138 lines
7.1 KiB
C
138 lines
7.1 KiB
C
/***********************************************************************
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Copyright (c) 2006-2011, Skype Limited. All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, (subject to the limitations in the disclaimer below)
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are permitted provided that the following conditions are met:
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- Redistributions of source code must retain the above copyright notice,
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this list of conditions and the following disclaimer.
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- Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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- Neither the name of Skype Limited, nor the names of specific
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contributors, may be used to endorse or promote products derived from
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this software without specific prior written permission.
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NO EXPRESS OR IMPLIED LICENSES TO ANY PARTY'S PATENT RIGHTS ARE GRANTED
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BY THIS LICENSE. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
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CONTRIBUTORS ''AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
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BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
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FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
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ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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***********************************************************************/
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#include "SKP_Silk_main.h"
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/* Control internal sampling rate */
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SKP_int SKP_Silk_control_audio_bandwidth(
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SKP_Silk_encoder_state *psEncC, /* I/O Pointer to Silk encoder state */
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const SKP_int32 TargetRate_bps /* I Target max bitrate (bps) */
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)
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{
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SKP_int fs_kHz;
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fs_kHz = psEncC->fs_kHz;
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if( fs_kHz == 0 ) {
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/* Encoder has just been initialized */
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if( TargetRate_bps >= SWB2WB_BITRATE_BPS ) {
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fs_kHz = 24;
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} else if( TargetRate_bps >= WB2MB_BITRATE_BPS ) {
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fs_kHz = 16;
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} else if( TargetRate_bps >= MB2NB_BITRATE_BPS ) {
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fs_kHz = 12;
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} else {
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fs_kHz = 8;
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}
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/* Make sure internal rate is not higher than external rate or maximum allowed, or lower than minimum allowed */
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fs_kHz = SKP_min( fs_kHz, SKP_DIV32_16( psEncC->API_fs_Hz, 1000 ) );
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fs_kHz = SKP_min( fs_kHz, psEncC->maxInternal_fs_kHz );
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} else if( SKP_SMULBB( fs_kHz, 1000 ) > psEncC->API_fs_Hz || fs_kHz > psEncC->maxInternal_fs_kHz ) {
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/* Make sure internal rate is not higher than external rate or maximum allowed */
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fs_kHz = SKP_DIV32_16( psEncC->API_fs_Hz, 1000 );
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fs_kHz = SKP_min( fs_kHz, psEncC->maxInternal_fs_kHz );
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} else {
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/* State machine for the internal sampling rate switching */
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if( psEncC->API_fs_Hz > 8000 ) {
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/* Accumulate the difference between the target rate and limit for switching down */
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psEncC->bitrateDiff += SKP_MUL( psEncC->PacketSize_ms, psEncC->TargetRate_bps - psEncC->bitrate_threshold_down );
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psEncC->bitrateDiff = SKP_min( psEncC->bitrateDiff, 0 );
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if( psEncC->vadFlag == NO_VOICE_ACTIVITY ) { /* Low speech activity */
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/* Check if we should switch down */
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#if SWITCH_TRANSITION_FILTERING
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if( ( psEncC->sLP.transition_frame_no == 0 ) && /* Transition phase not active */
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( psEncC->bitrateDiff <= -ACCUM_BITS_DIFF_THRESHOLD || /* Bitrate threshold is met */
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( psEncC->sSWBdetect.WB_detected * psEncC->fs_kHz == 24 ) ) ) { /* Forced down-switching due to WB input */
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psEncC->sLP.transition_frame_no = 1; /* Begin transition phase */
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psEncC->sLP.mode = 0; /* Switch down */
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} else if(
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( psEncC->sLP.transition_frame_no >= TRANSITION_FRAMES_DOWN ) && /* Transition phase complete */
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( psEncC->sLP.mode == 0 ) ) { /* Ready to switch down */
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psEncC->sLP.transition_frame_no = 0; /* Ready for new transition phase */
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#else
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if( psEncC->bitrateDiff <= -ACCUM_BITS_DIFF_THRESHOLD ) { /* Bitrate threshold is met */
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#endif
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psEncC->bitrateDiff = 0;
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/* Switch to a lower sample frequency */
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if( psEncC->fs_kHz == 24 ) {
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fs_kHz = 16;
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} else if( psEncC->fs_kHz == 16 ) {
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fs_kHz = 12;
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} else {
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SKP_assert( psEncC->fs_kHz == 12 );
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fs_kHz = 8;
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}
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}
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/* Check if we should switch up */
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if( ( ( psEncC->fs_kHz * 1000 < psEncC->API_fs_Hz ) &&
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( psEncC->TargetRate_bps >= psEncC->bitrate_threshold_up ) &&
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( psEncC->sSWBdetect.WB_detected * psEncC->fs_kHz < 16 ) ) &&
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( ( ( psEncC->fs_kHz == 16 ) && ( psEncC->maxInternal_fs_kHz >= 24 ) ) ||
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( ( psEncC->fs_kHz == 12 ) && ( psEncC->maxInternal_fs_kHz >= 16 ) ) ||
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( ( psEncC->fs_kHz == 8 ) && ( psEncC->maxInternal_fs_kHz >= 12 ) ) )
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#if SWITCH_TRANSITION_FILTERING
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&& ( psEncC->sLP.transition_frame_no == 0 ) ) { /* No transition phase running, ready to switch */
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psEncC->sLP.mode = 1; /* Switch up */
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#else
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) {
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#endif
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psEncC->bitrateDiff = 0;
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/* Switch to a higher sample frequency */
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if( psEncC->fs_kHz == 8 ) {
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fs_kHz = 12;
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} else if( psEncC->fs_kHz == 12 ) {
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fs_kHz = 16;
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} else {
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SKP_assert( psEncC->fs_kHz == 16 );
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fs_kHz = 24;
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}
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}
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}
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}
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#if SWITCH_TRANSITION_FILTERING
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/* After switching up, stop transition filter during speech inactivity */
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if( ( psEncC->sLP.mode == 1 ) &&
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( psEncC->sLP.transition_frame_no >= TRANSITION_FRAMES_UP ) &&
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( psEncC->vadFlag == NO_VOICE_ACTIVITY ) ) {
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psEncC->sLP.transition_frame_no = 0;
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/* Reset transition filter state */
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SKP_memset( psEncC->sLP.In_LP_State, 0, 2 * sizeof( SKP_int32 ) );
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}
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#endif
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}
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return fs_kHz;
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}
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