| 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 "libavutil/attributes.h" |
| 29 | #include "libavutil/avassert.h" |
| 30 | #include "avcodec.h" |
| 31 | #include "mpegutils.h" |
| 32 | #include "mpegvideo.h" |
| 33 | #include "h263.h" |
| 34 | #include "h261.h" |
| 35 | |
| 36 | static uint8_t uni_h261_rl_len [64*64*2*2]; |
| 37 | #define UNI_ENC_INDEX(last,run,level) ((last)*128*64 + (run)*128 + (level)) |
| 38 | |
| 39 | int ff_h261_get_picture_format(int width, int height) |
| 40 | { |
| 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 | |
| 52 | void ff_h261_encode_picture_header(MpegEncContext *s, int picture_number) |
| 53 | { |
| 54 | H261Context *h = (H261Context *)s; |
| 55 | int format, temp_ref; |
| 56 | |
| 57 | avpriv_align_put_bits(&s->pb); |
| 58 | |
| 59 | /* Update the pointer to last GOB */ |
| 60 | s->ptr_lastgob = put_bits_ptr(&s->pb); |
| 61 | |
| 62 | put_bits(&s->pb, 20, 0x10); /* PSC */ |
| 63 | |
| 64 | temp_ref = s->picture_number * (int64_t)30000 * s->avctx->time_base.num / |
| 65 | (1001 * (int64_t)s->avctx->time_base.den); // FIXME maybe this should use a timestamp |
| 66 | put_sbits(&s->pb, 5, temp_ref); /* TemporalReference */ |
| 67 | |
| 68 | put_bits(&s->pb, 1, 0); /* split screen off */ |
| 69 | put_bits(&s->pb, 1, 0); /* camera off */ |
| 70 | put_bits(&s->pb, 1, 0); /* freeze picture release off */ |
| 71 | |
| 72 | format = ff_h261_get_picture_format(s->width, s->height); |
| 73 | |
| 74 | put_bits(&s->pb, 1, format); /* 0 == QCIF, 1 == CIF */ |
| 75 | |
| 76 | put_bits(&s->pb, 1, 0); /* still image mode */ |
| 77 | put_bits(&s->pb, 1, 0); /* reserved */ |
| 78 | |
| 79 | put_bits(&s->pb, 1, 0); /* no PEI */ |
| 80 | if (format == 0) |
| 81 | h->gob_number = -1; |
| 82 | else |
| 83 | h->gob_number = 0; |
| 84 | s->mb_skip_run = 0; |
| 85 | } |
| 86 | |
| 87 | /** |
| 88 | * Encode a group of blocks header. |
| 89 | */ |
| 90 | static void h261_encode_gob_header(MpegEncContext *s, int mb_line) |
| 91 | { |
| 92 | H261Context *h = (H261Context *)s; |
| 93 | if (ff_h261_get_picture_format(s->width, s->height) == 0) { |
| 94 | h->gob_number += 2; // QCIF |
| 95 | } else { |
| 96 | h->gob_number++; // CIF |
| 97 | } |
| 98 | put_bits(&s->pb, 16, 1); /* GBSC */ |
| 99 | put_bits(&s->pb, 4, h->gob_number); /* GN */ |
| 100 | put_bits(&s->pb, 5, s->qscale); /* GQUANT */ |
| 101 | put_bits(&s->pb, 1, 0); /* no GEI */ |
| 102 | s->mb_skip_run = 0; |
| 103 | s->last_mv[0][0][0] = 0; |
| 104 | s->last_mv[0][0][1] = 0; |
| 105 | } |
| 106 | |
| 107 | void ff_h261_reorder_mb_index(MpegEncContext *s) |
| 108 | { |
| 109 | int index = s->mb_x + s->mb_y * s->mb_width; |
| 110 | |
| 111 | if (index % 11 == 0) { |
| 112 | if (index % 33 == 0) |
| 113 | h261_encode_gob_header(s, 0); |
| 114 | s->last_mv[0][0][0] = 0; |
| 115 | s->last_mv[0][0][1] = 0; |
