1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
|
/* ------------------------------------------------------------------------
* Creative YUV Video Decoder
*
* Dr. Tim Ferguson, 2001.
* For more details on the algorithm:
* http://www.csse.monash.edu.au/~timf/videocodec.html
*
* Code restructured, and adopted to MPlayer's mpi by A'rpi, 2002.
*
* This is a very simple predictive coder. A video frame is coded in YUV411
* format. The first pixel of each scanline is coded using the upper four
* bits of its absolute value. Subsequent pixels for the scanline are coded
* using the difference between the last pixel and the current pixel (DPCM).
* The DPCM values are coded using a 16 entry table found at the start of the
* frame. Thus four bits per component are used and are as follows:
* UY VY YY UY VY YY UY VY...
* ------------------------------------------------------------------------ */
#include <stdio.h>
#include <stdlib.h>
#include "config.h"
#include "mp_msg.h"
#include "vd_internal.h"
static vd_info_t info = {
"Creative YUV decoder",
"cyuv",
"A'rpi",
"Dr. Tim Ferguson",
"native codec"
};
LIBVD_EXTERN(cyuv)
// to set/get/query special features/parameters
static int control(sh_video_t *sh,int cmd,void* arg,...){
return CONTROL_UNKNOWN;
}
// init driver
static int init(sh_video_t *sh){
return mpcodecs_config_vo(sh,sh->disp_w,sh->disp_h,IMGFMT_411P);
}
// uninit driver
static void uninit(sh_video_t *sh){
}
// decode a frame
static mp_image_t* decode(sh_video_t *sh,void* data,int len,int flags){
mp_image_t* mpi;
unsigned int xpos, ypos;
unsigned char *delta_y_tbl = ((unsigned char*)data)+16;
unsigned char *delta_c_tbl = ((unsigned char*)data)+32;
unsigned char *ptr = ((unsigned char*)data)+48;
if(len<=48) return NULL; // skipped/broken frame
mpi=mpcodecs_get_image(sh, MP_IMGTYPE_TEMP, MP_IMGFLAG_ACCEPT_STRIDE,
sh->disp_w, sh->disp_h);
if(!mpi) return NULL;
for(ypos = 0; ypos < mpi->h; ypos++){
unsigned int i;
unsigned char cur_Y1,cur_Y2,cur_U,cur_V;
unsigned char *frame=mpi->planes[0]+mpi->stride[0]*ypos;
unsigned char *uframe=mpi->planes[1]+mpi->stride[1]*ypos;
unsigned char *vframe=mpi->planes[2]+mpi->stride[2]*ypos;
for(xpos = 0; xpos < mpi->w; xpos += 2){
if(xpos&2){
i = *(ptr++);
cur_Y1 = (cur_Y2 + delta_y_tbl[i & 0x0f])/* & 0xff*/;
cur_Y2 = (cur_Y1 + delta_y_tbl[i >> 4])/* & 0xff*/;
} else {
if(xpos == 0) { /* first pixels in scanline */
cur_U = *(ptr++);
cur_Y1= (cur_U & 0x0f) << 4;
cur_U = cur_U & 0xf0;
cur_V = *(ptr++);
cur_Y2= (cur_Y1 + delta_y_tbl[cur_V & 0x0f])/* & 0xff*/;
cur_V = cur_V & 0xf0;
} else { /* subsequent pixels in scanline */
i = *(ptr++);
cur_U = (cur_U + delta_c_tbl[i >> 4])/* & 0xff*/;
cur_Y1= (cur_Y2 + delta_y_tbl[i & 0x0f])/* & 0xff*/;
i = *(ptr++);
cur_V = (cur_V + delta_c_tbl[i >> 4])/* & 0xff*/;
cur_Y2= (cur_Y1 + delta_y_tbl[i & 0x0f])/* & 0xff*/;
}
}
// ok, store the pixels:
switch(mpi->imgfmt){
case IMGFMT_YUY2:
*frame++ = cur_Y1;
*frame++ = cur_U;
*frame++ = cur_Y2;
*frame++ = cur_V;
break;
case IMGFMT_UYVY:
*frame++ = cur_U;
*frame++ = cur_Y1;
*frame++ = cur_V;
*frame++ = cur_Y2;
break;
case IMGFMT_422P:
*uframe++ = cur_U;
*vframe++ = cur_V;
*frame++ = cur_Y1;
*frame++ = cur_Y2;
break;
case IMGFMT_411P:
if(!(xpos&2)){
*uframe++ = cur_U;
*vframe++ = cur_V;
}
*frame++ = cur_Y1;
*frame++ = cur_Y2;
break;
}
} // xpos
} // ypos
return mpi;
}
|
