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Diffstat (limited to 'src/libmad/layer12.c')
| -rw-r--r-- | src/libmad/layer12.c | 534 |
1 files changed, 0 insertions, 534 deletions
diff --git a/src/libmad/layer12.c b/src/libmad/layer12.c index 6981f9ce1..e69de29bb 100644 --- a/src/libmad/layer12.c +++ b/src/libmad/layer12.c @@ -1,534 +0,0 @@ -/* - * libmad - MPEG audio decoder library - * Copyright (C) 2000-2004 Underbit Technologies, Inc. - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation; either version 2 of the License, or - * (at your option) any later version. - * - * This program 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 General Public License for more details. - * - * You should have received a copy of the GNU General Public License - * along with this program; if not, write to the Free Software - * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA - * - * $Id: layer12.c,v 1.17 2004/02/05 09:02:39 rob Exp $ - */ - -# ifdef HAVE_CONFIG_H -# include "config.h" -# endif - -# include "global.h" - -# ifdef HAVE_LIMITS_H -# include <limits.h> -# else -# define CHAR_BIT 8 -# endif - -# include "fixed.h" -# include "bit.h" -# include "stream.h" -# include "frame.h" -# include "layer12.h" - -/* - * scalefactor table - * used in both Layer I and Layer II decoding - */ -static -mad_fixed_t const sf_table[64] = { -# include "sf_table.dat" -}; - -/* --- Layer I ------------------------------------------------------------- */ - -/* linear scaling table */ -static -mad_fixed_t const linear_table[14] = { - MAD_F(0x15555555), /* 2^2 / (2^2 - 1) == 1.33333333333333 */ - MAD_F(0x12492492), /* 2^3 / (2^3 - 1) == 1.14285714285714 */ - MAD_F(0x11111111), /* 2^4 / (2^4 - 1) == 1.06666666666667 */ - MAD_F(0x10842108), /* 2^5 / (2^5 - 1) == 1.03225806451613 */ - MAD_F(0x10410410), /* 2^6 / (2^6 - 1) == 1.01587301587302 */ - MAD_F(0x10204081), /* 2^7 / (2^7 - 1) == 1.00787401574803 */ - MAD_F(0x10101010), /* 2^8 / (2^8 - 1) == 1.00392156862745 */ - MAD_F(0x10080402), /* 2^9 / (2^9 - 1) == 1.00195694716243 */ - MAD_F(0x10040100), /* 2^10 / (2^10 - 1) == 1.00097751710655 */ - MAD_F(0x10020040), /* 2^11 / (2^11 - 1) == 1.00048851978505 */ - MAD_F(0x10010010), /* 2^12 / (2^12 - 1) == 1.00024420024420 */ - MAD_F(0x10008004), /* 2^13 / (2^13 - 1) == 1.00012208521548 */ - MAD_F(0x10004001), /* 2^14 / (2^14 - 1) == 1.00006103888177 */ - MAD_F(0x10002000) /* 2^15 / (2^15 - 1) == 1.00003051850948 */ -}; - -/* - * NAME: I_sample() - * DESCRIPTION: decode one requantized Layer I sample from a bitstream - */ -static -mad_fixed_t I_sample(struct mad_bitptr *ptr, unsigned int nb) -{ - mad_fixed_t sample; - - sample = mad_bit_read(ptr, nb); - - /* invert most significant bit, extend sign, then scale to fixed format */ - - sample ^= 1 << (nb - 1); - sample |= -(sample & (1 << (nb - 1))); - - sample <<= MAD_F_FRACBITS - (nb - 1); - - /* requantize the sample */ - - /* s'' = (2^nb / (2^nb - 1)) * (s''' + 2^(-nb + 1)) */ - - sample += MAD_F_ONE >> (nb - 1); - - return mad_f_mul(sample, linear_table[nb - 2]); - - /* s' = factor * s'' */ - /* (to be performed by caller) */ -} - -/* - * NAME: layer->I() - * DESCRIPTION: decode a single Layer I frame - */ -int mad_layer_I(struct mad_stream *stream, struct mad_frame *frame) -{ - struct mad_header *header = &frame->header; - unsigned int nch, bound, ch, s, sb, nb; - unsigned char allocation[2][32], scalefactor[2][32]; - - nch = MAD_NCHANNELS(header); - - bound = 32; - if (header->mode == MAD_MODE_JOINT_STEREO) { - header->flags |= MAD_FLAG_I_STEREO; - bound = 4 + header->mode_extension * 4; - } - - /* check CRC word */ - - if (header->flags & MAD_FLAG_PROTECTION) { - header->crc_check = - mad_bit_crc(stream->ptr, 4 * (bound * nch + (32 - bound)), - header->crc_check); - - if (header->crc_check != header->crc_target && - !