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Diffstat (limited to 'src/opus-1.1/silk/NLSF2A.c')
| -rw-r--r-- | src/opus-1.1/silk/NLSF2A.c | 178 |
1 files changed, 0 insertions, 178 deletions
diff --git a/src/opus-1.1/silk/NLSF2A.c b/src/opus-1.1/silk/NLSF2A.c deleted file mode 100644 index b1c559ea..00000000 --- a/src/opus-1.1/silk/NLSF2A.c +++ /dev/null @@ -1,178 +0,0 @@ -/*********************************************************************** -Copyright (c) 2006-2011, Skype Limited. All rights reserved. -Redistribution and use in source and binary forms, with or without -modification, are permitted provided that the following conditions -are met: -- Redistributions of source code must retain the above copyright notice, -this list of conditions and the following disclaimer. -- Redistributions in binary form must reproduce the above copyright -notice, this list of conditions and the following disclaimer in the -documentation and/or other materials provided with the distribution. -- Neither the name of Internet Society, IETF or IETF Trust, nor the -names of specific contributors, may be used to endorse or promote -products derived from this software without specific prior written -permission. -THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" -AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE -IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE -ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE -LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR -CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF -SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS -INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN -CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) -ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE -POSSIBILITY OF SUCH DAMAGE. -***********************************************************************/ - -#ifdef HAVE_CONFIG_H -#include "config.h" -#endif - -/* conversion between prediction filter coefficients and LSFs */ -/* order should be even */ -/* a piecewise linear approximation maps LSF <-> cos(LSF) */ -/* therefore the result is not accurate LSFs, but the two */ -/* functions are accurate inverses of each other */ - -#include "SigProc_FIX.h" -#include "tables.h" - -#define QA 16 - -/* helper function for NLSF2A(..) */ -static OPUS_INLINE void silk_NLSF2A_find_poly( - opus_int32 *out, /* O intermediate polynomial, QA [dd+1] */ - const opus_int32 *cLSF, /* I vector of interleaved 2*cos(LSFs), QA [d] */ - opus_int dd /* I polynomial order (= 1/2 * filter order) */ -) -{ - opus_int k, n; - opus_int32 ftmp; - - out[0] = silk_LSHIFT( 1, QA ); - out[1] = -cLSF[0]; - for( k = 1; k < dd; k++ ) { - ftmp = cLSF[2*k]; /* QA*/ - out[k+1] = silk_LSHIFT( out[k-1], 1 ) - (opus_int32)silk_RSHIFT_ROUND64( silk_SMULL( ftmp, out[k] ), QA ); - for( n = k; n > 1; n-- ) { - out[n] += out[n-2] - (opus_int32)silk_RSHIFT_ROUND64( silk_SMULL( ftmp, out[n-1] ), QA ); - } - out[1] -= ftmp; - } -} - -/* compute whitening filter coefficients from normalized line spectral frequencies */ -void silk_NLSF2A( - opus_int16 *a_Q12, /* O monic whitening filter coefficients in Q12, [ d ] */ - const opus_int16 *NLSF, /* I normalized line spectral frequencies in Q15, [ d ] */ - const opus_int d /* I filter order (should be even) */ -) -{ - /* This ordering was found to maximize quality. It improves numerical accuracy of - silk_NLSF2A_find_poly() compared to "standard" ordering. */ - static const unsigned char ordering16[16] = { - 0, 15, 8, 7, 4, 11, 12, 3, 2, 13, 10, 5, 6, 9, 