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

   1 /* Linux driver for Philips webcam
   2    Decompression frontend.
   3    (C) 1999-2003 Nemosoft Unv.
   4    (C) 2004-2006 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    vim: set ts=8:
  27 */
  28
  29 #include <asm/current.h>
  30 #include <asm/types.h>
  31
  32 #include "pwc.h"
  33 #include "pwc-uncompress.h"
  34 #include "pwc-dec1.h"
  35 #include "pwc-dec23.h"
  36
  37 int pwc_decompress(struct pwc_device *pdev)
  38 {
  39         struct pwc_frame_buf *fbuf;
  40         int n, line, col, stride;
  41         void *yuv, *image;
  42         u16 *src;
  43         u16 *dsty, *dstu, *dstv;
  44
  45         if (pdev == NULL)
  46                 return -EFAULT;
  47
  48         fbuf = pdev->read_frame;
  49         if (fbuf == NULL)
  50                 return -EFAULT;
  51         image  = pdev->image_data;
  52         image += pdev->images[pdev->fill_image].offset;
  53
  54         yuv = fbuf->data + pdev->frame_header_size;  /* Skip header */
  55
  56         /* Raw format; that's easy... */
  57         if (pdev->pixfmt != V4L2_PIX_FMT_YUV420)
  58         {
  59                 struct pwc_raw_frame *raw_frame = image;
  60                 raw_frame->type = cpu_to_le16(pdev->type);
  61                 raw_frame->vbandlength = cpu_to_le16(pdev->vbandlength);
  62                         /* cmd_buf is always 4 bytes, but sometimes, only the
  63                          * first 3 bytes is filled (Nala case). We can
  64                          * determine this using the type of the webcam */
  65                 memcpy(raw_frame->cmd, pdev->cmd_buf, 4);
  66                 memcpy(raw_frame+1, yuv, pdev->frame_size);
  67                 return 0;
  68         }
  69
  70         if (pdev->vbandlength == 0) {
  71                 /* Uncompressed mode.
  72                  * We copy the data into the output buffer, using the viewport
  73                  * size (which may be larger than the image size).
  74                  * Unfortunately we have to do a bit of byte stuffing to get
  75                  * the desired output format/size.
  76                  *
  77                  * We do some byte shuffling here to go from the
  78                  * native format to YUV420P.
  79                  */
  80                 src = (u16 *)yuv;
  81                 n = pdev->view.x * pdev->view.y;
  82
  83                 /* offset in Y plane */
  84                 stride = pdev->view.x * pdev->offset.y + pdev->offset.x;
  85                 dsty = (u16 *)(image + stride);
  86
  87                 /* offsets in U/V planes */
  88                 stride = pdev->view.x * pdev->offset.y / 4 + pdev->offset.x / 2;
  89                 dstu = (u16 *)(image + n +         stride);
  90                 dstv = (u16 *)(image + n + n / 4 + stride);
  91
  92                 /* increment after each line */
  93                 stride = (pdev->view.x - pdev->image.x) / 2; /* u16 is 2 bytes */
  94
  95                 for (line = 0; line < pdev->image.y; line++) {
  96                         for (col = 0; col < pdev->image.x; col += 4) {
  97                                 *dsty++ = *src++;
  98                                 *dsty++ = *src++;
  99                                 if (line & 1)
 100                                         *dstv++ = *src++;
 101                                 else
 102                                         *dstu++ = *src++;
 103                         }
 104                         dsty += stride;
 105                         if (line & 1)
 106                                 dstv += (stride >> 1);
 107                         else
 108                                 dstu += (stride >> 1);
 109                 }
 110
 111                 return 0;
 112         }
 113
 114         /*
 115          * Compressed;
 116          * the decompressor routines will write the data in planar format
 117          * immediately.
 118          */
 119         if (pdev->vsize == PSZ_VGA && pdev->vframes == 5 && pdev->vsnapshot) {
 120                 PWC_ERROR("Mode Bayer is not supported for now\n");
 121                 /* flags |= PWCX_FLAG_BAYER; */
 122                 return -ENXIO; /* No such device or address: missing decompressor */
 123         }
 124
 125         if (DEVICE_USE_CODEC1(pdev->type)) {
 126
 127                 /* TODO & FIXME */
 128                 PWC_ERROR("This chipset is not supported for now\n");
 129                 return -ENXIO; /* No such device or address: missing decompressor */
 130
 131         } else {
 132                 pwc_dec23_decompress(pdev, yuv, image, PWCX_FLAG_PLANAR);
 133         }
 134         return 0;
 135 }
 136
 137
 138 /* vim: set cino= formatoptions=croql cindent shiftwidth=8 tabstop=8: */