xref: /frameworks/base/media/java/android/media/AudioAttributes.java

/*
 * Copyright (C) 2014 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package android.media;

import android.annotation.IntDef;
import android.annotation.SystemApi;
import android.os.Parcel;
import android.os.Parcelable;
import android.text.TextUtils;
import android.util.Log;

import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.util.Collections;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Objects;
import java.util.Set;

/**
 * A class to encapsulate a collection of attributes describing information about an audio
 * stream.
 * <p><code>AudioAttributes</code> supersede the notion of stream types (see for instance
 * {@link AudioManager#STREAM_MUSIC} or {@link AudioManager#STREAM_ALARM}) for defining the
 * behavior of audio playback. Attributes allow an application to specify more information than is
 * conveyed in a stream type by allowing the application to define:
 * <ul>
 * <li>usage: "why" you are playing a sound, what is this sound used for. This is achieved with
 *     the "usage" information. Examples of usage are {@link #USAGE_MEDIA} and {@link #USAGE_ALARM}.
 *     These two examples are the closest to stream types, but more detailed use cases are
 *     available. Usage information is more expressive than a stream type, and allows certain
 *     platforms or routing policies to use this information for more refined volume or routing
 *     decisions. Usage is the most important information to supply in <code>AudioAttributes</code>
 *     and it is recommended to build any instance with this information supplied, see
 *     {@link AudioAttributes.Builder} for exceptions.</li>
 * <li>content type: "what" you are playing. The content type expresses the general category of
 *     the content. This information is optional. But in case it is known (for instance
 *     {@link #CONTENT_TYPE_MOVIE} for a movie streaming service or {@link #CONTENT_TYPE_MUSIC} for
 *     a music playback application) this information might be used by the audio framework to
 *     selectively configure some audio post-processing blocks.</li>
 * <li>flags: "how" is playback to be affected, see the flag definitions for the specific playback
 *     behaviors they control. </li>
 * </ul>
 * <p><code>AudioAttributes</code> are used for example in one of the {@link AudioTrack}
 * constructors (see {@link AudioTrack#AudioTrack(AudioAttributes, AudioFormat, int, int, int)}),
 * to configure a {@link MediaPlayer}
 * (see {@link MediaPlayer#setAudioAttributes(AudioAttributes)} or a
 * {@link android.app.Notification} (see {@link android.app.Notification#audioAttributes}). An
 * <code>AudioAttributes</code> instance is built through its builder,
 * {@link AudioAttributes.Builder}.
 */
public final class AudioAttributes implements Parcelable {
    private final static String TAG = "AudioAttributes";

    /**
     * Content type value to use when the content type is unknown, or other than the ones defined.
     */
    public final static int CONTENT_TYPE_UNKNOWN = 0;
    /**
     * Content type value to use when the content type is speech.
     */
    public final static int CONTENT_TYPE_SPEECH = 1;
    /**
     * Content type value to use when the content type is music.
     */
    public final static int CONTENT_TYPE_MUSIC = 2;
    /**
     * Content type value to use when the content type is a soundtrack, typically accompanying
     * a movie or TV program.
     */
    public final static int CONTENT_TYPE_MOVIE = 3;
    /**
     * Content type value to use when the content type is a sound used to accompany a user
     * action, such as a beep or sound effect expressing a key click, or event, such as the
     * type of a sound for a bonus being received in a game. These sounds are mostly synthesized
     * or short Foley sounds.
     */
    public final static int CONTENT_TYPE_SONIFICATION = 4;

