mirror of
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preparing integration of new AC3 decoder
Originally committed as revision 1089 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Fabrice Bellard
parent
bb6f569072
commit
6107fa87b4
56
libavcodec/ac3.h
Normal file
56
libavcodec/ac3.h
Normal file
@ -0,0 +1,56 @@
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/*
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* Common code between AC3 encoder and decoder
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* Copyright (c) 2000, 2001, 2002 Fabrice Bellard.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#define AC3_MAX_CODED_FRAME_SIZE 3840 /* in bytes */
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#define AC3_MAX_CHANNELS 6 /* including LFE channel */
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#define NB_BLOCKS 6 /* number of PCM blocks inside an AC3 frame */
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#define AC3_FRAME_SIZE (NB_BLOCKS * 256)
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/* exponent encoding strategy */
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#define EXP_REUSE 0
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#define EXP_NEW 1
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#define EXP_D15 1
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#define EXP_D25 2
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#define EXP_D45 3
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typedef struct AC3BitAllocParameters {
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int fscod; /* frequency */
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int halfratecod;
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int sgain, sdecay, fdecay, dbknee, floor;
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int cplfleak, cplsleak;
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} AC3BitAllocParameters;
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extern const UINT16 ac3_freqs[3];
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extern const UINT16 ac3_bitratetab[19];
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extern const INT16 ac3_window[256];
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extern const UINT8 sdecaytab[4];
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extern const UINT8 fdecaytab[4];
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extern const UINT16 sgaintab[4];
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extern const UINT16 dbkneetab[4];
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extern const UINT16 floortab[8];
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extern const UINT16 fgaintab[8];
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void ac3_common_init(void);
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void ac3_parametric_bit_allocation(AC3BitAllocParameters *s, UINT8 *bap,
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INT8 *exp, int start, int end,
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int snroffset, int fgain, int is_lfe,
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int deltbae,int deltnseg,
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UINT8 *deltoffst, UINT8 *deltlen, UINT8 *deltba);
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@ -20,25 +20,46 @@
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//#define DEBUG_BITALLOC
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#include "avcodec.h"
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#include "ac3enc.h"
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#include "ac3tab.h"
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#include "ac3.h"
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typedef struct AC3EncodeContext {
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PutBitContext pb;
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int nb_channels;
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int nb_all_channels;
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int lfe_channel;
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int bit_rate;
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int sample_rate;
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int bsid;
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int frame_size_min; /* minimum frame size in case rounding is necessary */
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int frame_size; /* current frame size in words */
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int halfratecod;
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int frmsizecod;
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int fscod; /* frequency */
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int acmod;
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int lfe;
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int bsmod;
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short last_samples[AC3_MAX_CHANNELS][256];
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int chbwcod[AC3_MAX_CHANNELS];
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int nb_coefs[AC3_MAX_CHANNELS];
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/* bitrate allocation control */
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int sgaincod, sdecaycod, fdecaycod, dbkneecod, floorcod;
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AC3BitAllocParameters bit_alloc;
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int csnroffst;
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int fgaincod[AC3_MAX_CHANNELS];
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int fsnroffst[AC3_MAX_CHANNELS];
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/* mantissa encoding */
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int mant1_cnt, mant2_cnt, mant4_cnt;
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} AC3EncodeContext;
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#include "ac3tab.h"
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#define MDCT_NBITS 9
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#define N (1 << MDCT_NBITS)
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#define NB_BLOCKS 6 /* number of PCM blocks inside an AC3 frame */
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/* new exponents are sent if their Norm 1 exceed this number */
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#define EXP_DIFF_THRESHOLD 1000
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/* exponent encoding strategy */
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#define EXP_REUSE 0
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#define EXP_NEW 1
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#define EXP_D15 1
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#define EXP_D25 2
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#define EXP_D45 3
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static void fft_init(int ln);
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static void ac3_crc_init(void);
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@ -88,11 +109,12 @@ static inline int calc_lowcomp(int a, int b0, int b1, int bin)
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}
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/* AC3 bit allocation. The algorithm is the one described in the AC3
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spec with some optimizations because of our simplified encoding
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assumptions. */
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void parametric_bit_allocation(AC3EncodeContext *s, UINT8 *bap,
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INT8 *exp, int start, int end,
