xref: /aosp_15_r20/external/libopus/silk/float/encode_frame_FLP.c (revision a58d3d2adb790c104798cd88c8a3aff4fa8b82cc)

/***********************************************************************
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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <stdlib.h>
#include "main_FLP.h"
#include "tuning_parameters.h"

/* Low Bitrate Redundancy (LBRR) encoding. Reuse all parameters but encode with lower bitrate */
static OPUS_INLINE void silk_LBRR_encode_FLP(
    silk_encoder_state_FLP          *psEnc,                             /* I/O  Encoder state FLP                           */
    silk_encoder_control_FLP        *psEncCtrl,                         /* I/O  Encoder control FLP                         */
    const silk_float                xfw[],                              /* I    Input signal                                */
    opus_int                        condCoding                          /* I    The type of conditional coding used so far for this frame */
);

void silk_encode_do_VAD_FLP(
    silk_encoder_state_FLP          *psEnc,                             /* I/O  Encoder state FLP                           */
    opus_int                        activity                            /* I    Decision of Opus voice activity detector    */
)
{
    const opus_int activity_threshold = SILK_FIX_CONST( SPEECH_ACTIVITY_DTX_THRES, 8 );

    /****************************/
    /* Voice Activity Detection */
    /****************************/
    silk_VAD_GetSA_Q8( &psEnc->sCmn, psEnc->sCmn.inputBuf + 1, psEnc->sCmn.arch );
    /* If Opus VAD is inactive and Silk VAD is active: lower Silk VAD to just under the threshold */
    if( activity == VAD_NO_ACTIVITY && psEnc->sCmn.speech_activity_Q8 >= activity_threshold ) {
        psEnc->sCmn.speech_activity_Q8 = activity_threshold - 1;
    }

    /**************************************************/
    /* Convert speech activity into VAD and DTX flags */
    /**************************************************/
    if( psEnc->sCmn.speech_activity_Q8 < activity_threshold ) {
        psEnc->sCmn.indices.signalType = TYPE_NO_VOICE_ACTIVITY;
        psEnc->sCmn.noSpeechCounter++;
        if( psEnc->sCmn.noSpeechCounter <= NB_SPEECH_FRAMES_BEFORE_DTX ) {
            psEnc->sCmn.inDTX = 0;
        } else if( psEnc->sCmn.noSpeechCounter > MAX_CONSECUTIVE_DTX + NB_SPEECH_FRAMES_BEFORE_DTX ) {
            psEnc->sCmn.noSpeechCounter = NB_SPEECH_FRAMES_BEFORE_DTX;
            psEnc->sCmn.inDTX           = 0;
        }
        psEnc->sCmn.VAD_flags[ psEnc->sCmn.nFramesEncoded ] = 0;
    } else {
        psEnc->sCmn.noSpeechCounter    = 0;
        psEnc->sCmn.inDTX              = 0;
        psEnc->sCmn.indices.signalType = TYPE_UNVOICED;
        psEnc->sCmn.VAD_flags[ psEnc->sCmn.nFramesEncoded ] = 1;
    }
}

/****************/
/* Encode frame */
/****************/
opus_int silk_encode_frame_FLP(
    silk_encoder_state_FLP          *psEnc,                             /* I/O  Encoder state FLP                           */
    opus_int32                      *pnBytesOut,                        /* O    Number of payload bytes;                    */
    ec_enc                          *psRangeEnc,                        /* I/O  compressor data structure                   */
    opus_int                        condCoding,                         /* I    The type of conditional coding to use       */
    opus_int                        maxBits,                            /* I    If > 0: maximum number of output bits       */
    opus_int                        useCBR                              /* I    Flag to force constant-bitrate operation    */
)
{
    silk_encoder_control_FLP sEncCtrl;
    opus_int     i, iter, maxIter, found_upper, found_lower, ret = 0;
    silk_float   *x_frame, *res_pitch_frame;
    silk_float   res_pitch[ 2 * MAX_FRAME_LENGTH + LA_PITCH_MAX ];
    ec_enc       sRangeEnc_copy, sRangeEnc_copy2;
    silk_nsq_state sNSQ_copy, sNSQ_copy2;
    opus_int32   seed_copy, nBits, nBits_lower, nBits_upper, gainMult_lower, gainMult_upper;
    opus_int32   gainsID, gainsID_lower, gainsID_upper;
    opus_int16   gainMult_Q8;
    opus_int16   ec_prevLagIndex_copy;
    opus_int     ec_prevSignalType_copy;
    opus_int8    LastGainIndex_copy2;
    opus_int32   pGains_Q16[ MAX_NB_SUBFR ];
    opus_uint8   ec_buf_copy[ 1275 ];
    opus_int     gain_lock[ MAX_NB_SUBFR ] = {0};
    opus_int16   best_gain_mult[ MAX_NB_SUBFR ];
    opus_int     best_sum[ MAX_NB_SUBFR ];
    opus_int     bits_margin;

