cannam@154: /***********************************************************************
cannam@154: Copyright (c) 2006-2011, Skype Limited. All rights reserved.
cannam@154: Redistribution and use in source and binary forms, with or without
cannam@154: modification, are permitted provided that the following conditions
cannam@154: are met:
cannam@154: - Redistributions of source code must retain the above copyright notice,
cannam@154: this list of conditions and the following disclaimer.
cannam@154: - Redistributions in binary form must reproduce the above copyright
cannam@154: notice, this list of conditions and the following disclaimer in the
cannam@154: documentation and/or other materials provided with the distribution.
cannam@154: - Neither the name of Internet Society, IETF or IETF Trust, nor the
cannam@154: names of specific contributors, may be used to endorse or promote
cannam@154: products derived from this software without specific prior written
cannam@154: permission.
cannam@154: THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
cannam@154: AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
cannam@154: IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
cannam@154: ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
cannam@154: LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
cannam@154: CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
cannam@154: SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
cannam@154: INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
cannam@154: CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
cannam@154: ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
cannam@154: POSSIBILITY OF SUCH DAMAGE.
cannam@154: ***********************************************************************/
cannam@154: 
cannam@154: #ifdef HAVE_CONFIG_H
cannam@154: #include "config.h"
cannam@154: #endif
cannam@154: 
cannam@154: #include "main.h"
cannam@154: 
cannam@154: /* Decode mid/side predictors */
cannam@154: void silk_stereo_decode_pred(
cannam@154:     ec_dec                      *psRangeDec,                    /* I/O  Compressor data structure                   */
cannam@154:     opus_int32                  pred_Q13[]                      /* O    Predictors                                  */
cannam@154: )
cannam@154: {
cannam@154:     opus_int   n, ix[ 2 ][ 3 ];
cannam@154:     opus_int32 low_Q13, step_Q13;
cannam@154: 
cannam@154:     /* Entropy decoding */
cannam@154:     n = ec_dec_icdf( psRangeDec, silk_stereo_pred_joint_iCDF, 8 );
cannam@154:     ix[ 0 ][ 2 ] = silk_DIV32_16( n, 5 );
cannam@154:     ix[ 1 ][ 2 ] = n - 5 * ix[ 0 ][ 2 ];
cannam@154:     for( n = 0; n < 2; n++ ) {
cannam@154:         ix[ n ][ 0 ] = ec_dec_icdf( psRangeDec, silk_uniform3_iCDF, 8 );
cannam@154:         ix[ n ][ 1 ] = ec_dec_icdf( psRangeDec, silk_uniform5_iCDF, 8 );
cannam@154:     }
cannam@154: 
cannam@154:     /* Dequantize */
cannam@154:     for( n = 0; n < 2; n++ ) {
cannam@154:         ix[ n ][ 0 ] += 3 * ix[ n ][ 2 ];
cannam@154:         low_Q13 = silk_stereo_pred_quant_Q13[ ix[ n ][ 0 ] ];
cannam@154:         step_Q13 = silk_SMULWB( silk_stereo_pred_quant_Q13[ ix[ n ][ 0 ] + 1 ] - low_Q13,
cannam@154:             SILK_FIX_CONST( 0.5 / STEREO_QUANT_SUB_STEPS, 16 ) );
cannam@154:         pred_Q13[ n ] = silk_SMLABB( low_Q13, step_Q13, 2 * ix[ n ][ 1 ] + 1 );
cannam@154:     }
cannam@154: 
cannam@154:     /* Subtract second from first predictor (helps when actually applying these) */
cannam@154:     pred_Q13[ 0 ] -= pred_Q13[ 1 ];
cannam@154: }
cannam@154: 
cannam@154: /* Decode mid-only flag */
cannam@154: void silk_stereo_decode_mid_only(
cannam@154:     ec_dec                      *psRangeDec,                    /* I/O  Compressor data structure                   */
cannam@154:     opus_int                    *decode_only_mid                /* O    Flag that only mid channel has been coded   */
cannam@154: )
cannam@154: {
cannam@154:     /* Decode flag that only mid channel is coded */
cannam@154:     *decode_only_mid = ec_dec_icdf( psRangeDec, silk_stereo_only_code_mid_iCDF, 8 );
cannam@154: }