Android import for Libwebp

[Panagiotis Paraskeva]

I am an android developer that works for a start-up company.

I would like to import the libwebp library to our project and use it to generate animated webps and remove the dependency we have on FFMPEG.

Unfortunately, I do not have much experience with the android ndk to import the project.
Furthermore, i am already using the android ndk/cmake for audio optimization.

Can you please send me an explanation on how to import the library using my current cmake file?


Regards,
Panagiotis Paraskeva

[James Zern]

Hi,

On its own, libwebp can be build using the Android toolchain file:
cmake ../libwebp -DCMAKE_TOOLCHAIN_FILE=<path-to-ndk>/build/cmake/android.toolchain.cmake [-DANDROID_ABI=...]

You could install that and use find_package() [1] or instead use add_subdirectory() [2] to pull in the targets and have them built along with your project:
add_subdirectory("libwebp" EXCLUDE_FROM_ALL)

You can then depend on the targets from libwebp like 'webp' and 'libwebpmux'.

[1] https://cmake.org/cmake/help/latest/command/find_package.html

[2] https://cmake.org/cmake/help/latest/command/add_subdirectory.html

[Udara Wanasinghe]

Hi,

I experimented with this months ago and created JNI bindings to encode a series of android bitmap images to an animated WebP image. I made my work public for your reference. Please check my repository on GitHub.

[Pem Code]

cd libwebp/android-build
cmake .. -DCMAKE_TOOLCHAIN_FILE=/sarc-c/gpusw/users/p.mowry/android-ndk-r25b/build/cmake/android.toolchain.cmake -DANDROID_ABI=arm64-v8a
make

This outputs files to libwebp root directory.  Unfortunately it does not output to android-build.  However, it does appear to output binary files: webp_quality img2webp dwebp get_disto cwebp webpinfo webpmux dwebp get_disto libcpufeatures.a  libexampleutil.a  libextras.a  libimagedec.a  libimageenc.a  libimageioutil.a  libsharpyuv.a  libwebp.a  libwebpdecoder.a  libwebpdemux.a  libwebpmux.a

I have an existing C++ project that builds using cmake command line on Linux for Android.  My existing code has an array of RGBA pixels (R8 G8 B8 A8) that writes the uint8_t array to a bmp file.  I want my project's cmake file to reference the appropriate webp Android binary and modify the C++ code to write to a webp file (instead of a bmp file).  How do I do this?

[Udara Wanasinghe]

You can allocate space for a new WebPPicture struct and copy pixel data directly to it. See how this is done in my project https://github.com/UdaraWanasinghe/webp-android/blob/dbd5ff0f7765b723c648c0919164a66ddc2d213c/webp-android/src/main/cpp/encoder.cpp#L446

[James Zern]

On Mon, Oct 10, 2022 at 1:19 AM Pem Code <pem.s...@gmail.com> wrote:

cd libwebp/android-build
cmake .. -DCMAKE_TOOLCHAIN_FILE=/sarc-c/gpusw/users/p.mowry/android-ndk-r25b/build/cmake/android.toolchain.cmake -DANDROID_ABI=arm64-v8a
make

This outputs files to libwebp root directory. Unfortunately it does not output to android-build.  However, it does appear to output binary files: webp_quality img2webp dwebp get_disto cwebp webpinfo webpmux dwebp get_disto libcpufeatures.a  libexampleutil.a  libextras.a  libimagedec.a  libimageenc.a  libimageioutil.a  libsharpyuv.a  libwebp.a  libwebpdecoder.a  libwebpdemux.a  libwebpmux.a

All outputs should be under android-build unless you have already run cmake in the source directory. Starting with a fresh tree or deleting all CMakeFiles and CMakeCache.txt files and running cmake again should work

 

I have an existing C++ project that builds using cmake command line on Linux for Android.  My existing code has an array of RGBA pixels (R8 G8 B8 A8) that writes the uint8_t array to a bmp file.  I want my project's cmake file to reference the appropriate webp Android binary and modify the C++ code to write to a webp file (instead of a bmp file).  How do I do this?

On Wednesday, August 31, 2022 at 9:49:32 AM UTC-7 udara.d...@gmail.com wrote:

Hi,

I experimented with this months ago and created JNI bindings to encode a series of android bitmap images to an animated WebP image. I made my work public for your reference. Please check my repository on GitHub.

On Monday, August 29, 2022 at 6:21:30 PM UTC+5:30 panag...@beatroot.app wrote:

I am an android developer that works for a start-up company.

I would like to import the libwebp library to our project and use it to generate animated webps and remove the dependency we have on FFMPEG.

Unfortunately, I do not have much experience with the android ndk to import the project.
Furthermore, i am already using the android ndk/cmake for audio optimization.

Can you please send me an explanation on how to import the library using my current cmake file?