    /**
     * Usage value to use when the usage is unknown.
     */
    public final static int USAGE_UNKNOWN = 0;
    /**
     * Usage value to use when the usage is media, such as music, or movie
     * soundtracks.
     */
    public final static int USAGE_MEDIA = 1;
    /**
     * Usage value to use when the usage is voice communications, such as telephony
     * or VoIP.
     */
    public final static int USAGE_VOICE_COMMUNICATION = 2;
    /**
     * Usage value to use when the usage is in-call signalling, such as with
     * a "busy" beep, or DTMF tones.
     */
    public final static int USAGE_VOICE_COMMUNICATION_SIGNALLING = 3;
    /**
     * Usage value to use when the usage is an alarm (e.g. wake-up alarm).
     */
    public final static int USAGE_ALARM = 4;
    /**
     * Usage value to use when the usage is notification. See other
     * notification usages for more specialized uses.
     */
    public final static int USAGE_NOTIFICATION = 5;
    /**
     * Usage value to use when the usage is telephony ringtone.
     */
    public final static int USAGE_NOTIFICATION_RINGTONE = 6;
    /**
     * Usage value to use when the usage is a request to enter/end a
     * communication, such as a VoIP communication or video-conference.
     */
    public final static int USAGE_NOTIFICATION_COMMUNICATION_REQUEST = 7;
    /**
     * Usage value to use when the usage is notification for an "instant"
     * communication such as a chat, or SMS.
     */
    public final static int USAGE_NOTIFICATION_COMMUNICATION_INSTANT = 8;
    /**
     * Usage value to use when the usage is notification for a
     * non-immediate type of communication such as e-mail.
     */
    public final static int USAGE_NOTIFICATION_COMMUNICATION_DELAYED = 9;
    /**
     * Usage value to use when the usage is to attract the user's attention,
     * such as a reminder or low battery warning.
     */
    public final static int USAGE_NOTIFICATION_EVENT = 10;
    /**
     * Usage value to use when the usage is for accessibility, such as with
     * a screen reader.
     */
    public final static int USAGE_ASSISTANCE_ACCESSIBILITY = 11;
    /**
     * Usage value to use when the usage is driving or navigation directions.
     */
    public final static int USAGE_ASSISTANCE_NAVIGATION_GUIDANCE = 12;
    /**
     * Usage value to use when the usage is sonification, such as  with user
     * interface sounds.
     */
    public final static int USAGE_ASSISTANCE_SONIFICATION = 13;
    /**
     * Usage value to use when the usage is for game audio.
     */
    public final static int USAGE_GAME = 14;
    /**
     * @hide
     * Usage value to use when feeding audio to the platform and replacing "traditional" audio
     * source, such as audio capture devices.
     */
    public final static int USAGE_VIRTUAL_SOURCE = 15;

    /**
     * Flag defining a behavior where the audibility of the sound will be ensured by the system.
     */
    public final static int FLAG_AUDIBILITY_ENFORCED = 0x1 << 0;
    /**
     * @hide
     * Flag defining a behavior where the playback of the sound is ensured without
     * degradation only when going to a secure sink.
     */
    // FIXME not guaranteed yet
    // TODO  add in FLAG_ALL_PUBLIC when supported and in public API
    public final static int FLAG_SECURE = 0x1 << 1;
    /**
     * @hide
     * Flag to enable when the stream is associated with SCO usage.
     * Internal use only for dealing with legacy STREAM_BLUETOOTH_SCO
     */
    public final static int FLAG_SCO = 0x1 << 2;
    /**
     * @hide
     * Flag defining a behavior where the system ensures that the playback of the sound will
     * be compatible with its use as a broadcast for surrounding people and/or devices.
     * Ensures audibility with no or minimal post-processing applied.
     */
    @SystemApi
    public final static int FLAG_BEACON = 0x1 << 3;

    /**
     * Flag requesting the use of an output stream supporting hardware A/V synchronization.
     */
    public final static int FLAG_HW_AV_SYNC = 0x1 << 4;

