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1 /*
2  * Copyright (C) 2018 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 package com.android.car.audio;
17 
18 import android.media.AudioAttributes;
19 import android.media.AudioAttributes.AttributeUsage;
20 import android.media.AudioFormat;
21 import android.media.AudioManager;
22 import android.media.audiopolicy.AudioMix;
23 import android.media.audiopolicy.AudioMixingRule;
24 import android.media.audiopolicy.AudioPolicy;
25 import android.util.Log;
26 import android.util.Slog;
27 import android.util.SparseArray;
28 
29 import com.android.car.CarLog;
30 
31 import java.util.Arrays;
32 
33 /**
34  * Builds dynamic audio routing in a car from audio zone configuration.
35  */
36 final class CarAudioDynamicRouting {
37     // For legacy stream type based volume control.
38     // Values in STREAM_TYPES and STREAM_TYPE_USAGES should be aligned.
39     static final int[] STREAM_TYPES = new int[] {
40             AudioManager.STREAM_MUSIC,
41             AudioManager.STREAM_ALARM,
42             AudioManager.STREAM_RING
43     };
44     static final int[] STREAM_TYPE_USAGES = new int[] {
45             AudioAttributes.USAGE_MEDIA,
46             AudioAttributes.USAGE_ALARM,
47             AudioAttributes.USAGE_NOTIFICATION_RINGTONE
48     };
49 
setupAudioDynamicRouting(AudioPolicy.Builder builder, SparseArray<CarAudioZone> carAudioZones)50     static void setupAudioDynamicRouting(AudioPolicy.Builder builder,
51             SparseArray<CarAudioZone> carAudioZones) {
52         for (int i = 0; i < carAudioZones.size(); i++) {
53             CarAudioZone zone = carAudioZones.valueAt(i);
54             for (CarVolumeGroup group : zone.getVolumeGroups()) {
55                 setupAudioDynamicRoutingForGroup(group, builder);
56             }
57         }
58     }
59 
60     /**
61      * Enumerates all physical buses in a given volume group and attach the mixing rules.
62      * @param group {@link CarVolumeGroup} instance to enumerate the buses with
63      * @param builder {@link AudioPolicy.Builder} to attach the mixing rules
64      */
setupAudioDynamicRoutingForGroup(CarVolumeGroup group, AudioPolicy.Builder builder)65     private static void setupAudioDynamicRoutingForGroup(CarVolumeGroup group,
66             AudioPolicy.Builder builder) {
67         // Note that one can not register audio mix for same bus more than once.
68         for (String address : group.getAddresses()) {
69             boolean hasContext = false;
70             CarAudioDeviceInfo info = group.getCarAudioDeviceInfoForAddress(address);
71             AudioFormat mixFormat = new AudioFormat.Builder()
72                     .setSampleRate(info.getSampleRate())
73                     .setEncoding(info.getEncodingFormat())
74                     .setChannelMask(info.getChannelCount())
75                     .build();
76             AudioMixingRule.Builder mixingRuleBuilder = new AudioMixingRule.Builder();
77             for (int carAudioContext : group.getContextsForAddress(address)) {
78                 hasContext = true;
79                 int[] usages = CarAudioContext.getUsagesForContext(carAudioContext);
80                 for (int usage : usages) {
81                     AudioAttributes attributes = buildAttributesWithUsage(usage);
82                     mixingRuleBuilder.addRule(attributes,
83                             AudioMixingRule.RULE_MATCH_ATTRIBUTE_USAGE);
84                 }
85                 if (Log.isLoggable(CarLog.TAG_AUDIO, Log.DEBUG)) {
86                     Slog.d(CarLog.TAG_AUDIO, String.format(
87                             "Address: %s AudioContext: %s sampleRate: %d channels: %d usages: %s",
88                             address, carAudioContext, info.getSampleRate(), info.getChannelCount(),
89                             Arrays.toString(usages)));
90                 }
91             }
92             if (hasContext) {
93                 // It's a valid case that an audio output address is defined in
94                 // audio_policy_configuration and no context is assigned to it.
95                 // In such case, do not build a policy mix with zero rules.
96                 AudioMix audioMix = new AudioMix.Builder(mixingRuleBuilder.build())
97                         .setFormat(mixFormat)
98                         .setDevice(info.getAudioDeviceInfo())
99                         .setRouteFlags(AudioMix.ROUTE_FLAG_RENDER)
100                         .build();
101                 builder.addMix(audioMix);
102             }
103         }
104     }
105 
buildAttributesWithUsage(@ttributeUsage int usage)106     private static AudioAttributes buildAttributesWithUsage(@AttributeUsage int usage) {
107         AudioAttributes.Builder attributesBuilder = new AudioAttributes.Builder();
108         if (AudioAttributes.isSystemUsage(usage)) {
109             attributesBuilder.setSystemUsage(usage);
110         } else {
111             attributesBuilder.setUsage(usage);
112         }
113         return attributesBuilder.build();
114     }
115 }
116