ref: 6cd4e2cd010b50cdba9991252ed1ff83ff9a8392
dir: /silk/silk_control_audio_bandwidth.c/
/***********************************************************************
Copyright (c) 2006-2011, Skype Limited. All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, (subject to the limitations in the disclaimer below)
are permitted provided that the following conditions are met:
- Redistributions of source code must retain the above copyright notice,
this list of conditions and the following disclaimer.
- Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
- Neither the name of Skype Limited, nor the names of specific
contributors, may be used to endorse or promote products derived from
this software without specific prior written permission.
NO EXPRESS OR IMPLIED LICENSES TO ANY PARTY'S PATENT RIGHTS ARE GRANTED
BY THIS LICENSE. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
CONTRIBUTORS ''AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
***********************************************************************/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "silk_main.h"
#include "silk_tuning_parameters.h"
/* Control internal sampling rate */
opus_int silk_control_audio_bandwidth(
silk_encoder_state *psEncC /* I/O Pointer to Silk encoder state */
)
{
opus_int fs_kHz;
opus_int32 fs_Hz;
fs_kHz = psEncC->fs_kHz;
fs_Hz = SKP_SMULBB( fs_kHz, 1000 );
if( fs_Hz == 0 ) {
/* Encoder has just been initialized */
fs_Hz = SKP_min( psEncC->desiredInternal_fs_Hz, psEncC->API_fs_Hz );
fs_kHz = SKP_DIV32_16( fs_Hz, 1000 );
} else if( fs_Hz > psEncC->API_fs_Hz || fs_Hz > psEncC->maxInternal_fs_Hz || fs_Hz < psEncC->minInternal_fs_Hz ) {
/* Make sure internal rate is not higher than external rate or maximum allowed, or lower than minimum allowed */
fs_Hz = psEncC->API_fs_Hz;
fs_Hz = SKP_min( fs_Hz, psEncC->maxInternal_fs_Hz );
fs_Hz = SKP_max( fs_Hz, psEncC->minInternal_fs_Hz );
fs_kHz = SKP_DIV32_16( fs_Hz, 1000 );
} else {
/* State machine for the internal sampling rate switching */
if( psEncC->sLP.transition_frame_no >= TRANSITION_FRAMES ) {
/* Stop transition phase */
psEncC->sLP.mode = 0;
}
if( psEncC->allow_bandwidth_switch ) {
/* Check if we should switch down */
if( SKP_SMULBB( psEncC->fs_kHz, 1000 ) > psEncC->desiredInternal_fs_Hz )
{
/* Switch down */
if( psEncC->sLP.mode == 0 ) {
/* New transition */
psEncC->sLP.transition_frame_no = TRANSITION_FRAMES;
/* Reset transition filter state */
SKP_memset( psEncC->sLP.In_LP_State, 0, sizeof( psEncC->sLP.In_LP_State ) );
}
if( psEncC->sLP.transition_frame_no <= 0 ) {
/* Stop transition phase */
psEncC->sLP.mode = 0;
/* Switch to a lower sample frequency */
fs_kHz = psEncC->fs_kHz == 16 ? 12 : 8;
} else {
/* Direction: down (at double speed) */
psEncC->sLP.mode = -2;
}
}
else
/* Check if we should switch up */
if( SKP_SMULBB( psEncC->fs_kHz, 1000 ) < psEncC->desiredInternal_fs_Hz )
{
/* Switch up */
if( psEncC->sLP.mode == 0 ) {
/* Switch to a higher sample frequency */
fs_kHz = psEncC->fs_kHz == 8 ? 12 : 16;
/* New transition */
psEncC->sLP.transition_frame_no = 0;
/* Reset transition filter state */
SKP_memset( psEncC->sLP.In_LP_State, 0, sizeof( psEncC->sLP.In_LP_State ) );
}
/* Direction: up */
psEncC->sLP.mode = 1;
}
}
}
#ifdef FORCE_INTERNAL_FS_KHZ
fs_kHz = FORCE_INTERNAL_FS_KHZ;
#endif
return fs_kHz;
}