Whisper module (Vulkan) - build outside docker container

[j4ckp0t85]

Hi Andrey, since i'm using Android Studio on Windows (i'm a newbie) to build Fermata, my guess is that something in the CMakeLists.txt file inside Whisper module is "hardcoded" to compile under the docker linux container.

Could you make it more "cross platform" in order to be compiled even outside of the docker container?

[AndreyPavlenko]

What's the error do you have? If it's only Vulkan related, you can disable it with GGML_VULKAN OFF in CMakeLists.txt. You can also disable the entire whisper addon, either in CMakeLists.txt or just remove the folder. If you want to compile it, first of all, make sure that you can compile https://github.com/ggml-org/whisper.cpp in your env. The addon depends on this project.

[j4ckp0t85]

I've tried to fix the Vulkan_INCLUDE_DIR and Vulkan_GLSLC_EXECUTABLE in order to fix the correct references under windows.

Now it seems it doesn't like the Ninja build tool

`Execution failed for task ':whisper:buildCMakeRelease[arm64-v8a]'.

com.android.ide.common.process.ProcessException: ninja: Entering directory `C:\Users\mazze\Desktop\Fermata\modules\whisper.cxx\Release\4v2o425u\arm64-v8a'
[0/2] Re-checking globbed directories...
[1/296] Building C object _deps/whispercpp-build/ggml/src/CMakeFiles/ggml-base.dir/ggml-alloc.c.o
[2/296] Creating directories for 'vulkan-shaders-gen'
[3/296] Building C object _deps/whispercpp-build/ggml/src/CMakeFiles/ggml-base.dir/ggml.c.o
[4/296] Building C object _deps/whispercpp-build/ggml/src/CMakeFiles/ggml-cpu.dir/ggml-cpu/ggml-cpu.c.o
[5/296] Building CXX object _deps/whispercpp-build/ggml/src/CMakeFiles/ggml-cpu.dir/ggml-cpu/hbm.cpp.o
[6/296] No download step for 'vulkan-shaders-gen'
[7/296] Building CXX object _deps/whispercpp-build/ggml/src/CMakeFiles/ggml-base.dir/ggml-threading.cpp.o
[8/296] Building CXX object _deps/whispercpp-build/ggml/src/CMakeFiles/ggml-base.dir/ggml.cpp.o
[9/296] Building C object _deps/whispercpp-build/ggml/src/CMakeFiles/ggml-cpu.dir/ggml-cpu/quants.c.o
[10/296] Building C object _deps/whispercpp-build/ggml/src/CMakeFiles/ggml-base.dir/ggml-quants.c.o
[11/296] Building CXX object _deps/whispercpp-build/ggml/src/CMakeFiles/ggml-base.dir/ggml-backend.cpp.o
[12/296] Building CXX object _deps/whispercpp-build/ggml/src/CMakeFiles/ggml-base.dir/ggml-opt.cpp.o
[13/296] No update step for 'vulkan-shaders-gen'
[14/296] Building CXX object _deps/whispercpp-build/ggml/src/CMakeFiles/ggml-cpu.dir/ggml-cpu/ggml-cpu.cpp.o
[15/296] No patch step for 'vulkan-shaders-gen'
[16/296] Building CXX object _deps/whispercpp-build/ggml/src/CMakeFiles/ggml-base.dir/gguf.cpp.o
[17/296] Building CXX object _deps/whispercpp-build/ggml/src/CMakeFiles/ggml-cpu.dir/ggml-cpu/repack.cpp.o
[18/296] Performing configure step for 'vulkan-shaders-gen'
FAILED: _deps/whispercpp-build/ggml/src/ggml-vulkan/vulkan-shaders-gen-prefix/src/vulkan-shaders-gen-stamp/vulkan-shaders-gen-configure C:/Users/mazze/Desktop/Fermata/modules/whisper/.cxx/Release/4v2o425u/arm64-v8a/_deps/whispercpp-build/ggml/src/ggml-vulkan/vulkan-shaders-gen-prefix/src/vulkan-shaders-gen-stamp/vulkan-shaders-gen-configure
