Android上使用MP3格式录制声音
0. 下载LAME 并解压缩
http://lame.sourceforge.net/download.php
http://sourceforge.net/projects/lame/files/lame/3.99/lame-3.99.5.tar.gz
1. 创建jni/libmp3lame/src目录, 将解压缩后的lame-3.99.5/libmp3lame/ 目录下的
bitstream.c fft.h l3side.h presets.c quantize_pvt.c set_get.h util.h version.c bitstream.h gain_analysis.c lame-analysis.h machine.h psymodel.c quantize_pvt.h tables.c vbrquantize.c version.h encoder.c gain_analysis.h lame.c mpglib_interface.c psymodel.h reservoir.c tables.h vbrquantize.h encoder.h id3tag.c lame_global_flags.h newmdct.c quantize.c reservoir.h takehiro.c VbrTag.c fft.c id3tag.h newmdct.h quantize.h set_get.c util.c VbrTag.h
基本上就是所有的.c和.h文件, 除了lameerror.h可以不用
等文件 全部复制到 jni/libmp3lame/src
将 lame-3.99.5/include/ 目录下的 lame.h 也复制到 jni/libmp3lame/src
2.创建jni/Android.mk
ROOT_PATH := $(call my-dir) # make speex and lame LOCAL_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 := src LOCAL_MODULE := mp3lame LOCAL_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.c include $(BUILD_SHARED_LIBRARY)
jni/application.mk
APP_ABI := armeabi armeabi-v7a APP_PLATFORM := android-8 APP_PLATFORM := android-9 APP_STL := stlport_static STLPORT_FORCE_REBUILD := true
3. 修改源代码
fft.c中去掉
//#include “vector/lame_intrin.h”
这个是用Intel CPU的特性进行优化, ARM上用不到
set_get.h中将
#include
改成
#include “lame.h”
utils.h中将
extern ieee754_float32_t fast_log2(ieee754_float32_t x);
用
extern float fast_log2(float x);
替换
4. 创建封装文件
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 (这个文件其实是在 javah li.zhiwei.mp3recorder.SimpleLame 命令生成的)
/* DO NOT EDIT THIS FILE - it is machine generated */
#include
/* Header for class li_zhiwei_mp3recorder_SimpleLame */
#ifndef _Included_li_zhiwei_mp3recorder_SimpleLame
#define _Included_li_zhiwei_mp3recorder_SimpleLame
#ifdef __cplusplus
extern "C" {
#endif
/*
* Class: li_zhiwei_mp3recorder_SimpleLame
* Method: close
* Signature: ()V
*/
JNIEXPORT void JNICALL Java_li_zhiwei_mp3recorder_SimpleLame_close
(JNIEnv *, jclass);
/*
* Class: li_zhiwei_mp3recorder_SimpleLame
* 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, jbyteArray);
/*
* Class: li_zhiwei_mp3recorder_SimpleLame
* Method: init
* Signature: (IIIII)V
*/
JNIEXPORT void JNICALL Java_li_zhiwei_mp3recorder_SimpleLame_init
(JNIEnv *, jclass, jint, jint, jint, jint, jint);
#ifdef __cplusplus
}
#endif
#endif
6. 运行 ndk_build 即可
参考资料
http://developer.samsung.com/android/technical-docs/Porting-and-using-LAME-MP3-on-Android-with-JNI