author | kergoth <kergoth> | 2002-01-25 22:14:26 (UTC) |
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committer | kergoth <kergoth> | 2002-01-25 22:14:26 (UTC) |
commit | 15318cad33835e4e2dc620d033e43cd930676cdd (patch) (unidiff) | |
tree | c2fa0399a2c47fda8e2cd0092c73a809d17f68eb /core/multimedia/opieplayer/libmpeg3/video/idct.c | |
download | opie-15318cad33835e4e2dc620d033e43cd930676cdd.zip opie-15318cad33835e4e2dc620d033e43cd930676cdd.tar.gz opie-15318cad33835e4e2dc620d033e43cd930676cdd.tar.bz2 |
Initial revision
Diffstat (limited to 'core/multimedia/opieplayer/libmpeg3/video/idct.c') (more/less context) (show whitespace changes)
-rw-r--r-- | core/multimedia/opieplayer/libmpeg3/video/idct.c | 160 |
1 files changed, 160 insertions, 0 deletions
diff --git a/core/multimedia/opieplayer/libmpeg3/video/idct.c b/core/multimedia/opieplayer/libmpeg3/video/idct.c new file mode 100644 index 0000000..c79f90a --- a/dev/null +++ b/core/multimedia/opieplayer/libmpeg3/video/idct.c | |||
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1 | #include "idct.h" | ||
2 | #include <stdlib.h> | ||
3 | |||
4 | /**********************************************************/ | ||
5 | /* inverse two dimensional DCT, Chen-Wang algorithm */ | ||
6 | /* (cf. IEEE ASSP-32, pp. 803-816, Aug. 1984) */ | ||
7 | /* 32-bit integer arithmetic (8 bit coefficients) */ | ||
8 | /* 11 mults, 29 adds per DCT */ | ||
9 | /* sE, 18.8.91 */ | ||
10 | /**********************************************************/ | ||
11 | /* coefficients extended to 12 bit for IEEE1180-1990 */ | ||
12 | /* compliance sE, 2.1.94 */ | ||
13 | /**********************************************************/ | ||
14 | |||
15 | /* this code assumes >> to be a two's-complement arithmetic */ | ||
16 | /* right shift: (-2)>>1 == -1 , (-3)>>1 == -2 */ | ||
17 | |||
18 | #define W1 2841 /* 2048*sqrt(2)*cos(1*pi/16) */ | ||
19 | #define W2 2676 /* 2048*sqrt(2)*cos(2*pi/16) */ | ||
20 | #define W3 2408 /* 2048*sqrt(2)*cos(3*pi/16) */ | ||
21 | #define W5 1609 /* 2048*sqrt(2)*cos(5*pi/16) */ | ||
22 | #define W6 1108 /* 2048*sqrt(2)*cos(6*pi/16) */ | ||
23 | #define W7 565 /* 2048*sqrt(2)*cos(7*pi/16) */ | ||
24 | |||
25 | /* row (horizontal) IDCT | ||
26 | * | ||
27 | * 7 pi 1 | ||
28 | * dst[k] = sum c[l] * src[l] * cos( -- * ( k + - ) * l ) | ||
29 | * l=0 8 2 | ||
30 | * | ||
31 | * where: c[0] = 128 | ||
32 | * c[1..7] = 128*sqrt(2) | ||
33 | */ | ||
34 | |||
35 | int mpeg3video_idctrow(short *blk) | ||
36 | { | ||
37 | int x0, x1, x2, x3, x4, x5, x6, x7, x8; | ||
38 | |||
39 | /* shortcut */ | ||
40 | if (!((x1 = blk[4]<<11) | (x2 = blk[6]) | (x3 = blk[2]) | | ||
41 | (x4 = blk[1]) | (x5 = blk[7]) | (x6 = blk[5]) | (x7 = blk[3]))) | ||
42 | { | ||
43 | blk[0]=blk[1]=blk[2]=blk[3]=blk[4]=blk[5]=blk[6]=blk[7]=blk[0]<<3; | ||
44 | return 0; | ||
45 | } | ||
46 | |||
47 | x0 = (blk[0]<<11) + 128; /* for proper rounding in the fourth stage */ | ||
48 | |||
49 | /* first stage */ | ||
50 | x8 = W7*(x4+x5); | ||
51 | x4 = x8 + (W1-W7)*x4; | ||
52 | x5 = x8 - (W1+W7)*x5; | ||
53 | x8 = W3*(x6+x7); | ||
54 | x6 = x8 - (W3-W5)*x6; | ||
