Setup

Table of contents

  1. Prerequisites
  2. Installing BlueCaster
    1. Upgrading from v1
    2. Upgrading from 2.0.x (A2DP Windows Bridge)
  3. Step 1: First-Run Setup
  4. Step 2: Assign WinUSB to the Adapter
    1. Using Zadig instead
    2. By hand in Device Manager
  5. Step 3: Find Your Headphones
  6. Firmware (Realtek Adapters)
    1. In the App (Guided Download)
    2. Bluetooth Chip setting
    3. Manual Download
  7. Recommended Adapters

Prerequisites

  • Windows 10 (22H2) / 11 (x64 or ARM64)
  • A USB Bluetooth adapter for BlueCaster: a separate dongle is recommended; a built-in USB adapter works too, but Windows then has no Bluetooth of its own (see Step 2)

BlueCaster assigns the WinUSB driver to the adapter itself. Zadig is not needed any more (it still works, see Using Zadig instead).

Installing BlueCaster

Each release comes in two forms with the same files:

  • Installer (BlueCaster-<version>-win64-setup.exe, on ARM64 -arm64-setup.exe): installs for the current user without administrator rights, adds a Start menu entry (BlueCaster) and an uninstaller, and installs the Microsoft Edge WebView2 Runtime if it is missing (Windows 11 includes it). Updates install themselves from the app (Settings > Updates > Update now). The programs go to %LOCALAPPDATA%\BlueCaster\ (the three programs, the uninstaller and a licenses\ folder with the license texts)
  • Portable (BlueCaster-<version>-win64-portable.zip, on ARM64 -arm64-portable.zip): extract anywhere and run bluecaster.exe. Keep the three programs (bluecaster.exe, bluecaster-core.exe, bluecaster-driver.exe) together. The portable copy only tells you about updates; it needs the WebView2 Runtime installed

Both keep settings, profiles, link keys and firmware in %APPDATA%\BlueCaster, so you can switch between them. Uninstalling deletes that folder unless you turn Delete user data off (a silent uninstall keeps it).

Upgrading from v1

Run the installer over v1. Its Ready page says which earlier versions it uninstalls first (v1, or any 2.0.x). It asks you to close v1 if it is running, then uninstalls v1 and keeps the settings folder: profiles, the pairing with your headphones and the firmware files carry over, and the headphones do not need to be paired again. An adapter that already has WinUSB (from Zadig) keeps it. If Start with Windows was on, it now starts v2.

At its first start v2 copies the v1 settings to %APPDATA%\BlueCaster\backup\v1\ before it reads them.

Upgrading from 2.0.x (A2DP Windows Bridge)

BlueCaster 3.0.0 is the new name of A2DP Windows Bridge. Run the 3.0.0 installer over the installed 2.0.x: the setup uninstalls the old version by itself and keeps your settings. The Start menu entry and the Start with Windows entry move to “BlueCaster”.

At its first start 3.0.0 renames the folder %APPDATA%\A2DPWB to %APPDATA%\BlueCaster and sorts its files into subfolders (see Settings and Files). backup\v2\ holds a copy of the 2.0.x settings and pairings, so that 2.0.2 can be installed again: copy those files back to %APPDATA%\A2DPWB.

The headphones may keep showing the old Bluetooth name “A2DPWB” until you pair them again.

Step 1: First-Run Setup

Plug in the USB Bluetooth adapter and start BlueCaster. On the first start (no audio device yet, or no adapter has WinUSB), BlueCaster opens the Setup Wizard, four steps. Once it was finished or skipped, it does not open by itself again: devices are added on Home or Audio Devices.

