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Commit f4e0836f authored by Nadav Bar's avatar Nadav Bar
Browse files

Add support for USAGE_VOICE_COMMUNICATION playback capture 

Allow audio playback capture for the USAGE_VOICE_COMMUNICATION usage
only for priveliged apps that are granted with the
CAPTURE_VOICE_COMMUNICATION_OUTPUT permission which is also introduced
in this change.

Test: atest android.media.cts.AudioPlaybackCaptureTest
Test: Manually
Bug: 124653474
Change-Id: I2ce0ad9cae01d6882e6c410d2a319617ffd99853
parent 3e26863d

api/system-current.txt

+1 −0
Original line number Diff line number Diff line
@@ -55,6 +55,7 @@ package android { 
    field public static final String CAPTURE_AUDIO_HOTWORD = "android.permission.CAPTURE_AUDIO_HOTWORD";

    field public static final String CAPTURE_MEDIA_OUTPUT = "android.permission.CAPTURE_MEDIA_OUTPUT";

    field public static final String CAPTURE_TV_INPUT = "android.permission.CAPTURE_TV_INPUT";

    field public static final String CAPTURE_VOICE_COMMUNICATION_OUTPUT = "android.permission.CAPTURE_VOICE_COMMUNICATION_OUTPUT";

    field public static final String CHANGE_APP_IDLE_STATE = "android.permission.CHANGE_APP_IDLE_STATE";

    field public static final String CHANGE_DEVICE_IDLE_TEMP_WHITELIST = "android.permission.CHANGE_DEVICE_IDLE_TEMP_WHITELIST";

    field public static final String CLEAR_APP_USER_DATA = "android.permission.CLEAR_APP_USER_DATA";

core/res/AndroidManifest.xml

+18 −0
Original line number Diff line number Diff line
@@ -3793,6 +3793,24 @@ 
    <permission android:name="android.permission.CAPTURE_MEDIA_OUTPUT"

        android:protectionLevel="signature|privileged" />



    <!-- @SystemApi Allows an application to capture the audio played by other apps

        with the {@code USAGE_VOICE_COMMUNICATION} usage.



        The application may opt out of capturing by setting an allow capture policy of

        {@link android.media.AudioAttributes#ALLOW_CAPTURE_BY_NONE}.



        There are strong restriction listed at

        {@link android.media.AudioAttributes#ALLOW_CAPTURE_BY_SYSTEM}

        on what an app can do with the captured audio.



        See {@code CAPTURE_AUDIO_OUTPUT} and {@code CAPTURE_MEDIA_OUTPUT} for capturing

        audio use cases other than voice communication playback.



        <p>Not for use by third-party applications.</p>

        @hide -->

    <permission android:name="android.permission.CAPTURE_VOICE_COMMUNICATION_OUTPUT"

        android:protectionLevel="signature|privileged" />



    <!-- @SystemApi Allows an application to capture audio for hotword detection.

         <p>Not for use by third-party applications.</p>

         @hide -->

services/core/java/com/android/server/audio/AudioService.java

+55 −2
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ import static android.media.AudioManager.RINGER_MODE_NORMAL; 
import static android.media.AudioManager.RINGER_MODE_SILENT;

import static android.media.AudioManager.RINGER_MODE_VIBRATE;

import static android.media.AudioManager.STREAM_SYSTEM;

import static android.media.audiopolicy.AudioMixingRule.RULE_MATCH_ATTRIBUTE_USAGE;

import static android.os.Process.FIRST_APPLICATION_UID;

import static android.provider.Settings.Secure.VOLUME_HUSH_MUTE;

import static android.provider.Settings.Secure.VOLUME_HUSH_OFF;
@@ -89,6 +90,7 @@ import android.media.PlayerBase; 
import android.media.VolumePolicy;

import android.media.audiofx.AudioEffect;

import android.media.audiopolicy.AudioMix;

import android.media.audiopolicy.AudioMixingRule.AudioMixMatchCriterion;

