NLSF_decode.c 4.7 KB

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  1. /***********************************************************************
  2. Copyright (c) 2006-2011, Skype Limited. All rights reserved.
  3. Redistribution and use in source and binary forms, with or without
  4. modification, are permitted provided that the following conditions
  5. are met:
  6. - Redistributions of source code must retain the above copyright notice,
  7. this list of conditions and the following disclaimer.
  8. - Redistributions in binary form must reproduce the above copyright
  9. notice, this list of conditions and the following disclaimer in the
  10. documentation and/or other materials provided with the distribution.
  11. - Neither the name of Internet Society, IETF or IETF Trust, nor the
  12. names of specific contributors, may be used to endorse or promote
  13. products derived from this software without specific prior written
  14. permission.
  15. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  16. AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  17. IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  18. ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  19. LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  20. CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  21. SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  22. INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  23. CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  24. ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  25. POSSIBILITY OF SUCH DAMAGE.
  26. ***********************************************************************/
  27. #ifdef HAVE_CONFIG_H
  28. #include "config.h"
  29. #endif
  30. #include "main.h"
  31. /* Predictive dequantizer for NLSF residuals */
  32. static OPUS_INLINE void silk_NLSF_residual_dequant( /* O Returns RD value in Q30 */
  33. opus_int16 x_Q10[], /* O Output [ order ] */
  34. const opus_int8 indices[], /* I Quantization indices [ order ] */
  35. const opus_uint8 pred_coef_Q8[], /* I Backward predictor coefs [ order ] */
  36. const opus_int quant_step_size_Q16, /* I Quantization step size */
  37. const opus_int16 order /* I Number of input values */
  38. )
  39. {
  40. opus_int i, out_Q10, pred_Q10;
  41. out_Q10 = 0;
  42. for( i = order-1; i >= 0; i-- ) {
  43. pred_Q10 = silk_RSHIFT( silk_SMULBB( out_Q10, (opus_int16)pred_coef_Q8[ i ] ), 8 );
  44. out_Q10 = silk_LSHIFT( indices[ i ], 10 );
  45. if( out_Q10 > 0 ) {
  46. out_Q10 = silk_SUB16( out_Q10, SILK_FIX_CONST( NLSF_QUANT_LEVEL_ADJ, 10 ) );
  47. } else if( out_Q10 < 0 ) {
  48. out_Q10 = silk_ADD16( out_Q10, SILK_FIX_CONST( NLSF_QUANT_LEVEL_ADJ, 10 ) );
  49. }
  50. out_Q10 = silk_SMLAWB( pred_Q10, (opus_int32)out_Q10, quant_step_size_Q16 );
  51. x_Q10[ i ] = out_Q10;
  52. }
  53. }
  54. /***********************/
  55. /* NLSF vector decoder */
  56. /***********************/
  57. void silk_NLSF_decode(
  58. opus_int16 *pNLSF_Q15, /* O Quantized NLSF vector [ LPC_ORDER ] */
  59. opus_int8 *NLSFIndices, /* I Codebook path vector [ LPC_ORDER + 1 ] */
  60. const silk_NLSF_CB_struct *psNLSF_CB /* I Codebook object */
  61. )
  62. {
  63. opus_int i;
  64. opus_uint8 pred_Q8[ MAX_LPC_ORDER ];
  65. opus_int16 ec_ix[ MAX_LPC_ORDER ];
  66. opus_int16 res_Q10[ MAX_LPC_ORDER ];
  67. opus_int32 NLSF_Q15_tmp;
  68. const opus_uint8 *pCB_element;
  69. const opus_int16 *pCB_Wght_Q9;
  70. /* Unpack entropy table indices and predictor for current CB1 index */
  71. silk_NLSF_unpack( ec_ix, pred_Q8, psNLSF_CB, NLSFIndices[ 0 ] );
  72. /* Predictive residual dequantizer */
  73. silk_NLSF_residual_dequant( res_Q10, &NLSFIndices[ 1 ], pred_Q8, psNLSF_CB->quantStepSize_Q16, psNLSF_CB->order );
  74. /* Apply inverse square-rooted weights to first stage and add to output */
  75. pCB_element = &psNLSF_CB->CB1_NLSF_Q8[ NLSFIndices[ 0 ] * psNLSF_CB->order ];
  76. pCB_Wght_Q9 = &psNLSF_CB->CB1_Wght_Q9[ NLSFIndices[ 0 ] * psNLSF_CB->order ];
  77. for( i = 0; i < psNLSF_CB->order; i++ ) {
  78. NLSF_Q15_tmp = silk_ADD_LSHIFT32( silk_DIV32_16( silk_LSHIFT( (opus_int32)res_Q10[ i ], 14 ), pCB_Wght_Q9[ i ] ), (opus_int16)pCB_element[ i ], 7 );
  79. pNLSF_Q15[ i ] = (opus_int16)silk_LIMIT( NLSF_Q15_tmp, 0, 32767 );
  80. }
  81. /* NLSF stabilization */
  82. silk_NLSF_stabilize( pNLSF_Q15, psNLSF_CB->deltaMin_Q15, psNLSF_CB->order );
  83. }