src/third_party/libvpx/vp8/common/extend.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.
 */

#include "extend.h"
#include "vpx_mem/vpx_mem.h"

static void copy_and_extend_plane(
    unsigned char *s,      /* source */
    int sp,                /* source pitch */
    unsigned char *d,      /* destination */
    int dp,                /* destination pitch */
    int h,                 /* height */
    int w,                 /* width */
    int et,                /* extend top border */
    int el,                /* extend left border */
    int eb,                /* extend bottom border */
    int er,                /* extend right border */
    int interleave_step) { /* step between pixels of the current plane */
  int i, j;
  unsigned char *src_ptr1, *src_ptr2;
  unsigned char *dest_ptr1, *dest_ptr2;
  int linesize;

  if (interleave_step < 1) interleave_step = 1;

  /* copy the left and right most columns out */
  src_ptr1 = s;
  src_ptr2 = s + (w - 1) * interleave_step;
  dest_ptr1 = d - el;
  dest_ptr2 = d + w;

  for (i = 0; i < h; ++i) {
    memset(dest_ptr1, src_ptr1[0], el);
    if (interleave_step == 1) {
      memcpy(dest_ptr1 + el, src_ptr1, w);
    } else {
      for (j = 0; j < w; j++) {
        dest_ptr1[el + j] = src_ptr1[interleave_step * j];
      }
    }
    memset(dest_ptr2, src_ptr2[0], er);
    src_ptr1 += sp;
    src_ptr2 += sp;
    dest_ptr1 += dp;
    dest_ptr2 += dp;
  }

  /* Now copy the top and bottom lines into each line of the respective
   * borders
   */
  src_ptr1 = d - el;
  src_ptr2 = d + dp * (h - 1) - el;
  dest_ptr1 = d + dp * (-et) - el;
  dest_ptr2 = d + dp * (h)-el;
  linesize = el + er + w;

  for (i = 0; i < et; ++i) {
    memcpy(dest_ptr1, src_ptr1, linesize);
    dest_ptr1 += dp;
  }

  for (i = 0; i < eb; ++i) {
    memcpy(dest_ptr2, src_ptr2, linesize);
    dest_ptr2 += dp;
  }
}

void vp8_copy_and_extend_frame(YV12_BUFFER_CONFIG *src,
                               YV12_BUFFER_CONFIG *dst) {
  int et = dst->border;
  int el = dst->border;
  int eb = dst->border + dst->y_height - src->y_height;
  int er = dst->border + dst->y_width - src->y_width;

  // detect nv12 colorspace
  int chroma_step = src->v_buffer - src->u_buffer == 1 ? 2 : 1;

  copy_and_extend_plane(src->y_buffer, src->y_stride, dst->y_buffer,
                        dst->y_stride, src->y_height, src->y_width, et, el, eb,
                        er, 1);

  et = dst->border >> 1;
  el = dst->border >> 1;
  eb = (dst->border >> 1) + dst->uv_height - src->uv_height;
  er = (dst->border >> 1) + dst->uv_width - src->uv_width;

  copy_and_extend_plane(src->u_buffer, src->uv_stride, dst->u_buffer,
                        dst->uv_stride, src->uv_height, src->uv_width, et, el,
                        eb, er, chroma_step);

  copy_and_extend_plane(src->v_buffer, src->uv_stride, dst->v_buffer,
                        dst->uv_stride, src->uv_height, src->uv_width, et, el,
                        eb, er, chroma_step);
}

void vp8_copy_and_extend_frame_with_rect(YV12_BUFFER_CONFIG *src,
                                         YV12_BUFFER_CONFIG *dst, int srcy,
                                         int srcx, int srch, int srcw) {
  int et = dst->border;
  int el = dst->border;
  int eb = dst->border + dst->y_height - src->y_height;
  int er = dst->border + dst->y_width - src->y_width;
  int src_y_offset = srcy * src->y_stride + srcx;
  int dst_y_offset = srcy * dst->y_stride + srcx;
  int src_uv_offset = ((srcy * src->uv_stride) >> 1) + (srcx >> 1);
  int dst_uv_offset = ((srcy * dst->uv_stride) >> 1) + (srcx >> 1);
  // detect nv12 colorspace
  int chroma_step = src->v_buffer - src->u_buffer == 1 ? 2 : 1;

  /* If the side is not touching the bounder then don't extend. */
  if (srcy) et = 0;
  if (srcx) el = 0;
  if (srcy + srch != src->y_height) eb = 0;
  if (srcx + srcw != src->y_width) er = 0;

  copy_and_extend_plane(src->y_buffer + src_y_offset, src->y_stride,
                        dst->y_buffer + dst_y_offset, dst->y_stride, srch, srcw,
                        et, el, eb, er, 1);

  et = (et + 1) >> 1;
  el = (el + 1) >> 1;
  eb = (eb + 1) >> 1;
  er = (er + 1) >> 1;
  srch = (srch + 1) >> 1;
  srcw = (srcw + 1) >> 1;

  copy_and_extend_plane(src->u_buffer + src_uv_offset, src->uv_stride,
                        dst->u_buffer + dst_uv_offset, dst->uv_stride, srch,
                        srcw, et, el, eb, er, chroma_step);

  copy_and_extend_plane(src->v_buffer + src_uv_offset, src->uv_stride,
                        dst->v_buffer + dst_uv_offset, dst->uv_stride, srch,
                        srcw, et, el, eb, er, chroma_step);
}

/* note the extension is only for the last row, for intra prediction purpose */
void vp8_extend_mb_row(YV12_BUFFER_CONFIG *ybf, unsigned char *YPtr,
                       unsigned char *UPtr, unsigned char *VPtr) {
  int i;

  YPtr += ybf->y_stride * 14;
  UPtr += ybf->uv_stride * 6;
  VPtr += ybf->uv_stride * 6;

  for (i = 0; i < 4; ++i) {
    YPtr[i] = YPtr[-1];
    UPtr[i] = UPtr[-1];
    VPtr[i] = VPtr[-1];
  }

  YPtr += ybf->y_stride;
  UPtr += ybf->uv_stride;
  VPtr += ybf->uv_stride;

  for (i = 0; i < 4; ++i) {
    YPtr[i] = YPtr[-1];
    UPtr[i] = UPtr[-1];
    VPtr[i] = VPtr[-1];
  }
}