Android中錄音使用AudioRecord錄音後的格式爲pcm,要想播放需要轉換格式,可以加入44字節的頭轉換爲wav格式然後播放,但是我們要在網絡上傳輸還是要把音頻壓縮一下,壓縮爲speex文件方便傳輸,節省流量,下面講解怎樣打speex的so庫,和怎樣使用speex在wav和spx文件之間相互轉換。
1.在speex官網上下載speex源碼 https://www.speex.org/downloads/
2.得到speex-1.2rc2.tar.gz ,然後解壓縮得到speex文件夾內容如圖
3.創建一個Android項目,命名爲Speex,項目中新建jni目錄,並把speex源碼目錄下的libspeex和include目錄及其子目錄文件全部拷貝到$project/jni
目錄下,拷貝完成如下圖:
4.創建幾個文件
- 在jni目錄下新增Android.mk文件,複製如下內容(意思是編譯speex_jni.cpp和libspeex下所有的c文件,有三個測試文件不用編譯testenc_uwb.c、testenc_wb.c 、testenc.c )
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 :=
LOCAL_SRC_FILES := speex_jni.cpp \
./libspeex/bits.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/filters.c \
./libspeex/gain_table_lbr.c \
./libspeex/gain_table.c \
./libspeex/hexc_10_32_table.c \
./libspeex/hexc_table.c \
./libspeex/high_lsp_tables.c \
./libspeex/kiss_fft.c \
./libspeex/kiss_fftr.c \
./libspeex/lpc.c \
./libspeex/lsp_tables_nb.c \
./libspeex/lsp.c \
./libspeex/ltp.c \
./libspeex/modes_wb.c \
./libspeex/modes.c \
./libspeex/nb_celp.c \
./libspeex/quant_lsp.c \
./libspeex/sb_celp.c \
./libspeex/smallft.c \
./libspeex/speex_callbacks.c \
./libspeex/speex_header.c \
./libspeex/speex.c \
./libspeex/stereo.c \
./libspeex/vbr.c \
./libspeex/vorbis_psy.c \
./libspeex/vq.c \
./libspeex/window.c \
include $(BUILD_SHARED_LIBRARY)
- 在jni目錄下增加Application.mk,複製內容如下(意思是編譯所有平臺下的so文件):
APP_ABI := all
- 在jni/include/speex/目錄下新增speex_config_types.h文件,複製內容如下:
#ifndef __SPEEX_TYPES_H__
#define __SPEEX_TYPES_H__
typedef short spx_int16_t;
typedef unsigned short spx_uint16_t;
typedef int spx_int32_t;
typedef unsigned int spx_uint32_t;
#endif
- 在包com.speex.util中新建SpeexUtil類,複製以下內容(主要定義native方法)
package com.speex.util;
/**
*
* @author jxn
* 2016年11月15日有更新,更改默認壓縮比,並增加單例模式,重新打jar包
*/
public class SpeexUtil {
/*
* 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)
*/
//設置爲4時壓縮比爲1/16(與編解碼密切相關)
private static final int DEFAULT_COMPRESSION = 4;
static {
try {
System.loadLibrary("speex");
} catch (Throwable e) {
e.printStackTrace();
}
}
private static SpeexUtil speexUtil = null;
SpeexUtil() {
open(DEFAULT_COMPRESSION);
}
public static SpeexUtil getInstance(){
if (speexUtil == null) {
synchronized (SpeexUtil.class) {
if (speexUtil == null) {
speexUtil = new SpeexUtil();
}
}
}
return speexUtil;
}
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();
}
- 在jni根目錄下新建speex_jni.cpp實現剛纔的native方法,複製內容:
#include <jni.h>
#include <string.h>
#include <unistd.h>
#include <speex/speex.h>
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_com_speex_util_SpeexUtil_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 JNICALL Java_com_speex_util_SpeexUtil_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_speex_util_SpeexUtil_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_speex_util_SpeexUtil_getFrameSize
(JNIEnv *env, jobject obj) {
if (!codec_open)
return 0;
return (jint)enc_frame_size;
}
extern "C"
JNIEXPORT void JNICALL Java_com_speex_util_SpeexUtil_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);
}
新增完成後目錄結構如下(共增加了5個文件):
5.下面開始生成so庫
使用ndk-build生成so文件,生成方法參考本文:HelloJni導入到Eclipse及命令行編譯
編譯完成,如圖:
刷新項目後,生成了obj文件夾:
6.將Speex提供爲jar包和so的形式供外部項目使用,使用時拷貝jar包到lib中,so拷貝到lib中對應的平臺下
打開cmd,運行下圖中命令將SpeexUtil.class打入jar包內
最後附上源碼和打包的jar和so庫下載地址:
http://download.csdn.net/detail/jianiuqi/9683657
下一篇文件中將介紹怎樣使用生成的jar完成wav轉speex和speex轉wav,並提供了使用示例源碼下載(包括AS和Eclipse版本):
Android語音——speex編碼解碼(二)