C:\WINDOWS\system32\cmd.exe /C "cd /D C:\Users\mazze\Desktop\Fermata\modules\whisper.cxx\Release\4v2o425u\arm64-v8a_deps\whispercpp-build\ggml\src\ggml-vulkan\vulkan-shaders-gen-prefix\src\vulkan-shaders-gen-build && C:\Users\mazze\AppData\Local\Android\Sdk\cmake\4.1.2\bin\cmake.exe -DCMAKE_INSTALL_PREFIX=C:/Users/mazze/Desktop/Fermata/modules/whisper/.cxx/Release/4v2o425u/arm64-v8a/Release -DCMAKE_INSTALL_BINDIR=. -DCMAKE_BUILD_TYPE=Release -DCMAKE_TOOLCHAIN_FILE=C:/Users/mazze/Desktop/Fermata/modules/whisper/.cxx/Release/4v2o425u/arm64-v8a/host-toolchain.cmake -GNinja -S C:/Users/mazze/Desktop/Fermata/modules/whisper/.cxx/Release/4v2o425u/arm64-v8a/_deps/whispercpp-src/ggml/src/ggml-vulkan/vulkan-shaders -B C:/Users/mazze/Desktop/Fermata/modules/whisper/.cxx/Release/4v2o425u/arm64-v8a/_deps/whispercpp-build/ggml/src/ggml-vulkan/vulkan-shaders-gen-prefix/src/vulkan-shaders-gen-build && C:\Users\mazze\AppData\Local\Android\Sdk\cmake\4.1.2\bin\cmake.exe -E touch C:/Users/mazze/Desktop/Fermata/modules/whisper/.cxx/Release/4v2o425u/arm64-v8a/_deps/whispercpp-build/ggml/src/ggml-vulkan/vulkan-shaders-gen-prefix/src/vulkan-shaders-gen-stamp/vulkan-shaders-gen-configure"
CMake Error: CMake was unable to find a build program corresponding to "Ninja". CMAKE_MAKE_PROGRAM is not set. You probably need to select a different build tool.
-- Configuring incomplete, errors occurred!
[19/296] Building CXX object _deps/whispercpp-build/ggml/src/CMakeFiles/ggml-cpu.dir/ggml-cpu/traits.cpp.o
[20/296] Building CXX object _deps/whispercpp-build/ggml/src/CMakeFiles/ggml-cpu.dir/ggml-cpu/amx/mmq.cpp.o
[21/296] Building CXX object _deps/whispercpp-build/ggml/src/CMakeFiles/ggml-cpu.dir/ggml-cpu/amx/amx.cpp.o
[22/296] Linking CXX static library _deps\whispercpp-build\ggml\src\libggml-base.a
[23/296] Building CXX object _deps/whispercpp-build/ggml/src/CMakeFiles/ggml-cpu.dir/ggml-cpu/binary-ops.cpp.o
[24/296] Building CXX object _deps/whispercpp-build/ggml/src/CMakeFiles/ggml-cpu.dir/ggml-cpu/vec.cpp.o
[25/296] Building C object _deps/whispercpp-build/ggml/src/CMakeFiles/ggml-cpu.dir/ggml-cpu/arch/arm/quants.c.o
[26/296] Building CXX object _deps/whispercpp-build/ggml/src/CMakeFiles/ggml-cpu.dir/ggml-cpu/unary-ops.cpp.o
[27/296] Building CXX object _deps/whispercpp-build/ggml/src/CMakeFiles/ggml-cpu.dir/ggml-cpu/ops.cpp.o
ninja: build stopped: subcommand failed.

C++ build system [build] failed while executing:
@echo off
"C:\Users\mazze\AppData\Local\Android\Sdk\cmake\4.1.2\bin\ninja.exe" ^
-C ^
"C:\Users\mazze\Desktop\Fermata\modules\whisper\.cxx\Release\4v2o425u\arm64-v8a" ^
VideoHppGenerator ^
VulkanHppGenerator ^
whisper_jni
from C:\Users\mazze\Desktop\Fermata\modules\whisper

• Try:

Run with --stacktrace option to get the stack trace.
Run with --info or --debug option to get more log output.
Run with --scan to get full insights.
Get more help at https://help.gradle.org.

Deprecated Gradle features were used in this build, making it incompatible with Gradle 9.0.

You can use '--warning-mode all' to show the individual deprecation warnings and determine if they come from your own scripts or plugins.

