Bluetooth Low Energy Audio in Android: What Is It & How Does It Work
Bluetooth Low Energy (LE) Audio is a new Bluetooth audio standard introduced by the Bluetooth SIG in early 2020. It builds on the existing Bluetooth Low Energy wireless technology that was originally designed for short-range, low-power devices like wearables and IoT products. The key difference with Bluetooth LE Audio is its focus on delivering a robust, reliable wireless audio experience with lower power consumption compared to classic Bluetooth audio.
Some key features of Bluetooth LE Audio include new audio codecs optimized for both sound quality and power efficiency, multi-stream audio for multiple audio connections, and lower latency. It uses the same Bluetooth 5 and Bluetooth 5.2 radios and protocol stack as other Bluetooth Low Energy devices, which allows dual-mode devices to support both LE Audio and classic Bluetooth audio.
By leveraging the advantages of Bluetooth Low Energy, such as reduced power consumption, LE Audio aims to enable new use cases like truly wireless earbuds with extremely low latency, hearing aids with direct streaming from smartphones, and audio sharing between multiple users. The Bluetooth SIG expects LE Audio to become the primary audio streaming solution over classic Bluetooth audio in the coming years.
Benefits of Bluetooth LE Audio
Bluetooth LE Audio brings several key improvements over classic Bluetooth audio, making it an appealing upgrade for both consumers and manufacturers. Some of the main benefits include:
Improved audio quality – Bluetooth LE Audio introduces a new audio codec called LC3 that provides improved sound quality over SBC and AAC at lower bitrates. This allows the same audio quality to be transmitted using less data, improving battery life. LC3 also enables broadcasting to multiple users simultaneously.
Lower power consumption – By requiring less data transmission, Bluetooth LE Audio greatly reduces power consumption compared to classic Bluetooth audio. The lower bandwidth enables smaller batteries while maintaining the same usage time. This is critical for true wireless earbuds and hearing aids.
Increased connectivity – Bluetooth LE Audio allows up to 65534 users to be connected to an audio source simultaneously via the new Auracast broadcast audio feature. This allows for innovative use cases like shared listening experiences.
Backwards compatibility – Importantly, Bluetooth LE Audio is backwards compatible with existing Bluetooth audio devices. So consumers won’t need to replace their current Bluetooth headphones and speakers to take advantage of the new technology. The upgrades happen seamlessly.
Bluetooth LE Audio Codecs
Bluetooth LE Audio introduces a new audio codec called LC3 (Low Complexity Communication Codec) to improve audio quality and efficiency. According to the Bluetooth SIG, LC3 provides high quality audio at low data rates while maintaining low latency. It is capable of transmitting high resolution 24-bit 96kHz audio using minimal power and bandwidth.
Compared to the SBC codec used in classic Bluetooth audio, LC3 offers improved sound quality and lower bitrates. At the same 24 kbps bitrate, LC3 provides comparable quality to SBC at 328 kbps. This allows LC3 to deliver better audio performance using less data. According to testing by the Bluetooth SIG, LC3 has a “perceptually transparent” audio quality at bitrates as low as 96 kbps.
The LC3 codec also achieves lower latency, down to 40 ms compared to 100-150 ms for SBC. This improves real-time interactivity for applications like gaming where lag needs to be minimized.
In addition to the standard LC3 codec, Bluetooth LE Audio includes an enhanced LC3plus codec for premium, immersive audio. LC3plus supports 48kHz stereo audio at bitrates up to 512 kbps along with loudness equalization and dynamic range control. This allows the highest quality wireless audio playback.
Overall, the LC3 and LC3plus codecs in Bluetooth LE Audio provide significant improvements in audio quality, efficiency, and latency compared to classic Bluetooth audio codecs like SBC and AAC. This enables a new generation of wireless audio devices and use cases.
Bluetooth LE Audio Implementation in Android
Google officially introduced support for Bluetooth LE Audio in Android starting with Android 13. This allows Android devices running Android 13 or newer to take advantage of the benefits of LE Audio such as lower power consumption and improved audio quality.
Devices running Android 12 or older do not have native support for LE Audio. While it’s theoretically possible to add LE Audio support via firmware updates, most older Android devices likely won’t receive those updates from manufacturers.
According to Google’s Android 13 release notes, the company implemented the LE Audio feature set within Android’s software stack to enable high quality audio via Bluetooth on supported devices. This included updates to the Bluetooth stack, audio HAL, and developer APIs [1].
Developers can check if a device supports LE Audio by calling isLeAudioSupported() on BluetoothAdapter. This will return true if the device is running Android 13+ and meets all requirements for LE Audio. The AudioManager class also contains additional methods like isLeAudioContentSupported() to check for specific LE Audio codec support.
Developer Support for Bluetooth LE Audio
Android provides robust developer support for integrating Bluetooth LE Audio into apps through various SDKs, APIs and tools. The BluetoothLeAudio API allows apps to interact with LE Audio profiles and protocols. Key classes like BluetoothLeAudio, BluetoothLeAudioClient and BluetoothLeAudioCallbacks help manage connections, data transfer and callbacks.
The Android Bluetooth API includes features to discover, pair and interact with nearby LE Audio devices. Apps can use BluetoothAdapter to get a list of paired devices, scan for new ones, and create profiles to send and receive data streams.
For audio development, the Android audio framework and Media API offer building blocks to handle playback, recording, streaming and effects. The MediaPlayer class can decode various audio codecs and output sound via AudioTrack. AudioRecord enables capturing audio input from microphones.
