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/*
* author: Todd Kirby <slapcat@pacbell.net>
*/
#include <stdio.h>
#include <stdlib.h>
#include "config.h"
#include "mp_msg.h"
#include "libavutil/common.h"
#include "mpbswap.h"
#include "vd_internal.h"
#define SGI_HEADER_LEN 512
#define SGI_MAGIC 474
#define SGI_GRAYSCALE_IMAGE 1
#define SGI_RGB_IMAGE 3
#define SGI_RGBA_IMAGE 4
#define OUT_PIXEL_STRIDE 3 /* RGB */
static vd_info_t info =
{
"SGI Image decoder",
"sgi",
"Todd Kirby",
"Todd Kirby",
""
};
LIBVD_EXTERN(sgi)
typedef struct {
short magic;
char rle;
char bytes_per_channel;
unsigned short dimension;
unsigned short xsize;
unsigned short ysize;
unsigned short zsize;
} SGIInfo;
static unsigned int outfmt = IMGFMT_BGR24;
static unsigned short last_x = -1;
static unsigned short last_y = -1;
/* to set/get/query special features/parameters */
static int
control(sh_video_t* sh, int cmd, void *arg, ...)
{
switch (cmd)
{
case VDCTRL_QUERY_FORMAT:
if (*((unsigned int *) arg) == outfmt) {
return CONTROL_TRUE;
}
return CONTROL_FALSE;
}
return CONTROL_UNKNOWN;
}
/* init driver */
static int
init(sh_video_t *sh)
{
sh->context = (SGIInfo *) calloc(1, sizeof(SGIInfo));
last_x = -1;
return 1;
}
/* uninit driver */
static void
uninit(sh_video_t *sh)
{
SGIInfo *info = sh->context;
free(info);
}
/* expand an rle row into a channel */
static void
expandrow(unsigned char *optr, unsigned char *iptr, int chan_offset)
{
unsigned char pixel, count;
optr += chan_offset;
while (1) {
pixel = *iptr++;
if (!(count = (pixel & 0x7f))) {
return;
}
if(pixel & 0x80) {
while (count--) {
*optr = *iptr;
optr += OUT_PIXEL_STRIDE;
iptr++;
}
} else {
pixel = *iptr++;
while (count--) {
*optr = pixel;
optr += OUT_PIXEL_STRIDE;
}
}
}
}
/* expand an rle row into all 3 channels.
a separate function for grayscale so we don't slow down the
more common case rgb function with a bunch of ifs. */
static void
expandrow_gs(unsigned char *optr, unsigned char *iptr)
{
unsigned char pixel, count;
while (1) {
pixel = *iptr++;
if (!(count = (pixel & 0x7f))) {
return;
}
if(pixel & 0x80) {
while (count--) {
optr[0] = *iptr;
optr[1] = *iptr;
optr[2] = *iptr;
optr += OUT_PIXEL_STRIDE;
iptr++;
}
} else {
pixel = *iptr++;
while (count--) {
optr[0] = pixel;
optr[1] = pixel;
optr[2] = pixel;
optr += OUT_PIXEL_STRIDE;
}
}
}
}
/* decode a run length encoded sgi image */
static void
decode_rle_sgi(SGIInfo *info, unsigned char *data, mp_image_t *mpi)
{
unsigned char *rle_data, *dest_row;
uint32_t *starttab;
int y, z, xsize, ysize, zsize, chan_offset;
long start_offset;
xsize = info->xsize;
ysize = info->ysize;
zsize = info->zsize;
/* rle offset table is right after the header */
starttab = (uint32_t*)(data + SGI_HEADER_LEN);
for (z = 0; z < zsize; z++) {
/* set chan_offset so RGB ends up BGR */
chan_offset = (zsize - 1) - z;
/* The origin for SGI images is the lower-left corner
so read scan lines from bottom to top */
for (y = ysize - 1; y >= 0; y--) {
dest_row = mpi->planes[0] + mpi->stride[0] * (ysize - 1 - y);
/* set start of next run (offsets are from start of header) */
start_offset = be2me_32(*(uint32_t*) &starttab[y + z * ysize]);
rle_data = &data[start_offset];
if(info->zsize == SGI_GRAYSCALE_IMAGE) {
expandrow_gs(dest_row, rle_data);
} else {
