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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 
     28 #ifdef HAVE_CONFIG_H
     29 #include "config.h"
     30 #endif
     31 
     32 #include "main.h"
     33 
     34 /* shell coder; pulse-subframe length is hardcoded */
     35 
     36 static inline void combine_pulses(
     37     opus_int         *out,   /* O    combined pulses vector [len] */
     38     const opus_int   *in,    /* I    input vector       [2 * len] */
     39     const opus_int   len     /* I    number of OUTPUT samples     */
     40 )
     41 {
     42     opus_int k;
     43     for( k = 0; k < len; k++ ) {
     44         out[ k ] = in[ 2 * k ] + in[ 2 * k + 1 ];
     45     }
     46 }
     47 
     48 static inline void encode_split(
     49     ec_enc                      *psRangeEnc,    /* I/O  compressor data structure                   */
     50     const opus_int              p_child1,       /* I    pulse amplitude of first child subframe     */
     51     const opus_int              p,              /* I    pulse amplitude of current subframe         */
     52     const opus_uint8            *shell_table    /* I    table of shell cdfs                         */
     53 )
     54 {
     55     if( p > 0 ) {
     56         ec_enc_icdf( psRangeEnc, p_child1, &shell_table[ silk_shell_code_table_offsets[ p ] ], 8 );
     57     }
     58 }
     59 
     60 static inline void decode_split(
     61     opus_int                    *p_child1,      /* O    pulse amplitude of first child subframe     */
     62     opus_int                    *p_child2,      /* O    pulse amplitude of second child subframe    */
     63     ec_dec                      *psRangeDec,    /* I/O  Compressor data structure                   */
     64     const opus_int              p,              /* I    pulse amplitude of current subframe         */
     65     const opus_uint8            *shell_table    /* I    table of shell cdfs                         */
     66 )
     67 {
     68     if( p > 0 ) {
     69         p_child1[ 0 ] = ec_dec_icdf( psRangeDec, &shell_table[ silk_shell_code_table_offsets[ p ] ], 8 );
     70         p_child2[ 0 ] = p - p_child1[ 0 ];
     71     } else {
     72         p_child1[ 0 ] = 0;
     73         p_child2[ 0 ] = 0;
     74     }
     75 }
     76 
     77 /* Shell encoder, operates on one shell code frame of 16 pulses */
     78 void silk_shell_encoder(
     79     ec_enc                      *psRangeEnc,                    /* I/O  compressor data structure                   */
     80     const opus_int              *pulses0                        /* I    data: nonnegative pulse amplitudes          */
     81 )
     82 {
     83     opus_int pulses1[ 8 ], pulses2[ 4 ], pulses3[ 2 ], pulses4[ 1 ];
     84 
     85     /* this function operates on one shell code frame of 16 pulses */
     86     silk_assert( SHELL_CODEC_FRAME_LENGTH == 16 );
     87 
     88     /* tree representation per pulse-subframe */
     89     combine_pulses( pulses1, pulses0, 8 );
     90     combine_pulses( pulses2, pulses1, 4 );
     91     combine_pulses( pulses3, pulses2, 2 );
     92     combine_pulses( pulses4, pulses3, 1 );
     93 
     94     encode_split( psRangeEnc, pulses3[  0 ], pulses4[ 0 ], silk_shell_code_table3 );
     95 
     96     encode_split( psRangeEnc, pulses2[  0 ], pulses3[ 0 ], silk_shell_code_table2 );
     97 
     98     encode_split( psRangeEnc, pulses1[  0 ], pulses2[ 0 ], silk_shell_code_table1 );
     99     encode_split( psRangeEnc, pulses0[  0 ], pulses1[ 0 ], silk_shell_code_table0 );