| 116 | } |
| 117 | |
| 118 | /* for CIF the GOB's are fragmented in the middle of a scanline |
| 119 | * that's why we need to adjust the x and y index of the macroblocks */ |
| 120 | if (ff_h261_get_picture_format(s->width, s->height) == 1) { // CIF |
| 121 | s->mb_x = index % 11; |
| 122 | index /= 11; |
| 123 | s->mb_y = index % 3; |
| 124 | index /= 3; |
| 125 | s->mb_x += 11 * (index % 2); |
| 126 | index /= 2; |
| 127 | s->mb_y += 3 * index; |
| 128 | |
| 129 | ff_init_block_index(s); |
| 130 | ff_update_block_index(s); |
| 131 | } |
| 132 | } |
| 133 | |
| 134 | static void h261_encode_motion(H261Context *h, int val) |
| 135 | { |
| 136 | MpegEncContext *const s = &h->s; |
| 137 | int sign, code; |
| 138 | if (val == 0) { |
| 139 | code = 0; |
| 140 | put_bits(&s->pb, ff_h261_mv_tab[code][1], ff_h261_mv_tab[code][0]); |
| 141 | } else { |
| 142 | if (val > 15) |
| 143 | val -= 32; |
| 144 | if (val < -16) |
| 145 | val += 32; |
| 146 | sign = val < 0; |
| 147 | code = sign ? -val : val; |
| 148 | put_bits(&s->pb, ff_h261_mv_tab[code][1], ff_h261_mv_tab[code][0]); |
| 149 | put_bits(&s->pb, 1, sign); |
| 150 | } |
| 151 | } |
| 152 | |
| 153 | static inline int get_cbp(MpegEncContext *s, int16_t block[6][64]) |
| 154 | { |
| 155 | int i, cbp; |
| 156 | cbp = 0; |
| 157 | for (i = 0; i < 6; i++) |
| 158 | if (s->block_last_index[i] >= 0) |
| 159 | cbp |= 1 << (5 - i); |
| 160 | return cbp; |
| 161 | } |
| 162 | |
| 163 | /** |
| 164 | * Encode an 8x8 block. |
| 165 | * @param block the 8x8 block |
| 166 | * @param n block index (0-3 are luma, 4-5 are chroma) |
| 167 | */ |
| 168 | static void h261_encode_block(H261Context *h, int16_t *block, int n) |
| 169 | { |
| 170 | MpegEncContext *const s = &h->s; |
| 171 | int level, run, i, j, last_index, last_non_zero, sign, slevel, code; |
| 172 | RLTable *rl; |
| 173 | |
| 174 | rl = &ff_h261_rl_tcoeff; |
| 175 | if (s->mb_intra) { |
| 176 | /* DC coef */ |
| 177 | level = block[0]; |
| 178 | /* 255 cannot be represented, so we clamp */ |
| 179 | if (level > 254) { |
| 180 | level = 254; |
| 181 | block[0] = 254; |
| 182 | } |
| 183 | /* 0 cannot be represented also */ |
| 184 | else if (level < 1) { |
| 185 | level = 1; |
| 186 | block[0] = 1; |
| 187 | } |
| 188 | if (level == 128) |
| 189 | put_bits(&s->pb, 8, 0xff); |
| 190 | else |
| 191 | put_bits(&s->pb, 8, level); |
| 192 | i = 1; |
| 193 | } else if ((block[0] == 1 || block[0] == -1) && |
| 194 | (s->block_last_index[n] > -1)) { |
| 195 | // special case |
| 196 | put_bits(&s->pb, 2, block[0] > 0 ? 2 : 3); |
| 197 | i = 1; |
| 198 | } else { |
| 199 | i = 0; |
| 200 | } |
| 201 | |
| 202 | /* AC coefs */ |
| 203 | last_index = s->block_last_index[n]; |
| 204 | last_non_zero = i - 1; |
| 205 | for (; i <= last_index; i++) { |
| 206 | j = s->intra_scantable.permutated[i]; |