expandrow(dest_row, rle_data, chan_offset);
}
}
}
}
/* decode an sgi image */
static void
decode_uncompressed_sgi(SGIInfo *info, unsigned char *data, mp_image_t *mpi)
{
unsigned char *src_row, *dest_row;
int x, y, z, xsize, ysize, zsize, chan_offset;
xsize = info->xsize;
ysize = info->ysize;
zsize = info->zsize;
/* skip header */
data += SGI_HEADER_LEN;
for (z = 0; z < zsize; z++) {
/* set row ptr to start of current plane */
src_row = data + (xsize * ysize * z);
/* set chan_offset for RGB -> BGR */
chan_offset = (zsize - 1) - z;
/* the origin for SGI images is the lower-left corner
so read scan lines from bottom to top. */
for (y = ysize - 1; y >= 0; y--) {
dest_row = mpi->planes[0] + mpi->stride[0] * y;
for (x = 0; x < xsize; x++) {
/* we only do 24 bit output so promote 8 bit pixels to 24 */
if (zsize == SGI_GRAYSCALE_IMAGE) {
/* write greyscale value into all channels */
dest_row[0] = src_row[x];
dest_row[1] = src_row[x];
dest_row[2] = src_row[x];
} else {
dest_row[chan_offset] = src_row[x];
}
dest_row += OUT_PIXEL_STRIDE;
}
/* move to next row of the current source plane */
src_row += xsize;
}
}
}
/* read sgi header fields */
static void
read_sgi_header(unsigned char *buf, SGIInfo *info)
{
/* sgi data is always stored in big endian byte order */
info->magic = be2me_16(*(unsigned short *) &buf[0]);
info->rle = buf[2];
info->bytes_per_channel = buf[3];
info->dimension = be2me_16(*(unsigned short *) &buf[4]);
info->xsize = be2me_16(*(unsigned short *) &buf[6]);
info->ysize = be2me_16(*(unsigned short *) &buf[8]);
info->zsize = be2me_16(*(unsigned short *) &buf[10]);
}
/* decode a frame */
static
mp_image_t *decode(sh_video_t *sh, void *raw, int len, int flags)
{
SGIInfo *info = sh->context;
unsigned char *data = raw;
mp_image_t *mpi;
if (len <= 0) {
return NULL; /* skip frame */
}
read_sgi_header(data, info);
/* make sure this is an SGI image file */
if (info->magic != SGI_MAGIC) {
mp_msg(MSGT_DECVIDEO, MSGL_INFO, "Bad magic number in image.\n");
return NULL;
}
/* check image depth */
if (info->bytes_per_channel != 1) {
mp_msg(MSGT_DECVIDEO, MSGL_INFO,
"Unsupported bytes per channel value %i.\n", info->bytes_per_channel);
return NULL;
}
/* check image dimension */
if (info->dimension != 2 && info->dimension != 3) {
mp_msg(MSGT_DECVIDEO, MSGL_INFO, "Unsupported image dimension %i.\n",
info->dimension);
return NULL;
}
/* change rgba images to rgb so alpha channel will be ignored */
if (info->zsize == SGI_RGBA_IMAGE) {
info->zsize = SGI_RGB_IMAGE;
}
/* check image depth */
if (info->zsize != SGI_RGB_IMAGE && info->zsize != SGI_GRAYSCALE_IMAGE) {
mp_msg(MSGT_DECVIDEO, MSGL_INFO, "Unsupported image depth.\n");
return NULL;
}
/* (re)init libvo if image size is changed */
if (last_x != info->xsize || last_y != info->ysize)
{
last_x = info->xsize;
last_y = info->ysize;
if (!mpcodecs_config_vo(sh, info->xsize, info->ysize, outfmt)) {
mp_msg(MSGT_DECVIDEO, MSGL_INFO, "Config vo failed:\n");
return NULL;
}
}
if (!(mpi = mpcodecs_get_image(sh, MP_IMGTYPE_TEMP, MP_IMGFLAG_ACCEPT_STRIDE,
info->xsize, info->ysize))) {
return NULL;
}
if (info->rle) {
decode_rle_sgi(info, data, mpi);
} else {
decode_uncompressed_sgi(info, data, mpi);
}
return mpi;
}
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