    /* For CBR, 5 bits below budget is close enough. For VBR, allow up to 25% below the cap if we initially busted the budget. */
    bits_margin = useCBR ? 5 : maxBits/4;
    /* This is totally unnecessary but many compilers (including gcc) are too dumb to realise it */
    LastGainIndex_copy2 = nBits_lower = nBits_upper = gainMult_lower = gainMult_upper = 0;

    psEnc->sCmn.indices.Seed = psEnc->sCmn.frameCounter++ & 3;

    /**************************************************************/
    /* Set up Input Pointers, and insert frame in input buffer    */
    /**************************************************************/
    /* pointers aligned with start of frame to encode */
    x_frame         = psEnc->x_buf + psEnc->sCmn.ltp_mem_length;    /* start of frame to encode */
    res_pitch_frame = res_pitch    + psEnc->sCmn.ltp_mem_length;    /* start of pitch LPC residual frame */

    /***************************************/
    /* Ensure smooth bandwidth transitions */
    /***************************************/
    silk_LP_variable_cutoff( &psEnc->sCmn.sLP, psEnc->sCmn.inputBuf + 1, psEnc->sCmn.frame_length );

    /*******************************************/
    /* Copy new frame to front of input buffer */
    /*******************************************/
    silk_short2float_array( x_frame + LA_SHAPE_MS * psEnc->sCmn.fs_kHz, psEnc->sCmn.inputBuf + 1, psEnc->sCmn.frame_length );

    /* Add tiny signal to avoid high CPU load from denormalized floating point numbers */
    for( i = 0; i < 8; i++ ) {
        x_frame[ LA_SHAPE_MS * psEnc->sCmn.fs_kHz + i * ( psEnc->sCmn.frame_length >> 3 ) ] += ( 1 - ( i & 2 ) ) * 1e-6f;
    }

    if( !psEnc->sCmn.prefillFlag ) {
        /*****************************************/
        /* Find pitch lags, initial LPC analysis */
        /*****************************************/
        silk_find_pitch_lags_FLP( psEnc, &sEncCtrl, res_pitch, x_frame, psEnc->sCmn.arch );

        /************************/
        /* Noise shape analysis */
        /************************/
        silk_noise_shape_analysis_FLP( psEnc, &sEncCtrl, res_pitch_frame, x_frame );

        /***************************************************/
        /* Find linear prediction coefficients (LPC + LTP) */
        /***************************************************/
        silk_find_pred_coefs_FLP( psEnc, &sEncCtrl, res_pitch_frame, x_frame, condCoding );

        /****************************************/
        /* Process gains                        */
        /****************************************/
        silk_process_gains_FLP( psEnc, &sEncCtrl, condCoding );

        /****************************************/
        /* Low Bitrate Redundant Encoding       */
        /****************************************/
        silk_LBRR_encode_FLP( psEnc, &sEncCtrl, x_frame, condCoding );

        /* Loop over quantizer and entroy coding to control bitrate */
        maxIter = 6;
        gainMult_Q8 = SILK_FIX_CONST( 1, 8 );
        found_lower = 0;
        found_upper = 0;
        gainsID = silk_gains_ID( psEnc->sCmn.indices.GainsIndices, psEnc->sCmn.nb_subfr );
        gainsID_lower = -1;
        gainsID_upper = -1;
        /* Copy part of the input state */
        silk_memcpy( &sRangeEnc_copy, psRangeEnc, sizeof( ec_enc ) );
        silk_memcpy( &sNSQ_copy, &psEnc->sCmn.sNSQ, sizeof( silk_nsq_state ) );
        seed_copy = psEnc->sCmn.indices.Seed;
        ec_prevLagIndex_copy = psEnc->sCmn.ec_prevLagIndex;
        ec_prevSignalType_copy = psEnc->sCmn.ec_prevSignalType;
        for( iter = 0; ; iter++ ) {
            if( gainsID == gainsID_lower ) {
                nBits = nBits_lower;
            } else if( gainsID == gainsID_upper ) {
                nBits = nBits_upper;
            } else {
                /* Restore part of the input state */
                if( iter > 0 ) {
                    silk_memcpy( psRangeEnc, &sRangeEnc_copy, sizeof( ec_enc ) );
                    silk_memcpy( &psEnc->sCmn.sNSQ, &sNSQ_copy, sizeof( silk_nsq_state ) );
                    psEnc->sCmn.indices.Seed = seed_copy;
                    psEnc->sCmn.ec_prevLagIndex = ec_prevLagIndex_copy;
                    psEnc->sCmn.ec_prevSignalType = ec_prevSignalType_copy;
                }

