lyra_android_example.apk crashed.

[TangYuFan]

Hello, the Android example compiled according to the readme file runs well on some phones and crashes on some phones。

The compilation script I tried：
(1) bazel build -c opt lyra/android_example:lyra_android_example --config=android_arm64 --copt=-DBENCHMARK
(2) bazel build -c opt lyra/android_example:lyra_android_example --fat_apk_cpu=armeabi-v7a,arm64-v8a --copt=-DBENCHMARK

Running apk on some phones has crashed. The following is the error log:

May I ask how to solve the above problems? Is compiling a script requiring special instructions? Because I use encoding and decoding interfaces to package it into SO for Android phones, some phones may not run properly。

[JianhaoPeng]

@TangYuFan Hi, I also encountered this problem, have you solved this yet? I tried upgrade the version of sdk, but the compiling process failed, only version 30 can build successfully. Besides, is this apk can be adapted to android 15? Thank you so much.

[TangYuFan]

My colleague solved this problem, probably because there is an issue with the destructor:

[JianhaoPeng]

@TangYuFan Hi, thanks, I found this line in DenseStorge.h, should I comment out this line, can you tell me how do you solve this? By the way, I found that the app didn't crash after I commented out the encode and decode methods in jni_lyra_benchmark_lib.cpp. Can we use email to discuss it, i struggle with this problem for weeks, my email is 2580979439@qq.com, thanks a million.

[TangYuFan]

My colleague found through GDB debugging that it is hanging on this destructor. Sorry, I don't know the specific modifications. My algorithm colleague fixed the problem and directly provided me with the .so dynamic library file.

[JianhaoPeng]

We're trying to implement the encode and decode method separately using the .so dynamic library file, can you share it? Really appreciate your help.

[TangYuFan]

You can obtain the Android SO library file through the following methods:
The idea comes from another issue

1. Add codec dependency to android_example / BUILD
   deps = [
   "//lyra:lyra_encoder",
   "//lyra:lyra_decoder",
   ]
   2.Add the codec jni function to jni_lyra_benchmarked_lib.cc

#include "lyra/lyra_encoder.h"
#include "lyra/lyra_decoder.h"

namespace {
std::unique_ptrchromemedia::codec::LyraEncoder encoder;
std::unique_ptrchromemedia::codec::LyraDecoder decoder;
}

Next, you can call Lyra to provide JNI functions such as initialization, release, encoding, decoding, etc
like this：
extern "C" JNIEXPORT int JNICALL Java_com_lyra_LyraCodec_codecInit(JNIEnv* env, jobject this_obj, jint sampleRateHz, jint numChannels, jint bitrate, jboolean enableDtx, jstring modelPath){
const char* modelPathCStr = env->GetStringUTFChars(modelPath, nullptr);
if (modelPathCStr == nullptr) {
return 0;
}
ghc::filesystem::path model(modelPathCStr);
env->ReleaseStringUTFChars(modelPath, modelPathCStr);
encoder = chromemedia::codec::LyraEncoder::Create(sampleRateHz, numChannels, bitrate, enableDtx, model);
decoder = chromemedia::codec::LyraDecoder::Create(sampleRateHz, numChannels, model);
return (encoder != nullptr) && (decoder != nullptr);
}
3. Compile android_deample and extract so file

[smallpotato85]

Hi @TangYuFan
Could you describe your solution with more details?
I have tried your suggestion but it is not working.
It looks like your approach is just same as using "jni_lyra_benchmark_lib.cc" that is already suggested in BUILD source code.
I made my own library through "my_lyra_lib.cc".
And because I want to use chromemedia::codec::DecodeFeatures() & chromemedia::codec::EncodeWav,
I called those functions on "my_lyra_lib.cc" and hooked dependencies on //lyra/cli_example:decoder_main_lib & encoder_main_lib.
And built those ones by specifying cc_library in the BUILD file. (Sorry I have not understand how .cc files can be libraries without cc_library grammer)
And then set & build void MainActivity.java through android_library() with dependency on my_lyra_lib.
And finally I built my own lyra_android_example.so through android_binary() with dependency on the library.

Please check my modification and tell me which is wrong.
I wasted a couple of weeks for this problem... Really need your help.

Hi @JianhaoPeng
It looks like you have got clue from TangYuFan's comment and got a solution.
Could you share your solution how to build the .so ?

Many thanks in advance

[smallpotato85]

I found a solution but it's very hacky one.
I don't know the details, but anyway it looks like the _Unwind_Backtrace() has some problem.
I disassembled liblyra_android_example.so and made the _Unwind_Backtrace() as void function.
(return immediately after calling the function)
After this, the crash disappeared and I could do Dec & Enc through Lyra as I wanted.

By searching, it looks like the function is related to process of exception in general code.
I also tried to find some option to disable such exceptional processing related the function but also failed.

[TangYuFan]

After my attempts, I found that the problem occurred with the version of the Eigen library. My final solution was to extract the relevant models and deploy them directly on Android or iOS using the TFLite inference engine, without the need to use the cumbersome Bazel to compile Lyra source code.

Successfully deployed using this version in Android:
org.tensorflow:tensorflow-lite:2.17.0

The extraction, restoration, and quantification models for corresponding features are as follows:
lyragan.tflite quantizer.tflite soundstream_encoder.tflite

The Android deployment example code can refer to this example [link]:
https://github.com/TangYuFan/deeplearn-mobile/tree/main/android_tflite_lyra_demo