Overall, Android’s Bluetooth, Media and Audio APIs combined provide full-featured options for implementing high-quality wireless audio and bidirectional streaming powered by LE Audio. With Kotlin and Java language support, developers have flexibility in crafting robust, battery-friendly audio experiences on Android.
Bluetooth LE Audio Device Compatibility
As of now, the number of devices that support Bluetooth LE Audio is still limited. In order to support Bluetooth LE Audio, a device must have Bluetooth 5.2 or Bluetooth 5.3. However, not all devices with those Bluetooth versions will necessarily support LE Audio (1). This is because device manufacturers also need to include the LE Audio codec in their chipsets.
Currently, there are only a handful of wireless earbuds and headphones that support LE Audio, such as some models from Audio-Technica, Sennheiser, and 1More. On the smartphone side, the Xiaomi Mix 4, Samsung Galaxy S22 series, and Google Pixel 7 and 7 Pro are among the few that include LE Audio support so far (2). However, more mobile devices and audio gear integrating LE Audio are expected to arrive in 2023 and beyond.
For those looking to take advantage of LE Audio features like multi-stream audio, checking technical specifications of a device is key to confirming if LE Audio is present. As adoption increases over time, Bluetooth LE Audio compatibility will become more common across headphones, speakers, phones, tablets, and other gadgets.
Power and Latency Improvements
Bluetooth LE Audio brings significant improvements in power efficiency and latency compared to classic Bluetooth audio. The new LC3 codec used in LE Audio is designed to provide high quality audio at much lower bitrates than SBC, resulting in substantial power savings.
According to Bluetooth SIG, LC3 can provide better than CD-quality audio at bitrates between 128kbps and 512kbps, whereas SBC requires 512kbps to 768kbps for comparable quality [1]. This means LC3 can cut the bitrate and power consumption roughly in half while maintaining or improving audio quality.
In terms of latency, tests by Bluetooth SIG show LC3 can achieve 20-30ms of latency, a major reduction from the 150-200ms typical of classic Bluetooth audio using SBC [2]. This ultra-low latency enables new use cases like wireless gaming headphones and seamless multi-stream audio.
The power and latency gains of LE Audio stand to greatly improve the wireless audio experience for consumers across many devices and applications.
Multi-Stream Audio
One of the most significant new capabilities introduced in Bluetooth LE Audio is support for multiple audio streams. This allows a single Bluetooth audio source device to transmit audio to multiple “sink” devices simultaneously.
For example, a smartphone could stream music to a pair of wireless earbuds and a Bluetooth speaker at the same time. Or a smart TV could transmit audio to a soundbar and surround speakers simultaneously for an immersive home theater experience.
Multi-stream audio is enabled through a new feature called Audio Sharing. This allows a source device to broadcast audio over a shared communication channel using isochronous channels. Sink devices can dynamically join and leave these shared channels to tap into the audio stream.
From the user perspective, this makes it seamless to connect multiple devices. There’s no longer a need to manually disconnect and reconnect to switch between audio outputs. The source device handles transmitting to all synced sinks automatically.
Multi-stream support also enables new use cases like stereo audio, where a left and right audio channel could be sent to two separate earbuds simultaneously. This helps recreate a more natural listening experience.
For public environments, multi-stream audio could enable audio transmission to multiple headphones or hearing aids without needing multiple separate audio sources. This brings exciting new possibilities for shared listening experiences.
With its ability to simplify audio sharing across an ecosystem of devices, multi-stream support stands out as a compelling new feature in the Bluetooth LE Audio standard.
The Future of Bluetooth LE Audio
The future looks bright for Bluetooth LE Audio technology. According to forecasts from Bluetooth SIG, the market for Bluetooth audio devices is expected to grow substantially in the coming years as LE Audio is adopted. Key improvements that will drive adoption include multi-stream audio, lower latency, and lower power consumption.
Industry analysis firm ABI Research predicts that standalone Bluetooth LE Audio devices will emerge over time and make up over 50% of total shipped Bluetooth headphones by 2024 (https://www.bluetooth.com/blog/new-forecasts-highlight-the-future-of-the-wireless-audio-market/). The ability to connect multiple audio streams simultaneously will allow for new use cases like augmented reality audio and customizable audio setups.
Lower latency offered by LE Audio will significantly improve audio-video synchronization, making it feasible for wireless headphones to be used for gaming, TV, and movies where lag is currently an issue. Lower power consumption will enable smaller devices with longer battery life.
Overall, the enhancements in LE Audio are expected to transform and expand the Bluetooth audio market according to analysis from Bluetooth SIG (https://www.bluetooth.com/bluetooth-resources/mrn-le-audio/). Consumer adoption will accelerate as more audio devices with LE Audio capabilities are released.
Conclusion
In summary, Bluetooth Low Energy Audio brings several key improvements for wireless audio on Android devices. By utilizing a new audio compression codec, it allows high-quality audio streaming while using very little power. This leads to reduced battery drain compared to classic Bluetooth audio.
Bluetooth LE Audio also enables new multi-stream capabilities, allowing multiple audio streams to be sent to multiple devices simultaneously. This opens up new wireless audio use cases like transmitting to multiple headphones or speakers at once.
For Android users specifically, Bluetooth LE Audio will bring benefits like lower latency wireless audio for uses like gaming and watching video. It also allows Android to support next-generation wireless audio devices and functionality moving forward.
Overall, Bluetooth LE Audio is an exciting new wireless audio standard that will enhance the experience for Android users. It brings meaningful improvements in audio quality, battery life, latency, and multi-device streaming capabilities. As adoption of Bluetooth LE Audio grows, Android users can expect a richer and more seamless wireless audio experience.
