1.配置NDK环境
# 在.bash_profile中配置如下代码
export ANDROID_NDK=/Users/xxx/android-ndk
export PATH=$ANDROID_NDK:$PATH
# 然后执行如下代码，更新配置文件
source .bash_profile
# 在loca.properties文件中
ndk.dir=/Users/your_name/android-ndk
2.拷贝speex源码
将speex源码文件夹下面的include和libspeex两个文件夹拷贝到jni目录下
3. 编写Android.mk文件和Application.mk文件
Android.mk文件如下:
LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_MODULE:= libspeex
LOCAL_CFLAGS = -DFIXED_POINT -DUSE_KISS_FFT -DEXPORT="" -UHAVE_CONFIG_H
LOCAL_C_INCLUDES := $(LOCAL_PATH)/include
LOCAL_SRC_FILES :=\
libspeex/bits.c \
libspeex/buffer.c \
libspeex/cb_search.c \
libspeex/exc_10_16_table.c \
libspeex/exc_10_32_table.c \
libspeex/exc_20_32_table.c \
libspeex/exc_5_256_table.c \
libspeex/exc_5_64_table.c \
libspeex/exc_8_128_table.c \
libspeex/fftwrap.c \
libspeex/filterbank.c \
libspeex/filters.c \
libspeex/gain_table.c \
libspeex/gain_table_lbr.c \
libspeex/hexc_10_32_table.c \
libspeex/hexc_table.c \
libspeex/high_lsp_tables.c \
libspeex/jitter.c \
libspeex/kiss_fft.c \
libspeex/kiss_fftr.c \
libspeex/lpc.c \
libspeex/lsp.c \
libspeex/lsp_tables_nb.c \
libspeex/ltp.c \
libspeex/mdf.c \
libspeex/modes.c \
libspeex/modes_wb.c \
libspeex/nb_celp.c \
libspeex/preprocess.c \
libspeex/quant_lsp.c \
libspeex/resample.c \
libspeex/sb_celp.c \
libspeex/scal.c \
libspeex/smallft.c \
libspeex/speex.c \
libspeex/speex_callbacks.c \
libspeex/speex_header.c \
libspeex/stereo.c \
libspeex/vbr.c \
libspeex/vq.c \
libspeex/window.c \
speex_jni.cpp \
include $(BUILD_SHARED_LIBRARY)
至于Android.mk文件编写的说明,可以参考谷歌官方的文档,在这里:
Applicaiton.mk用来配置要编译哪些环境的,如下:
APP_ABI := armeabi armeabi-v7a x86 mips
这样我们会输出四个版本的so包了.
4.新建speex_config_types.h文件
这一步应该是映射Java数据类型的,在刚才拷贝过来的speex源码目录下面的include/speex文件夹下面有一个speex_config_types.h.in文件,可以在这个include/speex目录下面创建speex_config_types.h,把speex_config_types.h.in的内容拷贝过来,然后把@SIZE16@改成short,把@SIZE32@改成int就可以了.这个文件的内容如下:
#ifndef __SPEEX_TYPES_H__
#define __SPEEX_TYPES_H__
/* these are filled in by configure */
typedef short spx_int16_t;
typedef unsigned short spx_uint16_t;
typedef int spx_int32_t;
typedef unsigned int spx_uint32_t;
#endif
5.Speex.java
先写Java层的代码 (这里的代码来自于第二篇参考博文)
```
package com.webank.common.media.speex;
/**
* Speex音频编解码
* @author Baoyz
*
*/
public class Speex {
/*
* quality 1 : 4kbps (very noticeable artifacts, usually intelligible)
* 2 : 6kbps (very noticeable artifacts, good intelligibility)
* 4 : 8kbps (noticeable artifacts sometimes)
* 6 : 11kpbs (artifacts usually only noticeable with headphones)
* 8 : 15kbps (artifacts not usually noticeable)
*/
private static final int DEFAULT_COMPRESSION = 4;
public Speex() {
}
public void init() {
load();
open(DEFAULT_COMPRESSION);
}
private void load() {
try {
System.loadLibrary("speex_jni");
} catch (Throwable e) {
e.printStackTrace();
}
}
public native int open(int compression);
public native int getFrameSize();
public native int decode(byte encoded[], short lin[], int size);
public native int encode(short lin[], int offset, byte encoded[], int size);
public native void close();
}
```
注意
这里的包名非常重要:com.webank.common.media.speex
System.loadLibrary中的名称,如果你的so包以lib开头,就不要再写lib了.
