release/src/router/ffmpeg/libavcodec/h261enc.c

   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
  35 extern uint8_t ff_h261_rl_table_store[2][2*MAX_RUN + MAX_LEVEL + 3];
  36
  37 static void h261_encode_block(H261Context * h, DCTELEM * block,
  38                               int n);
  39
  40 int 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
  52 void 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  */
  89 static 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
 107 void 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
 126 static 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
 145 static 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 }
 156 void 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
 238 void 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  */
 258 static 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
 324 AVCodec 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