1 /* Copyright 2016 The Chromium OS Authors. All rights reserved.
2 * Use of this source code is governed by a BSD-style license that can be
3 * found in the LICENSE file.
4 */
5
6 #include <syslog.h>
7
8 #include "cras_ramp.h"
9
10 /*
11 * Struct to hold ramping information.
12 * Members:
13 * state: Current state. One of CRAS_RAMP_STATE.
14 * ramped_frames: Number of frames that have passed after starting ramping.
15 * duration_frames: The targeted number of frames for whole ramping duration.
16 * increment: The scaler increment that should be added to scaler for
17 * every frame.
18 * start_scaler: The initial scaler.
19 * cb: Callback function to call after ramping is done.
20 * cb_data: Data passed to cb.
21 */
22 struct cras_ramp {
23 int active;
24 int ramped_frames;
25 int duration_frames;
26 float increment;
27 float start_scaler;
28 float target;
29 void (*cb)(void *data);
30 void *cb_data;
31 };
32
cras_ramp_destroy(struct cras_ramp * ramp)33 void cras_ramp_destroy(struct cras_ramp *ramp)
34 {
35 free(ramp);
36 }
37
cras_ramp_create()38 struct cras_ramp *cras_ramp_create()
39 {
40 struct cras_ramp *ramp;
41 ramp = (struct cras_ramp *)malloc(sizeof(*ramp));
42 if (ramp == NULL) {
43 return NULL;
44 }
45 cras_ramp_reset(ramp);
46 return ramp;
47 }
48
cras_ramp_reset(struct cras_ramp * ramp)49 int cras_ramp_reset(struct cras_ramp *ramp)
50 {
51 ramp->active = 0;
52 ramp->ramped_frames = 0;
53 ramp->duration_frames = 0;
54 ramp->increment = 0;
55 ramp->start_scaler = 1.0;
56 ramp->target = 1.0;
57 return 0;
58 }
59
cras_ramp_start(struct cras_ramp * ramp,int mute_ramp,float from,float to,int duration_frames,cras_ramp_cb cb,void * cb_data)60 int cras_ramp_start(struct cras_ramp *ramp, int mute_ramp, float from, float to,
61 int duration_frames, cras_ramp_cb cb, void *cb_data)
62 {
63 struct cras_ramp_action action;
64
65 if (from == to)
66 return 0;
67
68 /* Get current scaler position so it can serve as new start scaler. */
69 action = cras_ramp_get_current_action(ramp);
70 if (action.type == CRAS_RAMP_ACTION_INVALID)
71 return -EINVAL;
72
73 /* Set initial scaler to current scaler so ramping up/down can be
74 * smoothly switched. */
75 ramp->active = 1;
76 if (action.type == CRAS_RAMP_ACTION_NONE) {
77 ramp->start_scaler = from;
78 } else {
79 /* If this a mute ramp, we want to match the previous multiplier
80 * so that there is not a jump in the audio. Otherwise, we are
81 * applying a volume ramp so we need to multiply |from| by the
82 * previous scaler so that we can stack volume ramps. */
83 ramp->start_scaler = action.scaler;
84 if (!mute_ramp)
85 ramp->start_scaler *= from;
86 }
87 ramp->increment = (to - ramp->start_scaler) / duration_frames;
88 ramp->target = to;
89 ramp->ramped_frames = 0;
90 ramp->duration_frames = duration_frames;
91 ramp->cb = cb;
92 ramp->cb_data = cb_data;
93 return 0;
94 }
95
96 struct cras_ramp_action
cras_ramp_get_current_action(const struct cras_ramp * ramp)97 cras_ramp_get_current_action(const struct cras_ramp *ramp)
98 {
99 struct cras_ramp_action action;
100
101 if (ramp->ramped_frames < 0) {
102 action.type = CRAS_RAMP_ACTION_INVALID;
103 action.scaler = 1.0;
104 action.increment = 0.0;
105 action.target = 1.0;
106 } else if (ramp->active) {
107 action.type = CRAS_RAMP_ACTION_PARTIAL;
108 action.scaler = ramp->start_scaler +
109 ramp->ramped_frames * ramp->increment;
110 action.increment = ramp->increment;
111 action.target = ramp->target;
112 } else {
113 action.type = CRAS_RAMP_ACTION_NONE;
114 action.scaler = 1.0;
115 action.increment = 0.0;
116 action.target = 1.0;
117 }
118 return action;
119 }
120
cras_ramp_update_ramped_frames(struct cras_ramp * ramp,int num_frames)121 int cras_ramp_update_ramped_frames(struct cras_ramp *ramp, int num_frames)
122 {
123 if (!ramp->active)
124 return -EINVAL;
125 ramp->ramped_frames += num_frames;
126 if (ramp->ramped_frames >= ramp->duration_frames) {
127 ramp->active = 0;
128 if (ramp->cb)
129 ramp->cb(ramp->cb_data);
130 }
131 return 0;
132 }
133