| 207 | level = block[j]; |
| 208 | if (level) { |
| 209 | run = i - last_non_zero - 1; |
| 210 | sign = 0; |
| 211 | slevel = level; |
| 212 | if (level < 0) { |
| 213 | sign = 1; |
| 214 | level = -level; |
| 215 | } |
| 216 | code = get_rl_index(rl, 0 /*no last in H.261, EOB is used*/, |
| 217 | run, level); |
| 218 | if (run == 0 && level < 16) |
| 219 | code += 1; |
| 220 | put_bits(&s->pb, rl->table_vlc[code][1], rl->table_vlc[code][0]); |
| 221 | if (code == rl->n) { |
| 222 | put_bits(&s->pb, 6, run); |
| 223 | av_assert1(slevel != 0); |
| 224 | av_assert1(level <= 127); |
| 225 | put_sbits(&s->pb, 8, slevel); |
| 226 | } else { |
| 227 | put_bits(&s->pb, 1, sign); |
| 228 | } |
| 229 | last_non_zero = i; |
| 230 | } |
| 231 | } |
| 232 | if (last_index > -1) |
| 233 | put_bits(&s->pb, rl->table_vlc[0][1], rl->table_vlc[0][0]); // EOB |
| 234 | } |
| 235 | |
| 236 | void ff_h261_encode_mb(MpegEncContext *s, int16_t block[6][64], |
| 237 | int motion_x, int motion_y) |
| 238 | { |
| 239 | H261Context *h = (H261Context *)s; |
| 240 | int mvd, mv_diff_x, mv_diff_y, i, cbp; |
| 241 | cbp = 63; // avoid warning |
| 242 | mvd = 0; |
| 243 | |
| 244 | h->mtype = 0; |
| 245 | |
| 246 | if (!s->mb_intra) { |
| 247 | /* compute cbp */ |
| 248 | cbp = get_cbp(s, block); |
| 249 | |
| 250 | /* mvd indicates if this block is motion compensated */ |
| 251 | mvd = motion_x | motion_y; |
| 252 | |
| 253 | if ((cbp | mvd | s->dquant) == 0) { |
| 254 | /* skip macroblock */ |
| 255 | s->skip_count++; |
| 256 | s->mb_skip_run++; |
| 257 | s->last_mv[0][0][0] = 0; |
| 258 | s->last_mv[0][0][1] = 0; |
| 259 | return; |
| 260 | } |
| 261 | } |
| 262 | |
| 263 | /* MB is not skipped, encode MBA */ |
| 264 | put_bits(&s->pb, |
| 265 | ff_h261_mba_bits[s->mb_skip_run], |
| 266 | ff_h261_mba_code[s->mb_skip_run]); |
| 267 | s->mb_skip_run = 0; |
| 268 | |
| 269 | /* calculate MTYPE */ |
| 270 | if (!s->mb_intra) { |
| 271 | h->mtype++; |
| 272 | |
| 273 | if (mvd || s->loop_filter) |
| 274 | h->mtype += 3; |
| 275 | if (s->loop_filter) |
| 276 | h->mtype += 3; |
| 277 | if (cbp || s->dquant) |
| 278 | h->mtype++; |
| 279 | av_assert1(h->mtype > 1); |
| 280 | } |
| 281 | |
| 282 | if (s->dquant) |
| 283 | h->mtype++; |
| 284 | |
| 285 | put_bits(&s->pb, |
| 286 | ff_h261_mtype_bits[h->mtype], |
| 287 | ff_h261_mtype_code[h->mtype]); |
| 288 | |
| 289 | h->mtype = ff_h261_mtype_map[h->mtype]; |
| 290 | |
| 291 | if (IS_QUANT(h->mtype)) { |
| 292 | ff_set_qscale(s, s->qscale + s->dquant); |
| 293 | put_bits(&s->pb, 5, s->qscale); |
| 294 | } |
| 295 | |
| 296 | if (IS_16X16(h->mtype)) { |
| 297 | mv_diff_x = (motion_x >> 1) - s->last_mv[0][0][0]; |
| 298 | mv_diff_y = (motion_y >> 1) - s->last_mv[0][0][1]; |
| 299 | s->last_mv[0][0][0] = (motion_x >> 1); |
| 300 | s->last_mv[0][0][1] = (motion_y >> 1); |