For more on this, please refer to https://docs.gradle.org/8.13/userguide/command_line_interface.html#sec:command_line_warnings in the Gradle documentation.
Ask Gemini
`

[AndreyPavlenko]

Probaby whisper.cpp build is unable to locate ninja. Try setting the CMAKE_MAKE_PROGRAM="C:\Users\mazze\AppData\Local\Android\Sdk\cmake\4.1.2\bin\ninja.exe" variable or add the folder C:\Users\mazze\AppData\Local\Android\Sdk\cmake\4.1.2\bin to Path

[j4ckp0t85]

The problem seems to be related to the build of the shaders under Windows.

Maybe it should use precompiled one?

Or exclude all completely, as you said.

But i was interested first in try to make it available

[AndreyPavlenko]

I don't know, never built it under Windows. You can build it without Vulkan. It's not much faster than runing on CPU and does not work on some devices ggml-org/whisper.cpp#3551. Besides, enabling Vulkan adds ~20mb to the apk size.
I think, another good option for windows is WSL.

[j4ckp0t85]

I've already built it without Vulkan. This is not for the build stuffs itself, it's for having more control over debugging attaching my device (logcat).

Thank you for your support anyway

[j4ckp0t85]

I've made several attempts, and thanks also to Gemini Pro and Claude LLM i ended up with this solution.

Let me know if it seems legit to you, a bit complex for sure.

Basically what it does in a windows batch file is pulling up the designed docker image, compiling the vulkan shaders and copy it into the target folder.

Once the shaders are copied, the build process can continue outside of the docker container (in my case, in android studio): in the configuration if the files are found it skips the build process and use them.

CMakeLists.txt (edited including host toolchain)

if (CMAKE_ANDROID_ARCH_ABI MATCHES "arm64")
    set(GGML_VULKAN ON CACHE BOOL "Enable Vulkan" FORCE)
    FetchContent_Declare(vk_hpp GIT_REPOSITORY https://github.com/KhronosGroup/Vulkan-Hpp
            GIT_TAG v1.3.275
    )
    FetchContent_MakeAvailable(vk_hpp)
    include_directories(${vk_hpp_SOURCE_DIR})
    
    # Vulkan paths for Linux NDK (used in Docker build)
    set(Vulkan_INCLUDE_DIR "${ANDROID_NDK}/toolchains/llvm/prebuilt/linux-x86_64/sysroot/usr/include")
    set(Vulkan_GLSLC_EXECUTABLE "${ANDROID_NDK}/shader-tools/linux-x86_64/glslc")
    
    # Set host toolchain for vulkan-shaders-gen build
    set(GGML_VULKAN_SHADERS_GEN_TOOLCHAIN "${CMAKE_CURRENT_SOURCE_DIR}/cmake/host-toolchain.cmake" CACHE STRING "" FORCE)
    
    find_library(Vulkan_LIBRARY vulkan)
endif ()

host-toolchain.cmake (new)

# Host toolchain for building vulkan-shaders-gen in Docker (Linux)
set(CMAKE_SYSTEM_NAME Linux)
set(CMAKE_SYSTEM_PROCESSOR x86_64)

# Use system compilers (available in cimg/android Docker image)
set(CMAKE_C_COMPILER /usr/bin/gcc)
set(CMAKE_CXX_COMPILER /usr/bin/g++)

# Ninja will be installed in Docker image
set(CMAKE_MAKE_PROGRAM /usr/bin/ninja CACHE FILEPATH "Ninja build tool")

# Standard flags
set(CMAKE_C_FLAGS "-O3" CACHE STRING "" FORCE)
set(CMAKE_CXX_FLAGS "-O3" CACHE STRING "" FORCE)

whisper build-gradle (edited)

// Skip native build on Windows if pre-built libraries exist (from Docker build)
    // This allows debugging in Android Studio on Windows while using Docker-compiled libs
    if (System.getProperty('os.name').toLowerCase().contains('windows')) {
        def jniLibsDir = file('src/main/jniLibs')
        if (jniLibsDir.exists() && jniLibsDir.listFiles()?.length > 0) {
            println "✓ Using pre-built whisper libraries from Docker (found in jniLibs)"
            println "  Run docker/build-whisper.bat to rebuild native code"
            externalNativeBuild.cmake.path = null  // Skip CMake build
        } else {
            println "⚠ No pre-built libraries found. Run docker/build-whisper.bat first!"
        }
    }

Dockerfile (edited)

FROM cimg/android:2025.11.1-ndk

# Install ninja-build for Vulkan shader compilation
USER root
RUN apt-get update && apt-get install -y ninja-build && rm -rf /var/lib/apt/lists/*
USER circleci

# Set working directory
WORKDIR /workspace

# Default command
CMD ["/bin/bash"]

build-whisper.bat (new, placed in docker folder)

@echo off
REM Script per Windows per compilare il modulo whisper usando Docker

setlocal enabledelayedexpansion

echo Building whisper module in Docker...

