ref: 4b7baf805f1577daa47b874d291d5bc242a7d03c
dir: libvpx/vpx_scale/generic/vpx_scale.c
/*
* Copyright (c) 2010 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.
*/
/****************************************************************************
*
* Module Title : scale.c
*
* Description : Image scaling functions.
*
***************************************************************************/
/****************************************************************************
* Header Files
****************************************************************************/
#include "./vpx_scale_rtcd.h"
#include "vpx_mem/vpx_mem.h"
#include "vpx_scale/vpx_scale.h"
#include "vpx_scale/yv12config.h"
typedef struct {
int expanded_frame_width;
int expanded_frame_height;
int HScale;
int HRatio;
int VScale;
int VRatio;
YV12_BUFFER_CONFIG *src_yuv_config;
YV12_BUFFER_CONFIG *dst_yuv_config;
} SCALE_VARS;
/****************************************************************************
*
* ROUTINE : scale1d_2t1_i
*
* INPUTS : const unsigned char *source : Pointer to data to be scaled.
* int source_step : Number of pixels to step on in
* source.
* unsigned int source_scale : Scale for source (UNUSED).
* unsigned int source_length : Length of source (UNUSED).
* unsigned char *dest : Pointer to output data array.
* int dest_step : Number of pixels to step on in
* destination.
* unsigned int dest_scale : Scale for destination
* (UNUSED).
* unsigned int dest_length : Length of destination.
*
* OUTPUTS : None.
*
* RETURNS : void
*
* FUNCTION : Performs 2-to-1 interpolated scaling.
*
* SPECIAL NOTES : None.
*
****************************************************************************/
static void scale1d_2t1_i(const unsigned char *source, int source_step,
unsigned int source_scale, unsigned int source_length,
unsigned char *dest, int dest_step,
unsigned int dest_scale, unsigned int dest_length) {
unsigned int i, j;
unsigned int temp;
int source_pitch = source_step;
(void)source_length;
(void)source_scale;
(void)dest_scale;
source_step *= 2;
dest[0] = source[0];
for (i = dest_step, j = source_step; i < dest_length * dest_step;
i += dest_step, j += source_step) {
temp = 8;
temp += 3 * source[j - source_pitch];
temp += 10 * source[j];
temp += 3 * source[j + source_pitch];
temp >>= 4;
dest[i] = (char)(temp);
}
}
/****************************************************************************
*
* ROUTINE : scale1d_2t1_ps
*
* INPUTS : const unsigned char *source : Pointer to data to be scaled.
* int source_step : Number of pixels to step on in
* source.
* unsigned int source_scale : Scale for source (UNUSED).
* unsigned int source_length : Length of source (UNUSED).
* unsigned char *dest : Pointer to output data array.
* int dest_step : Number of pixels to step on in
* destination.
* unsigned int dest_scale : Scale for destination
* (UNUSED).
* unsigned int dest_length : Length of destination.
*
* OUTPUTS : None.
*
* RETURNS : void
*
* FUNCTION : Performs 2-to-1 point subsampled scaling.
*
* SPECIAL NOTES : None.
*
****************************************************************************/
static void scale1d_2t1_ps(const unsigned char *source, int source_step,
unsigned int source_scale,
unsigned int source_length, unsigned char *dest,
int dest_step, unsigned int dest_scale,
unsigned int dest_length) {
unsigned int i, j;
(void)source_length;
(void)source_scale;
(void)dest_scale;
source_step *= 2;
j = 0;
for (i = 0; i < dest_length * dest_step; i += dest_step, j += source_step)
dest[i] = source[j];
}
/****************************************************************************
*
* ROUTINE : scale1d_c
*
* INPUTS : const unsigned char *source : Pointer to data to be scaled.
* int source_step : Number of pixels to step on in
* source.
* unsigned int source_scale : Scale for source.
* unsigned int source_length : Length of source (UNUSED).
* unsigned char *dest : Pointer to output data array.
* int dest_step : Number of pixels to step on in
* destination.
* unsigned int dest_scale : Scale for destination.
* unsigned int dest_length : Length of destination.
*
* OUTPUTS : None.
*
* RETURNS : void
*
* FUNCTION : Performs linear interpolation in one dimension.
*
* SPECIAL NOTES : None.