55 | x7 = x8 - (W3+W5)*x7; | ||
56 | |||
57 | /* second stage */ | ||
58 | x8 = x0 + x1; | ||
59 | x0 -= x1; | ||
60 | x1 = W6*(x3+x2); | ||
61 | x2 = x1 - (W2+W6)*x2; | ||
62 | x3 = x1 + (W2-W6)*x3; | ||
63 | x1 = x4 + x6; | ||
64 | x4 -= x6; | ||
65 | x6 = x5 + x7; | ||
66 | x5 -= x7; | ||
67 | |||
68 | /* third stage */ | ||
69 | x7 = x8 + x3; | ||
70 | x8 -= x3; | ||
71 | x3 = x0 + x2; | ||
72 | x0 -= x2; | ||
73 | x2 = (181*(x4+x5)+128)>>8; | ||
74 | x4 = (181*(x4-x5)+128)>>8; | ||
75 | |||
76 | /* fourth stage */ | ||
77 | blk[0] = (x7+x1)>>8; | ||
78 | blk[1] = (x3+x2)>>8; | ||
79 | blk[2] = (x0+x4)>>8; | ||
80 | blk[3] = (x8+x6)>>8; | ||
81 | blk[4] = (x8-x6)>>8; | ||
82 | blk[5] = (x0-x4)>>8; | ||
83 | blk[6] = (x3-x2)>>8; | ||
84 | blk[7] = (x7-x1)>>8; | ||
85 | |||
86 | return 1; | ||
87 | } | ||
88 | |||
89 | /* column (vertical) IDCT | ||
90 | * | ||
91 | * 7 pi 1 | ||
92 | * dst[8*k] = sum c[l] * src[8*l] * cos( -- * ( k + - ) * l ) | ||
93 | * l=0 8 2 | ||
94 | * | ||
95 | * where: c[0] = 1/1024 | ||
96 | * c[1..7] = (1/1024)*sqrt(2) | ||
97 | */ | ||
98 | |||
99 | int mpeg3video_idctcol(short *blk) | ||
100 | { | ||
101 | int x0, x1, x2, x3, x4, x5, x6, x7, x8; | ||
102 | |||
103 | /* shortcut */ | ||
104 | if (!((x1 = (blk[8 * 4]<<8)) | (x2 = blk[8 * 6]) | (x3 = blk[8 * 2]) | | ||
105 | (x4 = blk[8*1]) | (x5 = blk[8 * 7]) | (x6 = blk[8 * 5]) | (x7 = blk[8 * 3]))){ | ||
106 | blk[8*0]=blk[8*1]=blk[8 * 2]=blk[8 * 3]=blk[8 * 4]=blk[8 * 5]=blk[8 * 6]=blk[8 * 7]= | ||
107 | (blk[8*0]+32)>>6; | ||
108 | return 0; | ||
109 | } | ||
110 | |||
111 | x0 = (blk[8*0]<<8) + 8192; | ||
112 | |||
113 | /* first stage */ | ||
114 | x8 = W7*(x4+x5) + 4; | ||
115 | x4 = (x8+(W1-W7)*x4)>>3; | ||
116 | x5 = (x8-(W1+W7)*x5)>>3; | ||
117 | x8 = W3*(x6+x7) + 4; | ||
118 | x6 = (x8-(W3-W5)*x6)>>3; | ||
119 | x7 = (x8-(W3+W5)*x7)>>3; | ||
120 | |||
121 | /* second stage */ | ||
122 | x8 = x0 + x1; | ||
123 | x0 -= x1; | ||
124 | x1 = W6*(x3+x2) + 4; | ||
125 | x2 = (x1-(W2+W6)*x2)>>3; | ||
126 | x3 = (x1+(W2-W6)*x3)>>3; | ||
127 | x1 = x4 + x6; | ||
128 | x4 -= x6; | ||
129 | x6 = x5 + x7; | ||
130 | x5 -= x7; | ||
131 | |||
132 | /* third stage */ | ||
133 | x7 = x8 + x3; | ||
134 | x8 -= x3; | ||
135 | x3 = x0 + x2; | ||
136 | x0 -= x2; | ||
137 | x2 = (181 * (x4 + x5) + 128) >> 8; | ||
138 | x4 = (181 * (x4 - x5) + 128) >> 8; | ||
139 | |||
140 | /* fourth stage */ | ||
141 | blk[8 * 0] = (x7 + x1) >> 14; | ||
142 | blk[8 * 1] = (x3 + x2) >> 14; | ||
143 | blk[8 * 2] = (x0 + x4) >> 14; | ||
144 | blk[8 * 3] = (x8 + x6) >> 14; | ||
145 | blk[8 * 4] = (x8 - x6) >> 14; | ||
146 | blk[8 * 5] = (x0 - x4) >> 14; | ||
147 | blk[8 * 6] = (x3 - x2) >> 14; | ||
148 | blk[8 * 7] = (x7 - x1) >> 14; | ||
149 | |||
150 | return 1; | ||
151 | } | ||
152 | |||
153 | |||
154 | /* two dimensional inverse discrete cosine transform */ | ||
155 | void mpeg3video_idct_conversion(short* block) | ||
156 | { | ||
157 | int i; | ||
158 | for(i = 0; i < 8; i++) mpeg3video_idctrow(block + 8 * i); | ||
159 | for(i = 0; i < 8; i++) mpeg3video_idctcol(block + i); | ||
160 | } | ||