REM Verifica che Docker sia in esecuzione
docker info >nul 2>&1
if errorlevel 1 (
    echo Error: Docker is not running. Please start Docker Desktop.
    exit /b 1
)

REM Ottieni la directory del progetto (rimuovi trailing backslash)
set SCRIPT_DIR=%~dp0
set SCRIPT_DIR=%SCRIPT_DIR:~0,-1%
set PROJECT_DIR=%SCRIPT_DIR%\..
cd /d "%PROJECT_DIR%"

echo Building Docker image...
docker build -t fermata-builder "%SCRIPT_DIR%"
if errorlevel 1 (
    echo Error: Failed to build Docker image
    exit /b 1
)

echo Compiling whisper native libraries...
docker run --rm -v "%CD%:/workspace" -w /workspace fermata-builder bash -c "dos2unix gradlew 2>/dev/null || sed -i 's/\r$//' gradlew && chmod +x gradlew && echo 'storeFile=res/fermata.jks' > local.properties && echo 'keyAlias=fermata' >> local.properties && echo 'keyPassword=fermata' >> local.properties && echo 'storePassword=fermata' >> local.properties && ./gradlew :whisper:externalNativeBuildAutoRelease --no-daemon && find modules/whisper/.cxx -name '*.so' -type f"
if errorlevel 1 (
    echo Error: Failed to compile native libraries
    exit /b 1
)

echo Copying compiled libraries to jniLibs...
set JNILIBS_DIR=%PROJECT_DIR%\modules\whisper\src\main\jniLibs
if not exist "%JNILIBS_DIR%" mkdir "%JNILIBS_DIR%"

REM Copia le librerie per ogni ABI
set COPIED=0
for %%A in (arm64-v8a armeabi-v7a x86 x86_64) do (
    set "SO_FILE=%PROJECT_DIR%\modules\whisper\build\intermediates\cmake\autoRelease\obj\%%A\libwhisper_jni.so"
    if exist "!SO_FILE!" (
        if not exist "%JNILIBS_DIR%\%%A" mkdir "%JNILIBS_DIR%\%%A"
        copy "!SO_FILE!" "%JNILIBS_DIR%\%%A\" >nul
        echo   Copied %%A/libwhisper_jni.so
        set COPIED=1
    )
)

if "%COPIED%"=="0" (
    echo Warning: No .so files were found to copy
    echo Check the Docker build output above for errors
)

echo.
echo Done! Native libraries are ready.
echo You can now use Android Studio normally for debugging.
echo.
echo Tip: Run this script again only when you need to rebuild native code.

endlocal

[AndreyPavlenko]

RUN apt-get update && apt-get install -y ninja-build && rm -rf /var/lib/apt/lists/*

I think you don't need this. Ninja should already be installed in this env. You can probably use the existing image

docker run -ti --name Fermata andreypavlenko/fermata

To find ninja:

find /opt -type f -name ninja

[SchmilK]

I got windows compile working by replacing linux-x86_x64 with windows-x86_64 and moving cmake folder from appdata to C:\Program Files\Android\Android Studio\cmake
Compiled successfully in 2 minutes and some seconds. App installed and now I'm showing Fermata Media Service in the customize android launcher. 90 minutes before I can leave work and test in my car

[AndreyPavlenko]

Hope you know, that you need AAWireless to see the app in the car?

[AndreyPavlenko]

You can also test with the emulator - https://developer.android.com/training/cars/testing/dhu

[SchmilK]

@AndreyPavlenko I was not aware of that requirement! Now I have to wait until Monday night.

[AndreyPavlenko]

Unfortunately AA shows on the car screen only the apps installed from google play. Or when the phone is connected to the emulator.

[SchmilK]

My compiled version works, I can hear audio from YouTube just no video. So you say with the AAWireless adapter video will transfer?

[AndreyPavlenko]

Yes, it works with AAWireless #432