Use MP3 format to record sound on Android

0. Download lame and Unzip

http://lame.sourceforge.net/download.php

Http://sourceforge.net/projects/lame/files/lame/3.99/lame-3.99.5.tar.gz

1. Create the JNI/LIBMP3LAME/SRC directory, and the uncompressed lame-3.99.5/libmp3lame/directory will be

BITSTREAM.C  fft.h            l3side.h                         presets.c   quantize_pvt.c  set_get.h   util.h         Version.cbitstream.h  gain_analysis.c  lame-analysis.h      machine.h           psymodel.c  quantize_pvt.h  tables.c    vbrquantize.c  version.hencoder.c    gain_analysis.h  lame.c               mpglib_ interface.c  psymodel.h  reservoir.c     tables.h    vbrquantize.hencoder.h    id3tag.c         Lame _global_flags.h  newmdct.c           quantize.c  reservoir.h     takehiro.c  vbrtag.cfft.c        Id3tag.h                     newmdct.h           quantize.h  set_get.c       util.c      VbrTag.h

Basically all the. c and. h files, except that lameerror.h can be used without

Copy all of the files to Jni/libmp3lame/src

Copy the lame.h from the lame-3.99.5/include/directory to JNI/LIBMP3LAME/SRC

2. Create Jni/android.mk

Root_path: = $ (call my-dir) # do Speex and Lamelocal_path: = $ (call My-dir) include $ (root_path)/libmp3lame/android.mk

Jni/libmp3lame/android.mk

Local_path: = $ (call My-dir) include $ (clear_vars) Lame_libmp3_dir: = Srclocal_module    : = mp3lamelocal_src_files: = $ ( Lame_libmp3_dir)/bitstream.c $ (lame_libmp3_dir)/fft.c $ (lame_libmp3_dir)/id3tag.c $ (lame_libmp3_dir)/mpglib_ INTERFACE.C $ (Lame_libmp3_dir)/PRESETS.C $ (lame_libmp3_dir)/quantize.c $ (lame_libmp3_dir)/reservoir.c $ (LAME_ Libmp3_dir)/TABLES.C $ (lame_libmp3_dir)/UTIL.C $ (lame_libmp3_dir)/vbrtag.c $ (lame_libmp3_dir)/encoder.c $ (LAME_ Libmp3_dir)/GAIN_ANALYSIS.C $ (lame_libmp3_dir)/lame.c $ (lame_libmp3_dir)/newmdct.c $ (lame_libmp3_dir)/PSYMODEL.C $ (Lame_libmp3_dir)/quantize_pvt.c $ (lame_libmp3_dir)/set_get.c $ (lame_libmp3_dir)/takehiro.c $ (LAME_LIBMP3_DIR)/ VBRQUANTIZE.C $ (lame_libmp3_dir)/version.c Li_zhiwei_mp3recorder_simplelame.cinclude $ (BUILD_SHARED_LIBRARY)

Jni/application.mk

App_abi: = Armeabi armeabi-v7aapp_platform: = android-8 app_platform: = android-9 App_stl: = stlport_static stlport_force_ REBUILD: = True

3. Modify the source code
Fft.c removed from the
#include "Vector/lame_intrin.h"

This is optimized with Intel CPU features, which are not available on arm

Lieutenant General Set_get.h
#include
Change into
#include "lame.h"

Lieutenant General Utils.h
extern ieee754_float32_t fast_log2 (ieee754_float32_t x);
Use
extern float fast_log2 (float x);
Replace