    100     encode_split( psRangeEnc, pulses0[  2 ], pulses1[ 1 ], silk_shell_code_table0 );
    101 
    102     encode_split( psRangeEnc, pulses1[  2 ], pulses2[ 1 ], silk_shell_code_table1 );
    103     encode_split( psRangeEnc, pulses0[  4 ], pulses1[ 2 ], silk_shell_code_table0 );
    104     encode_split( psRangeEnc, pulses0[  6 ], pulses1[ 3 ], silk_shell_code_table0 );
    105 
    106     encode_split( psRangeEnc, pulses2[  2 ], pulses3[ 1 ], silk_shell_code_table2 );
    107 
    108     encode_split( psRangeEnc, pulses1[  4 ], pulses2[ 2 ], silk_shell_code_table1 );
    109     encode_split( psRangeEnc, pulses0[  8 ], pulses1[ 4 ], silk_shell_code_table0 );
    110     encode_split( psRangeEnc, pulses0[ 10 ], pulses1[ 5 ], silk_shell_code_table0 );
    111 
    112     encode_split( psRangeEnc, pulses1[  6 ], pulses2[ 3 ], silk_shell_code_table1 );
    113     encode_split( psRangeEnc, pulses0[ 12 ], pulses1[ 6 ], silk_shell_code_table0 );
    114     encode_split( psRangeEnc, pulses0[ 14 ], pulses1[ 7 ], silk_shell_code_table0 );
    115 }
    116 
    117 
    118 /* Shell decoder, operates on one shell code frame of 16 pulses */
    119 void silk_shell_decoder(
    120     opus_int                    *pulses0,                       /* O    data: nonnegative pulse amplitudes          */
    121     ec_dec                      *psRangeDec,                    /* I/O  Compressor data structure                   */
    122     const opus_int              pulses4                         /* I    number of pulses per pulse-subframe         */
    123 )
    124 {
    125     opus_int pulses3[ 2 ], pulses2[ 4 ], pulses1[ 8 ];
    126 
    127     /* this function operates on one shell code frame of 16 pulses */
    128     silk_assert( SHELL_CODEC_FRAME_LENGTH == 16 );
    129 
    130     decode_split( &pulses3[  0 ], &pulses3[  1 ], psRangeDec, pulses4,      silk_shell_code_table3 );
    131 
    132     decode_split( &pulses2[  0 ], &pulses2[  1 ], psRangeDec, pulses3[ 0 ], silk_shell_code_table2 );
    133 
    134     decode_split( &pulses1[  0 ], &pulses1[  1 ], psRangeDec, pulses2[ 0 ], silk_shell_code_table1 );
    135     decode_split( &pulses0[  0 ], &pulses0[  1 ], psRangeDec, pulses1[ 0 ], silk_shell_code_table0 );
    136     decode_split( &pulses0[  2 ], &pulses0[  3 ], psRangeDec, pulses1[ 1 ], silk_shell_code_table0 );
    137 
    138     decode_split( &pulses1[  2 ], &pulses1[  3 ], psRangeDec, pulses2[ 1 ], silk_shell_code_table1 );
    139     decode_split( &pulses0[  4 ], &pulses0[  5 ], psRangeDec, pulses1[ 2 ], silk_shell_code_table0 );
    140     decode_split( &pulses0[  6 ], &pulses0[  7 ], psRangeDec, pulses1[ 3 ], silk_shell_code_table0 );
    141 
    142     decode_split( &pulses2[  2 ], &pulses2[  3 ], psRangeDec, pulses3[ 1 ], silk_shell_code_table2 );
    143 
    144     decode_split( &pulses1[  4 ], &pulses1[  5 ], psRangeDec, pulses2[ 2 ], silk_shell_code_table1 );
    145     decode_split( &pulses0[  8 ], &pulses0[  9 ], psRangeDec, pulses1[ 4 ], silk_shell_code_table0 );
    146     decode_split( &pulses0[ 10 ], &pulses0[ 11 ], psRangeDec, pulses1[ 5 ], silk_shell_code_table0 );
    147 
    148     decode_split( &pulses1[  6 ], &pulses1[  7 ], psRangeDec, pulses2[ 3 ], silk_shell_code_table1 );
    149     decode_split( &pulses0[ 12 ], &pulses0[ 13 ], psRangeDec, pulses1[ 6 ], silk_shell_code_table0 );
    150     decode_split( &pulses0[ 14 ], &pulses0[ 15 ], psRangeDec, pulses1[ 7 ], silk_shell_code_table0 );
    151 }
    152