| 301 | h261_encode_motion(h, mv_diff_x); |
| 302 | h261_encode_motion(h, mv_diff_y); |
| 303 | } |
| 304 | |
| 305 | if (HAS_CBP(h->mtype)) { |
| 306 | av_assert1(cbp > 0); |
| 307 | put_bits(&s->pb, |
| 308 | ff_h261_cbp_tab[cbp - 1][1], |
| 309 | ff_h261_cbp_tab[cbp - 1][0]); |
| 310 | } |
| 311 | for (i = 0; i < 6; i++) |
| 312 | /* encode each block */ |
| 313 | h261_encode_block(h, block[i], i); |
| 314 | |
| 315 | if (!IS_16X16(h->mtype)) { |
| 316 | s->last_mv[0][0][0] = 0; |
| 317 | s->last_mv[0][0][1] = 0; |
| 318 | } |
| 319 | } |
| 320 | |
| 321 | static av_cold void init_uni_h261_rl_tab(RLTable *rl, uint32_t *bits_tab, |
| 322 | uint8_t *len_tab) |
| 323 | { |
| 324 | int slevel, run, last; |
| 325 | |
| 326 | av_assert0(MAX_LEVEL >= 64); |
| 327 | av_assert0(MAX_RUN >= 63); |
| 328 | |
| 329 | for(slevel=-64; slevel<64; slevel++){ |
| 330 | if(slevel==0) continue; |
| 331 | for(run=0; run<64; run++){ |
| 332 | for(last=0; last<=1; last++){ |
| 333 | const int index= UNI_ENC_INDEX(last, run, slevel+64); |
| 334 | int level= slevel < 0 ? -slevel : slevel; |
| 335 | int len, code; |
| 336 | |
| 337 | len_tab[index]= 100; |
| 338 | |
| 339 | /* ESC0 */ |
| 340 | code= get_rl_index(rl, 0, run, level); |
| 341 | len= rl->table_vlc[code][1] + 1; |
| 342 | if(last) |
| 343 | len += 2; |
| 344 | |
| 345 | if(code!=rl->n && len < len_tab[index]){ |
| 346 | len_tab [index]= len; |
| 347 | } |
| 348 | /* ESC */ |
| 349 | len = rl->table_vlc[rl->n][1]; |
| 350 | if(last) |
| 351 | len += 2; |
| 352 | |
| 353 | if(len < len_tab[index]){ |
| 354 | len_tab [index]= len; |
| 355 | } |
| 356 | } |
| 357 | } |
| 358 | } |
| 359 | } |
| 360 | |
| 361 | av_cold void ff_h261_encode_init(MpegEncContext *s) |
| 362 | { |
| 363 | ff_h261_common_init(); |
| 364 | |
| 365 | s->min_qcoeff = -127; |
| 366 | s->max_qcoeff = 127; |
| 367 | s->y_dc_scale_table = |
| 368 | s->c_dc_scale_table = ff_mpeg1_dc_scale_table; |
| 369 | s->ac_esc_length = 6+6+8; |
| 370 | |
| 371 | init_uni_h261_rl_tab(&ff_h261_rl_tcoeff, NULL, uni_h261_rl_len); |
| 372 | |
| 373 | s->intra_ac_vlc_length = s->inter_ac_vlc_length = uni_h261_rl_len; |
| 374 | s->intra_ac_vlc_last_length = s->inter_ac_vlc_last_length = uni_h261_rl_len + 128*64; |
| 375 | } |
| 376 | |
| 377 | FF_MPV_GENERIC_CLASS(h261) |
| 378 | |
| 379 | AVCodec ff_h261_encoder = { |
| 380 | .name = "h261", |
| 381 | .long_name = NULL_IF_CONFIG_SMALL("H.261"), |
| 382 | .type = AVMEDIA_TYPE_VIDEO, |
| 383 | .id = AV_CODEC_ID_H261, |
| 384 | .priv_data_size = sizeof(H261Context), |
| 385 | .init = ff_mpv_encode_init, |
| 386 | .encode2 = ff_mpv_encode_picture, |
| 387 | .close = ff_mpv_encode_end, |
| 388 | .pix_fmts = (const enum AVPixelFormat[]) { AV_PIX_FMT_YUV420P, |
| 389 | AV_PIX_FMT_NONE }, |
| 390 | .priv_class = &h261_class, |
| 391 | }; |