[Audiosharing] Update QR code format to follow BT SIG standard (4abfa5be) · Commits · e / os / android_frameworks_base

packages/SettingsLib/src/com/android/settingslib/bluetooth/BluetoothBroadcastUtils.java

+1 −1

Original line number	Diff line number	Diff line
		@@ -43,5 +43,5 @@ public final class BluetoothBroadcastUtils {
		/**
		* Bluetooth scheme.
		*/
		public static final String SCHEME_BT_BROADCAST_METADATA = "BT:";
		public static final String SCHEME_BT_BROADCAST_METADATA = "BLUETOOTH:UUID:184F;";
		}

packages/SettingsLib/src/com/android/settingslib/bluetooth/BluetoothLeBroadcastMetadataExt.kt

+211 −186

Original line number	Diff line number	Diff line
		@@ -31,38 +31,34 @@ import com.android.settingslib.bluetooth.BluetoothBroadcastUtils.SCHEME_BT_BROAD
		object BluetoothLeBroadcastMetadataExt {
		private const val TAG = "BtLeBroadcastMetadataExt"

		// BluetoothLeBroadcastMetadata
		private const val KEY_BT_QR_VER = "R"
		private const val KEY_BT_ADDRESS_TYPE = "T"
		private const val KEY_BT_DEVICE = "D"
		private const val KEY_BT_ADVERTISING_SID = "AS"
		private const val KEY_BT_BROADCAST_ID = "B"
		// Data Elements for directing Broadcast Assistants
		private const val KEY_BT_BROADCAST_NAME = "BN"
		private const val KEY_BT_PUBLIC_BROADCAST_DATA = "PM"
		private const val KEY_BT_SYNC_INTERVAL = "SI"
		private const val KEY_BT_BROADCAST_CODE = "C"
		private const val KEY_BT_SUBGROUPS = "SG"
		private const val KEY_BT_VENDOR_SPECIFIC = "V"
		private const val KEY_BT_ANDROID_VERSION = "VN"

		// Subgroup data
		private const val KEY_BT_ADVERTISER_ADDRESS_TYPE = "AT"
		private const val KEY_BT_ADVERTISER_ADDRESS = "AD"
		private const val KEY_BT_BROADCAST_ID = "BI"
		private const val KEY_BT_BROADCAST_CODE = "BC"
		private const val KEY_BT_STREAM_METADATA = "MD"
		private const val KEY_BT_STANDARD_QUALITY = "SQ"
		private const val KEY_BT_HIGH_QUALITY = "HQ"

		// Extended Bluetooth URI Data Elements
		private const val KEY_BT_ADVERTISING_SID = "AS"
		private const val KEY_BT_PA_INTERVAL = "PI"
		private const val KEY_BT_NUM_SUBGROUPS = "NS"

		// Subgroup data elements
		private const val KEY_BTSG_BIS_SYNC = "BS"
		private const val KEY_BTSG_BIS_MASK = "BM"
		private const val KEY_BTSG_AUDIO_CONTENT = "AC"
		private const val KEY_BTSG_NUM_BISES = "NB"
		private const val KEY_BTSG_METADATA = "SM"

		// Vendor specific data
		private const val KEY_BTVSD_COMPANY_ID = "VI"
		private const val KEY_BTVSD_VENDOR_DATA = "VD"
		// Vendor specific data, not being used
		private const val KEY_BTVSD_VENDOR_DATA = "VS"

		private const val DELIMITER_KEY_VALUE = ":"
		private const val DELIMITER_BT_LEVEL_1 = ";"
		private const val DELIMITER_BT_LEVEL_2 = ","
		private const val DELIMITER_ELEMENT = ";"

		private const val SUFFIX_QR_CODE = ";;"

