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/* Linux driver for Philips webcam
Decompression frontend.
(C) 1999-2003 Nemosoft Unv.
(C) 2004 Luc Saillard (luc@saillard.org)
NOTE: this version of pwc is an unofficial (modified) release of pwc & pcwx
driver and thus may have bugs that are not present in the original version.
Please send bug reports and support requests to <luc@saillard.org>.
The decompression routines have been implemented by reverse-engineering the
Nemosoft binary pwcx module. Caveat emptor.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <asm/types.h>
#include "pwc.h"
#include "pwc-uncompress.h"
int pwc_decompress(struct pwc_device *pdev)
{
struct pwc_frame_buf *fbuf;
int n, line, col, stride;
void *yuv, *image;
u16 *src;
u16 *dsty, *dstu, *dstv;
if (pdev == NULL)
return -EFAULT;
#if defined(__KERNEL__) && defined(PWC_MAGIC)
if (pdev->magic != PWC_MAGIC) {
Err("pwc_decompress(): magic failed.\n");
return -EFAULT;
}
#endif
fbuf = pdev->read_frame;
if (fbuf == NULL)
return -EFAULT;
image = pdev->image_ptr[pdev->fill_image];
if (!image)
return -EFAULT;
yuv = fbuf->data + pdev->frame_header_size; /* Skip header */
/* Raw format; that's easy... */
if (pdev->vpalette == VIDEO_PALETTE_RAW)
{
memcpy(image, yuv, pdev->frame_size);
return 0;
}
if (pdev->vbandlength == 0) {
/* Uncompressed mode. We copy the data into the output buffer,
using the viewport size (which may be larger than the image
size). Unfortunately we have to do a bit of byte stuffing
to get the desired output format/size.
*/
/*
* We do some byte shuffling here to go from the
* native format to YUV420P.
*/
src = (u16 *)yuv;
n = pdev->view.x * pdev->view.y;
/* offset in Y plane */
stride = pdev->view.x * pdev->offset.y + pdev->offset.x;
dsty = (u16 *)(image + stride);
/* offsets in U/V planes */
stride = pdev->view.x * pdev->offset.y / 4 + pdev->offset.x / 2;
dstu = (u16 *)(image + n + stride);
dstv = (u16 *)(image + n + n / 4 + stride);
/* increment after each line */
stride = (pdev->view.x - pdev->image.x) / 2; /* u16 is 2 bytes */
for (line = 0; line < pdev->image.y; line++) {
for (col = 0; col < pdev->image.x; col += 4) {
*dsty++ = *src++;
*dsty++ = *src++;
if (line & 1)
*dstv++ = *src++;
else
*dstu++ = *src++;
}
dsty += stride;
if (line & 1)
dstv += (stride >> 1);
else
dstu += (stride >> 1);
}
}
else {
/* Compressed; the decompressor routines will write the data
in planar format immediately.
*/
int flags;
flags = PWCX_FLAG_PLANAR;
if (pdev->vsize == PSZ_VGA && pdev->vframes == 5 && pdev->vsnapshot)
{
printk(KERN_ERR "pwc: Mode Bayer is not supported for now\n");
flags |= PWCX_FLAG_BAYER;
return -ENXIO; /* No such device or address: missing decompressor */
}
#if 0
switch (pdev->type)
{
case 675:
case 680:
case 690:
case 720:
case 730:
case 740:
case 750:
pwc_dec23_decompress(&pdev->image, &pdev->view,
&pdev->offset, yuv, image, flags,
pdev->decompress_data, pdev->vbandlength);
break;
case 645:
case 646:
/* TODO & FIXME */
return -ENXIO; /* Missing decompressor */
break;
}
#endif
}
return 0;
}
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