ref: a6b4e25628b3ea2671aec87058805b83c5b48b34
dir: /silk/silk_shell_coder.c/
/***********************************************************************
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***********************************************************************/
#include "silk_main.h"
/* shell coder; pulse-subframe length is hardcoded */
SKP_INLINE void combine_pulses(
opus_int *out, /* O: combined pulses vector [len] */
const opus_int *in, /* I: input vector [2 * len] */
const opus_int len /* I: number of OUTPUT samples */
)
{
opus_int k;
for( k = 0; k < len; k++ ) {
out[ k ] = in[ 2 * k ] + in[ 2 * k + 1 ];
}
}
SKP_INLINE void encode_split(
ec_enc *psRangeEnc, /* I/O compressor data structure */
const opus_int p_child1, /* I: pulse amplitude of first child subframe */
const opus_int p, /* I: pulse amplitude of current subframe */
const opus_uint8 *shell_table /* I: table of shell cdfs */
)
{
if( p > 0 ) {
ec_enc_icdf( psRangeEnc, p_child1, &shell_table[ silk_shell_code_table_offsets[ p ] ], 8 );
}
}
SKP_INLINE void decode_split(
opus_int *p_child1, /* O: pulse amplitude of first child subframe */
opus_int *p_child2, /* O: pulse amplitude of second child subframe */
ec_dec *psRangeDec, /* I/O Compressor data structure */
const opus_int p, /* I: pulse amplitude of current subframe */
const opus_uint8 *shell_table /* I: table of shell cdfs */
)
{
if( p > 0 ) {
p_child1[ 0 ] = ec_dec_icdf( psRangeDec, &shell_table[ silk_shell_code_table_offsets[ p ] ], 8 );
p_child2[ 0 ] = p - p_child1[ 0 ];
} else {
p_child1[ 0 ] = 0;
p_child2[ 0 ] = 0;
}
}
/* Shell encoder, operates on one shell code frame of 16 pulses */
void silk_shell_encoder(
ec_enc *psRangeEnc, /* I/O compressor data structure */
const opus_int *pulses0 /* I data: nonnegative pulse amplitudes */
)
{
opus_int pulses1[ 8 ], pulses2[ 4 ], pulses3[ 2 ], pulses4[ 1 ];
/* this function operates on one shell code frame of 16 pulses */
SKP_assert( SHELL_CODEC_FRAME_LENGTH == 16 );
/* tree representation per pulse-subframe */
combine_pulses( pulses1, pulses0, 8 );
combine_pulses( pulses2, pulses1, 4 );
combine_pulses( pulses3, pulses2, 2 );
combine_pulses( pulses4, pulses3, 1 );
encode_split( psRangeEnc, pulses3[ 0 ], pulses4[ 0 ], silk_shell_code_table3 );
encode_split( psRangeEnc, pulses2[ 0 ], pulses3[ 0 ], silk_shell_code_table2 );
encode_split( psRangeEnc, pulses1[ 0 ], pulses2[ 0 ], silk_shell_code_table1 );
encode_split( psRangeEnc, pulses0[ 0 ], pulses1[ 0 ], silk_shell_code_table0 );
encode_split( psRangeEnc, pulses0[ 2 ], pulses1[ 1 ], silk_shell_code_table0 );
encode_split( psRangeEnc, pulses1[ 2 ], pulses2[ 1 ], silk_shell_code_table1 );
encode_split( psRangeEnc, pulses0[ 4 ], pulses1[ 2 ], silk_shell_code_table0 );
encode_split( psRangeEnc, pulses0[ 6 ], pulses1[ 3 ], silk_shell_code_table0 );
encode_split( psRangeEnc, pulses2[ 2 ], pulses3[ 1 ], silk_shell_code_table2 );
encode_split( psRangeEnc, pulses1[ 4 ], pulses2[ 2 ], silk_shell_code_table1 );
encode_split( psRangeEnc, pulses0[ 8 ], pulses1[ 4 ], silk_shell_code_table0 );
encode_split( psRangeEnc, pulses0[ 10 ], pulses1[ 5 ], silk_shell_code_table0 );
encode_split( psRangeEnc, pulses1[ 6 ], pulses2[ 3 ], silk_shell_code_table1 );
encode_split( psRangeEnc, pulses0[ 12 ], pulses1[ 6 ], silk_shell_code_table0 );
encode_split( psRangeEnc, pulses0[ 14 ], pulses1[ 7 ], silk_shell_code_table0 );
}
/* Shell decoder, operates on one shell code frame of 16 pulses */
void silk_shell_decoder(
opus_int *pulses0, /* O data: nonnegative pulse amplitudes */
ec_dec *psRangeDec, /* I/O Compressor data structure */
const opus_int pulses4 /* I number of pulses per pulse-subframe */
)
{
opus_int pulses3[ 2 ], pulses2[ 4 ], pulses1[ 8 ];
/* this function operates on one shell code frame of 16 pulses */
SKP_assert( SHELL_CODEC_FRAME_LENGTH == 16 );
decode_split( &pulses3[ 0 ], &pulses3[ 1 ], psRangeDec, pulses4, silk_shell_code_table3 );
decode_split( &pulses2[ 0 ], &pulses2[ 1 ], psRangeDec, pulses3[ 0 ], silk_shell_code_table2 );
decode_split( &pulses1[ 0 ], &pulses1[ 1 ], psRangeDec, pulses2[ 0 ], silk_shell_code_table1 );
decode_split( &pulses0[ 0 ], &pulses0[ 1 ], psRangeDec, pulses1[ 0 ], silk_shell_code_table0 );
decode_split( &pulses0[ 2 ], &pulses0[ 3 ], psRangeDec, pulses1[ 1 ], silk_shell_code_table0 );
decode_split( &pulses1[ 2 ], &pulses1[ 3 ], psRangeDec, pulses2[ 1 ], silk_shell_code_table1 );
decode_split( &pulses0[ 4 ], &pulses0[ 5 ], psRangeDec, pulses1[ 2 ], silk_shell_code_table0 );
decode_split( &pulses0[ 6 ], &pulses0[ 7 ], psRangeDec, pulses1[ 3 ], silk_shell_code_table0 );
decode_split( &pulses2[ 2 ], &pulses2[ 3 ], psRangeDec, pulses3[ 1 ], silk_shell_code_table2 );
decode_split( &pulses1[ 4 ], &pulses1[ 5 ], psRangeDec, pulses2[ 2 ], silk_shell_code_table1 );
decode_split( &pulses0[ 8 ], &pulses0[ 9 ], psRangeDec, pulses1[ 4 ], silk_shell_code_table0 );
decode_split( &pulses0[ 10 ], &pulses0[ 11 ], psRangeDec, pulses1[ 5 ], silk_shell_code_table0 );
decode_split( &pulses1[ 6 ], &pulses1[ 7 ], psRangeDec, pulses2[ 3 ], silk_shell_code_table1 );
decode_split( &pulses0[ 12 ], &pulses0[ 13 ], psRangeDec, pulses1[ 6 ], silk_shell_code_table0 );
decode_split( &pulses0[ 14 ], &pulses0[ 15 ], psRangeDec, pulses1[ 7 ], silk_shell_code_table0 );
}