(frame->options & MAD_OPTION_IGNORECRC)) { - stream->error = MAD_ERROR_BADCRC; - return -1; - } - } - - /* decode bit allocations */ - - for (sb = 0; sb < bound; ++sb) { - for (ch = 0; ch < nch; ++ch) { - nb = mad_bit_read(&stream->ptr, 4); - - if (nb == 15) { - stream->error = MAD_ERROR_BADBITALLOC; - return -1; - } - - allocation[ch][sb] = nb ? nb + 1 : 0; - } - } - - for (sb = bound; sb < 32; ++sb) { - nb = mad_bit_read(&stream->ptr, 4); - - if (nb == 15) { - stream->error = MAD_ERROR_BADBITALLOC; - return -1; - } - - allocation[0][sb] = - allocation[1][sb] = nb ? nb + 1 : 0; - } - - /* decode scalefactors */ - - for (sb = 0; sb < 32; ++sb) { - for (ch = 0; ch < nch; ++ch) { - if (allocation[ch][sb]) { - scalefactor[ch][sb] = mad_bit_read(&stream->ptr, 6); - -# if defined(OPT_STRICT) - /* - * Scalefactor index 63 does not appear in Table B.1 of - * ISO/IEC 11172-3. Nonetheless, other implementations accept it, - * so we only reject it if OPT_STRICT is defined. - */ - if (scalefactor[ch][sb] == 63) { - stream->error = MAD_ERROR_BADSCALEFACTOR; - return -1; - } -# endif - } - } - } - - /* decode samples */ - - for (s = 0; s < 12; ++s) { - for (sb = 0; sb < bound; ++sb) { - for (ch = 0; ch < nch; ++ch) { - nb = allocation[ch][sb]; - frame->sbsample[ch][s][sb] = nb ? - mad_f_mul(I_sample(&stream->ptr, nb), - sf_table[scalefactor[ch][sb]]) : 0; - } - } - - for (sb = bound; sb < 32; ++sb) { - if ((nb = allocation[0][sb])) { - mad_fixed_t sample; - - sample = I_sample(&stream->ptr, nb); - - for (ch = 0; ch < nch; ++ch) { - frame->sbsample[ch][s][sb] = - mad_f_mul(sample, sf_table[scalefactor[ch][sb]]); - } - } - else { - for (ch = 0; ch < nch; ++ch) - frame->sbsample[ch][s][sb] = 0; - } - } - } - - return 0; -} - -/* --- Layer II ------------------------------------------------------------ */ - -/* possible quantization per subband table */ -static -struct { - unsigned int sblimit; - unsigned char const offsets[30]; -} const sbquant_table[5] = { - /* ISO/IEC 11172-3 Table B.2a */ - { 27, { 7, 7, 7, 6, 6, 6, 6, 6, 6, 6, 6, 3, 3, 3, 3, 3, /* 0 */ - 3, 3, 3, 3, 3, 3, 3, 0, 0, 0, 0 } }, - /* ISO/IEC 11172-3 Table B.2b */ - { 30, { 7, 7, 7, 6, 6, 6, 6, 6, 6, 6, 6, 3, 3, 3, 3, 3, /* 1 */ - 3, 3, 3, 3, 3, 3, 3, 0, 0, 0, 0, 0, 0, 0 } }, - /* ISO/IEC 11172-3 Table B.2c */ - { 8, { 5, 5, 2, 2, 2, 2, 2, 2 } }, /* 2 */ - /* ISO/IEC 11172-3 Table B.2d */ - { 12, { 5, 5, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2 } }, /* 3 */ - /* ISO/IEC 13818-3 Table B.1 */ - { 30, { 4, 4, 4, 4, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, /* 4 */ - 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 } } -}; - -/* bit allocation table */ -static -struct { - unsigned short nbal; - unsigned short offset; -} const bitalloc_table[8] = { - { 2, 0 }, /* 0 */ - { 2, 3 }, /* 1 */ - { 3, 3 }, /* 2 */ - { 3, 1 }, /* 3 */ - { 4, 2 }, /* 4 */ - { 4, 3 }, /* 5 */ - { 4, 4 }, /* 