4. Creating an Encapsulated file
Li_zhiwei_mp3recorder_simplelame.c

#include "src/lame.h" #include "li_zhiwei_mp3recorder_simplelame.h" static lame_global_flags *GLF = NULL; Jniexport void Jnicall java_li_zhiwei_mp3recorder_simplelame_init (jnienv *env, Jclass cls, Jint insamplerate, Jint Outchannel,jint outsamplerate, Jint outbitrate, jint quality) {if (GLF! = NULL) {lame_close (GLF); GLF = NULL;} GLF = Lame_init (); Lame_set_in_samplerate (GLF, insamplerate); Lame_set_num_channels (GLF, outchannel); lame_set_out_ Samplerate (GLF, outsamplerate); Lame_set_brate (GLF, outbitrate); Lame_set_quality (GLF, quality); Lame_init_params ( GLF);} Jniexport jint jnicall Java_li_zhiwei_mp3recorder_simplelame_encode (jnienv *env, Jclass cls, JshortArray buffer_l, Jshortarray buffer_r,jint samples, Jbytearray mp3buf) {jshort* j_buffer_l = (*env)->getshortarrayelements (env, buffer_l, NULL); jshort* j_buffer_r = (*env)->getshortarrayelements (env, buffer_r, NULL); const JSIZE Mp3buf_size = (* ENV)->getarraylength (env, mp3buf); jbyte* j_mp3buf = (*env)->getbytearrayelements (env, mp3bUF, NULL); int result = Lame_encode_buffer (GLF, j_buffer_l, J_buffer_r,samples, J_mp3buf, mp3buf_size);(*env) Releaseshortarrayelements (env, buffer_l, j_buffer_l, 0);(*env)->releaseshortarrayelements (env, Buffer_r, j_ Buffer_r, 0);(*env)->releasebytearrayelements (env, MP3BUF, j_mp3buf, 0); return result; Jniexport jint jnicall Java_li_zhiwei_mp3recorder_simplelame_flush (jnienv *env, Jclass cls, JbyteArray mp3buf) {const Jsize mp3buf_size = (*env)->getarraylength (env, mp3buf); jbyte* j_mp3buf = (*env)->getbytearrayelements (env, Mp3buf, NULL); int result = Lame_encode_flush (GLF, J_mp3buf, mp3buf_size);(*env)->releasebytearrayelements (env, Mp3buf, j_mp3buf, 0); return result;} Jniexport void Jnicall java_li_zhiwei_mp3recorder_simplelame_close (jnienv *env, Jclass cls) {lame_close (GLF); GLF = NULL ;}

Li_zhiwei_mp3recorder_simplelame.h (this file is actually generated in the Javah li.zhiwei.mp3recorder.SimpleLame command)

/* Don't EDIT this file-it are machine generated */#include/* Header for Class Li_zhiwei_mp3recorder_simplelame */#ifnd EF _included_li_zhiwei_mp3recorder_simplelame#define _included_li_zhiwei_mp3recorder_simplelame#ifdef __ Cplusplusextern "C" {#endif/* * class:li_zhiwei_mp3recorder_simplelame * method:close * Signature: () V */jniexpor T void Jnicall java_li_zhiwei_mp3recorder_simplelame_close (jnienv *, jclass);/* * Class:li_zhiwei_mp3recorder_simpl Elame * Method:encode * Signature: ([s[si[b) I */jniexport jint jnicall Java_li_zhiwei_mp3recorder_simplelame_encode (    JNIEnv *, Jclass, Jshortarray, Jshortarray, Jint, Jbytearray);/* * Class:li_zhiwei_mp3recorder_simplelame * Method: Flush * Signature: ([B) I */jniexport jint jnicall java_li_zhiwei_mp3recorder_simplelame_flush (jnienv *, Jclass, Jbytea Rray);/* * Class:li_zhiwei_mp3recorder_simplelame * method:init * Signature: (IIIII) V */jniexport void Jnicall Ja  Va_li_zhiwei_mp3recorder_simplelame_init(JNIEnv *, Jclass, Jint, Jint, Jint, Jint, jint); #ifdef __cplusplus} #endif #endif 

6. Run Ndk_build to

Resources

Http://developer.samsung.com/android/technical-docs/Porting-and-using-LAME-MP3-on-Android-with-JNI

Https://github.com/talzeus/AndroidMp3Recorder

http://ikinglai.blog.51cto.com/6220785/1228730

Use MP3 format to record sound on Android