    /**
     * @hide
     * Flag requesting capture from the source used for hardware hotword detection.
     * To be used with capture preset MediaRecorder.AudioSource.HOTWORD or
     * MediaRecorder.AudioSource.VOICE_RECOGNITION.
     */
    @SystemApi
    public final static int FLAG_HW_HOTWORD = 0x1 << 5;

    private final static int FLAG_ALL = FLAG_AUDIBILITY_ENFORCED | FLAG_SECURE | FLAG_SCO |
            FLAG_BEACON | FLAG_HW_AV_SYNC | FLAG_HW_HOTWORD;
    private final static int FLAG_ALL_PUBLIC = FLAG_AUDIBILITY_ENFORCED | FLAG_HW_AV_SYNC;

    private int mUsage = USAGE_UNKNOWN;
    private int mContentType = CONTENT_TYPE_UNKNOWN;
    private int mSource = MediaRecorder.AudioSource.AUDIO_SOURCE_INVALID;
    private int mFlags = 0x0;
    private HashSet<String> mTags;
    private String mFormattedTags;

    private AudioAttributes() {
    }

    /**
     * Return the content type.
     * @return one of the values that can be set in {@link Builder#setContentType(int)}
     */
    public int getContentType() {
        return mContentType;
    }

    /**
     * Return the usage.
     * @return one of the values that can be set in {@link Builder#setUsage(int)}
     */
    public int getUsage() {
        return mUsage;
    }

    /**
     * @hide
     * Return the capture preset.
     * @return one of the values that can be set in {@link Builder#setCapturePreset(int)} or a
     *    negative value if none has been set.
     */
    @SystemApi
    public int getCapturePreset() {
        return mSource;
    }

    /**
     * Return the flags.
     * @return a combined mask of all flags
     */
    public int getFlags() {
        // only return the flags that are public
        return (mFlags & (FLAG_ALL_PUBLIC));
    }

    /**
     * @hide
     * Return all the flags, even the non-public ones.
     * Internal use only
     * @return a combined mask of all flags
     */
    public int getAllFlags() {
        return (mFlags & FLAG_ALL);
    }

    /**
     * @hide
     * Return the set of tags.
     * @return a read-only set of all tags stored as strings.
     */
    public Set<String> getTags() {
        return Collections.unmodifiableSet(mTags);
    }

    /**
     * Builder class for {@link AudioAttributes} objects.
     * <p> Here is an example where <code>Builder</code> is used to define the
     * {@link AudioAttributes} to be used by a new <code>AudioTrack</code> instance:
     *
     * <pre class="prettyprint">
     * AudioTrack myTrack = new AudioTrack(
     *         new AudioAttributes.Builder()
     *             .setUsage(AudioAttributes.USAGE_MEDIA)
     *             .setContentType(AudioAttributes.CONTENT_TYPE_MUSIC)
     *             .build(),
     *         myFormat, myBuffSize, AudioTrack.MODE_STREAM, mySession);
     * </pre>
     *
     * <p>By default all types of information (usage, content type, flags) conveyed by an
     * <code>AudioAttributes</code> instance are set to "unknown". Unknown information will be
     * interpreted as a default value that is dependent on the context of use, for instance a
     * {@link MediaPlayer} will use a default usage of {@link AudioAttributes#USAGE_MEDIA}.
     */
    public static class Builder {
        private int mUsage = USAGE_UNKNOWN;
        private int mContentType = CONTENT_TYPE_UNKNOWN;
        private int mSource = MediaRecorder.AudioSource.AUDIO_SOURCE_INVALID;
        private int mFlags = 0x0;
        private HashSet<String> mTags = new HashSet<String>();

        /**
         * Constructs a new Builder with the defaults.
         * By default, usage and content type are respectively {@link AudioAttributes#USAGE_UNKNOWN}
         * and {@link AudioAttributes#CONTENT_TYPE_UNKNOWN}, and flags are 0. It is recommended to
         * configure the usage (with {@link #setUsage(int)}) or deriving attributes from a legacy
         * stream type (with {@link #setLegacyStreamType(int)}) before calling {@link #build()}
         * to override any default playback behavior in terms of routing and volume management.
         */
        public Builder() {
        }

