未定义的me脚解码功能 [英] undefined lame decode function

问题描述

我正在尝试向我的Android应用程序添加MP3读写功能.我正在使用lame4android应用程序作为起点.对文件进行编码对我来说有效，但是我在使用解码功能时遇到了问题-我获得了对解码功能的未定义引用.

I'm trying to add MP3 read and write capabilities to my Android app. I'm using the lame4android app as a starting point. Encoding a file works for me, but I'm having a problem with the decode functions -- I'm getting undefined references to the decode functions.

这是我包装器的摘录.

#include "libmp3lame/lame.h"
#include "jni.h"

lame_t lame;

jint Java_com_intonia_dandy_WavStream_initEncoder(JNIEnv *env,
                                                  jobject jobj,
                                                  jint in_num_channels,
                                                  jint in_samplerate)
{
    lame = lame_init();
    ...
    return lame_init_params(lame);
}

hip_t hip;

jint Java_com_intonia_dandy_WavStream_initDecoder(JNIEnv *env, jobject jobj)
{
    hip = hip_decode_init();
    return hip != 0;
}

这是来自lame.h的声明:

And here are the declarations from lame.h:

lame_global_flags * CDECL lame_init(void);

typedef hip_global_flags *hip_t;
hip_t CDECL hip_decode_init(void);

我收到一条错误消息:

C:/ACode/dandy/src/main/jni/./wrapper.c:62: undefined reference to `hip_decode_init`

我也得到了对hip_decode和hip_decode_exit的未定义引用.但是lame_init，lame_init_params，lame_encode_buffer和lame_encode_flush不会产生任何错误.我使用命令行运行ndk-build时遇到这些错误，而让Android Studio管理编译时也会遇到相同的错误.

I'm also getting undefined references to hip_decode and and hip_decode_exit. But lame_init, lame_init_params, lame_encode_buffer, and lame_encode_flush do not generate any errors. I get these errors using the command line to run ndk-build, and I get the same errors when I let Android Studio manage the compilation.

lame_*功能与hip_decode_*功能有何不同?我应该使用不推荐使用的lame_decode_*吗?

How are the lame_* functions different from the hip_decode_* functions? Should I be using the deprecated lame_decode_*?

我正在看ndk-build命令的输出. .c文件在编译时会在控制台上列出. hip_decode_init是在jni/libmp3lame/mpglib_interface.c中定义的，但是即使mpglib_interface在jni/Android.mk中列出了，也不会对其进行编译.为什么不呢?

I'm looking at the output of the ndk-build command. The .c files are listed on the console as they are compiled. hip_decode_init is defined in jni/libmp3lame/mpglib_interface.c, but mpglib_interface is not getting compiled, even though it's listed in jni/Android.mk. Why not???

推荐答案

事实证明，分布式LAME库未启用解码.为了使其正常工作，我必须执行以下操作:

It turns out that the LAME library as distributed does not have decoding enabled. To get it working, I had to do the following:

1. 将#define HAVE_MPGLIB 1添加到mpglib_interface.c

从LAME发行版的mpglib目录中复制所有.c和.h文件.

Copy all .c and .h files from the mpglib directory of the LAME distribution.

编辑Android.mk以包括mpglib中的.c文件.

Edit Android.mk to include the .c files from mpglib.

不是修改mpglib_interface.c来定义HAVE_MPGLIB， 最好设置编译标志.

instead of modifying mpglib_interface.c to define HAVE_MPGLIB, it's better to set compilation flags.

在使用Android Studio 2+时，build.gradle应该包含

Working with Android Studio 2+, build.gradle should contain

android {
    defaultConfig {
        ndk {
            moduleName "libmp3lame"
            cFlags "-DSTDC_HEADERS -DHAVE_MPGLIB"
        }
    }
}

或者在Android.mk中:

Or in Android.mk:

LOCAL_CFLAGS = -DSTDC_HEADERS -DHAVE_MPGLIB

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