How to link mp3lame on Android?

Android
1

I am attempting to build an Android app which requires MP3 encoding, via DirectLAMEEncoderAudioFormat

Couple of issues neither of which I have been able to solve yet:

  1. If I try and run on the emulator, the linker attempts to link my local version /usr/local/lib/libmp3lame.a. This is annoying, but since I currently only need ARM builds its not a deal breaker.
  2. When I run the app on a device, it crashes on java.lang.UnsatisfiedLinkError: dlopen failed: library "libmp3lame.so" not found

Initially we had .so builds. I then thought we needed .a builds. Currently I have both .a and .so in the folder pointed at in “Extra Library Search Paths”

Can anyone shed some light on this issue?

2

Solved it:

Added this to the Projucer section “Extra module’s build.gradle content”

    sourceSets {
        main {
            jniLibs.srcDirs = ['<<path to .so files split by ABI>>']
        }
    }
1 Like
3

So I managed to get a device build working in debug mode. But now I am trying to generate an app bundle or APK for upload to Google Play I am still hitting the issue where it’s trying to link the static library in /usr/local/lib not the Android dynamic library. I added the following to the “Extra module’s build.gradle content” above:

// Attempt to prevent the local `libmp3lame.a` from being used for an x86_64 build
    packagingOptions {
        pickFirst '<<path to .so files split by ABI>>/x86/libmp3lame.so'
        pickFirst '<<path to .so files split by ABI>>/x86_64/libmp3lame.so'
        exclude "/usr/local/lib/**"
    }

…but it still links the local file! If I move/rename the local libmp3lame.a I get

 ninja: error: '/usr/local/lib/libmp3lame.a', needed by
 '../../../../build/intermediates/cmake/debug_/debug/obj/x86_64/libjuce_jni.so', 
missing and no known rule to make it

Has anyone here successfully used DirectLameEncoderAudioFormat on Android?

4

Hi,
I’m working on a similar issue, with another lib (libpd). What does your CMakesLists.txt look like?

Do you maybe have :

add_library( <yourLibraryName>
        STATIC
        IMPORTED )

instead of :

add_library( <yourLibraryName>
        SHARED
        IMPORTED )

?

1 Like
5

@adamski Were you able to solve your issue? I’m working my way up to linking a shared library (from a pure Android project to a Juce-Android project), and I still can’t figure out how to configure Projucer to link with a shared lib. I can do it only by editing the generated
CMakeLists.txt file (as pointed out in this thread)

6

At some point I just renamed the libraries, so there was no confusion with system libs. That worked pretty well.

7

But appart from that, are you able to link the shared library only by editing the Projucer? No need to edit the CMakeLists.txt after generating your Android project?

8

Although renaming the libs gets rid of the issue with the linker trying to link to a system lib, it looks like the call to LoadLibrary is in inaccessible Java bytecode, so I cannot rename the library in that call. So for now looks like custom edited CMakeLists.txt might be required. Projucer could offer a field for an alternative name for libmp3lame - that’s assuming that the compiled Java bytecode can accept a parameter set in Projucer…