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int snroffset, int fgain, int is_lfe)
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spec. */
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void ac3_parametric_bit_allocation(AC3BitAllocParameters *s, UINT8 *bap,
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INT8 *exp, int start, int end,
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int snroffset, int fgain, int is_lfe,
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int deltbae,int deltnseg,
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UINT8 *deltoffst, UINT8 *deltlen, UINT8 *deltba)
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{
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int bin,i,j,k,end1,v,v1,bndstrt,bndend,lowcomp,begin;
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int fastleak,slowleak,address,tmp;
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@ -138,48 +160,57 @@ void parametric_bit_allocation(AC3EncodeContext *s, UINT8 *bap,
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bndstrt = masktab[start];
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bndend = masktab[end-1] + 1;
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lowcomp = 0;
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lowcomp = calc_lowcomp1(lowcomp, bndpsd[0], bndpsd[1]) ;
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excite[0] = bndpsd[0] - fgain - lowcomp ;
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lowcomp = calc_lowcomp1(lowcomp, bndpsd[1], bndpsd[2]) ;
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excite[1] = bndpsd[1] - fgain - lowcomp ;
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begin = 7 ;
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for (bin = 2; bin < 7; bin++) {
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if (!(is_lfe && bin == 6))
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lowcomp = calc_lowcomp1(lowcomp, bndpsd[bin], bndpsd[bin+1]) ;
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fastleak = bndpsd[bin] - fgain ;
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slowleak = bndpsd[bin] - s->sgain ;
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excite[bin] = fastleak - lowcomp ;
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if (!(is_lfe && bin == 6)) {
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if (bndpsd[bin] <= bndpsd[bin+1]) {
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begin = bin + 1 ;
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break ;
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}
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}
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}
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if (bndstrt == 0) {
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lowcomp = 0;
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lowcomp = calc_lowcomp1(lowcomp, bndpsd[0], bndpsd[1]) ;
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excite[0] = bndpsd[0] - fgain - lowcomp ;
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lowcomp = calc_lowcomp1(lowcomp, bndpsd[1], bndpsd[2]) ;
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excite[1] = bndpsd[1] - fgain - lowcomp ;
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begin = 7 ;
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for (bin = 2; bin < 7; bin++) {
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if (!(is_lfe && bin == 6))
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lowcomp = calc_lowcomp1(lowcomp, bndpsd[bin], bndpsd[bin+1]) ;
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fastleak = bndpsd[bin] - fgain ;
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slowleak = bndpsd[bin] - s->sgain ;
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excite[bin] = fastleak - lowcomp ;
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if (!(is_lfe && bin == 6)) {
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if (bndpsd[bin] <= bndpsd[bin+1]) {
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begin = bin + 1 ;
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break ;
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}
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}
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}
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end1=bndend;
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if (end1 > 22) end1=22;
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end1=bndend;
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if (end1 > 22) end1=22;
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for (bin = begin; bin < end1; bin++) {
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if (!(is_lfe && bin == 6))
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lowcomp = calc_lowcomp(lowcomp, bndpsd[bin], bndpsd[bin+1], bin) ;
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for (bin = begin; bin < end1; bin++) {
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if (!(is_lfe && bin == 6))
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lowcomp = calc_lowcomp(lowcomp, bndpsd[bin], bndpsd[bin+1], bin) ;
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fastleak -= s->fdecay ;
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v = bndpsd[bin] - fgain;
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if (fastleak < v) fastleak = v;
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fastleak -= s->fdecay ;
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v = bndpsd[bin] - fgain;
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if (fastleak < v) fastleak = v;
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slowleak -= s->sdecay ;
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v = bndpsd[bin] - s->sgain;
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if (slowleak < v) slowleak = v;
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slowleak -= s->sdecay ;
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v = bndpsd[bin] - s->sgain;
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if (slowleak < v) slowleak = v;
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v=fastleak - lowcomp;
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if (slowleak > v) v=slowleak;
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v=fastleak - lowcomp;
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if (slowleak > v) v=slowleak;
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excite[bin] = v;
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excite[bin] = v;
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}
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begin = 22;
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} else {
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/* coupling channel */
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begin = bndstrt;
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fastleak = (s->cplfleak << 8) + 768;
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slowleak = (s->cplsleak << 8) + 768;
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}
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for (bin = 22; bin < bndend; bin++) {
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for (bin = begin; bin < bndend; bin++) {
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fastleak -= s->fdecay ;
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v = bndpsd[bin] - fgain;
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if (fastleak < v) fastleak = v;
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@ -205,6 +236,25 @@ void parametric_bit_allocation(AC3EncodeContext *s, UINT8 *bap,
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mask[bin] = v;
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}