  1. Choose the adapter: the USB Bluetooth adapters found. If yours is missing, plug it in and press Refresh. A green Supported or a red Unsupported says whether BlueCaster can use each one; an unsupported one is listed but cannot be chosen
  2. Driver and firmware: the step lists what it will do, and Set up this adapter does it: it replaces the adapter’s driver with WinUSB (Windows asks for administrator permission, see Step 2) and downloads the Realtek firmware files the adapter needs (see Firmware). Firmware BlueCaster cannot download is put into the firmware folder by hand. When Windows has devices paired through this adapter (a keyboard or mouse on a built-in adapter, say), the button names them first: they stop working with Windows while BlueCaster uses the adapter, and Cancel keeps them. Devices on their own USB receiver are not affected; to keep the others, use BlueCaster with a separate USB adapter. The Adapters screen’s Replace with WinUSB driver names them too
  3. Find your audio devices: the scan starts by itself. Put the audio device into pairing mode and press Connect next to it (or type its address and press Use): BlueCaster saves it with the best codec it has (Auto) and connects. It then stands under Paired Devices with a dot for its state, and the scan stops. Add a device disconnects it and resumes the scan for another device; it stays saved, and a wrong device can be forgotten there. Import pairings from Windows shows when Windows paired devices through this adapter: its Import button lists them, each ticked (see Step 3). Next works without a device too; audio devices can be added later on Audio Devices. New devices capture the Hi-Fi Cable when it is installed, else VB-CABLE: the Hi-Fi Cable adds the least delay, so it is recommended for the sound, and VB-CABLE for the headphones’ microphone. The step suggests the cables that are missing, each with a × to close it (both stay under Settings > Virtual cables): Install VB-CABLE downloads VB-Audio’s VB-CABLE package from VB-Audio (1.3 MB) and installs it (an administrator prompt; if it does not appear, restart Windows), and Download Hi-Fi Cable opens VB-Audio’s page. Both are donationware by VB-Audio (vb-cable.com): BlueCaster does not include VB-CABLE, and donations go to VB-Audio. In a company or other organisation, VB-Audio asks for a licence per installation (licensing). The first time BlueCaster finds a cable later, devices on the Default device capture it (VB-CABLE only while the Hi-Fi Cable is not installed), and devices whose microphone has no working output play it there. Its codec can be changed later on Codecs
  4. General Settings: the theme, Startup, Notifications and update checks, the same controls as in Settings, saved at once. A first setup turns Start with Windows and Start in the tray on

Set up later skips the rest; Settings > Run setup opens it again.

Step 2: Assign WinUSB to the Adapter

BlueCaster communicates directly with a USB Bluetooth adapter via WinUSB, the generic USB driver included in Windows. A dedicated adapter is recommended – your built-in Bluetooth then continues to work normally for regular Windows Bluetooth.

  1. Open the Adapters screen (the setup’s Driver and firmware step does steps 2 to 4 with Set up this adapter)
  2. The adapter’s Driver reads Original driver (or No driver): the driver Windows or the manufacturer installed, which WinUSB replaces. Click Replace with WinUSB driver
  3. Read the confirmation and continue: Windows asks for administrator permission (UAC)
  4. The driver now reads WinUSB driver

If Windows could not load WinUSB right away (the adapter was in use), BlueCaster says so and the driver line shows Replug or restart Windows. Unplug the adapter and plug it back in; for a built-in adapter, restart Windows. Until then, connecting fails with failed to initialize WinUSB (error 50) in the log.

While WinUSB is assigned, Windows’ own Bluetooth no longer sees the adapter: devices paired with Windows through it stop working until the driver is restored. Use your built-in Bluetooth for normal peripherals (keyboard, mouse, etc.). A built-in adapter that is a USB device (a Realtek one on many laptops) can be given to BlueCaster too, but then the PC has no Windows Bluetooth at all (Bluetooth settings, mice, keyboards, other audio devices) until you restore its driver.

