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 25 * H.261 encoder. 26 */ 27 28#include "dsputil.h" 29#include "avcodec.h" 30#include "mpegvideo.h" 31#include "h263.h" 32#include "h261.h" 33#include "h261data.h" 34 35extern uint8_t ff_h261_rl_table_store[2][2*MAX_RUN + MAX_LEVEL + 3]; 36 37static void h261_encode_block(H261Context * h, DCTELEM * block, 38 int n); 39 40int ff_h261_get_picture_format(int width, int height){ 41 // QCIF 42 if (width == 176 && height == 144) 43 return 0; 44 // CIF 45 else if (width == 352 && height == 288) 46 return 1; 47 // ERROR 48 else 49 return -1; 50} 51 52void ff_h261_encode_picture_header(MpegEncContext * s, int picture_number){ 53 H261Context * h = (H261Context *) s; 54 int format, temp_ref; 55 56 align_put_bits(&s->pb); 57 58 /* Update the pointer to last GOB */ 59 s->ptr_lastgob = put_bits_ptr(&s->pb); 60 61 put_bits(&s->pb, 20, 0x10); /* PSC */ 62 63 temp_ref= s->picture_number * (int64_t)30000 * s->avctx->time_base.num / 64 (1001 * (int64_t)s->avctx->time_base.den); //FIXME maybe this should use a timestamp 65 put_sbits(&s->pb, 5, temp_ref); /* TemporalReference */ 66 67 put_bits(&s->pb, 1, 0); /* split screen off */ 68 put_bits(&s->pb, 1, 0); /* camera off */ 69 put_bits(&s->pb, 1, 0); /* freeze picture release off */ 70 71 format = ff_h261_get_picture_format(s->width, s->height); 72 73 put_bits(&s->pb, 1, format); /* 0 == QCIF, 1 == CIF */ 74 75 put_bits(&s->pb, 1, 0); /* still image mode */ 76 put_bits(&s->pb, 1, 0); /* reserved */ 77 78 put_bits(&s->pb, 1, 0); /* no PEI */ 79 if(format == 0) 80 h->gob_number = -1; 81 else 82 h->gob_number = 0; 83 h->current_mba = 0; 84} 85 86/** 87 * Encodes a group of blocks header. 88 */ 89static void h261_encode_gob_header(MpegEncContext * s, int mb_line){ 90 H261Context * h = (H261Context *)s; 91 if(ff_h261_get_picture_format(s->width, s->height) == 0){ 92 h->gob_number+=2; // QCIF 93 } 94 else{ 95 h->gob_number++; // CIF 96 } 97 put_bits(&s->pb, 16, 1); /* GBSC */ 98 put_bits(&s->pb, 4, h->gob_number); /* GN */ 99 put_bits(&s->pb, 5, s->qscale); /* GQUANT */ 100 put_bits(&s->pb, 1, 0); /* no GEI */ 101 h->current_mba = 0; 102 h->previous_mba = 0; 103 h->current_mv_x=0; 104 h->current_mv_y=0; 105} 106 107void ff_h261_reorder_mb_index(MpegEncContext* s){ 108 int index= s->mb_x + s->mb_y*s->mb_width; 109 110 if(index % 33 == 0) 111 h261_encode_gob_header(s,0); 112 113 /* for CIF the GOB's are fragmented in the middle of a scanline 114 that's why we need to adjust the x and y index of the macroblocks */ 115 if(ff_h261_get_picture_format(s->width,s->height) == 1){ // CIF 116 s->mb_x = index % 11 ; index /= 11; 117 s->mb_y = index % 3 ; index /= 3; 118 s->mb_x+= 11*(index % 2); index /= 2; 119 s->mb_y+= 3*index; 120 121 ff_init_block_index(s); 122 ff_update_block_index(s); 123 } 124} 125 126static void h261_encode_motion(H261Context * h, int val){ 127 MpegEncContext * const s = &h->s; 128 int sign, code; 129 if(val==0){ 130 code = 0; 131 put_bits(&s->pb,h261_mv_tab[code][1],h261_mv_tab[code][0]); 132 } 133 else{ 134 if(val > 15) 135 val -=32; 136 if(val < -16) 137 val+=32; 138 sign = val < 0; 139 code = sign ? -val : val; 140 put_bits(&s->pb,h261_mv_tab[code][1],h261_mv_tab[code][0]); 141 put_bits(&s->pb,1,sign); 142 } 143} 144 145static inline int get_cbp(MpegEncContext * s, 146 DCTELEM block[6][64]) 147{ 148 int i, cbp; 149 cbp= 0; 150 for (i = 0; i < 6; i++) { 151 if (s->block_last_index[i] >= 0) 152 cbp |= 1 << (5 - i); 153 } 154 return cbp; 155} 156void ff_h261_encode_mb(MpegEncContext * s, 157 DCTELEM block[6][64], 158 int motion_x, int motion_y) 159{ 160 H261Context * h = (H261Context *)s; 161 int