14, 1 - }; - static const unsigned char ordering10[10] = { - 0, 9, 6, 3, 4, 5, 8, 1, 2, 7 - }; - const unsigned char *ordering; - opus_int k, i, dd; - opus_int32 cos_LSF_QA[ SILK_MAX_ORDER_LPC ]; - opus_int32 P[ SILK_MAX_ORDER_LPC / 2 + 1 ], Q[ SILK_MAX_ORDER_LPC / 2 + 1 ]; - opus_int32 Ptmp, Qtmp, f_int, f_frac, cos_val, delta; - opus_int32 a32_QA1[ SILK_MAX_ORDER_LPC ]; - opus_int32 maxabs, absval, idx=0, sc_Q16; - - silk_assert( LSF_COS_TAB_SZ_FIX == 128 ); - silk_assert( d==10||d==16 ); - - /* convert LSFs to 2*cos(LSF), using piecewise linear curve from table */ - ordering = d == 16 ? ordering16 : ordering10; - for( k = 0; k < d; k++ ) { - silk_assert(NLSF[k] >= 0 ); - - /* f_int on a scale 0-127 (rounded down) */ - f_int = silk_RSHIFT( NLSF[k], 15 - 7 ); - - /* f_frac, range: 0..255 */ - f_frac = NLSF[k] - silk_LSHIFT( f_int, 15 - 7 ); - - silk_assert(f_int >= 0); - silk_assert(f_int < LSF_COS_TAB_SZ_FIX ); - - /* Read start and end value from table */ - cos_val = silk_LSFCosTab_FIX_Q12[ f_int ]; /* Q12 */ - delta = silk_LSFCosTab_FIX_Q12[ f_int + 1 ] - cos_val; /* Q12, with a range of 0..200 */ - - /* Linear interpolation */ - cos_LSF_QA[ordering[k]] = silk_RSHIFT_ROUND( silk_LSHIFT( cos_val, 8 ) + silk_MUL( delta, f_frac ), 20 - QA ); /* QA */ - } - - dd = silk_RSHIFT( d, 1 ); - - /* generate even and odd polynomials using convolution */ - silk_NLSF2A_find_poly( P, &cos_LSF_QA[ 0 ], dd ); - silk_NLSF2A_find_poly( Q, &cos_LSF_QA[ 1 ], dd ); - - /* convert even and odd polynomials to opus_int32 Q12 filter coefs */ - for( k = 0; k < dd; k++ ) { - Ptmp = P[ k+1 ] + P[ k ]; - Qtmp = Q[ k+1 ] - Q[ k ]; - - /* the Ptmp and Qtmp values at this stage need to fit in int32 */ - a32_QA1[ k ] = -Qtmp - Ptmp; /* QA+1 */ - a32_QA1[ d-k-1 ] = Qtmp - Ptmp; /* QA+1 */ - } - - /* Limit the maximum absolute value of the prediction coefficients, so that they'll fit in int16 */ - for( i = 0; i < 10; i++ ) { - /* Find maximum absolute value and its index */ - maxabs = 0; - for( k = 0; k < d; k++ ) { - absval = silk_abs( a32_QA1[k] ); - if( absval > maxabs ) { - maxabs = absval; - idx = k; - } - } - maxabs = silk_RSHIFT_ROUND( maxabs, QA + 1 - 12 ); /* QA+1 -> Q12 */ - - if( maxabs > silk_int16_MAX ) { - /* Reduce magnitude of prediction coefficients */ - maxabs = silk_min( maxabs, 163838 ); /* ( silk_int32_MAX >> 14 ) + silk_int16_MAX = 163838 */ - sc_Q16 = SILK_FIX_CONST( 0.999, 16 ) - silk_DIV32( silk_LSHIFT( maxabs - silk_int16_MAX, 14 ), - silk_RSHIFT32( silk_MUL( maxabs, idx + 1), 2 ) ); - silk_bwexpander_32( a32_QA1, d, sc_Q16 ); - } else { - break; - } - } - - if( i == 10 ) { - /* Reached the last iteration, clip the coefficients */ - for( k = 0; k < d; k++ ) { - a_Q12[ k ] = (opus_int16)silk_SAT16( silk_RSHIFT_ROUND( a32_QA1[ k ], QA + 1 - 12 ) ); /* QA+1 -> Q12 */ - a32_QA1[ k ] = silk_LSHIFT( (opus_int32)a_Q12[ k ], QA + 1 - 12 ); - } - } else { - for( k = 0; k < d; k++ ) { - a_Q12[ k ] = (opus_int16)silk_RSHIFT_ROUND( a32_QA1[ k ], QA + 1 - 12 ); /* QA+1 -> Q12 */ - } - } - - for( i = 0; i < MAX_LPC_STABILIZE_ITERATIONS; i++ ) { - if( silk_LPC_inverse_pred_gain( a_Q12, d ) < SILK_FIX_CONST( 1.0 / MAX_PREDICTION_POWER_GAIN, 30 ) ) { - /* Prediction coefficients are (too close to) unstable; apply bandwidth expansion */ - /* on the unscaled coefficients, convert to Q12 and measure again */ - silk_bwexpander_32( a32_QA1, d, 65536 - silk_LSHIFT( 2, i ) ); - for( k = 0; k < d; k++ ) { - a_Q12[ k ] = (opus_int16)silk_RSHIFT_ROUND( a32_QA1[ k ], QA + 1 - 12 ); /* QA+1 -> Q12 */ - } - } else { - break; - } - } -} - |