1*a58d3d2aSXin Li /***********************************************************************
2*a58d3d2aSXin Li Copyright (c) 2006-2011, Skype Limited. All rights reserved.
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5*a58d3d2aSXin Li are met:
6*a58d3d2aSXin Li - Redistributions of source code must retain the above copyright notice,
7*a58d3d2aSXin Li this list of conditions and the following disclaimer.
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26*a58d3d2aSXin Li ***********************************************************************/
27*a58d3d2aSXin Li
28*a58d3d2aSXin Li #ifdef HAVE_CONFIG_H
29*a58d3d2aSXin Li #include "config.h"
30*a58d3d2aSXin Li #endif
31*a58d3d2aSXin Li
32*a58d3d2aSXin Li #include "main.h"
33*a58d3d2aSXin Li
34*a58d3d2aSXin Li /* Decode mid/side predictors */
silk_stereo_decode_pred(ec_dec * psRangeDec,opus_int32 pred_Q13[])35*a58d3d2aSXin Li void silk_stereo_decode_pred(
36*a58d3d2aSXin Li ec_dec *psRangeDec, /* I/O Compressor data structure */
37*a58d3d2aSXin Li opus_int32 pred_Q13[] /* O Predictors */
38*a58d3d2aSXin Li )
39*a58d3d2aSXin Li {
40*a58d3d2aSXin Li opus_int n, ix[ 2 ][ 3 ];
41*a58d3d2aSXin Li opus_int32 low_Q13, step_Q13;
42*a58d3d2aSXin Li
43*a58d3d2aSXin Li /* Entropy decoding */
44*a58d3d2aSXin Li n = ec_dec_icdf( psRangeDec, silk_stereo_pred_joint_iCDF, 8 );
45*a58d3d2aSXin Li ix[ 0 ][ 2 ] = silk_DIV32_16( n, 5 );
46*a58d3d2aSXin Li ix[ 1 ][ 2 ] = n - 5 * ix[ 0 ][ 2 ];
47*a58d3d2aSXin Li for( n = 0; n < 2; n++ ) {
48*a58d3d2aSXin Li ix[ n ][ 0 ] = ec_dec_icdf( psRangeDec, silk_uniform3_iCDF, 8 );
49*a58d3d2aSXin Li ix[ n ][ 1 ] = ec_dec_icdf( psRangeDec, silk_uniform5_iCDF, 8 );
50*a58d3d2aSXin Li }
51*a58d3d2aSXin Li
52*a58d3d2aSXin Li /* Dequantize */
53*a58d3d2aSXin Li for( n = 0; n < 2; n++ ) {
54*a58d3d2aSXin Li ix[ n ][ 0 ] += 3 * ix[ n ][ 2 ];
55*a58d3d2aSXin Li low_Q13 = silk_stereo_pred_quant_Q13[ ix[ n ][ 0 ] ];
56*a58d3d2aSXin Li step_Q13 = silk_SMULWB( silk_stereo_pred_quant_Q13[ ix[ n ][ 0 ] + 1 ] - low_Q13,
57*a58d3d2aSXin Li SILK_FIX_CONST( 0.5 / STEREO_QUANT_SUB_STEPS, 16 ) );
58*a58d3d2aSXin Li pred_Q13[ n ] = silk_SMLABB( low_Q13, step_Q13, 2 * ix[ n ][ 1 ] + 1 );
59*a58d3d2aSXin Li }
60*a58d3d2aSXin Li
61*a58d3d2aSXin Li /* Subtract second from first predictor (helps when actually applying these) */
62*a58d3d2aSXin Li pred_Q13[ 0 ] -= pred_Q13[ 1 ];
63*a58d3d2aSXin Li }
64*a58d3d2aSXin Li
65*a58d3d2aSXin Li /* Decode mid-only flag */
silk_stereo_decode_mid_only(ec_dec * psRangeDec,opus_int * decode_only_mid)66*a58d3d2aSXin Li void silk_stereo_decode_mid_only(
67*a58d3d2aSXin Li ec_dec *psRangeDec, /* I/O Compressor data structure */
68*a58d3d2aSXin Li opus_int *decode_only_mid /* O Flag that only mid channel has been coded */
69*a58d3d2aSXin Li )
70*a58d3d2aSXin Li {
71*a58d3d2aSXin Li /* Decode flag that only mid channel is coded */
72*a58d3d2aSXin Li *decode_only_mid = ec_dec_icdf( psRangeDec, silk_stereo_only_code_mid_iCDF, 8 );
73*a58d3d2aSXin Li }
74