Android 11 DP2 hints at supporting multi-device media output and switching audio to/from wired headsets
With the release of the Galaxy S8, Samsung introduced the Dual Audio feature to allow users to stream Bluetooth audio to two connected Bluetooth devices. Every flagship Galaxy S, Galaxy Note, and Galaxy Tab device has supported Dual Audio since the Galaxy S8, but the ability to stream audio to multiple Bluetooth devices is missing on the vast majority of Android devices out there, with the exception of a handful of phones from Motorola, HMD Global, and TCL that use Tempow’s technology. A common misconception is that this feature is enabled by Bluetooth 5.0, but many Android devices these days support Bluetooth 5.0 and can’t stream media to multiple devices. Android 9 Pie added support for connecting to up to 5 Bluetooth devices at the same time, and now it seems that Android 11 may add support for choosing multiple devices to stream media to. What’s more, it seems that Google is also adding the ability to change the media output to or from the currently connected wired audio device.
In Android 11, you can currently switch media output between 2 or more connected Bluetooth devices, but you can’t choose multiple devices to stream to simultaneously.
While looking at SettingsGoogle in the latest preview build, we spotted new strings beginning with the title “media_output_group” that seemingly suggest you’ll be able to select multiple audio devices to output to. One string mentions “casting,” which you may initially associate with the Google Cast protocol, but we don’t believe this feature is related to Google Cast. That’s because the existing “media_output” strings pertain to the ability to change the media output from one connected Bluetooth device to another; this feature is already accessible in the volume panel UI provided by a Slice or through Settings > Sound, as shown in the screenshot above. Second, Google Cast is controlled by Google Play Services and not by SettingsGoogle, which is the application that I found these strings in. Third, “cast” can also generically refer to streaming audio to connected Bluetooth devices, especially to Bluetooth speakers.
<string name="media_output_group">Group</string>\n<string name="media_output_group_panel_multiple_devices_summary">%1$d devices selected</string>\n<string name="media_output_group_panel_single_device_summary">1 device selected</string>\n<string name="media_output_group_panel_title">Add outputs</string>\n<string name="media_output_panel_stop_casting_button">Stop casting</string>
We also spotted a new string titled “media_transfer_wired_device_name” that suggests you’ll be able to select a currently connected wired headset (either via the USB Type-C port or 3.5mm headphone jack) to output media to. It’s unclear if the addition of this new transfer target will allow users to play audio through the device’s speakers while a wired headset is connected, as some OEMs let you do, or if this feature will simply let you swap media output to or from a wired headset while also connected to a Bluetooth audio device.
<string name="media_transfer_wired_device_name">Wired audio device</string>
We tested both features on our Pixel devices running Android 11 Developer Preview 2 to see if they were working. The multi-device media output did not work on a Pixel 4 XL, while the wired headset media transfer did not work on a Pixel 3a XL with a Type-C headset and a 3.5mm headset with and without a connected Bluetooth device. Besides the new strings, we didn’t find the corresponding code for either feature in the decompiled Settings app, so these features seem to be unfinished. We don’t know if it’s possible for the multi-device media output feature to be supported on any existing Pixel devices or if it’ll require changes to the Bluetooth stack and/or hardware that may show up in a future Pixel device. We also don’t know if these features are intended solely for Pixels even though the strings are in SettingsGoogle; we’ll likely find out if it’s a generic Android 11 feature when Google publishes the source code in a few months.