1 /*=============================================================================
3 // This software has been released under the terms of the GNU General Public
4 // license. See http://www.gnu.org/copyleft/gpl.html for details.
6 // Copyright 2002 Anders Johansson ajh@atri.curtin.edu.au
8 //=============================================================================
22 // Data for specific instances of this filter
23 typedef struct af_gate_s
25 int enable
[AF_NCH
]; // Enable/disable / channel
26 float time
[AF_NCH
]; // Forgetting factor for power estimate
27 float pow
[AF_NCH
]; // Estimated power level [dB]
28 float tresh
[AF_NCH
]; // Threshold [dB]
29 int attack
[AF_NCH
]; // Attack time [ms]
30 int release
[AF_NCH
]; // Release time [ms]
31 float range
[AF_NCH
]; // Range level [dB]
34 // Initialization and runtime control
35 static int control(struct af_instance_s
* af
, int cmd
, void* arg
)
37 af_gate_t
* s
= (af_gate_t
*)af
->setup
;
39 case AF_CONTROL_REINIT
:
41 if(!arg
) return AF_ERROR
;
43 af
->data
->rate
= ((af_data_t
*)arg
)->rate
;
44 af
->data
->nch
= ((af_data_t
*)arg
)->nch
;
45 af
->data
->format
= AF_FORMAT_FLOAT_NE
;
48 // Time constant set to 0.1s
49 // s->alpha = (1.0/0.2)/(2.0*M_PI*(float)((af_data_t*)arg)->rate);
50 return af_test_output(af
,(af_data_t
*)arg
);
51 case AF_CONTROL_COMMAND_LINE
:{
53 /* float vol[AF_NCH]; */
55 /* float clipp[AF_NCH]; */
57 /* sscanf((char*)arg,"%f:%f", &v, &s); */
58 /* for(i=0;i<AF_NCH;i++){ */
62 /* if(AF_OK != control(af,AF_CONTROL_VOLUME_SOFTCLIP | AF_CONTROL_SET, clipp)) */
63 /* return AF_ERROR; */
64 /* return control(af,AF_CONTROL_VOLUME_LEVEL | AF_CONTROL_SET, vol); */
67 case AF_CONTROL_GATE_ON_OFF
| AF_CONTROL_SET
:
68 memcpy(s
->enable
,(int*)arg
,AF_NCH
*sizeof(int));
70 case AF_CONTROL_GATE_ON_OFF
| AF_CONTROL_GET
:
71 memcpy((int*)arg
,s
->enable
,AF_NCH
*sizeof(int));
73 case AF_CONTROL_GATE_THRESH
| AF_CONTROL_SET
:
74 return af_from_dB(AF_NCH
,(float*)arg
,s
->tresh
,20.0,-60.0,-1.0);
75 case AF_CONTROL_GATE_THRESH
| AF_CONTROL_GET
:
76 return af_to_dB(AF_NCH
,s
->tresh
,(float*)arg
,10.0);
77 case AF_CONTROL_GATE_ATTACK
| AF_CONTROL_SET
:
78 return af_from_ms(AF_NCH
,(float*)arg
,s
->attack
,af
->data
->rate
,500.0,0.1);
79 case AF_CONTROL_GATE_ATTACK
| AF_CONTROL_GET
:
80 return af_to_ms(AF_NCH
,s
->attack
,(float*)arg
,af
->data
->rate
);
81 case AF_CONTROL_GATE_RELEASE
| AF_CONTROL_SET
:
82 return af_from_ms(AF_NCH
,(float*)arg
,s
->release
,af
->data
->rate
,3000.0,10.0);
83 case AF_CONTROL_GATE_RELEASE
| AF_CONTROL_GET
:
84 return af_to_ms(AF_NCH
,s
->release
,(float*)arg
,af
->data
->rate
);
85 case AF_CONTROL_GATE_RANGE
| AF_CONTROL_SET
:
86 return af_from_dB(AF_NCH
,(float*)arg
,s
->range
,20.0,100.0,0.0);
87 case AF_CONTROL_GATE_RANGE
| AF_CONTROL_GET
:
88 return af_to_dB(AF_NCH
,s
->range
,(float*)arg
,10.0);
94 static void uninit(struct af_instance_s
* af
)
102 // Filter data through filter
103 static af_data_t
* play(struct af_instance_s
* af
, af_data_t
* data
)
105 af_data_t
* c
= data
; // Current working data
106 af_gate_t
* s
= (af_gate_t
*)af
->setup
; // Setup for this instance
107 float* a
= (float*)c
->audio
; // Audio data
108 int len
= c
->len
/4; // Number of samples
109 int ch
= 0; // Channel counter
110 register int nch
= c
->nch
; // Number of channels
115 for(ch
= 0; ch
< nch
; ch
++){
117 float t
= 1.0 - s
->time
[ch
];
118 for(i
=ch
;i
<len
;i
+=nch
){
119 register float x
= a
[i
];
120 register float pow
= x
*x
;
121 s
->pow
[ch
] = t
*s
->pow
[ch
] +
122 pow
*s
->time
[ch
]; // LP filter
123 if(pow
< s
->pow
[ch
]){
136 // Allocate memory and set function pointers
137 static int open(af_instance_t
* af
){
143 af
->data
=calloc(1,sizeof(af_data_t
));
144 af
->setup
=calloc(1,sizeof(af_gate_t
));
145 if(af
->data
== NULL
|| af
->setup
== NULL
)
150 // Description of this filter
151 af_info_t af_info_gate
= {
152 "Noise gate audio filter",
156 AF_FLAGS_NOT_REENTRANT
,