diff options
Diffstat (limited to 'src_common/SKP_Silk_control_audio_bandwidth.c')
| -rw-r--r-- | src_common/SKP_Silk_control_audio_bandwidth.c | 137 |
1 files changed, 137 insertions, 0 deletions
diff --git a/src_common/SKP_Silk_control_audio_bandwidth.c b/src_common/SKP_Silk_control_audio_bandwidth.c new file mode 100644 index 00000000..7e4c5f77 --- /dev/null +++ b/src_common/SKP_Silk_control_audio_bandwidth.c @@ -0,0 +1,137 @@ +/***********************************************************************
+Copyright (c) 2006-2010, 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.
+***********************************************************************/
+
+#include "SKP_Silk_main.h"
+
+/* Control internal sampling rate */
+SKP_int SKP_Silk_control_audio_bandwidth(
+ SKP_Silk_encoder_state *psEncC, /* I/O Pointer to Silk encoder state */
+ const SKP_int32 TargetRate_bps /* I Target max bitrate (bps) */
+)
+{
+ SKP_int fs_kHz;
+
+ fs_kHz = psEncC->fs_kHz;
+ if( fs_kHz == 0 ) {
+ /* Encoder has just been initialized */
+ if( TargetRate_bps >= SWB2WB_BITRATE_BPS ) {
+ fs_kHz = 24;
+ } else if( TargetRate_bps >= WB2MB_BITRATE_BPS ) {
+ fs_kHz = 16;
+ } else if( TargetRate_bps >= MB2NB_BITRATE_BPS ) {
+ fs_kHz = 12;
+ } else {
+ fs_kHz = 8;
+ }
+ /* Make sure internal rate is not higher than external rate or maximum allowed, or lower than minimum allowed */
+ fs_kHz = SKP_min( fs_kHz, SKP_DIV32_16( psEncC->API_fs_Hz, 1000 ) );
+ fs_kHz = SKP_min( fs_kHz, psEncC->maxInternal_fs_kHz );
+ fs_kHz = SKP_max( fs_kHz, psEncC->minInternal_fs_kHz );
+ } else if( SKP_SMULBB( fs_kHz, 1000 ) > psEncC->API_fs_Hz || fs_kHz > psEncC->maxInternal_fs_kHz || fs_kHz < psEncC->minInternal_fs_kHz ) {
+ /* Make sure internal rate is not higher than external rate or maximum allowed, or lower than minimum allowed */
+ fs_kHz = SKP_DIV32_16( psEncC->API_fs_Hz, 1000 );
+ fs_kHz = SKP_min( fs_kHz, psEncC->maxInternal_fs_kHz );
+ fs_kHz = SKP_max( fs_kHz, psEncC->minInternal_fs_kHz );
+ } else {
+ /* State machine for the internal sampling rate switching */
+ if( psEncC->API_fs_Hz > 8000 ) {
+ /* Accumulate the difference between the target rate and limit for switching down */
+ psEncC->bitrateDiff += SKP_MUL( psEncC->PacketSize_ms, psEncC->TargetRate_bps - psEncC->bitrate_threshold_down );
+ psEncC->bitrateDiff = SKP_min( psEncC->bitrateDiff, 0 );
+
+ if( psEncC->vadFlag == NO_VOICE_ACTIVITY ) { /* Low speech activity */
+ /* Check if we should switch down */
+#if SWITCH_TRANSITION_FILTERING
+ if( ( psEncC->sLP.transition_frame_no == 0 ) && /* Transition phase not active */
+ ( psEncC->bitrateDiff <= -ACCUM_BITS_DIFF_THRESHOLD || /* Bitrate threshold is met */
+ ( psEncC->sSWBdetect.WB_detected * psEncC->fs_kHz == 24 ) ) ) { /* Forced down-switching due to WB input */
+ psEncC->sLP.transition_frame_no = 1; /* Begin transition phase */
+ psEncC->sLP.mode = 0; /* Switch down */
+ } else if(
+ ( psEncC->sLP.transition_frame_no >= TRANSITION_FRAMES_DOWN ) && /* Transition phase complete */
+ ( psEncC->sLP.mode == 0 ) ) { /* Ready to switch down */
+ psEncC->sLP.transition_frame_no = 0; /* Ready for new transition phase */
+#else
+ if( psEncC->bitrateDiff <= -ACCUM_BITS_DIFF_THRESHOLD ) { /* Bitrate threshold is met */
+#endif
+ psEncC->bitrateDiff = 0;
+
+ /* Switch to a lower sample frequency */
+ if( psEncC->fs_kHz == 24 ) {
+ fs_kHz = 16;
+ } else if( psEncC->fs_kHz == 16 ) {
+ fs_kHz = 12;
+ } else {
+ SKP_assert( psEncC->fs_kHz == 12 );
+ fs_kHz = 8;
+ }
+ }
+
+ /* Check if we should switch up */
+ if( ( ( psEncC->fs_kHz * 1000 < psEncC->API_fs_Hz ) &&
+ ( psEncC->TargetRate_bps >= psEncC->bitrate_threshold_up ) &&
+ ( psEncC->sSWBdetect.WB_detected * psEncC->fs_kHz < 16 ) ) &&
+ ( ( psEncC->fs_kHz == 16 ) && ( psEncC->maxInternal_fs_kHz >= 24 ) ||
+ ( psEncC->fs_kHz == 12 ) && ( psEncC->maxInternal_fs_kHz >= 16 ) ||
+ ( psEncC->fs_kHz == 8 ) && ( psEncC->maxInternal_fs_kHz >= 12 ) )
+#if SWITCH_TRANSITION_FILTERING
+ && ( psEncC->sLP.transition_frame_no == 0 ) ) { /* No transition phase running, ready to switch */
+ psEncC->sLP.mode = 1; /* Switch up */
+#else
+ ) {
+#endif
+ psEncC->bitrateDiff = 0;
+
+ /* Switch to a higher sample frequency */
+ if( psEncC->fs_kHz == 8 ) {
+ fs_kHz = 12;
+ } else if( psEncC->fs_kHz == 12 ) {
+ fs_kHz = 16;
+ } else {
+ SKP_assert( psEncC->fs_kHz == 16 );
+ fs_kHz = 24;
+ }
+ }
+ }
+ }
+
+#if SWITCH_TRANSITION_FILTERING
+ /* After switching up, stop transition filter during speech inactivity */
+ if( ( psEncC->sLP.mode == 1 ) &&
+ ( psEncC->sLP.transition_frame_no >= TRANSITION_FRAMES_UP ) &&
+ ( psEncC->vadFlag == NO_VOICE_ACTIVITY ) ) {
+
+ psEncC->sLP.transition_frame_no = 0;
+
+ /* Reset transition filter state */
+ SKP_memset( psEncC->sLP.In_LP_State, 0, 2 * sizeof( SKP_int32 ) );
+ }
+#endif
+ }
+
+ return fs_kHz;
+}
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