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/* delta bit allocation */
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if (deltbae == 0 || deltbae == 1) {
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int band, seg, delta;
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band = 0 ;
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for (seg = 0; seg < deltnseg; seg++) {
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band += deltoffst[seg] ;
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if (deltba[seg] >= 4) {
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delta = (deltba[seg] - 3) << 7;
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} else {
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delta = (deltba[seg] - 4) << 7;
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}
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for (k = 0; k < deltlen[seg]; k++) {
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mask[band] += delta ;
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band++ ;
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}
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}
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}
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/* compute bit allocation */
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i = start ;
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@ -600,12 +650,14 @@ static int bit_alloc(AC3EncodeContext *s,
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s->mant2_cnt = 0;
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s->mant4_cnt = 0;
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for(ch=0;ch<s->nb_all_channels;ch++) {
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parametric_bit_allocation(s, bap[i][ch], (INT8 *)encoded_exp[i][ch],
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0, s->nb_coefs[ch],
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(((csnroffst-15) << 4) +
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fsnroffst) << 2,
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fgaintab[s->fgaincod[ch]],
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ch == s->lfe_channel);
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ac3_parametric_bit_allocation(&s->bit_alloc,
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bap[i][ch], (INT8 *)encoded_exp[i][ch],
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0, s->nb_coefs[ch],
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(((csnroffst-15) << 4) +
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fsnroffst) << 2,
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fgaintab[s->fgaincod[ch]],
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ch == s->lfe_channel,
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2, 0, NULL, NULL, NULL);
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frame_bits += compute_mantissa_size(s, bap[i][ch],
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s->nb_coefs[ch]);
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}
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@ -641,12 +693,14 @@ static int compute_bit_allocation(AC3EncodeContext *s,
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s->fgaincod[ch] = 4;
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/* compute real values */
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s->sdecay = sdecaytab[s->sdecaycod] >> s->halfratecod;
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s->fdecay = fdecaytab[s->fdecaycod] >> s->halfratecod;
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s->sgain = sgaintab[s->sgaincod];
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s->dbknee = dbkneetab[s->dbkneecod];
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s->floor = floortab[s->floorcod];
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s->bit_alloc.fscod = s->fscod;
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s->bit_alloc.halfratecod = s->halfratecod;
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s->bit_alloc.sdecay = sdecaytab[s->sdecaycod] >> s->halfratecod;
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s->bit_alloc.fdecay = fdecaytab[s->fdecaycod] >> s->halfratecod;
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s->bit_alloc.sgain = sgaintab[s->sgaincod];
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s->bit_alloc.dbknee = dbkneetab[s->dbkneecod];
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s->bit_alloc.floor = floortab[s->floorcod];
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/* header size */
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frame_bits += 65;
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// if (s->acmod == 2)
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@ -738,16 +792,31 @@ static int compute_bit_allocation(AC3EncodeContext *s,
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return 0;
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}
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void ac3_common_init(void)
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{
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int i, j, k, l, v;
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/* compute bndtab and masktab from bandsz */
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k = 0;
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l = 0;
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for(i=0;i<50;i++) {
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bndtab[i] = l;
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v = bndsz[i];
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for(j=0;j<v;j++) masktab[k++]=i;
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l += v;
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}
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bndtab[50] = 0;
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}
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static int AC3_encode_init(AVCodecContext *avctx)
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{
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int freq = avctx->sample_rate;
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int bitrate = avctx->bit_rate;
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int channels = avctx->channels;
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AC3EncodeContext *s = avctx->priv_data;
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int i, j, k, l, ch, v;
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int i, j, ch;
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float alpha;
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static unsigned short freqs[3] = { 48000, 44100, 32000 };
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static int acmod_defs[6] = {
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static const UINT8 acmod_defs[6] = {
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0x01, /* C */
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0x02, /* L R */
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0x03, /* L C R */
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@ -771,7 +840,7 @@ static int AC3_encode_init(AVCodecContext *avctx)
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/* frequency */
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for(i=0;i<3;i++) {
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for(j=0;j<3;j++)
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if ((freqs[j] >> i) == freq)
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if ((ac3_freqs[j] >> i) == freq)
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goto found;
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}
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return -1;