                /*****************************************/
                /* Noise shaping quantization            */
                /*****************************************/
                silk_NSQ_wrapper_FLP( psEnc, &sEncCtrl, &psEnc->sCmn.indices, &psEnc->sCmn.sNSQ, psEnc->sCmn.pulses, x_frame );

                if ( iter == maxIter && !found_lower ) {
                    silk_memcpy( &sRangeEnc_copy2, psRangeEnc, sizeof( ec_enc ) );
                }

                /****************************************/
                /* Encode Parameters                    */
                /****************************************/
                silk_encode_indices( &psEnc->sCmn, psRangeEnc, psEnc->sCmn.nFramesEncoded, 0, condCoding );

                /****************************************/
                /* Encode Excitation Signal             */
                /****************************************/
                silk_encode_pulses( psRangeEnc, psEnc->sCmn.indices.signalType, psEnc->sCmn.indices.quantOffsetType,
                      psEnc->sCmn.pulses, psEnc->sCmn.frame_length );

                nBits = ec_tell( psRangeEnc );

                /* If we still bust after the last iteration, do some damage control. */
                if ( iter == maxIter && !found_lower && nBits > maxBits ) {
                    silk_memcpy( psRangeEnc, &sRangeEnc_copy2, sizeof( ec_enc ) );

                    /* Keep gains the same as the last frame. */
                    psEnc->sShape.LastGainIndex = sEncCtrl.lastGainIndexPrev;
                    for ( i = 0; i < psEnc->sCmn.nb_subfr; i++ ) {
                        psEnc->sCmn.indices.GainsIndices[ i ] = 4;
                    }
                    if (condCoding != CODE_CONDITIONALLY) {
                       psEnc->sCmn.indices.GainsIndices[ 0 ] = sEncCtrl.lastGainIndexPrev;
                    }
                    psEnc->sCmn.ec_prevLagIndex = ec_prevLagIndex_copy;
                    psEnc->sCmn.ec_prevSignalType = ec_prevSignalType_copy;
                    /* Clear all pulses. */
                    for ( i = 0; i < psEnc->sCmn.frame_length; i++ ) {
                        psEnc->sCmn.pulses[ i ] = 0;
                    }

                    silk_encode_indices( &psEnc->sCmn, psRangeEnc, psEnc->sCmn.nFramesEncoded, 0, condCoding );

                    silk_encode_pulses( psRangeEnc, psEnc->sCmn.indices.signalType, psEnc->sCmn.indices.quantOffsetType,
                        psEnc->sCmn.pulses, psEnc->sCmn.frame_length );

                    nBits = ec_tell( psRangeEnc );
                }

                if( useCBR == 0 && iter == 0 && nBits <= maxBits ) {
                    break;
                }
            }

            if( iter == maxIter ) {
                if( found_lower && ( gainsID == gainsID_lower || nBits > maxBits ) ) {
                    /* Restore output state from earlier iteration that did meet the bitrate budget */
                    silk_memcpy( psRangeEnc, &sRangeEnc_copy2, sizeof( ec_enc ) );
                    celt_assert( sRangeEnc_copy2.offs <= 1275 );
                    silk_memcpy( psRangeEnc->buf, ec_buf_copy, sRangeEnc_copy2.offs );
                    silk_memcpy( &psEnc->sCmn.sNSQ, &sNSQ_copy2, sizeof( silk_nsq_state ) );
                    psEnc->sShape.LastGainIndex = LastGainIndex_copy2;
                }
                break;
            }

