter = bilinear_filters[yoffset];
+    HFilter = vp8_bilinear_filters[xoffset];
+    VFilter = vp8_bilinear_filters[yoffset];
 #if 0
     {
         int i;
@@ -490,11 +470,11 @@ void vp8_bilinear_predict8x8_c
     int  dst_pitch
 )
 {
-    const int  *HFilter;
-    const int  *VFilter;
+    const short *HFilter;
+    const short *VFilter;
 
-    HFilter = bilinear_filters[xoffset];
-    VFilter = bilinear_filters[yoffset];
+    HFilter = vp8_bilinear_filters[xoffset];
+    VFilter = vp8_bilinear_filters[yoffset];
 
     vp8_filter_block2d_bil(src_ptr, dst_ptr, src_pixels_per_line, dst_pitch, HFilter, VFilter, 8, 8);
 
@@ -510,11 +490,11 @@ void vp8_bilinear_predict8x4_c
     int  dst_pitch
 )
 {
-    const int  *HFilter;
-    const int  *VFilter;
+    const short *HFilter;
+    const short *VFilter;
 
-    HFilter = bilinear_filters[xoffset];
-    VFilter = bilinear_filters[yoffset];
+    HFilter = vp8_bilinear_filters[xoffset];
+    VFilter = vp8_bilinear_filters[yoffset];
 
     vp8_filter_block2d_bil(src_ptr, dst_ptr, src_pixels_per_line, dst_pitch, HFilter, VFilter, 8, 4);
 
@@ -530,11 +510,11 @@ void vp8_bilinear_predict16x16_c
     int  dst_pitch
 )
 {
-    const int  *HFilter;
-    const int  *VFilter;
+    const short *HFilter;
+    const short *VFilter;
 
-    HFilter = bilinear_filters[xoffset];
-    VFilter = bilinear_filters[yoffset];
+    HFilter = vp8_bilinear_filters[xoffset];
+    VFilter = vp8_bilinear_filters[yoffset];
 
     vp8_filter_block2d_bil(src_ptr, dst_ptr, src_pixels_per_line, dst_pitch, HFilter, VFilter, 16, 16);
 }
diff --git a/vp8/common/filter.h b/vp8/common/filter.h
new file mode 100644
index 000000000..0f225c25a
--- /dev/null
+++ b/vp8/common/filter.h
@@ -0,0 +1,22 @@
+/*
+ *  Copyright (c) 2011 The WebM project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+
+#ifndef FILTER_H
+#define FILTER_H
+
+#define BLOCK_HEIGHT_WIDTH 4
+#define VP8_FILTER_WEIGHT 128
+#define VP8_FILTER_SHIFT  7
+
+extern const short vp8_bilinear_filters[8][2];
+extern const short vp8_sub_pel_filters[8][6];
+
+#endif //FILTER_H
diff --git a/vp8/vp8_common.mk b/vp8/vp8_common.mk
index c1b87d472..25909456a 100644
--- a/vp8/vp8_common.mk
+++ b/vp8/vp8_common.mk
@@ -35,7 +35,7 @@ VP8_COMMON_SRCS-yes += common/entropy.c
 VP8_COMMON_SRCS-yes += common/entropymode.c
 VP8_COMMON_SRCS-yes += common/entropymv.c
 VP8_COMMON_SRCS-yes += common/extend.c
-VP8_COMMON_SRCS-yes += common/filter_c.c
+VP8_COMMON_SRCS-yes += common/filter.c
 VP8_COMMON_SRCS-yes += common/findnearmv.c
 VP8_COMMON_SRCS-yes += common/generic/systemdependent.c
 VP8_COMMON_SRCS-yes += common/idctllm.c