1 /* putmpg.c, block and motion vector encoding routines */
3 /* Copyright (C) 1996, MPEG Software Simulation Group. All Rights Reserved. */
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34 /* generate variable length codes for an intra-coded block (6.2.6, 6.3.17) */
35 void putintrablk(slice_engine_t *engine,
40 int n, dct_diff, run, signed_level;
42 /* DC coefficient (7.2.1) */
43 dct_diff = blk[0] - engine->dc_dct_pred[cc]; /* difference to previous block */
44 engine->dc_dct_pred[cc] = blk[0];
47 putDClum(engine, dct_diff);
49 putDCchrom(engine, dct_diff);
51 /* AC coefficients (7.2.2) */
53 for(n = 1; n < 64; n++)
55 /* use appropriate entropy scanning pattern */
56 signed_level = blk[(picture->altscan ? alternate_scan_hv : mpeg2_zig_zag_scan)[n]];
59 //printf("putintrablk 1 %d\n", picture->altscan);slice_testbits(engine);
60 putAC(engine, run, signed_level, picture->intravlc);
61 //printf("putintrablk 2\n");slice_testbits(engine);
65 run++; /* count zero coefficients */
68 /* End of Block -- normative block punctuation */
69 if (picture->intravlc)
70 slice_putbits(engine, 6, 4); /* 0110 (Table B-15) */
72 slice_putbits(engine, 2, 2); /* 10 (Table B-14) */
75 /* generate variable length codes for a non-intra-coded block (6.2.6, 6.3.17) */
76 void putnonintrablk(slice_engine_t *engine,
80 int n, run, signed_level, first;
85 for(n = 0; n < 64; n++)
87 /* use appropriate entropy scanning pattern */
88 signed_level = blk[(picture->altscan ? alternate_scan_hv : mpeg2_zig_zag_scan)[n]];
94 /* first coefficient in non-intra block */
95 putACfirst(engine, run, signed_level);
99 putAC(engine, run, signed_level, 0);
104 run++; /* count zero coefficients */
107 /* End of Block -- normative block punctuation */
108 slice_putbits(engine, 2, 2);
111 /* generate variable length code for a motion vector component (7.6.3.1) */
112 void putmv(slice_engine_t *engine, int dmv, int f_code)
114 int r_size, f, vmin, vmax, dv, temp, motion_code, motion_residual;
116 r_size = f_code - 1; /* number of fixed length code ('residual') bits */
118 vmin = -16 * f; /* lower range limit */
119 vmax = 16 * f - 1; /* upper range limit */
122 /* fold vector difference into [vmin...vmax] */
130 if(dmv < vmin || dmv > vmax)
132 fprintf(stderr,"invalid motion vector\n");
134 /* split dmv into motion_code and motion_residual */
135 temp = ((dmv < 0) ? -dmv : dmv) + f - 1;
136 motion_code = temp >> r_size;
138 motion_code = -motion_code;
139 motion_residual = temp & (f - 1);
141 putmotioncode(engine, motion_code); /* variable length code */
143 if (r_size != 0 && motion_code != 0)
144 slice_putbits(engine, motion_residual, r_size); /* fixed length code */