6 */ - { 4, 5 } /* 7 */ -}; - -/* offsets into quantization class table */ -static -unsigned char const offset_table[6][15] = { - { 0, 1, 16 }, /* 0 */ - { 0, 1, 2, 3, 4, 5, 16 }, /* 1 */ - { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 }, /* 2 */ - { 0, 1, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 }, /* 3 */ - { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 16 }, /* 4 */ - { 0, 2, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 } /* 5 */ -}; - -/* quantization class table */ -static -struct quantclass { - unsigned short nlevels; - unsigned char group; - unsigned char bits; - mad_fixed_t C; - mad_fixed_t D; -} const qc_table[17] = { -# include "qc_table.dat" -}; - -/* - * NAME: II_samples() - * DESCRIPTION: decode three requantized Layer II samples from a bitstream - */ -static -void II_samples(struct mad_bitptr *ptr, - struct quantclass const *quantclass, - mad_fixed_t output[3]) -{ - unsigned int nb, s, sample[3]; - - if ((nb = quantclass->group)) { - unsigned int c, nlevels; - - /* degrouping */ - c = mad_bit_read(ptr, quantclass->bits); - nlevels = quantclass->nlevels; - - for (s = 0; s < 3; ++s) { - sample[s] = c % nlevels; - c /= nlevels; - } - } - else { - nb = quantclass->bits; - - for (s = 0; s < 3; ++s) - sample[s] = mad_bit_read(ptr, nb); - } - - for (s = 0; s < 3; ++s) { - mad_fixed_t requantized; - - /* invert most significant bit, extend sign, then scale to fixed format */ - - requantized = sample[s] ^ (1 << (nb - 1)); - requantized |= -(requantized & (1 << (nb - 1))); - - requantized <<= MAD_F_FRACBITS - (nb - 1); - - /* requantize the sample */ - - /* s'' = C * (s''' + D) */ - - output[s] = mad_f_mul(requantized + quantclass->D, quantclass->C); - - /* s' = factor * s'' */ - /* (to be performed by caller) */ - } -} - -/* - * NAME: layer->II() - * DESCRIPTION: decode a single Layer II frame - */ -int mad_layer_II(struct mad_stream *stream, struct mad_frame *frame) -{ - struct mad_header *header = &frame->header; - struct mad_bitptr start; - unsigned int index, sblimit, nbal, nch, bound, gr, ch, s, sb; - unsigned char const *offsets; - unsigned char allocation[2][32], scfsi[2][32], scalefactor[2][32][3]; - mad_fixed_t samples[3]; - - nch = MAD_NCHANNELS(header); - - if (header->flags & MAD_FLAG_LSF_EXT) - index = 4; - else if (header->flags & MAD_FLAG_FREEFORMAT) - goto freeformat; - else { - unsigned long bitrate_per_channel; - - bitrate_per_channel = header->bitrate; - if (nch == 2) { - bitrate_per_channel /= 2; - -# if defined(OPT_STRICT) - /* - * ISO/IEC 11172-3 allows only single channel mode for 32, 48, 56, and - * 80 kbps bitrates in Layer II, but some encoders ignore this - * restriction. We enforce it if OPT_STRICT is defined. - */ - if (bitrate_per_channel <= 28000 || bitrate_per_channel == 40000) { - stream->error = MAD_ERROR_BADMODE; - return -1; - } -# endif - } - else { /* nch == 1 */ - if (bitrate_per_channel > 192000) { - /* - * ISO/IEC 11172-3 does not allow single channel mode for 224, 256, - * 320, or 384 kbps bitrates in Layer II. - */ - stream->error = MAD_ERROR_BADMODE; - return -1; - } - } - - if (bitrate_per_channel <= 48000) - index = (header->samplerate == 32000) ? 3 : 2; - else if (bitrate_per_channel <= 80000) - index = 0; - else { - freeformat: - index = (header->samplerate == 48000) ? 