/** * @file vorbis.c * Common code for Vorbis I encoder and decoder * @author Denes Balatoni ( dbalatoni programozo hu ) * 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 */ #undef V_DEBUG //#define V_DEBUG #define ALT_BITSTREAM_READER_LE #include "avcodec.h" #include "bitstream.h" #include "vorbis.h" /* Helper functions */ unsigned int ff_vorbis_nth_root(unsigned int x, unsigned int n) { // x^(1/n) unsigned int ret=0, i, j; do { ++ret; for(i=0,j=ret;i<n-1;i++) j*=ret; } while (j<=x); return (ret-1); } // Generate vlc codes from vorbis huffman code lengths int ff_vorbis_len2vlc(uint8_t *bits, uint32_t *codes, uint_fast32_t num) { uint_fast32_t exit_at_level[33]={404,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}; uint_fast8_t i,j; uint_fast32_t code,p; #ifdef V_DEBUG GetBitContext gb; #endif for(p=0;(bits[p]==0) && (p<num);++p); if (p==num) { // av_log(vc->avccontext, AV_LOG_INFO, "An empty codebook. Heh?! \n"); return 0; } codes[p]=0; for(i=0;i<bits[p];++i) { exit_at_level[i+1]=1<<i; } #ifdef V_DEBUG av_log(NULL, AV_LOG_INFO, " %d. of %d code len %d code %d - ", p, num, bits[p], codes[p]); init_get_bits(&gb, (uint_fast8_t *)&codes[p], bits[p]); for(i=0;i<bits[p];++i) { av_log(NULL, AV_LOG_INFO, "%s", get_bits1(&gb) ? "1" : "0"); } av_log(NULL, AV_LOG_INFO, "\n"); #endif ++p; for(;p<num;++p) { if (bits[p]==0) continue; // find corresponding exit(node which the tree can grow further from) for(i=bits[p];i>0;--i) { if (exit_at_level[i]) break; } if (!i) return 1; // overspecified tree code=exit_at_level[i]; exit_at_level[i]=0; // construct code (append 0s to end) and introduce new exits for(j=i+1;j<=bits[p];++j) { exit_at_level[j]=code+(1<<(j-1)); } codes[p]=code; #ifdef V_DEBUG av_log(NULL, AV_LOG_INFO, " %d. code len %d code %d - ", p, bits[p], codes[p]); init_get_bits(&gb, (uint_fast8_t *)&codes[p], bits[p]); for(i=0;i<bits[p];++i) { av_log(NULL, AV_LOG_INFO, "%s", get_bits1(&gb) ? "1" : "0"); } av_log(NULL, AV_LOG_INFO, "\n"); #endif } //no exits should be left (underspecified tree - ie. unused valid vlcs - not allowed by SPEC) for (p=1; p<33; p++) if (exit_at_level[p]) return 1; return 0; } void ff_vorbis_ready_floor1_list(floor1_entry_t * list, int values) { int i; list[0].sort = 0; list[1].sort = 1; for (i = 2; i < values; i++) { int j; list[i].low = 0; list[i].high = 1; list[i].sort = i; for (j = 2; j < i; j++) { int tmp = list[j].x; if (tmp < list[i].x) { if (tmp > list[list[i].low].x) list[i].low = j; } else { if (tmp < list[list[i].high].x) list[i].high = j; } } } for (i = 0; i < values - 1; i++) { int j; for (j = i + 1; j < values; j++) { if (list[list[i].sort].x > list[list[j].sort].x) { int tmp = list[i].sort; list[i].sort = list[j].sort; list[j].sort = tmp; } } } } static void render_line(int x0, int y0, int x1, int y1, float * buf, int n) { int dy = y1 - y0; int adx = x1 - x0; int ady = FFABS(dy); int base = dy / adx; int x = x0; int y = y0; int err = 0; int sy; if (dy < 0) sy = base - 1; else sy = base + 1; ady = ady - FFABS(base) * adx; if (x >= n) return; buf[x] = ff_vorbis_floor1_inverse_db_table[y]; for (x = x0 + 1; x < x1; x++) { if (x >= n) return; err += ady; if (err >= adx) { err -= adx; y += sy; } else { y += base; } buf[x] = ff_vorbis_floor1_inverse_db_table[y]; } } void ff_vorbis_floor1_render_list(floor1_entry_t * list, int values, uint_fast16_t * y_list, int * flag, int multiplier, float * out, int samples) { int lx, ly, i; lx = 0; ly = y_list[0] * multiplier; for (i = 1; i < values; i++) { int pos = list[i].sort; if (flag[pos]) { render_line(lx, ly, list[pos].x, y_list[pos] * multiplier, out, samples); lx = list[pos].x; ly = y_list[pos] * multiplier; } if (lx >= samples) break; } if (lx < samples) render_line(lx, ly, samples, ly, out, samples); }