Restore original driver on the same screen gives the adapter back to Windows: Windows picks its own driver again (normally its Bluetooth driver) and the adapter works with Windows’ Bluetooth. BlueCaster cannot stream through it until WinUSB is assigned again. Windows runs one Bluetooth adapter at a time: if another one is in use, BlueCaster says so after the restore, and this adapter works in Windows only once you disable that one in Device Manager and replug this one. Headphones that BlueCaster paired again have a new key: the restore gives it to Windows too, for those Windows has paired through this adapter, so they connect there without pairing again. Limitation: only classic pairings are handed over, not LE keys: a device Windows uses through LE (LE Audio) needs pairing again in Windows (developer mode can try handing them over: Developer > Debug). The uninstaller offers the same: a page of the uninstall wizard has Restore the original Bluetooth driver (when BlueCaster put adapters on WinUSB; one administrator prompt) and Delete user data (settings, codecs, pairings and firmware in %APPDATA%\BlueCaster, and what the window remembers, such as Show only supported codecs), both on by default. When only adapters without that record are on WinUSB (set with Zadig or v1), the first choice is there but off: Windows then chooses their driver. Updates keep WinUSB, and so does a silent uninstall (/S).

Using Zadig instead

A WinUSB driver installed with Zadig works just as well:

  1. Open Zadig, go to Options > List All Devices
  2. Select your USB Bluetooth adapter from the dropdown
  3. Select WinUSB as the target driver and click Replace Driver

By hand in Device Manager

If the adapter is missing from BlueCaster’s list, a button on the Adapters screen fails, or your adapter behaves differently from others of its kind, Windows’ Device Manager (right-click Start > Device Manager) does the same by hand. Both need administrator rights. Menu names may differ slightly between Windows versions.

Replace with WinUSB driver

  1. Find the adapter: normally under Bluetooth with its own name (for example “TP-Link Bluetooth USB Adapter”), or with a yellow mark when its driver failed to start. View > Devices by connection helps tell it apart from the PC’s built-in Bluetooth, which you leave alone unless you mean to give it to BlueCaster
  2. Right-click it > Update driver > Browse my computer for drivers > Let me pick from a list of available drivers on my computer
  3. If Windows asks for a device type, choose Universal Serial Bus devices. Clear Show compatible hardware, choose the manufacturer WinUsb Device and the model WinUsb Device, click Next and confirm the warning
  4. The adapter now shows as WinUsb Device under Universal Serial Bus devices. Restart BlueCaster (or open the Adapters screen again): it uses the adapter as with Zadig

Restore the original driver

  1. Under Universal Serial Bus devices, right-click the adapter (WinUsb Device) > Uninstall device. If the WinUSB driver came from Zadig, also tick Attempt to remove the driver for this device, or Windows picks Zadig’s driver again
  2. Unplug the adapter and plug it in again (or Action > Scan for hardware changes). Windows installs its own driver and the adapter appears under Bluetooth
  3. If it shows a yellow mark there instead (its driver failed to start, for example Code 31), the manufacturer’s driver does not work with it: right-click > Update driver > Browse my computer for drivers > Let me pick from a list of available drivers on my computer > Generic Bluetooth Adapter, or assign WinUSB again as above to use it with BlueCaster

Step 3: Find Your Headphones

Scan Devices (on Audio Devices) finds nearby devices with the USB adapter for 30 seconds, listing them as they answer. In the setup the scan starts by itself and goes on until a device is connected (Add a device disconnects it and resumes the scan), Stop Scanning is pressed or the setup is closed. Put the headphones into pairing mode first. Devices BlueCaster has paired with before are listed as Paired.

If the scan does not find them, enter the Bluetooth address under Manual: and click Use. Typed or pasted addresses are formatted as you go: AA:BB:CC:DD:EE:FF, aa-bb-cc-dd-ee-ff, AABBCCDDEEFF and AA BB CC DD EE FF all become AA:BB:CC:DD:EE:FF.

