1/* 2 * H261 encoder 3 * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at> 4 * Copyright (c) 2004 Maarten Daniels 5 * 6 * This file is part of FFmpeg. 7 * 8 * FFmpeg is free software; you can redistribute it and/or 9 * modify it under the terms of the GNU Lesser General Public 10 * License as published by the Free Software Foundation; either 11 * version 2.1 of the License, or (at your option) any later version. 12 * 13 * FFmpeg is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 16 * Lesser General Public License for more details. 17 * 18 * You should have received a copy of the GNU Lesser General Public 19 * License along with FFmpeg; if not, write to the Free Software 20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 21 */ 22 23/** 24 * @file libavcodec/h261enc.c 25 * H.261 encoder. 26 */ 27 28#include "dsputil.h" 29#include "avcodec.h" 30#include "mpegvideo.h" 31#include "h261.h" 32#include "h261data.h" 33 34extern uint8_t ff_h261_rl_table_store[2][2*MAX_RUN + MAX_LEVEL + 3]; 35 36static void h261_encode_block(H261Context * h, DCTELEM * block, 37 int n); 38 39int ff_h261_get_picture_format(int width, int height){ 40 // QCIF 41 if (width == 176 && height == 144) 42 return 0; 43 // CIF 44 else if (width == 352 && height == 288) 45 return 1; 46 // ERROR 47 else 48 return -1; 49} 50 51void ff_h261_encode_picture_header(MpegEncContext * s, int picture_number){ 52 H261Context * h = (H261Context *) s; 53 int format, temp_ref; 54 55 align_put_bits(&s->pb); 56 57 /* Update the pointer to last GOB */ 58 s->ptr_lastgob = pbBufPtr(&s->pb); 59 60 put_bits(&s->pb, 20, 0x10); /* PSC */ 61 62 temp_ref= s->picture_number * (int64_t)30000 * s->avctx->time_base.num / 63 (1001 * (int64_t)s->avctx->time_base.den); //FIXME maybe this should use a timestamp 64 put_sbits(&s->pb, 5, temp_ref); /* TemporalReference */ 65 66 put_bits(&s->pb, 1, 0); /* split screen off */ 67 put_bits(&s->pb, 1, 0); /* camera off */ 68 put_bits(&s->pb, 1, 0); /* freeze picture release off */ 69 70 format = ff_h261_get_picture_format(s->width, s->height); 71 72 put_bits(&s->pb, 1, format); /* 0 == QCIF, 1 == CIF */ 73 74 put_bits(&s->pb, 1, 0); /* still image mode */ 75 put_bits(&s->pb, 1, 0); /* reserved */ 76 77 put_bits(&s->pb, 1, 0); /* no PEI */ 78 if(format == 0) 79 h->gob_number = -1; 80 else 81 h->gob_number = 0; 82 h->current_mba = 0; 83} 84 85/** 86 * Encodes a group of blocks header. 87 */ 88static void h261_encode_gob_header(MpegEncContext * s, int mb_line){ 89 H261Context * h = (H261Context *)s; 90 if(ff_h261_get_picture_format(s->width, s->height) == 0){ 91 h->gob_number+=2; // QCIF 92 } 93 else{ 94 h->gob_number++; // CIF 95 } 96 put_bits(&s->pb, 16, 1); /* GBSC */ 97 put_bits(&s->pb, 4, h->gob_number); /* GN */ 98 put_bits(&s->pb, 5, s->qscale); /* GQUANT */ 99 put_bits(&s->pb, 1, 0); /* no GEI */ 100 h->current_mba = 0; 101 h->previous_mba = 0; 102 