speex編解碼在android上實現 · Android JNI入門

以前在應用中使用到了Speex編解碼，近來總結了一下Speex在android上的實現。Speex是一套主要針對語音的開源免費，無專利保護的音頻壓縮格式。Speex工程著力于通過提供一個可以替代高性能語音編解碼來降低語音應用輸入門檻。另外，相對于其它編解碼，Speex也很適合網絡應用，在網絡應用上有著自己獨特的優勢。同時，Speex還是GNU工程的一部分，在改版的BSD協議中得到了很好的支持。Speex是基于CELP并且專門為碼率在2-44kbps的語音壓縮而設計的。Speex源碼是基于c語音實現的（也有java實現，效率相對較低）。 1、去Speex官網下載最新[Speex源碼](http://www.speex.org/downloads/)。 2、創建新的android工程，并創建jni文件夾。 3、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。 4、在jni目錄下新增Android.mk文件，編輯內容如下： ~~~ 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 $(BUILD_SHARED_LIBRARY) ~~~ 5.在jni目錄下新增Application.mk文件，編輯內容如下 ~~~ APP_ABI := armeabi armeabi-v7a ~~~ 6.在$project/jni/include/speex/目錄下新增speex_config_types.h文件，編輯內容如下 ~~~ 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.創建JNI包裝類speex_jni.cpp，用來調用Speex中的C代碼函數，編輯內容如下 ~~~ #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層創建Speex工具類，內容如下： ~~~ 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cygwin編譯，生成so文件。參考： http://code.google.com/p/android-recorder/downloads/list 這個是一個android recorder ，使用speex編碼，