		private const val ANDROID_VER = "U"
		private const val QR_CODE_VER = 0x010000

		// BT constants
		private const val BIS_SYNC_MAX_CHANNEL = 32
		private const val BIS_SYNC_NO_PREFERENCE = 0xFFFFFFFFu
		@@ -71,33 +67,55 @@ object BluetoothLeBroadcastMetadataExt {
		/**
		* Converts [BluetoothLeBroadcastMetadata] to QR code string.
		*
		* QR code string will prefix with "BT:".
		* QR code string will prefix with "BLUETOOTH:UUID:184F".
		*/
		fun BluetoothLeBroadcastMetadata.toQrCodeString(): String {
		val entries = mutableListOf<Pair<String, String>>()
		entries.add(Pair(KEY_BT_QR_VER, QR_CODE_VER.toString()))
		entries.add(Pair(KEY_BT_ADDRESS_TYPE, this.sourceAddressType.toString()))
		entries.add(Pair(KEY_BT_DEVICE, this.sourceDevice.address.replace(":", "-")))
		entries.add(Pair(KEY_BT_ADVERTISING_SID, this.sourceAdvertisingSid.toString()))
		entries.add(Pair(KEY_BT_BROADCAST_ID, this.broadcastId.toString()))
		if (this.broadcastName != null) {
		// Generate data elements for directing Broadcast Assistants
		require(this.broadcastName != null) { "Broadcast name is mandatory for QR code" }
		entries.add(Pair(KEY_BT_BROADCAST_NAME, Base64.encodeToString(
		this.broadcastName?.toByteArray(Charsets.UTF_8), Base64.NO_WRAP)))
		}
		if (this.publicBroadcastMetadata != null) {
		entries.add(Pair(KEY_BT_PUBLIC_BROADCAST_DATA, Base64.encodeToString(
		this.publicBroadcastMetadata?.rawMetadata, Base64.NO_WRAP)))
		}
		entries.add(Pair(KEY_BT_SYNC_INTERVAL, this.paSyncInterval.toString()))
		entries.add(Pair(KEY_BT_ADVERTISER_ADDRESS_TYPE, this.sourceAddressType.toString()))
		entries.add(Pair(KEY_BT_ADVERTISER_ADDRESS, this.sourceDevice.address.replace(":", "")))
		entries.add(Pair(KEY_BT_BROADCAST_ID, String.format("%X", this.broadcastId.toLong())))
		if (this.broadcastCode != null) {
		entries.add(Pair(KEY_BT_BROADCAST_CODE,
		Base64.encodeToString(this.broadcastCode, Base64.NO_WRAP)))
		}
		if (this.publicBroadcastMetadata != null &&
		this.publicBroadcastMetadata?.rawMetadata?.size != 0) {
		entries.add(Pair(KEY_BT_STREAM_METADATA, Base64.encodeToString(
		this.publicBroadcastMetadata?.rawMetadata, Base64.NO_WRAP)))
		}
		if ((this.audioConfigQuality and
		BluetoothLeBroadcastMetadata.AUDIO_CONFIG_QUALITY_STANDARD) != 0) {
		entries.add(Pair(KEY_BT_STANDARD_QUALITY, "1"))
		}
		if ((this.audioConfigQuality and
		BluetoothLeBroadcastMetadata.AUDIO_CONFIG_QUALITY_HIGH) != 0) {
		entries.add(Pair(KEY_BT_HIGH_QUALITY, "1"))
		}

		// Generate extended Bluetooth URI data elements
		entries.add(Pair(KEY_BT_ADVERTISING_SID,
		String.format("%X", this.sourceAdvertisingSid.toLong())))
		entries.add(Pair(KEY_BT_PA_INTERVAL, String.format("%X", this.paSyncInterval.toLong())))
		entries.add(Pair(KEY_BT_NUM_SUBGROUPS, String.format("%X", this.subgroups.size.toLong())))

