1/***********************************************************************
2Copyright (c) 2006-2011, Skype Limited. All rights reserved.
3Redistribution and use in source and binary forms, with or without
4modification, are permitted provided that the following conditions
5are met:
6- Redistributions of source code must retain the above copyright notice,
7this list of conditions and the following disclaimer.
8- Redistributions in binary form must reproduce the above copyright
9notice, this list of conditions and the following disclaimer in the
10documentation and/or other materials provided with the distribution.
11- Neither the name of Internet Society, IETF or IETF Trust, nor the
12names of specific contributors, may be used to endorse or promote
13products derived from this software without specific prior written
14permission.
15THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
16AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
19LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
20CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
21SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
22INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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24ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
25POSSIBILITY OF SUCH DAMAGE.
26***********************************************************************/
27
28#ifdef HAVE_CONFIG_H
29#include "config.h"
30#endif
31
32#include "main.h"
33#include "tuning_parameters.h"
34
35/* Control internal sampling rate */
36opus_int silk_control_audio_bandwidth(
37    silk_encoder_state          *psEncC,                        /* I/O  Pointer to Silk encoder state               */
38    silk_EncControlStruct       *encControl                     /* I    Control structure                           */
39)
40{
41    opus_int   fs_kHz;
42    opus_int32 fs_Hz;
43
44    fs_kHz = psEncC->fs_kHz;
45    fs_Hz = silk_SMULBB( fs_kHz, 1000 );
46    if( fs_Hz == 0 ) {
47        /* Encoder has just been initialized */
48        fs_Hz  = silk_min( psEncC->desiredInternal_fs_Hz, psEncC->API_fs_Hz );
49        fs_kHz = silk_DIV32_16( fs_Hz, 1000 );
50    } else if( fs_Hz > psEncC->API_fs_Hz || fs_Hz > psEncC->maxInternal_fs_Hz || fs_Hz < psEncC->minInternal_fs_Hz ) {
51        /* Make sure internal rate is not higher than external rate or maximum allowed, or lower than minimum allowed */
52        fs_Hz  = psEncC->API_fs_Hz;
53        fs_Hz  = silk_min( fs_Hz, psEncC->maxInternal_fs_Hz );
54        fs_Hz  = silk_max( fs_Hz, psEncC->minInternal_fs_Hz );
55        fs_kHz = silk_DIV32_16( fs_Hz, 1000 );
56    } else {
57        /* State machine for the internal sampling rate switching */
58        if( psEncC->sLP.transition_frame_no >= TRANSITION_FRAMES ) {
59            /* Stop transition phase */
60            psEncC->sLP.mode = 0;
61        }
62        if( psEncC->allow_bandwidth_switch || encControl->opusCanSwitch ) {
63            /* Check if we should switch down */
64            if( silk_SMULBB( psEncC->fs_kHz, 1000 ) > psEncC->desiredInternal_fs_Hz )
65            {
66                /* Switch down */
67                if( psEncC->sLP.mode == 0 ) {
68                    /* New transition */
69                    psEncC->sLP.transition_frame_no = TRANSITION_FRAMES;
70
71                    /* Reset transition filter state */
72                    silk_memset( psEncC->sLP.In_LP_State, 0, sizeof( psEncC->sLP.In_LP_State ) );
73                }
74                if( encControl->opusCanSwitch ) {
75                    /* Stop transition phase */
76                    psEncC->sLP.mode = 0;
77
78                    /* Switch to a lower sample frequency */
79                    fs_kHz = psEncC->fs_kHz == 16 ? 12 : 8;
80                } else {
81                   if( psEncC->sLP.transition_frame_no <= 0 ) {
82                       encControl->switchReady = 1;
83                       /* Make room for redundancy */
84                       encControl->maxBits -= encControl->maxBits * 5 / ( encControl->payloadSize_ms + 5 );
85                   } else {
86                       /* Direction: down (at double speed) */
87                       psEncC->sLP.mode = -2;
88                   }
89                }
90            }
91            else
92            /* Check if we should switch up */
93            if( silk_SMULBB( psEncC->fs_kHz, 1000 ) < psEncC->desiredInternal_fs_Hz )
94            {
95                /* Switch up */
96                if( encControl->opusCanSwitch ) {
97                    /* Switch to a higher sample frequency */
98                    fs_kHz = psEncC->fs_kHz == 8 ? 12 : 16;
99
100                    /* New transition */
101                    psEncC->sLP.transition_frame_no = 0;
102
103                    /* Reset transition filter state */
104                    silk_memset( psEncC->sLP.In_LP_State, 0, sizeof( psEncC->sLP.In_LP_State ) );
105
106                    /* Direction: up */
107                    psEncC->sLP.mode = 1;
108                } else {
109                   if( psEncC->sLP.mode == 0 ) {
110                       encControl->switchReady = 1;
111                       /* Make room for redundancy */
112                       encControl->maxBits -= encControl->maxBits * 5 / ( encControl->payloadSize_ms + 5 );
113                   } else {
114                       /* Direction: up */
115                       psEncC->sLP.mode = 1;
116                   }
117                }
118            } else {
119               if (psEncC->sLP.mode<0)
120                  psEncC->sLP.mode = 1;
121            }
122        }
123    }
124
125    return fs_kHz;
126}
127