Android录音并进行本地转码为MP3
**
Android录音并进行本地转码
**
通过安卓手机进行录音，
录音后，使用lame进行转码操作
开发中需要使用这个功能，只是一个简单的进行转码的工具，具体的代码信息如下
项目的基本结构图
1、下载工具包
下载lame工具包
使用的最新版本
安装NDK环境
2、lame内容复制
首先在 src/main/目录下新建一个 cpp文件夹，Lame源码中 libmp3lame拷贝到 cpp文件夹下，可以重命名，例如我命名为 lamemp3
将Lame源码中的 include文件夹下的 lame.h复制到 lamemp3文件夹中
剔除 lamemp3中不必要的文件和目录，.rc/am/in文件都可以删除，Android这里用不到，只保留 .c和 .h文件
修改 util.h的源码。在570行找到 ieee754_float32_t数据类型，将其修改为 float类型，因为 ieee754_float32_t是Linux或者是Unix下支持的数据类型，在Android下并不支持。
set_get.h中24行将 include
在 id3tag.c和 machine.h两个文件里，將 HAVE_STRCHR和 HAVE_MEMCPY的ifdef结构体注释掉，不然编译会报错。
3、build.gradle配置
因为Androidstudio已经更新到最新
defaultConfig {
applicationId "com.example.gz.testmp3"
minSdkVersion 23
targetSdkVersion 27
versionCode 1
versionName "1.0"
testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
externalNativeBuild{
cmake{
cppFlags "-frtti -fexceptions" //设置cpp配置参数，c文件请使用CFlags
abiFilters 'armeabi-v7a', "armeabi"
}
}
ndk{
abiFilters 'armeabi-v7a',"armeabi"
}
}
sourceSets{
main{
jniLibs.srcDirs = ['libs']
}
}
如果下载的是最新的NDK与cmake，报出了一下的错误，
abis [mips64, armeabi, mips] are not supported for platform. supported
abis are [armeabi-v7a, arm64-v8a, x86, x86_64].
解决办法将gradle中cmake abiFilters配置改为：abiFilters ‘x86’, ‘x86_64’,’arm64-v8a’, ‘armeabi-v7a’
Google NDK r18解释： Support for ARMv5 (armeabi), MIPS, and MIPS64 has been removed. Attempting to build any of these ABIs will result in an error
我这里的abiFilters 只写了两个
4、编写Java native方法 MP3Converter
public class MP3Converter {
static {
System.loadLibrary("lame-mp3-utils");//这里一定要写对名称
}
//测试lame环境是否安装成功
public static native String getLameVersion();
/**
* init lame
* @param inSampleRate
* input sample rate in Hz
* @param channel
* number of channels
* @param mode
* 0 = CBR, 1 = VBR, 2 = ABR. default = 0
* @param outSampleRate
* output sample rate in Hz
* @param outBitRate
* rate compression ratio in KHz
* @param quality
* quality=0..9. 0=best (very slow). 9=worst.
* recommended:
* 2 near-best quality, not too slow
* 5 good quality, fast
* 7 ok quality, really fast
*/
public native static void init(int inSampleRate, int channel, int mode,
int outSampleRate, int outBitRate, int quality);
/**
* file convert to mp3
* it may cost a lot of time and better put it in a thread
* @param inputPath
* file path to be converted
* @param mp3Path
* mp3 output file path
*/
public native static void convertMp3(String inputPath, String mp3Path);
/**
* get converted bytes in inputBuffer
* @return
* converted bytes in inputBuffer
* to ignore the deviation of the file size,when return to -1 represents convert complete
*/
public native static long getConvertBytes();
}
5、编写调用C/C++的cpp
这个直接使用的是百度上的，仅限于能看懂，对于c++不懂
extern "C"
JNIEXPORT void JNICALL
Java_jaygoo_library_converter_MP3Converter_convertMp3(JNIEnv * env, jobject obj, jstring jInputPath, jstring jMp3Path) {
const char* cInput = env->GetStringUTFChars(jInputPath, 0);
const char* cMp3 = env->GetStringUTFChars(jMp3Path, 0);
//open input file and output file
FILE* fInput = fopen(cInput,"rb");
FILE* fMp3 = fopen(cMp3,"wb");
short int inputBuffer[BUFFER_SIZE * 2];
unsigned char mp3Buffer[BUFFER_SIZE];//You must specified at least 7200
int read = 0; // number of bytes in inputBuffer, if in the end return 0
int write = 0;// number of bytes output in mp3buffer. can be 0
long total = 0; // the bytes of reading input file
nowConvertBytes = 0;
//if you don't init lame, it will init lame use the default value
if(lame == NULL){
lameInit(44100, 2, 0, 44100, 96, 7);
}
//convert to mp3
do{
read = static_cast(fread(inputBuffer, sizeof(short int) * 2, BUFFER_SIZE, fInput));
total += read * sizeof(short int)*2;
nowConvertBytes = total;
if(read != 0){
write = lame_encode_buffer_interleaved(lame, inputBuffer, read, mp3Buffer, BUFFER_SIZE);
//write the converted buffer to the file
fwrite(mp3Buffer, sizeof(unsigned char), static_cast(write), fMp3);
}
//if in the end flush
if(read == 0){
lame_encode_flush(lame,mp3Buffer, BUFFER_SIZE);
}
}while(read != 0);
//release resources
resetLame();
fclose(fInput);
fclose(fMp3);
env->ReleaseStringUTFChars(jInputPath, cInput);
env->ReleaseStringUTFChars(jMp3Path, cMp3);
nowConvertBytes = -1;
}
6、剩下就是调用了
/**
* 开始录音
* @param mFlag
*/
public void recode(int mFlag){
if(mState != -1){
Log.e(mState+"1", "mState: "+mState );
Message msg = new Message();
Bundle b = new Bundle();// 存放数据
b.putInt("cmd",CMD_RECORDFAIL);
b.putInt("msg", ErrorCode.E_STATE_RECODING);
msg.setData(b);
uiHandler.sendMessage(msg); // 向Handler发送消息,更新UI
return;
}
int mResult = -1;
AudioRecorderWav mRecord_1 = AudioRecorderWav.getInstance();
mResult = mRecord_1.startRecordAndFile(MainActivity.this);
if(mResult == ErrorCode.SUCCESS){
mState = mFlag;
uiThread = new UIThread();
new Thread(uiThread).start();
}else{
Message msg = new Message();
Bundle b = new Bundle();// 存放数据
b.putInt("cmd",CMD_RECORDFAIL);
b.putInt("msg", mResult);
msg.setData(b);
uiHandler.sendMessage(msg); // 向Handler发送消息,更新UI
}
}
可能遇到的问题：
rg.gradle.api.internal.tasks.compile.CompilationFailedException:
Compilation failedCompilation failed; see the compiler error output for details.
解决过程
terminal 输入
gradlew compileDebugSources
查看错误信息
代码下载地址
TestMp3
参考文章：
教你如何使用Android NDK实现一个MP3转码库
Android NDK开发(六)——使用开源LAME转码mp3
应用界面如下
