michael@0: /***********************************************************************
michael@0: Copyright (c) 2006-2011, Skype Limited. All rights reserved.
michael@0: Redistribution and use in source and binary forms, with or without
michael@0: modification, are permitted provided that the following conditions
michael@0: are met:
michael@0: - Redistributions of source code must retain the above copyright notice,
michael@0: this list of conditions and the following disclaimer.
michael@0: - Redistributions in binary form must reproduce the above copyright
michael@0: notice, this list of conditions and the following disclaimer in the
michael@0: documentation and/or other materials provided with the distribution.
michael@0: - Neither the name of Internet Society, IETF or IETF Trust, nor the
michael@0: names of specific contributors, may be used to endorse or promote
michael@0: products derived from this software without specific prior written
michael@0: permission.
michael@0: THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
michael@0: AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
michael@0: IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
michael@0: ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
michael@0: LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
michael@0: CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
michael@0: SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
michael@0: INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
michael@0: CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
michael@0: ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
michael@0: POSSIBILITY OF SUCH DAMAGE.
michael@0: ***********************************************************************/
michael@0: 
michael@0: #ifdef HAVE_CONFIG_H
michael@0: #include "config.h"
michael@0: #endif
michael@0: 
michael@0: #include "main.h"
michael@0: 
michael@0: /* Decode mid/side predictors */
michael@0: void silk_stereo_decode_pred(
michael@0:     ec_dec                      *psRangeDec,                    /* I/O  Compressor data structure                   */
michael@0:     opus_int32                  pred_Q13[]                      /* O    Predictors                                  */
michael@0: )
michael@0: {
michael@0:     opus_int   n, ix[ 2 ][ 3 ];
michael@0:     opus_int32 low_Q13, step_Q13;
michael@0: 
michael@0:     /* Entropy decoding */
michael@0:     n = ec_dec_icdf( psRangeDec, silk_stereo_pred_joint_iCDF, 8 );
michael@0:     ix[ 0 ][ 2 ] = silk_DIV32_16( n, 5 );
michael@0:     ix[ 1 ][ 2 ] = n - 5 * ix[ 0 ][ 2 ];
michael@0:     for( n = 0; n < 2; n++ ) {
michael@0:         ix[ n ][ 0 ] = ec_dec_icdf( psRangeDec, silk_uniform3_iCDF, 8 );
michael@0:         ix[ n ][ 1 ] = ec_dec_icdf( psRangeDec, silk_uniform5_iCDF, 8 );
michael@0:     }
michael@0: 
michael@0:     /* Dequantize */
michael@0:     for( n = 0; n < 2; n++ ) {
michael@0:         ix[ n ][ 0 ] += 3 * ix[ n ][ 2 ];
michael@0:         low_Q13 = silk_stereo_pred_quant_Q13[ ix[ n ][ 0 ] ];
michael@0:         step_Q13 = silk_SMULWB( silk_stereo_pred_quant_Q13[ ix[ n ][ 0 ] + 1 ] - low_Q13,
michael@0:             SILK_FIX_CONST( 0.5 / STEREO_QUANT_SUB_STEPS, 16 ) );
michael@0:         pred_Q13[ n ] = silk_SMLABB( low_Q13, step_Q13, 2 * ix[ n ][ 1 ] + 1 );
michael@0:     }
michael@0: 
michael@0:     /* Subtract second from first predictor (helps when actually applying these) */
michael@0:     pred_Q13[ 0 ] -= pred_Q13[ 1 ];
michael@0: }
michael@0: 
michael@0: /* Decode mid-only flag */
michael@0: void silk_stereo_decode_mid_only(
michael@0:     ec_dec                      *psRangeDec,                    /* I/O  Compressor data structure                   */
michael@0:     opus_int                    *decode_only_mid                /* O    Flag that only mid channel has been coded   */
michael@0: )
michael@0: {
michael@0:     /* Decode flag that only mid channel is coded */
michael@0:     *decode_only_mid = ec_dec_icdf( psRangeDec, silk_stereo_only_code_mid_iCDF, 8 );
michael@0: }