import android.media.audiopolicy.AudioPolicy;

import android.media.audiopolicy.AudioPolicyConfig;

import android.media.audiopolicy.AudioProductStrategy;
@@ -6774,6 +6776,7 @@ public class AudioService extends IAudioService.Stub 


        boolean requireValidProjection = false;

        boolean requireCaptureAudioOrMediaOutputPerm = false;

        boolean requireVoiceComunicationOutputPerm = false;

        boolean requireModifyRouting = false;



        if (hasFocusAccess || isVolumeController) {
@@ -6783,8 +6786,15 @@ public class AudioService extends IAudioService.Stub 
            requireModifyRouting |= true;

        }

        for (AudioMix mix : policyConfig.getMixes()) {

            // If mix is requesting a privileged capture

            if (mix.getRule().allowPrivilegedPlaybackCapture()) {

            // If mix is trying to capture USAGE_VOICE_COMMUNICATION using playback capture

            if (isVoiceCommunicationPlaybackCaptureMix(mix)) {

                // then it must have CAPTURE_USAGE_VOICE_COMMUNICATION_OUTPUT permission

                requireVoiceComunicationOutputPerm |= true;

            }

            // If mix is requesting privileged capture and is capturing at

            // least one usage which is not USAGE_VOICE_COMMUNICATION.

            if (mix.getRule().allowPrivilegedPlaybackCapture()

                    && isNonVoiceCommunicationCaptureMix(mix)) {

                // then it must have CAPTURE_MEDIA_OUTPUT or CAPTURE_AUDIO_OUTPUT permission

                requireCaptureAudioOrMediaOutputPerm |= true;

                // and its format must be low quality enough
@@ -6812,6 +6822,14 @@ public class AudioService extends IAudioService.Stub 
            return false;

        }



        if (requireVoiceComunicationOutputPerm

                && !callerHasPermission(

                        android.Manifest.permission.CAPTURE_VOICE_COMMUNICATION_OUTPUT)) {

            Log.e(TAG, "Privileged audio capture for voice communication requires "

                      + "CAPTURE_VOICE_COMMUNICATION_OUTPUT system permission");

            return false;

        }



        if (requireValidProjection && !canProjectAudio(projection)) {

            return false;

        }
@@ -6825,6 +6843,41 @@ public class AudioService extends IAudioService.Stub 
        return true;

    }



    /**

    * Checks whether a given AudioMix is used for playback capture

    * (has the ROUTE_FLAG_LOOP_BACK_RENDER flag) and has a matching

    * criterion for USAGE_VOICE_COMMUNICATION.

    */

    private boolean isVoiceCommunicationPlaybackCaptureMix(AudioMix mix) {

        if (mix.getRouteFlags() != mix.ROUTE_FLAG_LOOP_BACK_RENDER) {

            return false;

        }



        for (AudioMixMatchCriterion criterion : mix.getRule().getCriteria()) {

            if (criterion.getRule() == RULE_MATCH_ATTRIBUTE_USAGE

                    && criterion.getAudioAttributes().getUsage()

                    == AudioAttributes.USAGE_VOICE_COMMUNICATION) {

                return true;

            }

        }

        return false;

    }



    /**

    * Checks whether a given AudioMix has a matching

    * criterion for a usage which is not USAGE_VOICE_COMMUNICATION.

    */

    private boolean isNonVoiceCommunicationCaptureMix(AudioMix mix) {

        for (AudioMixMatchCriterion criterion : mix.getRule().getCriteria()) {

            if (criterion.getRule() == RULE_MATCH_ATTRIBUTE_USAGE

                    && criterion.getAudioAttributes().getUsage()

                    != AudioAttributes.USAGE_VOICE_COMMUNICATION) {

                return true;

            }

        }

        return false;

    }



    private boolean callerHasPermission(String permission) {

        return mContext.checkCallingPermission(permission) == PackageManager.PERMISSION_GRANTED;

    }