		this.subgroups.forEach {
		subgroup -> entries.add(Pair(KEY_BT_SUBGROUPS, subgroup.toQrCodeString())) }
		entries.add(Pair(KEY_BT_ANDROID_VERSION, ANDROID_VER))
		val (bisSync, bisCount) = getBisSyncFromChannels(it.channels)
		entries.add(Pair(KEY_BTSG_BIS_SYNC, String.format("%X", bisSync.toLong())))
		if (bisCount > 0u) {
		entries.add(Pair(KEY_BTSG_NUM_BISES, String.format("%X", bisCount.toLong())))
		}
		if (it.contentMetadata.rawMetadata.size != 0) {
		entries.add(Pair(KEY_BTSG_METADATA,
		Base64.encodeToString(it.contentMetadata.rawMetadata, Base64.NO_WRAP)))
		}
		}

		val qrCodeString = SCHEME_BT_BROADCAST_METADATA +
		entries.toQrCodeString(DELIMITER_BT_LEVEL_1) + SUFFIX_QR_CODE
		entries.toQrCodeString(DELIMITER_ELEMENT) + SUFFIX_QR_CODE
		Log.d(TAG, "Generated QR string : $qrCodeString")
		return qrCodeString
		}
		@@ -105,7 +123,7 @@ object BluetoothLeBroadcastMetadataExt {
		/**
		* Converts QR code string to [BluetoothLeBroadcastMetadata].
		*
		* QR code string should prefix with "BT:BluetoothLeBroadcastMetadata:".
		* QR code string should prefix with "BLUETOOTH:UUID:184F".
		*/
		fun convertToBroadcastMetadata(qrCodeString: String): BluetoothLeBroadcastMetadata? {
		if (!qrCodeString.startsWith(SCHEME_BT_BROADCAST_METADATA)) {
		@@ -126,15 +144,6 @@ object BluetoothLeBroadcastMetadataExt {
		}
		}

		private fun BluetoothLeBroadcastSubgroup.toQrCodeString(): String {
		val entries = mutableListOf<Pair<String, String>>()
		entries.add(Pair(KEY_BTSG_BIS_SYNC, getBisSyncFromChannels(this.channels).toString()))
		entries.add(Pair(KEY_BTSG_BIS_MASK, getBisMaskFromChannels(this.channels).toString()))
		entries.add(Pair(KEY_BTSG_AUDIO_CONTENT,
		Base64.encodeToString(this.contentMetadata.rawMetadata, Base64.NO_WRAP)))
		return entries.toQrCodeString(DELIMITER_BT_LEVEL_2)
		}

		private fun List<Pair<String, String>>.toQrCodeString(delimiter: String): String {
		val entryStrings = this.map{ it.first + DELIMITER_KEY_VALUE + it.second }
		return entryStrings.joinToString(separator = delimiter)
		@@ -143,23 +152,29 @@ object BluetoothLeBroadcastMetadataExt {
		@TargetApi(Build.VERSION_CODES.TIRAMISU)
		private fun parseQrCodeToMetadata(input: String): BluetoothLeBroadcastMetadata {
		// Split into a list of list
		val level1Fields = input.split(DELIMITER_BT_LEVEL_1)
		val elementFields = input.split(DELIMITER_ELEMENT)
		.map{it.split(DELIMITER_KEY_VALUE, limit = 2)}
		var qrCodeVersion = -1

		var sourceAddrType = BluetoothDevice.ADDRESS_TYPE_UNKNOWN
		var sourceAddrString: String? = null
		var sourceAdvertiserSid = -1
		var broadcastId = -1
		var broadcastName: String? = null
		var publicBroadcastMetadata: BluetoothLeAudioContentMetadata? = null
		var streamMetadata: BluetoothLeAudioContentMetadata? = null
		var paSyncInterval = -1
		var broadcastCode: ByteArray? = null
		// List of VendorID -> Data Pairs
		var vendorDataList = mutableListOf<Pair<Int, ByteArray?>>()
		var androidVersion: String? = null
		var audioConfigQualityStandard = -1
		var audioConfigQualityHigh = -1
		var numSubgroups = -1