*
****************************************************************************/
static void scale1d_c(const unsigned char *source, int source_step,
unsigned int source_scale, unsigned int source_length,
unsigned char *dest, int dest_step,
unsigned int dest_scale, unsigned int dest_length) {
unsigned int i;
unsigned int round_value = dest_scale / 2;
unsigned int left_modifier = dest_scale;
unsigned int right_modifier = 0;
unsigned char left_pixel = *source;
unsigned char right_pixel = *(source + source_step);
(void)source_length;
/* These asserts are needed if there are boundary issues... */
/*assert ( dest_scale > source_scale );*/
/*assert ( (source_length-1) * dest_scale >= (dest_length-1) * source_scale
* );*/
for (i = 0; i < dest_length * dest_step; i += dest_step) {
dest[i] = (char)((left_modifier * left_pixel +
right_modifier * right_pixel + round_value) /
dest_scale);
right_modifier += source_scale;
while (right_modifier > dest_scale) {
right_modifier -= dest_scale;
source += source_step;
left_pixel = *source;
right_pixel = *(source + source_step);
}
left_modifier = dest_scale - right_modifier;
}
}
/****************************************************************************
*
* ROUTINE : Scale2D
*
* INPUTS : const unsigned char *source : Pointer to data to be
* scaled.
* int source_pitch : Stride of source image.
* unsigned int source_width : Width of input image.
* unsigned int source_height : Height of input image.
* unsigned char *dest : Pointer to output data
* array.
* int dest_pitch : Stride of destination
* image.
* unsigned int dest_width : Width of destination image.
* unsigned int dest_height : Height of destination
* image.
* unsigned char *temp_area : Pointer to temp work area.
* unsigned char temp_area_height : Height of temp work area.
* unsigned int hscale : Horizontal scale factor
* numerator.
* unsigned int hratio : Horizontal scale factor
* denominator.
* unsigned int vscale : Vertical scale factor
* numerator.
* unsigned int vratio : Vertical scale factor
* denominator.
* unsigned int interlaced : Interlace flag.
*
* OUTPUTS : None.
*
* RETURNS : void
*
* FUNCTION : Performs 2-tap linear interpolation in two dimensions.
*
* SPECIAL NOTES : Expansion is performed one band at a time to help with
* caching.
*
****************************************************************************/
static void Scale2D(
/*const*/
unsigned char *source, int source_pitch, unsigned int source_width,
unsigned int source_height, unsigned char *dest, int dest_pitch,
unsigned int dest_width, unsigned int dest_height, unsigned char *temp_area,
unsigned char temp_area_height, unsigned int hscale, unsigned int hratio,
unsigned int vscale, unsigned int vratio, unsigned int interlaced) {
/*unsigned*/
int i, j, k;
int bands;
int dest_band_height;
int source_band_height;
typedef void (*Scale1D)(const unsigned char *source, int source_step,
unsigned int source_scale, unsigned int source_length,
unsigned char *dest, int dest_step,
unsigned int dest_scale, unsigned int dest_length);
Scale1D Scale1Dv = scale1d_c;
Scale1D Scale1Dh = scale1d_c;
void (*horiz_line_scale)(const unsigned char *, unsigned int, unsigned char *,
unsigned int) = NULL;
void (*vert_band_scale)(unsigned char *, unsigned int, unsigned char *,
unsigned int, unsigned int) = NULL;
int ratio_scalable = 1;
int interpolation = 0;
unsigned char *source_base;
unsigned char *line_src;
source_base = (unsigned char *)source;
if (source_pitch < 0) {
int offset;
offset = (source_height - 1);
offset *= source_pitch;
source_base += offset;
}
/* find out the ratio for each direction */
switch (hratio * 10 / hscale) {
case 8:
/* 4-5 Scale in Width direction */
horiz_line_scale = vp8_horizontal_line_5_4_scale;
break;
case 6:
/* 3-5 Scale in Width direction */
horiz_line_scale = vp8_horizontal_line_5_3_scale;
break;
case 5:
/* 1-2 Scale in Width direction */
horiz_line_scale = vp8_horizontal_line_2_1_scale;
break;
default:
/* The ratio is not acceptable now */
/* throw("The ratio is not acceptable for now!"); */