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@ -785,7 +854,7 @@ static int AC3_encode_init(AVCodecContext *avctx)
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/* bitrate & frame size */
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bitrate /= 1000;
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for(i=0;i<19;i++) {
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if ((bitratetab[i] >> s->halfratecod) == bitrate)
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if ((ac3_bitratetab[i] >> s->halfratecod) == bitrate)
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break;
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}
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if (i == 19)
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@ -810,16 +879,7 @@ static int AC3_encode_init(AVCodecContext *avctx)
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/* initial snr offset */
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s->csnroffst = 40;
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/* compute bndtab and masktab from bandsz */
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k = 0;
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l = 0;
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for(i=0;i<50;i++) {
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bndtab[i] = l;
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v = bndsz[i];
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for(j=0;j<v;j++) masktab[k++]=i;
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l += v;
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}
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bndtab[50] = 0;
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ac3_common_init();
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/* mdct init */
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fft_init(MDCT_NBITS - 2);
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@ -1282,8 +1342,8 @@ static int output_frame_end(AC3EncodeContext *s)
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return frame_size * 2;
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}
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int AC3_encode_frame(AVCodecContext *avctx,
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unsigned char *frame, int buf_size, void *data)
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static int AC3_encode_frame(AVCodecContext *avctx,
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unsigned char *frame, int buf_size, void *data)
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{
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AC3EncodeContext *s = avctx->priv_data;
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short *samples = data;
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@ -1,34 +0,0 @@
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#define AC3_FRAME_SIZE (6*256)
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#define AC3_MAX_CODED_FRAME_SIZE 3840 /* in bytes */
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#define AC3_MAX_CHANNELS 6
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|
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typedef struct AC3EncodeContext {
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PutBitContext pb;
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int nb_channels;
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int nb_all_channels;
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int lfe_channel;
|
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int bit_rate;
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int sample_rate;
|
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int bsid;
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int frame_size_min; /* minimum frame size in case rounding is necessary */
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int frame_size; /* current frame size in words */
|
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int halfratecod;
|
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int frmsizecod;
|
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int fscod; /* frequency */
|
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int acmod;
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int lfe;
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int bsmod;
|
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short last_samples[AC3_MAX_CHANNELS][256];
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int chbwcod[AC3_MAX_CHANNELS];
|
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int nb_coefs[AC3_MAX_CHANNELS];
|
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|
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/* bitrate allocation control */
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int sgaincod, sdecaycod, fdecaycod, dbkneecod, floorcod;
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int sgain, sdecay, fdecay, dbknee, floor;
|
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int csnroffst;
|
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int fgaincod[AC3_MAX_CHANNELS];
|
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int fsnroffst[AC3_MAX_CHANNELS];
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/* mantissa encoding */
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int mant1_cnt, mant2_cnt, mant4_cnt;
|
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} AC3EncodeContext;
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@ -1,7 +1,10 @@
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/* tables taken directly from AC3 spec */
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/* possible frequencies */
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const UINT16 ac3_freqs[3] = { 48000, 44100, 32000 };
|
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/* possible bitrates */
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static const UINT16 bitratetab[19] = {
|
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const UINT16 ac3_bitratetab[19] = {
|
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32, 40, 48, 56, 64, 80, 96, 112, 128,
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160, 192, 224, 256, 320, 384, 448, 512, 576, 640
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};
|
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@ -9,7 +12,7 @@ static const UINT16 bitratetab[19] = {
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/* AC3 MDCT window */
|
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|
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/* MDCT window */
|
||||
static const INT16 ac3_window[256]= {
|
||||
const INT16 ac3_window[256] = {
|
||||
4, 7, 12, 16, 21, 28, 34, 42,
|
||||
51, 61, 72, 84, 97, 111, 127, 145,
|
||||
164, 184, 207, 231, 257, 285, 315, 347,
|
||||
@ -138,27 +141,27 @@ static const UINT8 baptab[64]= {
|
||||
15, 15, 15, 15,
|
||||
};
|
||||
|
||||
static const UINT8 sdecaytab[4]={
|
||||
const UINT8 sdecaytab[4]={
|
||||
0x0f, 0x11, 0x13, 0x15,
|
||||
};
|
||||
|
||||
static const UINT8 fdecaytab[4]={
|
||||
const UINT8 fdecaytab[4]={
|
||||
0x3f, 0x53, 0x67, 0x7b,
|
||||
};
|
||||
|
||||
static const UINT16 sgaintab[4]= {
|
||||
const UINT16 sgaintab[4]= {
|
||||
0x540, 0x4d8, 0x478, 0x410,
|
||||
};
|
||||
|
||||
static const UINT16 dbkneetab[4]= {
|
||||
const UINT16 dbkneetab[4]= {
|
||||
0x000, 0x700, 0x900, 0xb00,
|
||||
};
|
||||
|
||||
static const UINT16 floortab[8]= {
|
||||
const UINT16 floortab[8]= {
|
||||
0x2f0, 0x2b0, 0x270, 0x230, 0x1f0, 0x170, 0x0f0, 0xf800,
|
||||
};
|
||||
|
||||
static const UINT16 fgaintab[8]= {
|
||||
const UINT16 fgaintab[8]= {
|
||||
0x080, 0x100, 0x180, 0x200, 0x280, 0x300, 0x380, 0x400,
|
||||
};
|
||||
|
||||
|
||||
Loading…
Reference in New Issue
Block a user