		// List of subgroup data
		var subgroupBisSyncList = mutableListOf<UInt>()
		var subgroupNumOfBisesList = mutableListOf<UInt>()
		var subgroupMetadataList = mutableListOf<ByteArray?>()

		val builder = BluetoothLeBroadcastMetadata.Builder()

		for (field: List<String> in level1Fields) {
		for (field: List<String> in elementFields) {
		if (field.isEmpty()) {
		continue
		}
		@@ -167,190 +182,200 @@ object BluetoothLeBroadcastMetadataExt {
		// Ignore 3rd value and after
		val value = if (field.size > 1) field[1] else ""
		when (key) {
		KEY_BT_QR_VER -> {
		require(qrCodeVersion == -1) { "Duplicate qrCodeVersion: $input" }
		qrCodeVersion = value.toInt()
		// Parse data elements for directing Broadcast Assistants
		KEY_BT_BROADCAST_NAME -> {
		require(broadcastName == null) { "Duplicate broadcastName: $input" }
		broadcastName = String(Base64.decode(value, Base64.NO_WRAP))
		}
		KEY_BT_ADDRESS_TYPE -> {
		KEY_BT_ADVERTISER_ADDRESS_TYPE -> {
		require(sourceAddrType == BluetoothDevice.ADDRESS_TYPE_UNKNOWN) {
		"Duplicate sourceAddrType: $input"
		}
		sourceAddrType = value.toInt()
		}
		KEY_BT_DEVICE -> {
		KEY_BT_ADVERTISER_ADDRESS -> {
		require(sourceAddrString == null) { "Duplicate sourceAddr: $input" }
		sourceAddrString = value.replace("-", ":")
		}
		KEY_BT_ADVERTISING_SID -> {
		require(sourceAdvertiserSid == -1) { "Duplicate sourceAdvertiserSid: $input" }
		sourceAdvertiserSid = value.toInt()
		sourceAddrString = value.chunked(2).joinToString(":")
		}
		KEY_BT_BROADCAST_ID -> {
		require(broadcastId == -1) { "Duplicate broadcastId: $input" }
		broadcastId = value.toInt()
		broadcastId = value.toInt(16)
		}
		KEY_BT_BROADCAST_NAME -> {
		require(broadcastName == null) { "Duplicate broadcastName: $input" }
		broadcastName = String(Base64.decode(value, Base64.NO_WRAP))
		KEY_BT_BROADCAST_CODE -> {
		require(broadcastCode == null) { "Duplicate broadcastCode: $input" }

		broadcastCode = Base64.decode(value.dropLastWhile { it.equals(0.toByte()) }
		.toByteArray(), Base64.NO_WRAP)
		}
		KEY_BT_PUBLIC_BROADCAST_DATA -> {
		require(publicBroadcastMetadata == null) {
		"Duplicate publicBroadcastMetadata $input"
		KEY_BT_STREAM_METADATA -> {
		require(streamMetadata == null) {
		"Duplicate streamMetadata $input"
		}
		publicBroadcastMetadata = BluetoothLeAudioContentMetadata
		streamMetadata = BluetoothLeAudioContentMetadata
		.fromRawBytes(Base64.decode(value, Base64.NO_WRAP))
		}
		KEY_BT_SYNC_INTERVAL -> {
		KEY_BT_STANDARD_QUALITY -> {
		require(audioConfigQualityStandard == -1) {
		"Duplicate audioConfigQualityStandard: $input"
		}
		audioConfigQualityStandard = value.toInt()
		}
		KEY_BT_HIGH_QUALITY -> {
		require(audioConfigQualityHigh == -1) {
		"Duplicate audioConfigQualityHigh: $input"
		}
		audioConfigQualityHigh = value.toInt()
		}