Headphones that Windows paired through this adapter before it got WinUSB can keep that pairing: Import pairings from Windows (in the setup’s device step, shown when there are such devices) lists them, each ticked, and takes over the ticked ones, so they connect without pairing mode. Windows asks for administrator permission. Such a device is usually not in pairing mode and does not show in the scan; if it does, or you type its address, Connect or Add warns first that Windows paired it; Add anyway pairs it again as a new device.

From Windows Settings (if the headphones were paired with the PC’s built-in Bluetooth):

  1. Open Settings > Bluetooth & devices
  2. Click on your audio device
  3. Click Properties
  4. The Bluetooth address is shown (format: AA:BB:CC:DD:EE:FF)

From the command line (quit BlueCaster first, tray > Exit):

bluecaster-core.exe --cli --scan

The headphones start with Auto as the codec (Codecs) and the system audio as the output source (Audio Devices); the defaults give the best sound. See Usage for everything else.

Firmware (Realtek Adapters)

Realtek-based USB Bluetooth adapters (e.g., TP-Link UB500, RTL8761BU dongles) require proprietary firmware to operate. CSR adapters need no firmware. Intel, MediaTek MT79xx, Qualcomm and Broadcom adapters may need firmware files of their own: see Recommended Adapters.

In the App (Guided Download)

The Adapters screen (and the setup’s Driver and firmware step) shows the firmware of the adapter: Firmware OK, No Realtek files needed (an adapter BlueCaster does not recognise, with the chip set to Not Realtek), or Firmware not found with the required file names. Use the Open Download Page button to open the linux-firmware/rtl_bt page in your browser, then use Open Firmware Folder to open the destination folder. Download the required .bin files and place them in the firmware folder.

An adapter of another vendor shows no Bluetooth Chip choice; its tag says where the firmware comes from: From MediaTek’s driver or From Qualcomm’s driver (read from the vendor’s Windows driver, which stays installed after WinUSB), From the Wi-Fi driver (Marvell; keep Wi-Fi on), From the firmware folder (Intel, with Open Download Page, Open Firmware Folder and Setup guide), Optional (Broadcom’s .hcd) or Not needed (CSR, Barrot, Actions). Once BlueCaster has loaded it on WinUSB the tag reads Loaded, or Not loaded when loading failed, with Open Download Page, Open Firmware Folder and a line saying where the firmware comes from.

For the chips in the Bluetooth Chip list, Download Firmware does this for you: after you confirm, BlueCaster downloads the files from linux-firmware (kernel.org), checks each one against the SHA-256 it expects and saves it in the firmware folder. A chip that linux-firmware has no config file for gets an empty _config.bin (the chip then uses its own settings). The files are not part of BlueCaster; they are downloaded only when you ask for them.

BlueCaster detects the adapter’s chipset and shows which firmware files are needed.

Without the firmware, a Realtek adapter still opens and answers on its ROM code, so it looks fine, but connecting or streaming fails. BlueCaster then says that the firmware is not loaded. A module keeps firmware uploaded in an earlier session until it loses power, so with the files gone it may keep working until the PC is restarted or the adapter is unplugged.

Bluetooth Chip setting

The Bluetooth Chip list on the Adapters screen decides whether BlueCaster runs Realtek initialization (firmware upload) on the adapter:

Choice Meaning
Auto (default) Decided from the detected adapter each time BlueCaster starts. A known Realtek adapter gets its chip; any other adapter gets no Realtek initialization
Not Realtek Never run Realtek initialization. Use it for Intel, Broadcom, CSR and other adapters if Auto does not recognize yours
RTL8761BU, RTL8822CU, … That Realtek chip. Needed for a Realtek-based adapter that Auto does not recognize (an OEM product under its own VID:PID). The status line shows whether its .bin files are in the firmware folder
Custom Uses custom_fw.bin and custom_config.bin from the firmware folder

Do not choose a Realtek chip or Custom for a non-Realtek adapter: BlueCaster would try to upload Realtek firmware to it, and the adapter may fail to start.

