speex编解码在android上实现

http://blog.csdn.net/xyz_lmn/article/details/8013490

      以前在应用中使用到了Speex编解码，近来总结了一下Speex在android上的实现。Speex是一套主要针对语音的开源免费，无专利保护的音频压缩格式。Speex工程着力于通过提供一个可以替代高性能语音编解码来降低语音应用输入门槛 。另外，相对于其它编解码，Speex也很适合网络应用，在网络应用上有着自己独特的优势。同时，Speex还是GNU工程的一部分，在改版的BSD协议中得到了很好的支持。Speex是基于CELP并且专门为码率在2-44kbps的语音压缩而设计的。Speex源码是基于c语音实现的（也有java实现，效率相对较低）。

       1、去Speex官网下载最新Speex源码。

       2、创建新的android工程，并创建jni文件夹。

       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。

     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 :=\
 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)

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

 01.#ifndef __SPEEX_TYPES_H__
 02.#define __SPEEX_TYPES_H__
 03.typedef short spx_int16_t;
 04.typedef unsigned short spx_uint16_t;
 05.typedef int spx_int32_t;
 06.typedef unsigned int spx_uint32_t;
 07.#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>

 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_trunkbow_speextest_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_trunkbow_speextest_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_com_trunkbow_speextest_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_trunkbow_speextest_Speex_getFrameSize
     (JNIEnv *env, jobject obj) {

     if (!codec_open)
         return 0;
     return (jint)enc_frame_size;

 }

 extern "C"
 JNIEXPORT void JNICALL Java_com_trunkbow_speextest_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.trunkbow.speextest;

 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 = 8;

     Speex() {
     }

     public void init() {
         load();
         open(DEFAULT_COMPRESSION);
     }

     private void load() {
         try {
             System.loadLibrary("speex");
         } 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();
 }

9、使用ndk-build编译，生成so文件。