		// Parse extended Bluetooth URI data elements
		KEY_BT_ADVERTISING_SID -> {
		require(sourceAdvertiserSid == -1) { "Duplicate sourceAdvertiserSid: $input" }
		sourceAdvertiserSid = value.toInt(16)
		}
		KEY_BT_PA_INTERVAL -> {
		require(paSyncInterval == -1) { "Duplicate paSyncInterval: $input" }
		paSyncInterval = value.toInt()
		paSyncInterval = value.toInt(16)
		}
		KEY_BT_BROADCAST_CODE -> {
		require(broadcastCode == null) { "Duplicate broadcastCode: $input" }
		broadcastCode = Base64.decode(value, Base64.NO_WRAP)
		KEY_BT_NUM_SUBGROUPS -> {
		require(numSubgroups == -1) { "Duplicate numSubgroups: $input" }
		numSubgroups = value.toInt(16)
		}
		KEY_BT_ANDROID_VERSION -> {
		require(androidVersion == null) { "Duplicate androidVersion: $input" }
		androidVersion = value
		Log.i(TAG, "QR code Android version: $androidVersion")

		// Repeatable subgroup elements
		KEY_BTSG_BIS_SYNC -> {
		subgroupBisSyncList.add(value.toUInt(16))
		}
		// Repeatable
		KEY_BT_SUBGROUPS -> {
		builder.addSubgroup(parseSubgroupData(value))
		KEY_BTSG_NUM_BISES -> {
		subgroupNumOfBisesList.add(value.toUInt(16))
		}
		// Repeatable
		KEY_BT_VENDOR_SPECIFIC -> {
		vendorDataList.add(parseVendorData(value))
		KEY_BTSG_METADATA -> {
		subgroupMetadataList.add(Base64.decode(value, Base64.NO_WRAP))
		}
		}
		}
		Log.d(TAG, "parseQrCodeToMetadata: sourceAddrType=$sourceAddrType, " +
		Log.d(TAG, "parseQrCodeToMetadata: main data elements sourceAddrType=$sourceAddrType, " +
		"sourceAddr=$sourceAddrString, sourceAdvertiserSid=$sourceAdvertiserSid, " +
		"broadcastId=$broadcastId, broadcastName=$broadcastName, " +
		"publicBroadcastMetadata=${publicBroadcastMetadata != null}, " +
		"streamMetadata=${streamMetadata != null}, " +
		"paSyncInterval=$paSyncInterval, " +
		"broadcastCode=${broadcastCode?.toString(Charsets.UTF_8)}")
		Log.d(TAG, "Not used in current code, but part of the specification: " +
		"qrCodeVersion=$qrCodeVersion, androidVersion=$androidVersion, " +
		"vendorDataListSize=${vendorDataList.size}")
		"broadcastCode=${broadcastCode?.toString(Charsets.UTF_8)}, " +
		"audioConfigQualityStandard=$audioConfigQualityStandard, " +
		"audioConfigQualityHigh=$audioConfigQualityHigh")

		val adapter = BluetoothAdapter.getDefaultAdapter()
		// add source device and set broadcast code
		val device = adapter.getRemoteLeDevice(requireNotNull(sourceAddrString), sourceAddrType)
		builder.apply {
		setSourceDevice(device, sourceAddrType)
		setSourceAdvertisingSid(sourceAdvertiserSid)
		setBroadcastId(broadcastId)
		setBroadcastName(broadcastName)
		setPublicBroadcast(publicBroadcastMetadata != null)
		setPublicBroadcastMetadata(publicBroadcastMetadata)
		setPaSyncInterval(paSyncInterval)
		setEncrypted(broadcastCode != null)
		setBroadcastCode(broadcastCode)
		// Presentation delay is unknown and not useful when adding source
		// Broadcast sink needs to sync to the Broadcast source to get presentation delay
		setPresentationDelayMicros(0)
		// Check parsed elements data
		require(broadcastName != null) {
		"broadcastName($broadcastName) must present in QR code string"
		}
		return builder.build()
		var addr = sourceAddrString
		var addrType = sourceAddrType
		if (sourceAddrString != null) {
		require(sourceAddrType != BluetoothDevice.ADDRESS_TYPE_UNKNOWN) {
		"sourceAddrType($sourceAddrType) must present if address present"
		}
		} else {
		// Use placeholder device if not present
		addr = "FF:FF:FF:FF:FF:FF"
		addrType = BluetoothDevice.ADDRESS_TYPE_RANDOM
		}
		val device = adapter.getRemoteLeDevice(requireNotNull(addr), addrType)

