freeswitch/libs/silk/src/SKP_Silk_encode_pulses.c

/***********************************************************************
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***********************************************************************/

#include "SKP_Silk_main.h"

/*********************************************/
/* Encode quantization indices of excitation */
/*********************************************/

SKP_INLINE SKP_int combine_and_check(       /* return ok */
    SKP_int         *pulses_comb,           /* O */
    const SKP_int   *pulses_in,             /* I */
    SKP_int         max_pulses,             /* I    max value for sum of pulses */
    SKP_int         len                     /* I    number of output values */
)
{
    SKP_int k, sum;

    for( k = 0; k < len; k++ ) {
        sum = pulses_in[ 2 * k ] + pulses_in[ 2 * k + 1 ];
        if( sum > max_pulses ) {
            return 1;
        }
        pulses_comb[ k ] = sum;
    }

    return 0;
}

/* Encode quantization indices of excitation */
void SKP_Silk_encode_pulses(
    SKP_Silk_range_coder_state      *psRC,          /* I/O  Range coder state               */
    const SKP_int                   sigtype,        /* I    Sigtype                         */
    const SKP_int                   QuantOffsetType,/* I    QuantOffsetType                 */
    const SKP_int8                  q[],            /* I    quantization indices            */
    const SKP_int                   frame_length    /* I    Frame length                    */
)
{
    SKP_int   i, k, j, iter, bit, nLS, scale_down, RateLevelIndex = 0;
    SKP_int32 abs_q, minSumBits_Q6, sumBits_Q6;
    SKP_int   abs_pulses[ MAX_FRAME_LENGTH ];
    SKP_int   sum_pulses[ MAX_NB_SHELL_BLOCKS ];
    SKP_int   nRshifts[   MAX_NB_SHELL_BLOCKS ];
    SKP_int   pulses_comb[ 8 ];
    SKP_int   *abs_pulses_ptr;
    const SKP_int8 *pulses_ptr;
    const SKP_uint16 *cdf_ptr;
    const SKP_int16 *nBits_ptr;

    SKP_memset( pulses_comb, 0, 8 * sizeof( SKP_int ) ); // Fixing Valgrind reported problem

    /****************************/
    /* Prepare for shell coding */
    /****************************/
    /* Calculate number of shell blocks */
    iter = frame_length / SHELL_CODEC_FRAME_LENGTH;

    /* Take the absolute value of the pulses */
    for( i = 0; i < frame_length; i+=4 ) {
        abs_pulses[i+0] = ( SKP_int )SKP_abs( q[ i + 0 ] );
        abs_pulses[i+1] = ( SKP_int )SKP_abs( q[ i + 1 ] );
        abs_pulses[i+2] = ( SKP_int )SKP_abs( q[ i + 2 ] );
        abs_pulses[i+3] = ( SKP_int )SKP_abs( q[ i + 3 ] );
    }

    /* Calc sum pulses per shell code frame */
    abs_pulses_ptr = abs_pulses;
    for( i = 0; i < iter; i++ ) {
        nRshifts[ i ] = 0;

        while( 1 ) {
            /* 1+1 -> 2 */
            scale_down = combine_and_check( pulses_comb, abs_pulses_ptr, SKP_Silk_max_pulses_table[ 0 ], 8 );

            /* 2+2 -> 4 */
            scale_down += combine_and_check( pulses_comb, pulses_comb, SKP_Silk_max_pulses_table[ 1 ], 4 );

            /* 4+4 -> 8 */
            scale_down += combine_and_check( pulses_comb, pulses_comb, SKP_Silk_max_pulses_table[ 2 ], 2 );