ratio_scalable = 0;
break;
}
switch (vratio * 10 / vscale) {
case 8:
/* 4-5 Scale in vertical direction */
vert_band_scale = vp8_vertical_band_5_4_scale;
source_band_height = 5;
dest_band_height = 4;
break;
case 6:
/* 3-5 Scale in vertical direction */
vert_band_scale = vp8_vertical_band_5_3_scale;
source_band_height = 5;
dest_band_height = 3;
break;
case 5:
/* 1-2 Scale in vertical direction */
if (interlaced) {
/* if the content is interlaced, point sampling is used */
vert_band_scale = vp8_vertical_band_2_1_scale;
} else {
interpolation = 1;
/* if the content is progressive, interplo */
vert_band_scale = vp8_vertical_band_2_1_scale_i;
}
source_band_height = 2;
dest_band_height = 1;
break;
default:
/* The ratio is not acceptable now */
/* throw("The ratio is not acceptable for now!"); */
ratio_scalable = 0;
break;
}
if (ratio_scalable) {
if (source_height == dest_height) {
/* for each band of the image */
for (k = 0; k < (int)dest_height; k++) {
horiz_line_scale(source, source_width, dest, dest_width);
source += source_pitch;
dest += dest_pitch;
}
return;
}
if (interpolation) {
if (source < source_base) source = source_base;
horiz_line_scale(source, source_width, temp_area, dest_width);
}
for (k = 0;
k < (int)(dest_height + dest_band_height - 1) / dest_band_height;
k++) {
/* scale one band horizontally */
for (i = 0; i < source_band_height; i++) {
/* Trap case where we could read off the base of the source buffer */
line_src = (unsigned char *)source + i * source_pitch;
if (line_src < source_base) line_src = source_base;
horiz_line_scale(line_src, source_width,
temp_area + (i + 1) * dest_pitch, dest_width);
}
/* Vertical scaling is in place */
vert_band_scale(temp_area + dest_pitch, dest_pitch, dest, dest_pitch,
dest_width);
if (interpolation)
memcpy(temp_area, temp_area + source_band_height * dest_pitch,
dest_width);
/* Next band... */
source += (unsigned long)source_band_height * source_pitch;
dest += (unsigned long)dest_band_height * dest_pitch;
}
return;
}
if (hscale == 2 && hratio == 1) Scale1Dh = scale1d_2t1_ps;
if (vscale == 2 && vratio == 1) {
if (interlaced)
Scale1Dv = scale1d_2t1_ps;
else
Scale1Dv = scale1d_2t1_i;
}
if (source_height == dest_height) {
/* for each band of the image */
for (k = 0; k < (int)dest_height; k++) {
Scale1Dh(source, 1, hscale, source_width + 1, dest, 1, hratio,
dest_width);
source += source_pitch;
dest += dest_pitch;
}
return;
}
if (dest_height > source_height) {
dest_band_height = temp_area_height - 1;
source_band_height = dest_band_height * source_height / dest_height;
} else {
source_band_height = temp_area_height - 1;
dest_band_height = source_band_height * vratio / vscale;
}
/* first row needs to be done so that we can stay one row ahead for vertical
* zoom */
Scale1Dh(source, 1, hscale, source_width + 1, temp_area, 1, hratio,
dest_width);
/* for each band of the image */
bands = (dest_height + dest_band_height - 1) / dest_band_height;
for (k = 0; k < bands; k++) {
/* scale one band horizontally */
for (i = 1; i < source_band_height + 1; i++) {
if (k * source_band_height + i < (int)source_height) {
Scale1Dh(source + i * source_pitch, 1, hscale, source_width + 1,
temp_area + i * dest_pitch, 1, hratio, dest_width);
} else { /* Duplicate the last row */
/* copy temp_area row 0 over from last row in the past */
memcpy(temp_area + i * dest_pitch, temp_area + (i - 1) * dest_pitch,
dest_pitch);
}
}
/* scale one band vertically */
for (j = 0; j < (int)dest_width; j++) {
Scale1Dv(&temp_area[j], dest_pitch, vscale, source_band_height + 1,
&dest[j], dest_pitch, vratio, dest_band_height);
}
/* copy temp_area row 0 over from last row in the past */
memcpy(temp_area, temp_area + source_band_height * dest_pitch, dest_pitch);
/* move to the next band */
source += source_band_height * source_pitch;
dest += dest_band_height * dest_pitch;
}
}
/****************************************************************************
*
* ROUTINE : vpx_scale_frame
*
* INPUTS : YV12_BUFFER_CONFIG *src : Pointer to frame to be
* scaled.