0 : 1; - } - } - - sblimit = sbquant_table[index].sblimit; - offsets = sbquant_table[index].offsets; - - bound = 32; - if (header->mode == MAD_MODE_JOINT_STEREO) { - header->flags |= MAD_FLAG_I_STEREO; - bound = 4 + header->mode_extension * 4; - } - - if (bound > sblimit) - bound = sblimit; - - start = stream->ptr; - - /* decode bit allocations */ - - for (sb = 0; sb < bound; ++sb) { - nbal = bitalloc_table[offsets[sb]].nbal; - - for (ch = 0; ch < nch; ++ch) - allocation[ch][sb] = mad_bit_read(&stream->ptr, nbal); - } - - for (sb = bound; sb < sblimit; ++sb) { - nbal = bitalloc_table[offsets[sb]].nbal; - - allocation[0][sb] = - allocation[1][sb] = mad_bit_read(&stream->ptr, nbal); - } - - /* decode scalefactor selection info */ - - for (sb = 0; sb < sblimit; ++sb) { - for (ch = 0; ch < nch; ++ch) { - if (allocation[ch][sb]) - scfsi[ch][sb] = mad_bit_read(&stream->ptr, 2); - } - } - - /* check CRC word */ - - if (header->flags & MAD_FLAG_PROTECTION) { - header->crc_check = - mad_bit_crc(start, mad_bit_length(&start, &stream->ptr), - header->crc_check); - - if (header->crc_check != header->crc_target && - !(frame->options & MAD_OPTION_IGNORECRC)) { - stream->error = MAD_ERROR_BADCRC; - return -1; - } - } - - /* decode scalefactors */ - - for (sb = 0; sb < sblimit; ++sb) { - for (ch = 0; ch < nch; ++ch) { - if (allocation[ch][sb]) { - scalefactor[ch][sb][0] = mad_bit_read(&stream->ptr, 6); - - switch (scfsi[ch][sb]) { - case 2: - scalefactor[ch][sb][2] = - scalefactor[ch][sb][1] = - scalefactor[ch][sb][0]; - break; - - case 0: - scalefactor[ch][sb][1] = mad_bit_read(&stream->ptr, 6); - /* fall through */ - - case 1: - case 3: - scalefactor[ch][sb][2] = mad_bit_read(&stream->ptr, 6); - } - - if (scfsi[ch][sb] & 1) - scalefactor[ch][sb][1] = scalefactor[ch][sb][scfsi[ch][sb] - 1]; - -# if defined(OPT_STRICT) - /* - * Scalefactor index 63 does not appear in Table B.1 of - * ISO/IEC 11172-3. Nonetheless, other implementations accept it, - * so we only reject it if OPT_STRICT is defined. - */ - if (scalefactor[ch][sb][0] == 63 || - scalefactor[ch][sb][1] == 63 || - scalefactor[ch][sb][2] == 63) { - stream->error = MAD_ERROR_BADSCALEFACTOR; - return -1; - } -# endif - } - } - } - - /* decode samples */ - - for (gr = 0; gr < 12; ++gr) { - for (sb = 0; sb < bound; ++sb) { - for (ch = 0; ch < nch; ++ch) { - if ((index = allocation[ch][sb])) { - index = offset_table[bitalloc_table[offsets[sb]].offset][index - 1]; - - II_samples(&stream->ptr, &qc_table[index], samples); - - for (s = 0; s < 3; ++s) { - frame->sbsample[ch][3 * gr + s][sb] = - mad_f_mul(samples[s], sf_table[scalefactor[ch][sb][gr / 4]]); - } - } - else { - for (s = 0; s < 3; ++s) - frame->sbsample[ch][3 * gr + s][sb] = 0; - } - } - } - - for (sb = bound; sb < sblimit; ++sb) { - if ((index = allocation[0][sb])) { - index = offset_table[bitalloc_table[offsets[sb]].offset][index - 1]; - - II_samples(&stream->ptr, &qc_table[index], samples); - - for (ch = 0; ch < nch; ++ch) { - for (s = 0; s < 3; ++s) { - frame->sbsample[ch][3 * gr + s][sb] = - mad_f_mul(samples[s], sf_table[scalefactor[ch][sb][gr / 4]]); - } - } - } - else { - for (ch = 0; ch < nch; ++ch) { - for (s = 0; s < 3; ++s) - frame->sbsample[ch][3 * gr + s][sb] = 0; - } - } - } - - for (ch = 0; ch < nch; ++ch) { - for (s = 0; s < 3; ++s) { - for (sb = sblimit; sb < 32; ++sb) - frame->sbsample[ch][3 * gr + s][sb] = 0; - } - } - } - - return 0; -} |