            /* 8+8 -> 16 */
            sum_pulses[ i ] = pulses_comb[ 0 ] + pulses_comb[ 1 ];
            if( sum_pulses[ i ] > SKP_Silk_max_pulses_table[ 3 ] ) {
                scale_down++;
            }

            if( scale_down ) {
                /* We need to down scale the quantization signal */
                nRshifts[ i ]++;
                for( k = 0; k < SHELL_CODEC_FRAME_LENGTH; k++ ) {
                    abs_pulses_ptr[ k ] = SKP_RSHIFT( abs_pulses_ptr[ k ], 1 );
                }
            } else {
                /* Jump out of while(1) loop and go to next shell coding frame */
                break;
            }
        }
        abs_pulses_ptr += SHELL_CODEC_FRAME_LENGTH;
    }

    /**************/
    /* Rate level */
    /**************/
    /* find rate level that leads to fewest bits for coding of pulses per block info */
    minSumBits_Q6 = SKP_int32_MAX;
    for( k = 0; k < N_RATE_LEVELS - 1; k++ ) {
        nBits_ptr  = SKP_Silk_pulses_per_block_BITS_Q6[ k ];
        sumBits_Q6 = SKP_Silk_rate_levels_BITS_Q6[sigtype][ k ];
        for( i = 0; i < iter; i++ ) {
            if( nRshifts[ i ] > 0 ) {
                sumBits_Q6 += nBits_ptr[ MAX_PULSES + 1 ];
            } else {
                sumBits_Q6 += nBits_ptr[ sum_pulses[ i ] ];
            }
        }
        if( sumBits_Q6 < minSumBits_Q6 ) {
            minSumBits_Q6 = sumBits_Q6;
            RateLevelIndex = k;
        }
    }
    SKP_Silk_range_encoder( psRC, RateLevelIndex, SKP_Silk_rate_levels_CDF[ sigtype ] );

    /***************************************************/
    /* Sum-Weighted-Pulses Encoding                    */
    /***************************************************/
    cdf_ptr = SKP_Silk_pulses_per_block_CDF[ RateLevelIndex ];
    for( i = 0; i < iter; i++ ) {
        if( nRshifts[ i ] == 0 ) {
            SKP_Silk_range_encoder( psRC, sum_pulses[ i ], cdf_ptr );
        } else {
            SKP_Silk_range_encoder( psRC, MAX_PULSES + 1, cdf_ptr );
            for( k = 0; k < nRshifts[ i ] - 1; k++ ) {
                SKP_Silk_range_encoder( psRC, MAX_PULSES + 1, SKP_Silk_pulses_per_block_CDF[ N_RATE_LEVELS - 1 ] );
            }
            SKP_Silk_range_encoder( psRC, sum_pulses[ i ], SKP_Silk_pulses_per_block_CDF[ N_RATE_LEVELS - 1 ] );
        }
    }

    /******************/
    /* Shell Encoding */
    /******************/
    for( i = 0; i < iter; i++ ) {
        if( sum_pulses[ i ] > 0 ) {
            SKP_Silk_shell_encoder( psRC, &abs_pulses[ i * SHELL_CODEC_FRAME_LENGTH ] );
        }
    }

    /****************/
    /* LSB Encoding */
    /****************/
    for( i = 0; i < iter; i++ ) {
        if( nRshifts[ i ] > 0 ) {
            pulses_ptr = &q[ i * SHELL_CODEC_FRAME_LENGTH ];
            nLS = nRshifts[ i ] - 1;
            for( k = 0; k < SHELL_CODEC_FRAME_LENGTH; k++ ) {
                abs_q = (SKP_int8)SKP_abs( pulses_ptr[ k ] );
                for( j = nLS; j > 0; j-- ) {
                    bit = SKP_RSHIFT( abs_q, j ) & 1;
                    SKP_Silk_range_encoder( psRC, bit, SKP_Silk_lsb_CDF );
                }
                bit = abs_q & 1;
                SKP_Silk_range_encoder( psRC, bit, SKP_Silk_lsb_CDF );
            }
        }
    }

    /****************/
    /* Encode signs */
    /****************/
    SKP_Silk_encode_signs( psRC, q, frame_length, sigtype, QuantOffsetType, RateLevelIndex );
}