drivers/media/video/pwc/pwc-uncompress.c

   1 /* Linux driver for Philips webcam
   2    Decompression frontend.
   3    (C) 1999-2003 Nemosoft Unv.
   4    (C) 2004      Luc Saillard (luc@saillard.org)
   5
   6    NOTE: this version of pwc is an unofficial (modified) release of pwc & pcwx
   7    driver and thus may have bugs that are not present in the original version.
   8    Please send bug reports and support requests to <luc@saillard.org>.
   9    The decompression routines have been implemented by reverse-engineering the
  10    Nemosoft binary pwcx module. Caveat emptor.
  11
  12    This program is free software; you can redistribute it and/or modify
  13    it under the terms of the GNU General Public License as published by
  14    the Free Software Foundation; either version 2 of the License, or
  15    (at your option) any later version.
  16
  17    This program is distributed in the hope that it will be useful,
  18    but WITHOUT ANY WARRANTY; without even the implied warranty of
  19    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20    GNU General Public License for more details.
  21
  22    You should have received a copy of the GNU General Public License
  23    along with this program; if not, write to the Free Software
  24    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  25 */
  26
  27 #include <asm/current.h>
  28 #include <asm/types.h>
  29
  30 #include "pwc.h"
  31 #include "pwc-uncompress.h"
  32
  33 int pwc_decompress(struct pwc_device *pdev)
  34 {
  35         struct pwc_frame_buf *fbuf;
  36         int n, line, col, stride;
  37         void *yuv, *image;
  38         u16 *src;
  39         u16 *dsty, *dstu, *dstv;
  40
  41         if (pdev == NULL)
  42                 return -EFAULT;
  43 #if defined(__KERNEL__) && defined(PWC_MAGIC)
  44         if (pdev->magic != PWC_MAGIC) {
  45                 Err("pwc_decompress(): magic failed.\n");
  46                 return -EFAULT;
  47         }
  48 #endif
  49
  50         fbuf = pdev->read_frame;
  51         if (fbuf == NULL)
  52                 return -EFAULT;
  53         image = pdev->image_ptr[pdev->fill_image];
  54         if (!image)
  55                 return -EFAULT;
  56
  57         yuv = fbuf->data + pdev->frame_header_size;  /* Skip header */
  58
  59         /* Raw format; that's easy... */
  60         if (pdev->vpalette == VIDEO_PALETTE_RAW)
  61         {
  62                 memcpy(image, yuv, pdev->frame_size);
  63                 return 0;
  64         }
  65
  66         if (pdev->vbandlength == 0) {
  67                 /* Uncompressed mode. We copy the data into the output buffer,
  68                    using the viewport size (which may be larger than the image
  69                    size). Unfortunately we have to do a bit of byte stuffing
  70                    to get the desired output format/size.
  71                  */
  72                         /*
  73                          * We do some byte shuffling here to go from the
  74                          * native format to YUV420P.
  75                          */
  76                         src = (u16 *)yuv;
  77                         n = pdev->view.x * pdev->view.y;
  78
  79                         /* offset in Y plane */
  80                         stride = pdev->view.x * pdev->offset.y + pdev->offset.x;
  81                         dsty = (u16 *)(image + stride);
  82
  83                         /* offsets in U/V planes */
  84                         stride = pdev->view.x * pdev->offset.y / 4 + pdev->offset.x / 2;
  85                         dstu = (u16 *)(image + n +         stride);
  86                         dstv = (u16 *)(image + n + n / 4 + stride);
  87
  88                         /* increment after each line */
  89                         stride = (pdev->view.x - pdev->image.x) / 2; /* u16 is 2 bytes */
  90
  91                         for (line = 0; line < pdev->image.y; line++) {
  92                                 for (col = 0; col < pdev->image.x; col += 4) {
  93                                         *dsty++ = *src++;
  94                                         *dsty++ = *src++;
  95                                         if (line & 1)
  96                                                 *dstv++ = *src++;
  97                                         else
  98                                                 *dstu++ = *src++;
  99                                 }
 100                                 dsty += stride;
 101                                 if (line & 1)
 102                                         dstv += (stride >> 1);
 103                                 else
 104                                         dstu += (stride >> 1);
 105                         }
 106         }
 107         else {
 108                 /* Compressed; the decompressor routines will write the data
 109                    in planar format immediately.
 110                  */
 111                 int flags;
 112
 113                 flags = PWCX_FLAG_PLANAR;
 114                 if (pdev->vsize == PSZ_VGA && pdev->vframes == 5 && pdev->vsnapshot)
 115                  {
 116                    printk(KERN_ERR "pwc: Mode Bayer is not supported for now\n");
 117                    flags |= PWCX_FLAG_BAYER;
 118                    return -ENXIO; /* No such device or address: missing decompressor */
 119                  }
 120
 121 #if 0
 122                 switch (pdev->type)
 123                  {
 124                   case 675:
 125                   case 680:
 126                   case 690:
 127                   case 720:
 128                   case 730:
 129                   case 740:
 130                   case 750:
 131                     pwc_dec23_decompress(&pdev->image, &pdev->view,
 132                                 &pdev->offset, yuv, image, flags,
 133                                 pdev->decompress_data, pdev->vbandlength);
 134                     break;
 135                   case 645:
 136                   case 646:
 137                     /* TODO & FIXME */
 138                     return -ENXIO; /* Missing decompressor */
 139                     break;
 140                  }
 141 #endif
 142         }
 143         return 0;
 144 }
 145
 146