            if( nBits > maxBits ) {
                if( found_lower == 0 && iter >= 2 ) {
                    /* Adjust the quantizer's rate/distortion tradeoff and discard previous "upper" results */
                    sEncCtrl.Lambda = silk_max_float(sEncCtrl.Lambda*1.5f, 1.5f);
                    /* Reducing dithering can help us hit the target. */
                    psEnc->sCmn.indices.quantOffsetType = 0;
                    found_upper = 0;
                    gainsID_upper = -1;
                } else {
                    found_upper = 1;
                    nBits_upper = nBits;
                    gainMult_upper = gainMult_Q8;
                    gainsID_upper = gainsID;
                }
            } else if( nBits < maxBits - bits_margin ) {
                found_lower = 1;
                nBits_lower = nBits;
                gainMult_lower = gainMult_Q8;
                if( gainsID != gainsID_lower ) {
                    gainsID_lower = gainsID;
                    /* Copy part of the output state */
                    silk_memcpy( &sRangeEnc_copy2, psRangeEnc, sizeof( ec_enc ) );
                    celt_assert( psRangeEnc->offs <= 1275 );
                    silk_memcpy( ec_buf_copy, psRangeEnc->buf, psRangeEnc->offs );
                    silk_memcpy( &sNSQ_copy2, &psEnc->sCmn.sNSQ, sizeof( silk_nsq_state ) );
                    LastGainIndex_copy2 = psEnc->sShape.LastGainIndex;
                }
            } else {
                /* Close enough */
                break;
            }

            if ( !found_lower && nBits > maxBits ) {
                int j;
                for ( i = 0; i < psEnc->sCmn.nb_subfr; i++ ) {
                    int sum=0;
                    for ( j = i*psEnc->sCmn.subfr_length; j < (i+1)*psEnc->sCmn.subfr_length; j++ ) {
                        sum += abs( psEnc->sCmn.pulses[j] );
                    }
                    if ( iter == 0 || (sum < best_sum[i] && !gain_lock[i]) ) {
                        best_sum[i] = sum;
                        best_gain_mult[i] = gainMult_Q8;
                    } else {
                        gain_lock[i] = 1;
                    }
                }
            }
            if( ( found_lower & found_upper ) == 0 ) {
                /* Adjust gain according to high-rate rate/distortion curve */
                if( nBits > maxBits ) {
                    gainMult_Q8 = silk_min_32( 1024, gainMult_Q8*3/2 );
                } else {
                    gainMult_Q8 = silk_max_32( 64, gainMult_Q8*4/5 );
                }
            } else {
                /* Adjust gain by interpolating */
                gainMult_Q8 = gainMult_lower + ( ( gainMult_upper - gainMult_lower ) * ( maxBits - nBits_lower ) ) / ( nBits_upper - nBits_lower );
                /* New gain multplier must be between 25% and 75% of old range (note that gainMult_upper < gainMult_lower) */
                if( gainMult_Q8 > silk_ADD_RSHIFT32( gainMult_lower, gainMult_upper - gainMult_lower, 2 ) ) {
                    gainMult_Q8 = silk_ADD_RSHIFT32( gainMult_lower, gainMult_upper - gainMult_lower, 2 );
                } else
                if( gainMult_Q8 < silk_SUB_RSHIFT32( gainMult_upper, gainMult_upper - gainMult_lower, 2 ) ) {
                    gainMult_Q8 = silk_SUB_RSHIFT32( gainMult_upper, gainMult_upper - gainMult_lower, 2 );
                }
            }

            for( i = 0; i < psEnc->sCmn.nb_subfr; i++ ) {
                opus_int16 tmp;
                if ( gain_lock[i] ) {
                    tmp = best_gain_mult[i];
                } else {
                    tmp = gainMult_Q8;
                }
                pGains_Q16[ i ] = silk_LSHIFT_SAT32( silk_SMULWB( sEncCtrl.GainsUnq_Q16[ i ], tmp ), 8 );
            }

            /* Quantize gains */
            psEnc->sShape.LastGainIndex = sEncCtrl.lastGainIndexPrev;
            silk_gains_quant( psEnc->sCmn.indices.GainsIndices, pGains_Q16,
                  &psEnc->sShape.LastGainIndex, condCoding == CODE_CONDITIONALLY, psEnc->sCmn.nb_subfr );

            /* Unique identifier of gains vector */
            gainsID = silk_gains_ID( psEnc->sCmn.indices.GainsIndices, psEnc->sCmn.nb_subfr );

            /* Overwrite unquantized gains with quantized gains and convert back to Q0 from Q16 */
            for( i = 0; i < psEnc->sCmn.nb_subfr; i++ ) {
                sEncCtrl.Gains[ i ] = pGains_Q16[ i ] / 65536.0f;
            }
        }
    }

    /* Update input buffer */
    silk_memmove( psEnc->x_buf, &psEnc->x_buf[ psEnc->sCmn.frame_length ],
        ( psEnc->sCmn.ltp_mem_length + LA_SHAPE_MS * psEnc->sCmn.fs_kHz ) * sizeof( silk_float ) );