        /**
         * Constructs a new Builder from a given AudioAttributes
         * @param aa the AudioAttributes object whose data will be reused in the new Builder.
         */
        @SuppressWarnings("unchecked") // for cloning of mTags
        public Builder(AudioAttributes aa) {
            mUsage = aa.mUsage;
            mContentType = aa.mContentType;
            mFlags = aa.mFlags;
            mTags = (HashSet<String>) aa.mTags.clone();
        }

        /**
         * Combines all of the attributes that have been set and return a new
         * {@link AudioAttributes} object.
         * @return a new {@link AudioAttributes} object
         */
        @SuppressWarnings("unchecked") // for cloning of mTags
        public AudioAttributes build() {
            AudioAttributes aa = new AudioAttributes();
            aa.mContentType = mContentType;
            aa.mUsage = mUsage;
            aa.mSource = mSource;
            aa.mFlags = mFlags;
            aa.mTags = (HashSet<String>) mTags.clone();
            aa.mFormattedTags = TextUtils.join(";", mTags);
            return aa;
        }

        /**
         * Sets the attribute describing what is the intended use of the the audio signal,
         * such as alarm or ringtone.
         * @param usage one of {@link AudioAttributes#USAGE_UNKNOWN},
         *     {@link AudioAttributes#USAGE_MEDIA},
         *     {@link AudioAttributes#USAGE_VOICE_COMMUNICATION},
         *     {@link AudioAttributes#USAGE_VOICE_COMMUNICATION_SIGNALLING},
         *     {@link AudioAttributes#USAGE_ALARM}, {@link AudioAttributes#USAGE_NOTIFICATION},
         *     {@link AudioAttributes#USAGE_NOTIFICATION_RINGTONE},
         *     {@link AudioAttributes#USAGE_NOTIFICATION_COMMUNICATION_REQUEST},
         *     {@link AudioAttributes#USAGE_NOTIFICATION_COMMUNICATION_INSTANT},
         *     {@link AudioAttributes#USAGE_NOTIFICATION_COMMUNICATION_DELAYED},
         *     {@link AudioAttributes#USAGE_NOTIFICATION_EVENT},
         *     {@link AudioAttributes#USAGE_ASSISTANCE_ACCESSIBILITY},
         *     {@link AudioAttributes#USAGE_ASSISTANCE_NAVIGATION_GUIDANCE},
         *     {@link AudioAttributes#USAGE_ASSISTANCE_SONIFICATION},
         *     {@link AudioAttributes#USAGE_GAME}.
         * @return the same Builder instance.
         */
        public Builder setUsage(@AttributeUsage int usage) {
            switch (usage) {
                case USAGE_UNKNOWN:
                case USAGE_MEDIA:
                case USAGE_VOICE_COMMUNICATION:
                case USAGE_VOICE_COMMUNICATION_SIGNALLING:
                case USAGE_ALARM:
                case USAGE_NOTIFICATION:
                case USAGE_NOTIFICATION_RINGTONE:
                case USAGE_NOTIFICATION_COMMUNICATION_REQUEST:
                case USAGE_NOTIFICATION_COMMUNICATION_INSTANT:
                case USAGE_NOTIFICATION_COMMUNICATION_DELAYED:
                case USAGE_NOTIFICATION_EVENT:
                case USAGE_ASSISTANCE_ACCESSIBILITY:
                case USAGE_ASSISTANCE_NAVIGATION_GUIDANCE:
                case USAGE_ASSISTANCE_SONIFICATION:
                case USAGE_GAME:
                case USAGE_VIRTUAL_SOURCE:
                     mUsage = usage;
                     break;
                default:
                     mUsage = USAGE_UNKNOWN;
            }
            return this;
        }