* YV12_BUFFER_CONFIG *dst : Pointer to buffer to hold
* scaled frame.
* unsigned char *temp_area : Pointer to temp work area.
* unsigned char temp_area_height : Height of temp work area.
* unsigned int hscale : Horizontal scale factor
* numerator.
* unsigned int hratio : Horizontal scale factor
* denominator.
* unsigned int vscale : Vertical scale factor
* numerator.
* unsigned int vratio : Vertical scale factor
* denominator.
* unsigned int interlaced : Interlace flag.
*
* OUTPUTS : None.
*
* RETURNS : void
*
* FUNCTION : Performs 2-tap linear interpolation in two dimensions.
*
* SPECIAL NOTES : Expansion is performed one band at a time to help with
* caching.
*
****************************************************************************/
void vpx_scale_frame(YV12_BUFFER_CONFIG *src, YV12_BUFFER_CONFIG *dst,
unsigned char *temp_area, unsigned char temp_height,
unsigned int hscale, unsigned int hratio,
unsigned int vscale, unsigned int vratio,
unsigned int interlaced) {
int i;
int dw = (hscale - 1 + src->y_width * hratio) / hscale;
int dh = (vscale - 1 + src->y_height * vratio) / vscale;
/* call our internal scaling routines!! */
Scale2D((unsigned char *)src->y_buffer, src->y_stride, src->y_width,
src->y_height, (unsigned char *)dst->y_buffer, dst->y_stride, dw, dh,
temp_area, temp_height, hscale, hratio, vscale, vratio, interlaced);
if (dw < (int)dst->y_width)
for (i = 0; i < dh; i++)
memset(dst->y_buffer + i * dst->y_stride + dw - 1,
dst->y_buffer[i * dst->y_stride + dw - 2], dst->y_width - dw + 1);
if (dh < (int)dst->y_height)
for (i = dh - 1; i < (int)dst->y_height; i++)
memcpy(dst->y_buffer + i * dst->y_stride,
dst->y_buffer + (dh - 2) * dst->y_stride, dst->y_width + 1);
Scale2D((unsigned char *)src->u_buffer, src->uv_stride, src->uv_width,
src->uv_height, (unsigned char *)dst->u_buffer, dst->uv_stride,
dw / 2, dh / 2, temp_area, temp_height, hscale, hratio, vscale,
vratio, interlaced);
if (dw / 2 < (int)dst->uv_width)
for (i = 0; i < dst->uv_height; i++)
memset(dst->u_buffer + i * dst->uv_stride + dw / 2 - 1,
dst->u_buffer[i * dst->uv_stride + dw / 2 - 2],
dst->uv_width - dw / 2 + 1);
if (dh / 2 < (int)dst->uv_height)
for (i = dh / 2 - 1; i < (int)dst->y_height / 2; i++)
memcpy(dst->u_buffer + i * dst->uv_stride,
dst->u_buffer + (dh / 2 - 2) * dst->uv_stride, dst->uv_width);
Scale2D((unsigned char *)src->v_buffer, src->uv_stride, src->uv_width,
src->uv_height, (unsigned char *)dst->v_buffer, dst->uv_stride,
dw / 2, dh / 2, temp_area, temp_height, hscale, hratio, vscale,
vratio, interlaced);
if (dw / 2 < (int)dst->uv_width)
for (i = 0; i < dst->uv_height; i++)
memset(dst->v_buffer + i * dst->uv_stride + dw / 2 - 1,
dst->v_buffer[i * dst->uv_stride + dw / 2 - 2],
dst->uv_width - dw / 2 + 1);
if (dh / 2 < (int)dst->uv_height)
for (i = dh / 2 - 1; i < (int)dst->y_height / 2; i++)
memcpy(dst->v_buffer + i * dst->uv_stride,
dst->v_buffer + (dh / 2 - 2) * dst->uv_stride, dst->uv_width);
}