Manual Download

  1. Download the firmware and config .bin files for your chipset from linux-firmware/rtl_bt (e.g., rtl8761bu_fw.bin and rtl8761bu_config.bin)
  2. Place both files in the BlueCaster firmware folder (%APPDATA%\BlueCaster\firmware, also opened by Open Firmware Folder)

These firmware files are proprietary Realtek binaries distributed via the linux-firmware project. They are not included in this repository. See WHENCE for redistribution terms.

Recommended Adapters

Which adapters and headphones have actually been used with BlueCaster, with the codecs and the reports: Verified Hardware.

Chipset Example Products Notes
Realtek TP-Link UB500, RTL8761BU Requires firmware download (see above). Best tested
Realtek RTL8852BD built into laptops (0BDA:B853) linux-firmware has no firmware for it: BlueCaster reads rtl8852bd_mp_chip_new.dat from Realtek’s Windows Bluetooth driver, so keep that driver installed (or put the file in the firmware folder). Not yet tested on the hardware
CSR Generic CSR8510 dongles Works out of the box, no firmware needed
Barrot Bluetooth 5.4 / 6.0 dongles (33FA:0010, 33FA:0012) Runs on ROM firmware, no firmware needed. One user report so far
Marvell Built into Microsoft Surface Pro / Surface Book (88W8897) No firmware files: the Wi-Fi driver loads the Bluetooth firmware too, so keep Wi-Fi on. Not yet tested on the hardware
Actions ATS2851 dongles (10D7:B012) Runs on ROM firmware, no firmware needed. It lists commands it cannot do; BlueCaster hides them. Not yet tested on the hardware
Broadcom ASUS BT400 (BCM20702) Adapters that report the vendor class FF/01/01 instead of Bluetooth E0/01/01 (BCM20702 OEM dongles) are detected too. Runs on ROM firmware; an optional PatchRAM .hcd (e.g. BCM20702A1-0b05-17cb.hcd) in the firmware folder is uploaded at startup
Intel Intel 7260 / 3160 / 7265 / 3165 / 3168 / 8260 / 8265 / 9260 / AX200 / AX201 / AX210 / AX211 In bootloader mode (e.g. after a cold boot) needs the matching ibt-*.sfi + ibt-*.ddc from linux-firmware intel/ in the firmware folder; the log names them (e.g. ibt-0180-0041.sfi). The 7260 / 3160 / 7265 / 3165 / 3168 run from ROM and need no files; the matching patch ibt-hw-*.bseq from the same folder is applied when present
MediaTek MT7925, MT7922, MT7921, MT7902 (Wi-Fi cards such as the AMD RZ717, RZ616, RZ608) Needs the chip’s BT_RAM_CODE_MT*_hdr.bin (e.g. BT_RAM_CODE_MT7925_1_1_hdr.bin), which BlueCaster reads from MediaTek’s Windows Bluetooth driver when it is installed; otherwise put the file from linux-firmware mediatek/ in the firmware folder; the log names it
Qualcomm QCA61x4, QCA9377 (ROME), WCN6855 (FastConnect 6900) Needs the chip’s rampatch and NVM (e.g. AthrBT_0x00000302.dfu and ramps_0x00000302_48.dfu), which BlueCaster reads from Qualcomm’s Windows Bluetooth driver when it is installed; otherwise put the files from linux-firmware qca/ (rampatch_usb_*.bin, nvm_usb_*.bin) in the firmware folder; the log names them. Not yet tested on the hardware
MediaTek, Qualcomm Other MediaTek chips (MT7927), other Qualcomm chips (QCA6290, WCN785x) Not supported: need firmware loaders BlueCaster does not have (help add one)

USB Bluetooth 5.0+ adapters generally work best for high-bitrate codecs like LDAC.

When several adapters have WinUSB, BlueCaster uses the first one it finds. Keep WinUSB on only the adapter you use for BlueCaster.