		private fun parseSubgroupData(input: String): BluetoothLeBroadcastSubgroup {
		Log.d(TAG, "parseSubgroupData: $input")
		val fields = input.split(DELIMITER_BT_LEVEL_2)
		var bisSync: UInt? = null
		var bisMask: UInt? = null
		var metadata: ByteArray? = null
		// add source device and set broadcast code
		var audioConfigQuality = BluetoothLeBroadcastMetadata.AUDIO_CONFIG_QUALITY_NONE or
		(if (audioConfigQualityStandard != -1) audioConfigQualityStandard else 0) or
		(if (audioConfigQualityHigh != -1) audioConfigQualityHigh else 0)

		fields.forEach { field ->
		val(key, value) = field.split(DELIMITER_KEY_VALUE)
		when (key) {
		KEY_BTSG_BIS_SYNC -> {
		require(bisSync == null) { "Duplicate bisSync: $input" }
		bisSync = value.toUInt()
		}
		KEY_BTSG_BIS_MASK -> {
		require(bisMask == null) { "Duplicate bisMask: $input" }
		bisMask = value.toUInt()
		}
		KEY_BTSG_AUDIO_CONTENT -> {
		require(metadata == null) { "Duplicate metadata: $input" }
		metadata = Base64.decode(value, Base64.NO_WRAP)
		}
		}
		}
		val channels = convertToChannels(requireNotNull(bisSync), requireNotNull(bisMask))
		// process subgroup data
		// metadata should include at least 1 subgroup for metadata, add a placeholder group if not present
		numSubgroups = if (numSubgroups > 0) numSubgroups else 1
		for (i in 0 until numSubgroups) {
		val bisSync = subgroupBisSyncList.getOrNull(i)
		val bisNum = subgroupNumOfBisesList.getOrNull(i)
		val metadata = subgroupMetadataList.getOrNull(i)

		val channels = convertToChannels(bisSync, bisNum)
		val audioCodecConfigMetadata = BluetoothLeAudioCodecConfigMetadata.Builder()
		.setAudioLocation(0).build()
		return BluetoothLeBroadcastSubgroup.Builder().apply {
		val subgroup = BluetoothLeBroadcastSubgroup.Builder().apply {
		setCodecId(SUBGROUP_LC3_CODEC_ID)
		setCodecSpecificConfig(audioCodecConfigMetadata)
		setContentMetadata(
		BluetoothLeAudioContentMetadata.fromRawBytes(metadata ?: ByteArray(0)))
		channels.forEach(::addChannel)
		}.build()
		}

		private fun parseVendorData(input: String): Pair<Int, ByteArray?> {
		var companyId = -1
		var data: ByteArray? = null
		val fields = input.split(DELIMITER_BT_LEVEL_2)
		fields.forEach { field ->
		val(key, value) = field.split(DELIMITER_KEY_VALUE)
		when (key) {
		KEY_BTVSD_COMPANY_ID -> {
		require(companyId == -1) { "Duplicate companyId: $input" }
		companyId = value.toInt()
		}
		KEY_BTVSD_VENDOR_DATA -> {
		require(data == null) { "Duplicate data: $input" }
		data = Base64.decode(value, Base64.NO_WRAP)
		}
		Log.d(TAG, "parseQrCodeToMetadata: subgroup $i elements bisSync=$bisSync, " +
		"bisNum=$bisNum, metadata=${metadata != null}")

