Diffstat (limited to 'core/multimedia/opieplayer/libmpeg3/video/idct.c') (more/less context) (ignore 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 @@ -0,0 +1,160 @@ +#include "idct.h" +#include <stdlib.h> + +/**********************************************************/ +/* inverse two dimensional DCT, Chen-Wang algorithm */ +/* (cf. IEEE ASSP-32, pp. 803-816, Aug. 1984) */ +/* 32-bit integer arithmetic (8 bit coefficients) */ +/* 11 mults, 29 adds per DCT */ +/* sE, 18.8.91 */ +/**********************************************************/ +/* coefficients extended to 12 bit for IEEE1180-1990 */ +/* compliance sE, 2.1.94 */ +/**********************************************************/ + +/* this code assumes >> to be a two's-complement arithmetic */ +/* right shift: (-2)>>1 == -1 , (-3)>>1 == -2 */ + +#define W1 2841 /* 2048*sqrt(2)*cos(1*pi/16) */ +#define W2 2676 /* 2048*sqrt(2)*cos(2*pi/16) */ +#define W3 2408 /* 2048*sqrt(2)*cos(3*pi/16) */ +#define W5 1609 /* 2048*sqrt(2)*cos(5*pi/16) */ +#define W6 1108 /* 2048*sqrt(2)*cos(6*pi/16) */ +#define W7 565 /* 2048*sqrt(2)*cos(7*pi/16) */ + +/* row (horizontal) IDCT + * + * 7 pi 1 + * dst[k] = sum c[l] * src[l] * cos( -- * ( k + - ) * l ) + * l=0 8 2 + * + * where: c[0] = 128 + * c[1..7] = 128*sqrt(2) + */ + +int mpeg3video_idctrow(short *blk) +{ + int x0, x1, x2, x3, x4, x5, x6, x7, x8; + + /* shortcut */ + if (!((x1 = blk[4]<<11) | (x2 = blk[6]) | (x3 = blk[2]) | + (x4 = blk[1]) | (x5 = blk[7]) | (x6 = blk[5]) | (x7 = blk[3]))) + { + blk[0]=blk[1]=blk[2]=blk[3]=blk[4]=blk[5]=blk[6]=blk[7]=blk[0]<<3; + return 0; + } + + x0 = (blk[0]<<11) + 128; /* for proper rounding in the fourth stage */ + + /* first stage */ + x8 = W7*(x4+x5); + x4 = x8 + (W1-W7)*x4; + x5 = x8 - (W1+W7)*x5; + x8 = W3*(x6+x7); + x6 = x8 - (W3-W5)*x6; + x7 = x8 - (W3+W5)*x7; + + /* second stage */ + x8 = x0 + x1; + x0 -= x1; + x1 = W6*(x3+x2); + x2 = x1 - (W2+W6)*x2; + x3 = x1 + (W2-W6)*x3; + x1 = x4 + x6; + x4 -= x6; + x6 = x5 + x7; + x5 -= x7; + + /* third stage */ + x7 = x8 + x3; + x8 -= x3; + x3 = x0 + x2; + x0 -= x2; + x2 = (181*(x4+x5)+128)>>8; + x4 = (181*(x4-x5)+128)>>8; + + /* fourth stage */ + blk[0] = (x7+x1)>>8; + blk[1] = (x3+x2)>>8; + blk[2] = (x0+x4)>>8; + blk[3] = (x8+x6)>>8; + blk[4] = (x8-x6)>>8; + blk[5] = (x0-x4)>>8; + blk[6] = (x3-x2)>>8; + blk[7] = (x7-x1)>>8; + + return 1; +} + +/* column (vertical) IDCT + * + * 7 pi 1 + * dst[8*k] = sum c[l] * src[8*l] * cos( -- * ( k + - ) * l ) + * l=0 8 2 + * + * where: c[0] = 1/1024 + * c[1..7] = (1/1024)*sqrt(2) + */ + +int mpeg3video_idctcol(short *blk) +{ + int x0, x1, x2, x3, x4, x5, x6, x7, x8; + + /* shortcut */ + if (!((x1 = (blk[8 * 4]<<8)) | (x2 = blk[8 * 6]) | (x3 = blk[8 * 2]) | + (x4 = blk[8*1]) | (x5 = blk[8 * 7]) | (x6 = blk[8 * 5]) | (x7 = blk[8 * 3]))){ + blk[8*0]=blk[8*1]=blk[8 * 2]=blk[8 * 3]=blk[8 * 4]=blk[8 * 5]=blk[8 * 6]=blk[8 * 7]= + (blk[8*0]+32)>>6; + return 0; + } + + x0 = (blk[8*0]<<8) + 8192; + + /* first stage */ + x8 = W7*(x4+x5) + 4; + x4 = (x8+(W1-W7)*x4)>>3; + x5 = (x8-(W1+W7)*x5)>>3; + x8 = W3*(x6+x7) + 4; + x6 = (x8-(W3-W5)*x6)>>3; + x7 = (x8-(W3+W5)*x7)>>3; + + /* second stage */ + x8 = x0 + x1; + x0 -= x1; + x1 = W6*(x3+x2) + 4; + x2 = (x1-(W2+W6)*x2)>>3; + x3 = (x1+(W2-W6)*x3)>>3; + x1 = x4 + x6; + x4 -= x6; + x6 = x5 + x7; + x5 -= x7; + + /* third stage */ + x7 = x8 + x3; + x8 -= x3; + x3 = x0 + x2; + x0 -= x2; + x2 = (181 * (x4 + x5) + 128) >> 8; + x4 = (181 * (x4 - x5) + 128) >> 8; + + /* fourth stage */ + blk[8 * 0] = (x7 + x1) >> 14; + blk[8 * 1] = (x3 + x2) >> 14; + blk[8 * 2] = (x0 + x4) >> 14; + blk[8 * 3] = (x8 + x6) >> 14; + blk[8 * 4] = (x8 - x6) >> 14; + blk[8 * 5] = (x0 - x4) >> 14; + blk[8 * 6] = (x3 - x2) >> 14; + blk[8 * 7] = (x7 - x1) >> 14; + + return 1; +} + + +/* two dimensional inverse discrete cosine transform */ +void mpeg3video_idct_conversion(short* block) +{ + int i; + for(i = 0; i < 8; i++) mpeg3video_idctrow(block + 8 * i); + for(i = 0; i < 8; i++) mpeg3video_idctcol(block + i); +} |