h->current_mv_x=0; 103 h->current_mv_y=0; 104} 105 106void ff_h261_reorder_mb_index(MpegEncContext* s){ 107 int index= s->mb_x + s->mb_y*s->mb_width; 108 109 if(index % 33 == 0) 110 h261_encode_gob_header(s,0); 111 112 /* for CIF the GOB's are fragmented in the middle of a scanline 113 that's why we need to adjust the x and y index of the macroblocks */ 114 if(ff_h261_get_picture_format(s->width,s->height) == 1){ // CIF 115 s->mb_x = index % 11 ; index /= 11; 116 s->mb_y = index % 3 ; index /= 3; 117 s->mb_x+= 11*(index % 2); index /= 2; 118 s->mb_y+= 3*index; 119 120 ff_init_block_index(s); 121 ff_update_block_index(s); 122 } 123} 124 125static void h261_encode_motion(H261Context * h, int val){ 126 MpegEncContext * const s = &h->s; 127 int sign, code; 128 if(val==0){ 129 code = 0; 130 put_bits(&s->pb,h261_mv_tab[code][1],h261_mv_tab[code][0]); 131 } 132 else{ 133 if(val > 15) 134 val -=32; 135 if(val < -16) 136 val+=32; 137 sign = val < 0; 138 code = sign ? -val : val; 139 put_bits(&s->pb,h261_mv_tab[code][1],h261_mv_tab[code][0]); 140 put_bits(&s->pb,1,sign); 141 } 142} 143 144static inline int get_cbp(MpegEncContext * s, 145 DCTELEM block[6][64]) 146{ 147 int i, cbp; 148 cbp= 0; 149 for (i = 0; i < 6; i++) { 150 if (s->block_last_index[i] >= 0) 151 cbp |= 1 << (5 - i); 152 } 153 return cbp; 154} 155void ff_h261_encode_mb(MpegEncContext * s, 156 DCTELEM block[6][64], 157 int motion_x, int motion_y) 158{ 159 H261Context * h = (H261Context *)s; 160 int mvd, mv_diff_x, mv_diff_y, i, cbp; 161 cbp = 63; // avoid warning 162 mvd = 0; 163 164 h->current_mba++; 165 h->mtype = 0; 166 167 if (!s->mb_intra){ 168 /* compute cbp */ 169 cbp= get_cbp(s, block); 170 171 /* mvd indicates if this block is motion compensated */ 172 mvd = motion_x | motion_y; 173 174 if((cbp | mvd | s->dquant ) == 0) { 175 /* skip macroblock */ 176 s->skip_count++; 177 h->current_mv_x=0; 178 h->current_mv_y=0; 179 return; 180 } 181 } 182 183 /* MB is not skipped, encode MBA */ 184 put_bits(&s->pb, h261_mba_bits[(h->current_mba-h->previous_mba)-1], h261_mba_code[(h->current_mba-h->previous_mba)-1]); 185 186 /* calculate MTYPE */ 187 if(!s->mb_intra){ 188 h->mtype++; 189 190 if(mvd || s->loop_filter) 191 h->mtype+=3; 192 if(s->loop_filter) 193 h->mtype+=3; 194 if(cbp || s->dquant) 195 h->mtype++; 196 assert(h->mtype > 1); 197 } 198 199 if(s->dquant) 200 h->mtype++; 201 202 put_bits(&s->pb, h261_mtype_bits[h->mtype], h261_mtype_code[h->mtype]); 203 204 h->mtype = h261_mtype_map[h->mtype]; 205 206 if(IS_QUANT(h->mtype)){ 207 ff_set_qscale(s,s->qscale+s->dquant); 208 put_bits(&s->pb, 5, s->qscale); 209 } 210 211 if(IS_16X16(h->mtype)){ 212 mv_diff_x = (motion_x >> 1) - h->current_mv_x; 213 mv_diff_y = (motion_y >> 1) - h->current_mv_y; 214 h->current_mv_x = (motion_x >> 1); 215 h->current_mv_y = (motion_y >> 1); 216 h261_encode_motion(h,mv_diff_x); 217 h261_encode_motion(h,mv_diff_y); 218 } 219 