		builder.addSubgroup(subgroup)
		}

		builder.apply {
		setSourceDevice(device, sourceAddrType)
		setSourceAdvertisingSid(sourceAdvertiserSid)
		setBroadcastId(broadcastId)
		setBroadcastName(broadcastName)
		// QR code should set PBP(public broadcast profile) for auracast
		setPublicBroadcast(true)
		setPublicBroadcastMetadata(streamMetadata)
		setPaSyncInterval(paSyncInterval)
		setEncrypted(broadcastCode != null)
		setBroadcastCode(broadcastCode)
		// Presentation delay is unknown and not useful when adding source
		// Broadcast sink needs to sync to the Broadcast source to get presentation delay
		setPresentationDelayMicros(0)
		setAudioConfigQuality(audioConfigQuality)
		}
		return Pair(companyId, data)
		return builder.build()
		}

		private fun getBisSyncFromChannels(channels: List<BluetoothLeBroadcastChannel>): UInt {
		private fun getBisSyncFromChannels(
		channels: List<BluetoothLeBroadcastChannel>
		): Pair<UInt, UInt> {
		var bisSync = 0u
		var bisCount = 0u
		// channel index starts from 1
		channels.forEach { channel ->
		if (channel.isSelected && channel.channelIndex > 0) {
		if (channel.channelIndex > 0) {
		bisCount++
		if (channel.isSelected) {
		bisSync = bisSync or (1u shl (channel.channelIndex - 1))
		}
		}
		// No channel is selected means no preference on Android platform
		return if (bisSync == 0u) BIS_SYNC_NO_PREFERENCE else bisSync
		}

		private fun getBisMaskFromChannels(channels: List<BluetoothLeBroadcastChannel>): UInt {
		var bisMask = 0u
		// channel index starts from 1
		channels.forEach { channel ->
		if (channel.channelIndex > 0) {
		bisMask = bisMask or (1u shl (channel.channelIndex - 1))
		}
		}
		return bisMask
		// No channel is selected means no preference on Android platform
		return if (bisSync == 0u) Pair(BIS_SYNC_NO_PREFERENCE, bisCount)
		else Pair(bisSync, bisCount)
		}

		private fun convertToChannels(bisSync: UInt, bisMask: UInt):
		List<BluetoothLeBroadcastChannel> {
		Log.d(TAG, "convertToChannels: bisSync=$bisSync, bisMask=$bisMask")
		var selectionMask = bisSync
		if (bisSync != BIS_SYNC_NO_PREFERENCE) {
		require(bisMask == (bisMask or bisSync)) {
		"bisSync($bisSync) must select a subset of bisMask($bisMask) if it has preferences"
		}
		} else {
		// No channel preference means no channel is selected
		selectionMask = 0u
		}
		private fun convertToChannels(
		bisSync: UInt?,
		bisNum: UInt?
		): List<BluetoothLeBroadcastChannel> {
		Log.d(TAG, "convertToChannels: bisSync=$bisSync, bisNum=$bisNum")
		// if no BIS_SYNC or BIS_NUM available or BIS_SYNC is no preference
		// return empty channel map with one placeholder channel
		var selectedChannels = if (bisSync != null && bisNum != null) bisSync else 0u
		val channels = mutableListOf<BluetoothLeBroadcastChannel>()
		val audioCodecConfigMetadata = BluetoothLeAudioCodecConfigMetadata.Builder()
		.setAudioLocation(0).build()

		if (bisSync == BIS_SYNC_NO_PREFERENCE \|\| selectedChannels == 0u) {
		// No channel preference means no channel is selected
		// Generate one placeholder channel for metadata
		val channel = BluetoothLeBroadcastChannel.Builder().apply {
		setSelected(false)
		setChannelIndex(1)
		setCodecMetadata(audioCodecConfigMetadata)
		}
		return listOf(channel.build())
		}

		for (i in 0 until BIS_SYNC_MAX_CHANNEL) {
		val channelMask = 1u shl i
		if ((bisMask and channelMask) != 0u) {
		if ((selectedChannels and channelMask) != 0u) {
		val channel = BluetoothLeBroadcastChannel.Builder().apply {
		setSelected((selectionMask and channelMask) != 0u)
		setSelected(true)
		setChannelIndex(i + 1)
		setCodecMetadata(audioCodecConfigMetadata)
		}