java - android 中的 speex 支持

Question

谁能帮我如何在android中使用speex或jspeex？

我搜索了很多但找不到任何地方。code.google.com/android 中有很多关于此的问题但没有人回答。这个问题也没有得到很好的回应，因为我的另一个问题是 Decoding speex encoded byte array in Android .因此，如果您对此有所了解，请向我提供相关信息。

我需要使用此编解码器对音频文件的字节数组进行编码和解码。

我试过了Android-ndk and got encoding done,但是在解码字节数组时遇到问题。是否有其他替代方法可以实现此目的？

编辑

我在原生c文件中的编码函数如下:

#include <jni.h>
#include "speex/speex.h"

#define FRAME_SIZE 320

int nbBytes;
/*Holds the state of the encoder*/
void *state;
void *decod_state;


/*Holds bits so they can be read and written to by the Speex routines*/

SpeexBits decod_bits;
SpeexBits bits;
int i, tmp;

void Java_com_mycom_speex_SpeexEncodingActivity_init(JNIEnv * env, jobject jobj) {
   /*Create a new encoder state in narrowband mode*/
   state = speex_encoder_init(&speex_wb_mode);

   /*Set the quality to 8*/
   tmp=8;
   speex_encoder_ctl(state, SPEEX_SET_QUALITY, &tmp);

   /*Initialization of the structure that holds the bits*/
   speex_bits_init(&bits);
}

jbyteArray Java_com_mycom_speex_SpeexEncodingActivity_encode(JNIEnv * env, jobject jobj, jshortArray inputData) {
        jbyteArray ret;

        jshort * inputArrayElements = (*env)->GetShortArrayElements(env, inputData, 0);

        /*Flush all the bits in the struct so we can encode a new frame*/
        speex_bits_reset(&bits);

        /*Encode the frame*/
        speex_encode_int(state, inputArrayElements, &bits);
        /*Copy the bits to an array of char that can be written*/
        nbBytes = speex_bits_nbytes(&bits);

        ret = (jbyteArray) ((*env)->NewByteArray(env, nbBytes));
        jbyte * arrayElements = (*env)->GetByteArrayElements(env, ret, 0);

        speex_bits_write(&bits, arrayElements, nbBytes);

        (*env)->ReleaseShortArrayElements(env, inputData, inputArrayElements, JNI_ABORT);
        (*env)->ReleaseByteArrayElements(env, ret, arrayElements, 0);
        return ret;
}

现在为了解码，我将转换后的短数组发送到解码函数，如下所示:

void Java_com_mycom_speex_SpeexEncodingActivity_initDecode(JNIEnv * env,
        jobject jobj) {

    decod_state = speex_decoder_init(&speex_wb_mode);

    tmp = 1;
    speex_decoder_ctl(decod_state, SPEEX_SET_ENH, &tmp);

    /*Initialization of the structure that holds the bits*/
    speex_bits_init(&decod_bits);
}

jshortArray Java_com_mycom_speex_SpeexEncodingActivity_decode(JNIEnv * env,
        jobject jobj, jshortArray inputData) {



    jshort * inputArrayElements = (*env)->GetShortArrayElements(env, inputData,
            0);

    /*Flush all the bits in the struct so we can decode a new frame*/
    speex_bits_reset(&decod_bits);
    /*Copy the bits to an array of char that can be written*/
    nbBytes = speex_bits_nbytes(&decod_bits);
    speex_bits_read_from(&decod_bits,inputArrayElements, nbBytes); // here it requires char * in second argument
    /*Decode the frame*/
    speex_decode_int(decod_state, &decod_bits, inputArrayElements);
    (*env)->ReleaseShortArrayElements(env, encodedData, inputArrayElements,
            JNI_ABORT);
    return inputArrayElements;
}

我的编码函数工作正常，示例在博客上提供 A JNI Wrapper for Speex on Android

另一种通过传递 char 数组并返回 short 数组进行解码的尝试如下:

jshortArray Java_com_mycom_speex_SpeexEncodingActivity_decode(JNIEnv * env,
        jobject jobj, jcharArray inputCharData) {

    jshortArray ret;
    jchar * inputArrayElements = (*env)->GetCharArrayElements(env,
            inputCharData, 0);
    /*Flush all the bits in the struct so we can decode a new frame*/
    speex_bits_reset(&decod_bits);
    /*Copy the bits to an array of char that can be written*/
    nbBytes = speex_bits_nbytes(&decod_bits);
    ret = (jshortArray)((*env)->NewShortArray(env, nbBytes));
    jshort * arrayElements = (*env)->GetShortArrayElements(env, ret, 0);

    speex_bits_read_from(&decod_bits,(char *) inputArrayElements, nbBytes);
    /*Decode the frame*/
    speex_decode_int(decod_state, &decod_bits, arrayElements);

    (*env)->ReleaseCharArrayElements(env, inputCharData, inputArrayElements,
            JNI_ABORT);
    (*env)->ReleaseShortArrayElements(env, ret, arrayElements, 0);
    return ret;
}

结果是

Returned empty array of short if i return ret and if i return arrayElements it 
gives an error Fatal signal 11 (SIGSEGV) at 0x00000018 (code=1)

Answer 1

speex_bits_reset 在其主体中执行以下操作:

bits->nbBits=0;

speex_bits_nbytes 返回 ((bits->nbBits+7)>>3); 所以如果你在 speex_bits_reset 之后立即调用 speex_bits_nbytes，你总是收到 0。所以你必须在数组分配之前调用 speex_bits_read_from:

/*Flush all the bits in the struct so we can decode a new frame*/
speex_bits_reset(&decod_bits);

/*Read bits in decod_bits struct from java array*/
speex_bits_read_from(&decod_bits,(char *) inputArrayElements, nbBytes);

/*Copy the bits to an array of char that can be written*/
nbBytes = speex_bits_nbytes(&decod_bits);
ret = (jshortArray)((*env)->NewShortArray(env, nbBytes));
jshort * arrayElements = (*env)->GetShortArrayElements(env, ret, 0);

/*Decode the frame*/
speex_decode_int(decod_state, &decod_bits, arrayElements);

(*env)->ReleaseCharArrayElements(env, inputCharData, inputArrayElements,
        JNI_ABORT);
(*env)->ReleaseShortArrayElements(env, ret, arrayElements, 0);
return ret;