        /**
         * Sets the attribute describing the content type of the audio signal, such as speech,
         * or music.
         * @param contentType the content type values, one of
         *     {@link AudioAttributes#CONTENT_TYPE_MOVIE},
         *     {@link AudioAttributes#CONTENT_TYPE_MUSIC},
         *     {@link AudioAttributes#CONTENT_TYPE_SONIFICATION},
         *     {@link AudioAttributes#CONTENT_TYPE_SPEECH},
         *     {@link AudioAttributes#CONTENT_TYPE_UNKNOWN}.
         * @return the same Builder instance.
         */
        public Builder setContentType(@AttributeContentType int contentType) {
            switch (contentType) {
                case CONTENT_TYPE_UNKNOWN:
                case CONTENT_TYPE_MOVIE:
                case CONTENT_TYPE_MUSIC:
                case CONTENT_TYPE_SONIFICATION:
                case CONTENT_TYPE_SPEECH:
                     mContentType = contentType;
                     break;
                default:
                     mUsage = CONTENT_TYPE_UNKNOWN;
            }
            return this;
        }

        /**
         * Sets the combination of flags.
         * @param flags the {@link AudioAttributes#FLAG_AUDIBILITY_ENFORCED} flag.
         * @return the same Builder instance.
         */
        public Builder setFlags(int flags) {
            flags &= AudioAttributes.FLAG_ALL;
            mFlags |= flags;
            return this;
        }

        /**
         * @hide
         * Add a custom tag stored as a string
         * @param tag
         * @return the same Builder instance.
         */
        public Builder addTag(String tag) {
            mTags.add(tag);
            return this;
        }

        /**
         * Sets attributes as inferred from the legacy stream types.
         * Use this method when building an {@link AudioAttributes} instance to initialize some of
         * the attributes by information derived from a legacy stream type.
         * @param streamType one of {@link AudioManager#STREAM_VOICE_CALL},
         *   {@link AudioManager#STREAM_SYSTEM}, {@link AudioManager#STREAM_RING},
         *   {@link AudioManager#STREAM_MUSIC}, {@link AudioManager#STREAM_ALARM},
         *    or {@link AudioManager#STREAM_NOTIFICATION}.
         * @return the same Builder instance.
         */
        public Builder setLegacyStreamType(int streamType) {
            return setInternalLegacyStreamType(streamType);
        }

        /**
         * @hide
         * For internal framework use only, enables building from hidden stream types.
         * @param streamType
         * @return the same Builder instance.
         */
        public Builder setInternalLegacyStreamType(int streamType) {
            switch(streamType) {
                case AudioSystem.STREAM_VOICE_CALL:
                    mContentType = CONTENT_TYPE_SPEECH;
                    break;
                case AudioSystem.STREAM_SYSTEM_ENFORCED:
                    mFlags |= FLAG_AUDIBILITY_ENFORCED;
                    // intended fall through, attributes in common with STREAM_SYSTEM
                case AudioSystem.STREAM_SYSTEM:
                    mContentType = CONTENT_TYPE_SONIFICATION;
                    break;
                case AudioSystem.STREAM_RING:
                    mContentType = CONTENT_TYPE_SONIFICATION;
                    break;
                case AudioSystem.STREAM_MUSIC:
                    mContentType = CONTENT_TYPE_MUSIC;
                    break;
                case AudioSystem.STREAM_ALARM:
                    mContentType = CONTENT_TYPE_SONIFICATION;
                    break;
                case AudioSystem.STREAM_NOTIFICATION:
                    mContentType = CONTENT_TYPE_SONIFICATION;
                    break;
                case AudioSystem.STREAM_BLUETOOTH_SCO:
                    mContentType = CONTENT_TYPE_SPEECH;
                    mFlags |= FLAG_SCO;
                    break;
                case AudioSystem.STREAM_DTMF:
                    mContentType = CONTENT_TYPE_SONIFICATION;
                    break;
                case AudioSystem.STREAM_TTS:
                    mContentType = CONTENT_TYPE_SPEECH;
                    break;
                default:
                    Log.e(TAG, "Invalid stream type " + streamType + " for AudioAttributes");
            }
            mUsage = usageForLegacyStreamType(streamType);
            return this;
        }

