在Android开发中,需要录音并发送到对方设备上。这时问题来了,手机常会是GPRS、3G等方式上网,所以节省流量是非常关键的,使用Speex来压缩音频文件,可以将音频压文件小数倍。
1.去Speex官网下载最新Speex源码。
2.创建一个新的应用(我创建的应用名为Audio),并创建一个jni目录($project/jni)。
3.把speex源码目录下的libspeex和include目录及其子目录文件全部拷贝到$project/jni目录下($project/jni/libspeex
and $project/jni/include)。
4.在jni目录下新增Android.mk文件,编辑内容如下
- 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
:= \
- ./speex_jni.cpp
\
- ./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
-
- include
$(BUILD_SHARED_LIBRARY)
5.在jni目录下新增Application.mk文件,编辑内容如下
- APP_ABI :=
armeabi armeabi-v7a
6.在$project/jni/include/speex/目录下新增speex_config_types.h文件,编辑内容如下
- #ifndef __SPEEX_TYPES_H__
- #define __SPEEX_TYPES_H__
- typedefshort
spx_int16_t;
- typedef
unsigned short
spx_uint16_t;
- typedefint
spx_int32_t;
- typedef
unsigned int
spx_uint32_t;
- #endif
7.创建JNI包装类speex_jni.cpp,用来调用Speex中的C代码函数,编辑内容如下
- #include <jni.h>
-
- #include <string.h>
- #include <unistd.h>
-
- #include <speex/speex.h>
-
- staticint
codec_open = 0;
-
- staticint
dec_frame_size;
- staticint
enc_frame_size;
-
- static
SpeexBits ebits, dbits;
- void
*enc_state;
- void
*dec_state;
-
- static
JavaVM *gJavaVM;
-
- extern"C"
- JNIEXPORT
jint JNICALL Java_com_audio_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_com_audio_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);
-
}
-
-
-
-
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_com_audio_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_com_audio_getFrameSize
-
(JNIEnv *env, jobject obj) {
-
-
if
(!codec_open)
-
return
0;
-
return
(jint)enc_frame_size;
-
- }
-
- extern"C"
- JNIEXPORT
void
JNICALL Java_com_audio_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);
- }
8.在Java层创建Speex工具类,内容如下
- package
com.audio;
-
- class
Speex {
-
-
-
-
-
-
-
-
-
privatestaticfinalint
DEFAULT_COMPRESSION = 8;
-
-
Speex() {
-
}
-
-
publicvoid
init() {
-
load();
-
open(DEFAULT_COMPRESSION);
-
}
-
-
privatevoid
load() {
-
try
{
-
System.loadLibrary("speex");
-
} catch
(Throwable e) {
-
e.printStackTrace();
-
}
-
-
}
-
-
publicnativeint
open(int
compression);
-
publicnativeint
getFrameSize();
-
publicnativeint
decode(byte
encoded[], short
lin[], int
size);
-
publicnativeint
encode(short
lin[], int
offset, byte
encoded[], int
size);
-
publicnativevoid
close();
-
- }
9.打开cygwin工具,切换到项目目录(我项目是在F:\workspace\Audio),输入$NDK/ndk-build
cygwin工具的安装与配置,可以看这篇文章——使用NDK与环境搭建
会在项目中生成libs目录和libspeex.so文件,这就是Speex类中System.loadLibrary("speex");代码引用的,系统会根据操作系统由"speex"找到对应的动态库libspeex.so,Windows下是.dll文件,linux下是.so文件。
当前,我的项目结构如下图
Speex for Android,布布扣,bubuko.com
Speex for Android
原文:http://www.cnblogs.com/jiayonghua/p/3763361.html