220 h->previous_mba = h->current_mba; 221 222 if(HAS_CBP(h->mtype)){ 223 assert(cbp>0); 224 put_bits(&s->pb,h261_cbp_tab[cbp-1][1],h261_cbp_tab[cbp-1][0]); 225 } 226 for(i=0; i<6; i++) { 227 /* encode each block */ 228 h261_encode_block(h, block[i], i); 229 } 230 231 if ( ( h->current_mba == 11 ) || ( h->current_mba == 22 ) || ( h->current_mba == 33 ) || ( !IS_16X16 ( h->mtype ) )){ 232 h->current_mv_x=0; 233 h->current_mv_y=0; 234 } 235} 236 237void ff_h261_encode_init(MpegEncContext *s){ 238 static int done = 0; 239 240 if (!done) { 241 done = 1; 242 init_rl(&h261_rl_tcoeff, ff_h261_rl_table_store); 243 } 244 245 s->min_qcoeff= -127; 246 s->max_qcoeff= 127; 247 s->y_dc_scale_table= 248 s->c_dc_scale_table= ff_mpeg1_dc_scale_table; 249} 250 251 252/** 253 * encodes a 8x8 block. 254 * @param block the 8x8 block 255 * @param n block index (0-3 are luma, 4-5 are chroma) 256 */ 257static void h261_encode_block(H261Context * h, DCTELEM * block, int n){ 258 MpegEncContext * const s = &h->s; 259 int level, run, last, i, j, last_index, last_non_zero, sign, slevel, code; 260 RLTable *rl; 261 262 rl = &h261_rl_tcoeff; 263 if (s->mb_intra) { 264 /* DC coef */ 265 level = block[0]; 266 /* 255 cannot be represented, so we clamp */ 267 if (level > 254) { 268 level = 254; 269 block[0] = 254; 270 } 271 /* 0 cannot be represented also */ 272 else if (level < 1) { 273 level = 1; 274 block[0] = 1; 275 } 276 if (level == 128) 277 put_bits(&s->pb, 8, 0xff); 278 else 279 put_bits(&s->pb, 8, level); 280 i = 1; 281 } else if((block[0]==1 || block[0] == -1) && (s->block_last_index[n] > -1)){ 282 //special case 283 put_bits(&s->pb,2,block[0]>0 ? 2 : 3 ); 284 i = 1; 285 } else { 286 i = 0; 287 } 288 289 /* AC coefs */ 290 last_index = s->block_last_index[n]; 291 last_non_zero = i - 1; 292 for (; i <= last_index; i++) { 293 j = s->intra_scantable.permutated[i]; 294 level = block[j]; 295 if (level) { 296 run = i - last_non_zero - 1; 297 last = (i == last_index); 298 sign = 0; 299 slevel = level; 300 if (level < 0) { 301 sign = 1; 302 level = -level; 303 } 304 code = get_rl_index(rl, 0 /*no last in H.261, EOB is used*/, run, level); 305 if(run==0 && level < 16) 306 code+=1; 307 put_bits(&s->pb, rl->table_vlc[code][1], rl->table_vlc[code][0]); 308 if (code == rl->n) { 309 put_bits(&s->pb, 6, run); 310 assert(slevel != 0); 311 assert(level <= 127); 312 put_sbits(&s->pb, 8, slevel); 313 } else { 314 put_bits(&s->pb, 1, sign); 315 } 316 last_non_zero = i; 317 } 318 } 319 if(last_index > -1){ 320 put_bits(&s->pb, rl->table_vlc[0][1], rl->table_vlc[0][0]);// END OF BLOCK 321 } 322} 323 324AVCodec h261_encoder = { 325 "h261", 326 CODEC_TYPE_VIDEO, 327 CODEC_ID_H261, 328 sizeof(H261Context), 329 MPV_encode_init, 330 MPV_encode_picture, 331 MPV_encode_end, 332 .pix_fmts= (enum PixelFormat[]){PIX_FMT_YUV420P, PIX_FMT_NONE}, 333 .long_name= NULL_IF_CONFIG_SMALL("H.261"), 334}; 335 336