        /**
         * @hide
         * Sets the capture preset.
         * Use this audio attributes configuration method when building an {@link AudioRecord}
         * instance with {@link AudioRecord#AudioRecord(AudioAttributes, AudioFormat, int)}.
         * @param preset one of {@link MediaRecorder.AudioSource#DEFAULT},
         *     {@link MediaRecorder.AudioSource#MIC}, {@link MediaRecorder.AudioSource#CAMCORDER},
         *     {@link MediaRecorder.AudioSource#VOICE_RECOGNITION} or
         *     {@link MediaRecorder.AudioSource#VOICE_COMMUNICATION}.
         * @return the same Builder instance.
         */
        @SystemApi
        public Builder setCapturePreset(int preset) {
            switch (preset) {
                case MediaRecorder.AudioSource.DEFAULT:
                case MediaRecorder.AudioSource.MIC:
                case MediaRecorder.AudioSource.CAMCORDER:
                case MediaRecorder.AudioSource.VOICE_RECOGNITION:
                case MediaRecorder.AudioSource.VOICE_COMMUNICATION:
                    mSource = preset;
                    break;
                default:
                    Log.e(TAG, "Invalid capture preset " + preset + " for AudioAttributes");
            }
            return this;
        }

        /**
         * @hide
         * Same as {@link #setCapturePreset(int)} but authorizes the use of HOTWORD,
         * REMOTE_SUBMIX and FM_TUNER.
         * @param preset
         * @return the same Builder instance.
         */
        public Builder setInternalCapturePreset(int preset) {
            if ((preset == MediaRecorder.AudioSource.HOTWORD)
                    || (preset == MediaRecorder.AudioSource.REMOTE_SUBMIX)
                    || (preset == MediaRecorder.AudioSource.FM_TUNER)) {
                mSource = preset;
            } else {
                setCapturePreset(preset);
            }
            return this;
        }
    };

    @Override
    public int describeContents() {
        return 0;
    }

    /**
     * @hide
     * Used to indicate that when parcelling, the tags should be parcelled through the flattened
     * formatted string, not through the array of strings.
     * Keep in sync with frameworks/av/media/libmediaplayerservice/MediaPlayerService.cpp
     * see definition of kAudioAttributesMarshallTagFlattenTags
     */
    public final static int FLATTEN_TAGS = 0x1;
    /**
     * When adding tags for writeToParcel(Parcel, int), add them in the list of flags (| NEW_FLAG)
     */
    private final static int ALL_PARCEL_FLAGS = FLATTEN_TAGS;
    @Override
    public void writeToParcel(Parcel dest, int flags) {
        dest.writeInt(mUsage);
        dest.writeInt(mContentType);
        dest.writeInt(mSource);
        dest.writeInt(mFlags);
        dest.writeInt(flags & ALL_PARCEL_FLAGS);
        if ((flags & FLATTEN_TAGS) == 0) {
            String[] tagsArray = new String[mTags.size()];
            mTags.toArray(tagsArray);
            dest.writeStringArray(tagsArray);
        } else if ((flags & FLATTEN_TAGS) == FLATTEN_TAGS) {
            dest.writeString(mFormattedTags);
        }
    }

    private AudioAttributes(Parcel in) {
        mUsage = in.readInt();
        mContentType = in.readInt();
        mSource = in.readInt();
        mFlags = in.readInt();
        boolean hasFlattenedTags = ((in.readInt() & FLATTEN_TAGS) == FLATTEN_TAGS);
        mTags = new HashSet<String>();
        if (hasFlattenedTags) {
            mFormattedTags = new String(in.readString());
            mTags.add(mFormattedTags);
        } else {
            String[] tagsArray = in.readStringArray();
            for (int i = tagsArray.length - 1 ; i >= 0 ; i--) {
                mTags.add(tagsArray[i]);
            }
            mFormattedTags = TextUtils.join(";", mTags);
        }
    }

    public static final Parcelable.Creator<AudioAttributes> CREATOR
            = new Parcelable.Creator<AudioAttributes>() {
        /**
         * Rebuilds an AudioAttributes previously stored with writeToParcel().
         * @param p Parcel object to read the AudioAttributes from
         * @return a new AudioAttributes created from the data in the parcel
         */
        public AudioAttributes createFromParcel(Parcel p) {
            return new AudioAttributes(p);
        }
        public AudioAttributes[] newArray(int size) {
            return new AudioAttributes[size];
        }
    };

