vpx_scale/generic/yv12config.c

   1 /*
   2  *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
   3  *
   4  *  Use of this source code is governed by a BSD-style license
   5  *  that can be found in the LICENSE file in the root of the source
   6  *  tree. An additional intellectual property rights grant can be found
   7  *  in the file PATENTS.  All contributing project authors may
   8  *  be found in the AUTHORS file in the root of the source tree.
   9  */
  10
  11
  12 #include "vpx_scale/yv12config.h"
  13 #include "vpx_mem/vpx_mem.h"
  14
  15 /****************************************************************************
  16 *  Exports
  17 ****************************************************************************/
  18
  19 /****************************************************************************
  20  *
  21  ****************************************************************************/
  22 int
  23 vp8_yv12_de_alloc_frame_buffer(YV12_BUFFER_CONFIG *ybf)
  24 {
  25     if (ybf)
  26     {
  27         vpx_free(ybf->buffer_alloc);
  28
  29         /* buffer_alloc isn't accessed by most functions.  Rather y_buffer,
  30           u_buffer and v_buffer point to buffer_alloc and are used.  Clear out
  31           all of this so that a freed pointer isn't inadvertently used */
  32         vpx_memset (ybf, 0, sizeof (YV12_BUFFER_CONFIG));
  33     }
  34     else
  35     {
  36         return -1;
  37     }
  38
  39     return 0;
  40 }
  41
  42 /****************************************************************************
  43  *
  44  ****************************************************************************/
  45 int
  46 vp8_yv12_alloc_frame_buffer(YV12_BUFFER_CONFIG *ybf, int width, int height, int border)
  47 {
  48 /*NOTE:*/
  49
  50     if (ybf)
  51     {
  52         int y_stride = ((width + 2 * border) + 31) & ~31;
  53         int yplane_size = (height + 2 * border) * y_stride;
  54         int uv_width = width >> 1;
  55         int uv_height = height >> 1;
  56         /** There is currently a bunch of code which assumes
  57           *  uv_stride == y_stride/2, so enforce this here. */
  58         int uv_stride = y_stride >> 1;
  59         int uvplane_size = (uv_height + border) * uv_stride;
  60
  61         vp8_yv12_de_alloc_frame_buffer(ybf);
  62
  63         /** Only support allocating buffers that have a height and width that
  64           *  are multiples of 16, and a border that's a multiple of 32.
  65           * The border restriction is required to get 16-byte alignment of the
  66           *  start of the chroma rows without intoducing an arbitrary gap
  67           *  between planes, which would break the semantics of things like
  68           *  vpx_img_set_rect(). */
  69         if ((width & 0xf) | (height & 0xf) | (border & 0x1f))
  70             return -3;
  71
  72         ybf->y_width  = width;
  73         ybf->y_height = height;
  74         ybf->y_stride = y_stride;
  75
  76         ybf->uv_width = uv_width;
  77         ybf->uv_height = uv_height;
  78         ybf->uv_stride = uv_stride;
  79
  80         ybf->border = border;
  81         ybf->frame_size = yplane_size + 2 * uvplane_size;
  82
  83         ybf->buffer_alloc = (unsigned char *) vpx_memalign(32, ybf->frame_size);
  84
  85         if (ybf->buffer_alloc == NULL)
  86             return -1;
  87
  88         ybf->y_buffer = ybf->buffer_alloc + (border * y_stride) + border;
  89         ybf->u_buffer = ybf->buffer_alloc + yplane_size + (border / 2  * uv_stride) + border / 2;
  90         ybf->v_buffer = ybf->buffer_alloc + yplane_size + uvplane_size + (border / 2  * uv_stride) + border / 2;
  91
  92         ybf->corrupted = 0; /* assume not currupted by errors */
  93     }
  94     else
  95     {
  96         return -2;
  97     }
  98
  99     return 0;
 100 }