    /* Exit without entropy coding */
    if( psEnc->sCmn.prefillFlag ) {
        /* No payload */
        *pnBytesOut = 0;
        return ret;
    }

    /* Parameters needed for next frame */
    psEnc->sCmn.prevLag        = sEncCtrl.pitchL[ psEnc->sCmn.nb_subfr - 1 ];
    psEnc->sCmn.prevSignalType = psEnc->sCmn.indices.signalType;

    /****************************************/
    /* Finalize payload                     */
    /****************************************/
    psEnc->sCmn.first_frame_after_reset = 0;
    /* Payload size */
    *pnBytesOut = silk_RSHIFT( ec_tell( psRangeEnc ) + 7, 3 );

    return ret;
}

/* Low-Bitrate Redundancy (LBRR) encoding. Reuse all parameters but encode excitation at lower bitrate  */
static OPUS_INLINE void silk_LBRR_encode_FLP(
    silk_encoder_state_FLP          *psEnc,                             /* I/O  Encoder state FLP                           */
    silk_encoder_control_FLP        *psEncCtrl,                         /* I/O  Encoder control FLP                         */
    const silk_float                xfw[],                              /* I    Input signal                                */
    opus_int                        condCoding                          /* I    The type of conditional coding used so far for this frame */
)
{
    opus_int     k;
    opus_int32   Gains_Q16[ MAX_NB_SUBFR ];
    silk_float   TempGains[ MAX_NB_SUBFR ];
    SideInfoIndices *psIndices_LBRR = &psEnc->sCmn.indices_LBRR[ psEnc->sCmn.nFramesEncoded ];
    silk_nsq_state sNSQ_LBRR;

    /*******************************************/
    /* Control use of inband LBRR              */
    /*******************************************/
    if( psEnc->sCmn.LBRR_enabled && psEnc->sCmn.speech_activity_Q8 > SILK_FIX_CONST( LBRR_SPEECH_ACTIVITY_THRES, 8 ) ) {
        psEnc->sCmn.LBRR_flags[ psEnc->sCmn.nFramesEncoded ] = 1;

        /* Copy noise shaping quantizer state and quantization indices from regular encoding */
        silk_memcpy( &sNSQ_LBRR, &psEnc->sCmn.sNSQ, sizeof( silk_nsq_state ) );
        silk_memcpy( psIndices_LBRR, &psEnc->sCmn.indices, sizeof( SideInfoIndices ) );

        /* Save original gains */
        silk_memcpy( TempGains, psEncCtrl->Gains, psEnc->sCmn.nb_subfr * sizeof( silk_float ) );

        if( psEnc->sCmn.nFramesEncoded == 0 || psEnc->sCmn.LBRR_flags[ psEnc->sCmn.nFramesEncoded - 1 ] == 0 ) {
            /* First frame in packet or previous frame not LBRR coded */
            psEnc->sCmn.LBRRprevLastGainIndex = psEnc->sShape.LastGainIndex;

            /* Increase Gains to get target LBRR rate */
            psIndices_LBRR->GainsIndices[ 0 ] += psEnc->sCmn.LBRR_GainIncreases;
            psIndices_LBRR->GainsIndices[ 0 ] = silk_min_int( psIndices_LBRR->GainsIndices[ 0 ], N_LEVELS_QGAIN - 1 );
        }

        /* Decode to get gains in sync with decoder */
        silk_gains_dequant( Gains_Q16, psIndices_LBRR->GainsIndices,
            &psEnc->sCmn.LBRRprevLastGainIndex, condCoding == CODE_CONDITIONALLY, psEnc->sCmn.nb_subfr );

        /* Overwrite unquantized gains with quantized gains and convert back to Q0 from Q16 */
        for( k = 0; k <  psEnc->sCmn.nb_subfr; k++ ) {
            psEncCtrl->Gains[ k ] = Gains_Q16[ k ] * ( 1.0f / 65536.0f );
        }

        /*****************************************/
        /* Noise shaping quantization            */
        /*****************************************/
        silk_NSQ_wrapper_FLP( psEnc, psEncCtrl, psIndices_LBRR, &sNSQ_LBRR,
            psEnc->sCmn.pulses_LBRR[ psEnc->sCmn.nFramesEncoded ], xfw );

        /* Restore original gains */
        silk_memcpy( psEncCtrl->Gains, TempGains, psEnc->sCmn.nb_subfr * sizeof( silk_float ) );
    }
}