mvd, mv_diff_x, mv_diff_y, i, cbp; 162 cbp = 63; // avoid warning 163 mvd = 0; 164 165 h->current_mba++; 166 h->mtype = 0; 167 168 if (!s->mb_intra){ 169 /* compute cbp */ 170 cbp= get_cbp(s, block); 171 172 /* mvd indicates if this block is motion compensated */ 173 mvd = motion_x | motion_y; 174 175 if((cbp | mvd | s->dquant ) == 0) { 176 /* skip macroblock */ 177 s->skip_count++; 178 h->current_mv_x=0; 179 h->current_mv_y=0; 180 return; 181 } 182 } 183 184 /* MB is not skipped, encode MBA */ 185 put_bits(&s->pb, h261_mba_bits[(h->current_mba-h->previous_mba)-1], h261_mba_code[(h->current_mba-h->previous_mba)-1]); 186 187 /* calculate MTYPE */ 188 if(!s->mb_intra){ 189 h->mtype++; 190 191 if(mvd || s->loop_filter) 192 h->mtype+=3; 193 if(s->loop_filter) 194 h->mtype+=3; 195 if(cbp || s->dquant) 196 h->mtype++; 197 assert(h->mtype > 1); 198 } 199 200 if(s->dquant) 201 h->mtype++; 202 203 put_bits(&s->pb, h261_mtype_bits[h->mtype], h261_mtype_code[h->mtype]); 204 205 h->mtype = h261_mtype_map[h->mtype]; 206 207 if(IS_QUANT(h->mtype)){ 208 ff_set_qscale(s,s->qscale+s->dquant); 209 put_bits(&s->pb, 5, s->qscale); 210 } 211 212 if(IS_16X16(h->mtype)){ 213 mv_diff_x = (motion_x >> 1) - h->current_mv_x; 214 mv_diff_y = (motion_y >> 1) - h->current_mv_y; 215 h->current_mv_x = (motion_x >> 1); 216 h->current_mv_y = (motion_y >> 1); 217 h261_encode_motion(h,mv_diff_x); 218 h261_encode_motion(h,mv_diff_y); 219 } 220 221 h->previous_mba = h->current_mba; 222 223 if(HAS_CBP(h->mtype)){ 224 assert(cbp>0); 225 put_bits(&s->pb,h261_cbp_tab[cbp-1][1],h261_cbp_tab[cbp-1][0]); 226 } 227 for(i=0; i<6; i++) { 228 /* encode each block */ 229 h261_encode_block(h, block[i], i); 230 } 231 232 if ( ( h->current_mba == 11 ) || ( h->current_mba == 22 ) || ( h->current_mba == 33 ) || ( !IS_16X16 ( h->mtype ) )){ 233 h->current_mv_x=0; 234 h->current_mv_y=0; 235 } 236} 237 238void ff_h261_encode_init(MpegEncContext *s){ 239 static int done = 0; 240 241 if (!done) { 242 done = 1; 243 init_rl(&h261_rl_tcoeff, ff_h261_rl_table_store); 244 } 245 246 s->min_qcoeff= -127; 247 s->max_qcoeff= 127; 248 s->y_dc_scale_table= 249 s->c_dc_scale_table= ff_mpeg1_dc_scale_table; 250} 251 252 253/** 254 * encodes a 8x8 block. 255 * @param block the 8x8 block 256 * @param n block index (0-3 are luma, 4-5 are chroma) 257 */ 258static void h261_encode_block(H261Context * h, DCTELEM * block, int n){ 259 MpegEncContext * const s = &h->s; 260 int level, run, i, j, last_index, last_non_zero, sign, slevel, code; 261 RLTable *rl; 262 263 rl = &h261_rl_tcoeff; 264 if (s->mb_intra) { 265 /* DC coef */ 266 level = block[0]; 267 /* 255 cannot be represented, so we clamp */ 268 if (level > 254) { 269 level = 254; 270 block[0] = 254; 271 } 272 /* 0 cannot be represented also */ 273 else if (level < 1) { 274 level = 1; 275 block[0] = 1; 276 } 277 if (level == 128) 278 put_bits(&s->pb, 8, 0xff); 279 else 280 put_bits(&s->pb, 8, level); 281 i = 1; 282 } else if((block[0]==1 || block[0] == -1) && (s->block_last_index[n] > -1)){ 283 //special case 284 put_bits(&s->pb,2,block[0]>0 ? 2 : 3 ); 285 i = 1; 286 } else { 287 i = 0; 288 } 289 290 /* AC coefs */ 291 last_index = s->block_last_index[n]; 292 last_non_zero = i - 1; 293 for (; i <= last_index; i++) { 294 j = s->intra_scantable.permutated[i]; 295 level = block[j]; 296 if (level) { 297 run = i - last_non_zero - 1; 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 AVMEDIA_TYPE_VIDEO, 327 CODEC_ID_H261, 328 sizeof(H261Context), 329 MPV_encode_init, 330 MPV_encode_picture, 331 MPV_encode_end, 332 .pix_fmts= (const enum PixelFormat[]){PIX_FMT_YUV420P, PIX_FMT_NONE}, 333 .long_name= NULL_IF_CONFIG_SMALL("H.261"), 334}; 335 336