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;

        AudioAttributes that = (AudioAttributes) o;

        return ((mContentType == that.mContentType)
                && (mFlags == that.mFlags)
                && (mSource == that.mSource)
                && (mUsage == that.mUsage)
                //mFormattedTags is never null due to assignment in Builder or unmarshalling
                && (mFormattedTags.equals(that.mFormattedTags)));
    }

    @Override
    public int hashCode() {
        return Objects.hash(mContentType, mFlags, mSource, mUsage, mFormattedTags);
    }

    @Override
    public String toString () {
        return new String("AudioAttributes:"
                + " usage=" + mUsage
                + " content=" + mContentType
                + " flags=0x" + Integer.toHexString(mFlags).toUpperCase()
                + " tags=" + mFormattedTags);
    }

    /** @hide */
    public String usageToString() {
        return usageToString(mUsage);
    }

    /** @hide */
    public static String usageToString(int usage) {
        switch(usage) {
            case USAGE_UNKNOWN:
                return new String("USAGE_UNKNOWN");
            case USAGE_MEDIA:
                return new String("USAGE_MEDIA");
            case USAGE_VOICE_COMMUNICATION:
                return new String("USAGE_VOICE_COMMUNICATION");
            case USAGE_VOICE_COMMUNICATION_SIGNALLING:
                return new String("USAGE_VOICE_COMMUNICATION");
            case USAGE_ALARM:
                return new String("USAGE_ALARM");
            case USAGE_NOTIFICATION:
                return new String("USAGE_NOTIFICATION");
            case USAGE_NOTIFICATION_RINGTONE:
                return new String("USAGE_NOTIFICATION");
            case USAGE_NOTIFICATION_COMMUNICATION_REQUEST:
                return new String("USAGE_NOTIFICATION");
            case USAGE_NOTIFICATION_COMMUNICATION_INSTANT:
                return new String("USAGE_NOTIFICATION_COMMUNICATION_INSTANT");
            case USAGE_NOTIFICATION_COMMUNICATION_DELAYED:
                return new String("USAGE_NOTIFICATION_COMMUNICATION_DELAYED");
            case USAGE_NOTIFICATION_EVENT:
                return new String("USAGE_NOTIFICATION_EVENT");
            case USAGE_ASSISTANCE_ACCESSIBILITY:
                return new String("USAGE_ASSISTANCE_ACCESSIBILITY");
            case USAGE_ASSISTANCE_NAVIGATION_GUIDANCE:
                return new String("USAGE_ASSISTANCE_NAVIGATION_GUIDANCE");
            case USAGE_ASSISTANCE_SONIFICATION:
                return new String("USAGE_ASSISTANCE_SONIFICATION");
            case USAGE_GAME:
                return new String("USAGE_GAME");
            default:
                return new String("unknown usage " + usage);
        }
    }