6.speex_jni.cpp
然后是speex_jni.cpp文件:
```
#include
#include
#include
#include
static int codec_open = 0;
static int dec_frame_size;
static int enc_frame_size;
static SpeexBits ebits, dbits;
void *enc_state;
void *dec_state;
static JavaVM *gJavaVM;
extern "C"
JNIEXPORT jint JNICALL Java_cc_itbox_testspeex_media_Speex_open
(JNIEnv *env, jobject obj, jint compression) {
int tmp;
if (codec_open++ != 0)
return (jint)0;
speex_bits_init(&ebits);
speex_bits_init(&dbits);
enc_state = speex_encoder_init(&speex_nb_mode);
dec_state = speex_decoder_init(&speex_nb_mode);
tmp = compression;
speex_encoder_ctl(enc_state, SPEEX_SET_QUALITY, &tmp);
speex_encoder_ctl(enc_state, SPEEX_GET_FRAME_SIZE, &enc_frame_size);
speex_decoder_ctl(dec_state, SPEEX_GET_FRAME_SIZE, &dec_frame_size);
return (jint)0;
}
extern "C"
JNIEXPORT jint Java_cc_itbox_testspeex_media_Speex_encode
(JNIEnv *env, jobject obj, jshortArray lin, jint offset, jbyteArray encoded, jint size) {
jshort buffer[enc_frame_size];
jbyte output_buffer[enc_frame_size];
int nsamples = (size-1)/enc_frame_size + 1;
int i, tot_bytes = 0;
if (!codec_open)
return 0;
speex_bits_reset(&ebits);
for (i = 0; i < nsamples; i++) {
env->GetShortArrayRegion(lin, offset + i*enc_frame_size, enc_frame_size, buffer);
speex_encode_int(enc_state, buffer, &ebits);
}
//env->GetShortArrayRegion(lin, offset, enc_frame_size, buffer);
//speex_encode_int(enc_state, buffer, &ebits);
tot_bytes = speex_bits_write(&ebits, (char *)output_buffer,
enc_frame_size);
env->SetByteArrayRegion(encoded, 0, tot_bytes,
output_buffer);
return (jint)tot_bytes;
}
extern "C"
JNIEXPORT jint JNICALL Java_cc_itbox_testspeex_media_Speex_decode
(JNIEnv *env, jobject obj, jbyteArray encoded, jshortArray lin, jint size) {
jbyte buffer[dec_frame_size];
jshort output_buffer[dec_frame_size];
jsize encoded_length = size;
if (!codec_open)
return 0;
env->GetByteArrayRegion(encoded, 0, encoded_length, buffer);
speex_bits_read_from(&dbits, (char *)buffer, encoded_length);
speex_decode_int(dec_state, &dbits, output_buffer);
env->SetShortArrayRegion(lin, 0, dec_frame_size,
output_buffer);
return (jint)dec_frame_size;
}
extern "C"
JNIEXPORT jint JNICALL Java_cc_itbox_testspeex_media_Speex_getFrameSize
(JNIEnv *env, jobject obj) {
if (!codec_open)
return 0;
return (jint)enc_frame_size;
}
extern "C"
JNIEXPORT void JNICALL Java_cc_itbox_testspeex_media_Speex_close
(JNIEnv *env, jobject obj) {
if (--codec_open != 0)
return;
speex_bits_destroy(&ebits);
speex_bits_destroy(&dbits);
speex_decoder_destroy(dec_state);
speex_encoder_destroy(enc_state);
}
```
我们可以看到,Java类里面的每个native方法都有一个对应的cpp里面的一个方法.cpp中的方法名为包名_类名_Java方法名,并且包名中的小圆点也要替换为_.
7.Android.mk配置
这里还要在Android.mk的配置文件中将我们的speex_jni.cpp文件加到LOCAL_SRC_FILES中去,如下:
...
LOCAL_SRC_FILES := \
./speex_jni.cpp \
./libspeex/bits.c \
./
...
8.ndk-build
命令行到Android.mk所在文件夹,然后执行如下命令:
ndk-build
要是找不到命令,说明你ndk配置没有成功.
执行完成以后,他会在jni所在目录下又生成两个文件夹,一个是libs文件夹,里面就是我们需要的so包了