Regards,
Panagiotis Paraskeva

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[Pem Code]

The following enabled me to reference libwebp binaries (in case it helps someone else) for Android C++ using cmake...

target_include_directories(foo PRIVATE

    ../../../../libwebp/src/webp
)
if(ANDROID)
    if(${ANDROID_ABI} STREQUAL "armeabi-v7a")
        SET(WEBP_ANDROID_FOLDER "build-android32")
    else()
        SET(WEBP_ANDROID_FOLDER "build-android")
    endif()
    target_link_libraries(xgl PRIVATE ${GLOBAL_ROOT_SRC_DIR}/../libwebp/${WEBP_ANDROID_FOLDER}/libcpufeatures.a)
    target_link_libraries(xgl PRIVATE ${GLOBAL_ROOT_SRC_DIR}/../libwebp/${WEBP_ANDROID_FOLDER}/libexampleutil.a)
    target_link_libraries(xgl PRIVATE ${GLOBAL_ROOT_SRC_DIR}/../libwebp/${WEBP_ANDROID_FOLDER}/libextras.a)
    target_link_libraries(xgl PRIVATE ${GLOBAL_ROOT_SRC_DIR}/../libwebp/${WEBP_ANDROID_FOLDER}/libimagedec.a)
    target_link_libraries(xgl PRIVATE ${GLOBAL_ROOT_SRC_DIR}/../libwebp/${WEBP_ANDROID_FOLDER}/libimageenc.a)
    target_link_libraries(xgl PRIVATE ${GLOBAL_ROOT_SRC_DIR}/../libwebp/${WEBP_ANDROID_FOLDER}/libimageioutil.a)
    target_link_libraries(xgl PRIVATE ${GLOBAL_ROOT_SRC_DIR}/../libwebp/${WEBP_ANDROID_FOLDER}/libsharpyuv.a)
    target_link_libraries(xgl PRIVATE ${GLOBAL_ROOT_SRC_DIR}/../libwebp/${WEBP_ANDROID_FOLDER}/libwebp.a)
    target_link_libraries(xgl PRIVATE ${GLOBAL_ROOT_SRC_DIR}/../libwebp/${WEBP_ANDROID_FOLDER}/libwebpdecoder.a)
    target_link_libraries(xgl PRIVATE ${GLOBAL_ROOT_SRC_DIR}/../libwebp/${WEBP_ANDROID_FOLDER}/libwebpdemux.a)
    target_link_libraries(xgl PRIVATE ${GLOBAL_ROOT_SRC_DIR}/../libwebp/${WEBP_ANDROID_FOLDER}/libwebpmux.a)
    target_link_libraries(xgl PRIVATE ${GLOBAL_ROOT_SRC_DIR}/../libwebp/${WEBP_ANDROID_FOLDER}/cwebp)

endif()

Next I will see if I can get this reference code from @udara to write a webp file (taking a uint8_t array as input) (btw the uint8_t array is data from a vulkan VkImage's such as VK_FORMAT_R8G8B8A8_UNORM from the swapchain)

[Udara Wanasinghe]

You can configure the build using configuration parameters available in libwebp.

set(WEBP_BUILD_ANIM_UTILS FALSE) # Build animation utilities.
set(WEBP_BUILD_CWEBP FALSE) # Build the cwebp command line tool.
set(WEBP_BUILD_DWEBP FALSE) # Build the dwebp command line tool.
set(WEBP_BUILD_GIF2WEBP FALSE) # Build the gif2webp conversion tool.
set(WEBP_BUILD_IMG2WEBP FALSE) # Build the img2webp animation tool.
set(WEBP_BUILD_VWEBP FALSE) # Build the vwebp viewer tool.
set(WEBP_BUILD_WEBPINFO FALSE) # Build the webpinfo command line tool.
set(WEBP_BUILD_LIBWEBPMUX TRUE) # Build the libwebpmux library.
set(WEBP_BUILD_WEBPMUX FALSE) # Build the webpmux command line tool.
set(WEBP_BUILD_EXTRAS FALSE) # Build extras.

Since we are required only the libwebpmux library, set WEBP_BUILD_LIBWEBPMUX to TRUE.

Avoid manually including library files. You can do this by adding libwebp as a subdirectory to your cmake build script.

set(LIBWEBP_PATH ../../libwebp CACHE STRING "libwebp path")
add_subdirectory(${LIBWEBP_PATH} ${CMAKE_CURRENT_BINARY_DIR}/libwebp)

See full example here https://github.com/UdaraWanasinghe/webp-android/blob/main/webp-android/CMakeLists.txt.

[Pem Code]

Oh maybe I should add libweb as an external aka git submodule...  I will try this way of building instead.  It does sound cleaner...

[Pem Code]

It is working now.  Thank you for the references