    /** @hide */
    public static int usageForLegacyStreamType(int streamType) {
        switch(streamType) {
            case AudioSystem.STREAM_VOICE_CALL:
                return USAGE_VOICE_COMMUNICATION;
            case AudioSystem.STREAM_SYSTEM_ENFORCED:
            case AudioSystem.STREAM_SYSTEM:
                return USAGE_ASSISTANCE_SONIFICATION;
            case AudioSystem.STREAM_RING:
                return USAGE_NOTIFICATION_RINGTONE;
            case AudioSystem.STREAM_MUSIC:
                return USAGE_MEDIA;
            case AudioSystem.STREAM_ALARM:
                return USAGE_ALARM;
            case AudioSystem.STREAM_NOTIFICATION:
                return USAGE_NOTIFICATION;
            case AudioSystem.STREAM_BLUETOOTH_SCO:
                return USAGE_VOICE_COMMUNICATION;
            case AudioSystem.STREAM_DTMF:
                return USAGE_VOICE_COMMUNICATION_SIGNALLING;
            case AudioSystem.STREAM_TTS:
                return USAGE_ASSISTANCE_ACCESSIBILITY;
            default:
                return USAGE_UNKNOWN;
        }
    }

    /** @hide */
    public static int toLegacyStreamType(AudioAttributes aa) {
        // flags to stream type mapping
        if ((aa.getFlags() & FLAG_AUDIBILITY_ENFORCED) == FLAG_AUDIBILITY_ENFORCED) {
            return AudioSystem.STREAM_SYSTEM_ENFORCED;
        }
        if ((aa.getFlags() & FLAG_SCO) == FLAG_SCO) {
            return AudioSystem.STREAM_BLUETOOTH_SCO;
        }

        // usage to stream type mapping
        switch (aa.getUsage()) {
            case USAGE_MEDIA:
            case USAGE_GAME:
            case USAGE_ASSISTANCE_ACCESSIBILITY:
            case USAGE_ASSISTANCE_NAVIGATION_GUIDANCE:
                return AudioSystem.STREAM_MUSIC;
            case USAGE_ASSISTANCE_SONIFICATION:
                return AudioSystem.STREAM_SYSTEM;
            case USAGE_VOICE_COMMUNICATION:
                return AudioSystem.STREAM_VOICE_CALL;
            case USAGE_VOICE_COMMUNICATION_SIGNALLING:
                return AudioSystem.STREAM_DTMF;
            case USAGE_ALARM:
                return AudioSystem.STREAM_ALARM;
            case USAGE_NOTIFICATION_RINGTONE:
                return AudioSystem.STREAM_RING;
            case USAGE_NOTIFICATION:
            case USAGE_NOTIFICATION_COMMUNICATION_REQUEST:
            case USAGE_NOTIFICATION_COMMUNICATION_INSTANT:
            case USAGE_NOTIFICATION_COMMUNICATION_DELAYED:
            case USAGE_NOTIFICATION_EVENT:
                return AudioSystem.STREAM_NOTIFICATION;
            case USAGE_UNKNOWN:
            default:
                return AudioSystem.STREAM_MUSIC;
        }
    }

    /** @hide */
    @IntDef({
        USAGE_UNKNOWN,
        USAGE_MEDIA,
        USAGE_VOICE_COMMUNICATION,
        USAGE_VOICE_COMMUNICATION_SIGNALLING,
        USAGE_ALARM,
        USAGE_NOTIFICATION,
        USAGE_NOTIFICATION_RINGTONE,
        USAGE_NOTIFICATION_COMMUNICATION_REQUEST,
        USAGE_NOTIFICATION_COMMUNICATION_INSTANT,
        USAGE_NOTIFICATION_COMMUNICATION_DELAYED,
        USAGE_NOTIFICATION_EVENT,
        USAGE_ASSISTANCE_ACCESSIBILITY,
        USAGE_ASSISTANCE_NAVIGATION_GUIDANCE,
        USAGE_ASSISTANCE_SONIFICATION,
        USAGE_GAME
    })
    @Retention(RetentionPolicy.SOURCE)
    public @interface AttributeUsage {}

    /** @hide */
    @IntDef({
        CONTENT_TYPE_UNKNOWN,
        CONTENT_TYPE_SPEECH,
        CONTENT_TYPE_MUSIC,
        CONTENT_TYPE_MOVIE,
        CONTENT_TYPE_SONIFICATION
    })
    @Retention(RetentionPolicy.SOURCE)
    public @interface AttributeContentType {}
}