/* * H261 encoder * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at> * Copyright (c) 2004 Maarten Daniels * * This file is part of FFmpeg. * * FFmpeg is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * FFmpeg is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ /** * @file h261enc.c * H.261 encoder. */ #include "dsputil.h" #include "avcodec.h" #include "mpegvideo.h" #include "h261.h" #include "h261data.h" extern uint8_t ff_h261_rl_table_store[2][2*MAX_RUN + MAX_LEVEL + 3]; static void h261_encode_block(H261Context * h, DCTELEM * block, int n); int ff_h261_get_picture_format(int width, int height){ // QCIF if (width == 176 && height == 144) return 0; // CIF else if (width == 352 && height == 288) return 1; // ERROR else return -1; } void ff_h261_encode_picture_header(MpegEncContext * s, int picture_number){ H261Context * h = (H261Context *) s; int format, temp_ref; align_put_bits(&s->pb); /* Update the pointer to last GOB */ s->ptr_lastgob = pbBufPtr(&s->pb); put_bits(&s->pb, 20, 0x10); /* PSC */ temp_ref= s->picture_number * (int64_t)30000 * s->avctx->time_base.num / (1001 * (int64_t)s->avctx->time_base.den); //FIXME maybe this should use a timestamp put_bits(&s->pb, 5, temp_ref & 0x1f); /* TemporalReference */ put_bits(&s->pb, 1, 0); /* split screen off */ put_bits(&s->pb, 1, 0); /* camera off */ put_bits(&s->pb, 1, 0); /* freeze picture release off */ format = ff_h261_get_picture_format(s->width, s->height); put_bits(&s->pb, 1, format); /* 0 == QCIF, 1 == CIF */ put_bits(&s->pb, 1, 0); /* still image mode */ put_bits(&s->pb, 1, 0); /* reserved */ put_bits(&s->pb, 1, 0); /* no PEI */ if(format == 0) h->gob_number = -1; else h->gob_number = 0; h->current_mba = 0; } /** * Encodes a group of blocks header. */ static void h261_encode_gob_header(MpegEncContext * s, int mb_line){ H261Context * h = (H261Context *)s; if(ff_h261_get_picture_format(s->width, s->height) == 0){ h->gob_number+=2; // QCIF } else{ h->gob_number++; // CIF } put_bits(&s->pb, 16, 1); /* GBSC */ put_bits(&s->pb, 4, h->gob_number); /* GN */ put_bits(&s->pb, 5, s->qscale); /* GQUANT */ put_bits(&s->pb, 1, 0); /* no GEI */ h->current_mba = 0; h->previous_mba = 0; h->current_mv_x=0; h->current_mv_y=0; } void ff_h261_reorder_mb_index(MpegEncContext* s){ int index= s->mb_x + s->mb_y*s->mb_width; if(index % 33 == 0) h261_encode_gob_header(s,0); /* for CIF the GOB's are fragmented in the middle of a scanline that's why we need to adjust the x and y index of the macroblocks */ if(ff_h261_get_picture_format(s->width,s->height) == 1){ // CIF s->mb_x = index % 11 ; index /= 11; s->mb_y = index % 3 ; index /= 3; s->mb_x+= 11*(index % 2); index /= 2; s->mb_y+= 3*index; ff_init_block_index(s); ff_update_block_index(s); } } static void h261_encode_motion(H261Context * h, int val){ MpegEncContext * const s = &h->s; int sign, code; if(val==0){ code = 0; put_bits(&s->pb,h261_mv_tab[code][1],h261_mv_tab[code][0]); } else{ if(val > 15) val -=32; if(val < -16) val+=32; sign = val < 0; code = sign ? -val : val; put_bits(&s->pb,h261_mv_tab[code][1],h261_mv_tab[code][0]); put_bits(&s->pb,1,sign); } } static inline int get_cbp(MpegEncContext * s, DCTELEM block[6][64]) { int i, cbp; cbp= 0; for (i = 0; i < 6; i++) { if (s->block_last_index[i] >= 0) cbp |= 1 << (5 - i); } return cbp; } void ff_h261_encode_mb(MpegEncContext * s, DCTELEM block[6][64], int motion_x, int motion_y) { H261Context * h = (H261Context *)s; int mvd, mv_diff_x, mv_diff_y, i, cbp; cbp = 63; // avoid warning mvd = 0; h->current_mba++; h->mtype = 0; if (!s->mb_intra){ /* compute cbp */ cbp= get_cbp(s, block); /* mvd indicates if this block is motion compensated */ mvd = motion_x | motion_y; if((cbp | mvd | s->dquant ) == 0) { /* skip macroblock */ s->skip_count++; h->current_mv_x=0; h->current_mv_y=0; return; } } /* MB is not skipped, encode MBA */ put_bits(&s->pb, h261_mba_bits[(h->current_mba-h->previous_mba)-1], h261_mba_code[(h->current_mba-h->previous_mba)-1]); /* calculate MTYPE */ if(!s->mb_intra){ h->mtype++; if(mvd || s->loop_filter) h->mtype+=3; if(s->loop_filter) h->mtype+=3; if(cbp || s->dquant) h->mtype++; assert(h->mtype > 1); } if(s->dquant) h->mtype++; put_bits(&s->pb, h261_mtype_bits[h->mtype], h261_mtype_code[h->mtype]); h->mtype = h261_mtype_map[h->mtype]; if(IS_QUANT(h->mtype)){ ff_set_qscale(s,s->qscale+s->dquant); put_bits(&s->pb, 5, s->qscale); } if(IS_16X16(h->mtype)){ mv_diff_x = (motion_x >> 1) - h->current_mv_x; mv_diff_y = (motion_y >> 1) - h->current_mv_y; h->current_mv_x = (motion_x >> 1); h->current_mv_y = (motion_y >> 1); h261_encode_motion(h,mv_diff_x); h261_encode_motion(h,mv_diff_y); } h->previous_mba = h->current_mba; if(HAS_CBP(h->mtype)){ assert(cbp>0); put_bits(&s->pb,h261_cbp_tab[cbp-1][1],h261_cbp_tab[cbp-1][0]); } for(i=0; i<6; i++) { /* encode each block */ h261_encode_block(h, block[i], i); } if ( ( h->current_mba == 11 ) || ( h->current_mba == 22 ) || ( h->current_mba == 33 ) || ( !IS_16X16 ( h->mtype ) )){ h->current_mv_x=0; h->current_mv_y=0; } } void ff_h261_encode_init(MpegEncContext *s){ static int done = 0; if (!done) { done = 1; init_rl(&h261_rl_tcoeff, ff_h261_rl_table_store); } s->min_qcoeff= -127; s->max_qcoeff= 127; s->y_dc_scale_table= s->c_dc_scale_table= ff_mpeg1_dc_scale_table; } /** * encodes a 8x8 block. * @param block the 8x8 block * @param n block index (0-3 are luma, 4-5 are chroma) */ static void h261_encode_block(H261Context * h, DCTELEM * block, int n){ MpegEncContext * const s = &h->s; int level, run, last, i, j, last_index, last_non_zero, sign, slevel, code; RLTable *rl; rl = &h261_rl_tcoeff; if (s->mb_intra) { /* DC coef */ level = block[0]; /* 255 cannot be represented, so we clamp */ if (level > 254) { level = 254; block[0] = 254; } /* 0 cannot be represented also */ else if (level < 1) { level = 1; block[0] = 1; } if (level == 128) put_bits(&s->pb, 8, 0xff); else put_bits(&s->pb, 8, level); i = 1; } else if((block[0]==1 || block[0] == -1) && (s->block_last_index[n] > -1)){ //special case put_bits(&s->pb,2,block[0]>0 ? 2 : 3 ); i = 1; } else { i = 0; } /* AC coefs */ last_index = s->block_last_index[n]; last_non_zero = i - 1; for (; i <= last_index; i++) { j = s->intra_scantable.permutated[i]; level = block[j]; if (level) { run = i - last_non_zero - 1; last = (i == last_index); sign = 0; slevel = level; if (level < 0) { sign = 1; level = -level; } code = get_rl_index(rl, 0 /*no last in H.261, EOB is used*/, run, level); if(run==0 && level < 16) code+=1; put_bits(&s->pb, rl->table_vlc[code][1], rl->table_vlc[code][0]); if (code == rl->n) { put_bits(&s->pb, 6, run); assert(slevel != 0); assert(level <= 127); put_bits(&s->pb, 8, slevel & 0xff); } else { put_bits(&s->pb, 1, sign); } last_non_zero = i; } } if(last_index > -1){ put_bits(&s->pb, rl->table_vlc[0][1], rl->table_vlc[0][0]);// END OF BLOCK } } AVCodec h261_encoder = { "h261", CODEC_TYPE_VIDEO, CODEC_ID_H261, sizeof(H261Context), MPV_encode_init, MPV_encode_picture, MPV_encode_end, .pix_fmts= (enum PixelFormat[]){PIX_FMT_YUV420P, -1}, .long_name= "H.261", };