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6. 完成音频重采样IResample模块初始化代码~1

发布时间：2021-06-11 17:00:27编辑：雪饮阅读（）

 音频重采样，首先需要在继承Iobserver然后主要以实现Resample为主：cpp/IResample.h:

#ifndef XPLAY_IRESAMPLE_H
#define XPLAY_IRESAMPLE_H

#include "XParameter.h"
#include "IObserver.h"

class IResample: public IObserver
{
public:
    virtual bool Open(XParameter in,XParameter out=XParameter()) = 0;
    virtual XData Resample(XData indata) = 0;
    virtual void Update(XData data);
    int outChannels = 2;
    int outFormat = 1;
};


#endif //XPLAY_IRESAMPLE_H
其具体实现，这里实现下update方法于cpp/IResample.cpp:

#include "IResample.h"
#include "XLog.h"

void IResample::Update(XData data)
{
    XData d = this->Resample(data);
    if(d.size > 0)
    {
        this->Notify(d);
    }
}

然后对于Open和Resample单独规划出来声明定义于cpp/FFResample.h: #ifndef XPLAY_FFRESAMPLE_H
#define XPLAY_FFRESAMPLE_H


#include "IResample.h"
struct SwrContext;
class FFResample: public IResample
{
public:
    virtual bool Open(XParameter in,XParameter out=XParameter());
    virtual XData Resample(XData indata);
protected:
    SwrContext *actx = 0;

};


#endif //XPLAY_FFRESAMPLE_H

然后最后就是具体的重采样实现cpp/FFResample.cpp: extern "C"
{
#include <libswresample/swresample.h>
}

#include "XLog.h"
#include <libavcodec/avcodec.h>
#include "FFResample.h"

bool FFResample::Open(XParameter in,XParameter out)
{

    //音频重采样上下文初始化
    actx = swr_alloc();
    actx = swr_alloc_set_opts(actx,
                              av_get_default_channel_layout(2),
                              AV_SAMPLE_FMT_S16,in.para->sample_rate,
                              av_get_default_channel_layout(in.para->channels),
                              (AVSampleFormat)in.para->format,in.para->sample_rate,
                              0,0 );

    int re = swr_init(actx);
    if(re != 0)
    {
        XLOGE("swr_init failed!");
        return false;
    }
    else
    {
        XLOGI("swr_init success!");
    }
    outChannels = in.para->channels;
    outFormat = AV_SAMPLE_FMT_S16;
    return true;

}

XData FFResample::Resample(XData indata)
{
    if(indata.size<=0 || !indata.data) return XData();
    if(!actx)
        return XData();
    //XLOGE("indata size is %d",indata.size);
    AVFrame *frame = (AVFrame *)indata.data;

    //输出空间的分配
    XData out;
    int outsize = outChannels * frame->nb_samples * av_get_bytes_per_sample((AVSampleFormat)outFormat);
    if(outsize <=0)return XData();
    out.Alloc(outsize);
    uint8_t *outArr[2] = {0};
    outArr[0] = out.data;
    int len = swr_convert(actx,outArr,frame->nb_samples,(const uint8_t **)frame->data,frame->nb_samples);
    if(len<=0)
    {
        out.Drop();
        return XData();
    }
    XLOGE("swr_convert success = %d",len);
    return out;
}

然后用cpp/CMakeLists.txt重新链接下新的c++: # For more information about using CMake with Android Studio, read the
# documentation: https://d.android.com/studio/projects/add-native-code.html

# Sets the minimum version of CMake required to build the native library.

cmake_minimum_required(VERSION 3.10.2)

# Declares and names the project.

project("xplay")

# Creates and names a library, sets it as either STATIC
# or SHARED, and provides the relative paths to its source code.
# You can define multiple libraries, and CMake builds them for you.
# Gradle automatically packages shared libraries with your APK.
#添加頭文件路徑(括號中的include是相對於本文件路徑)
include_directories(../../../include)
#設置ffmpeg庫所在路徑的變量，這裏的FF是自定義的一個名字
set(FF ${CMAKE_CURRENT_SOURCE_DIR}/../../../libs/${ANDROID_ABI})
#avcodec這個是自定義的一個名字
add_library(avcodec SHARED IMPORTED)
set_target_properties(avcodec PROPERTIES IMPORTED_LOCATION ${FF}/libavcodec.so)

add_library(avformat SHARED IMPORTED)
set_target_properties(avformat PROPERTIES IMPORTED_LOCATION ${FF}/libavformat.so)

add_library(avutil SHARED IMPORTED)
set_target_properties(avutil PROPERTIES IMPORTED_LOCATION ${FF}/libavutil.so)

add_library(swscale SHARED IMPORTED)
set_target_properties(swscale PROPERTIES IMPORTED_LOCATION ${FF}/libswscale.so)

add_library(swresample SHARED IMPORTED)
set_target_properties(swresample PROPERTIES IMPORTED_LOCATION ${FF}/libswresample.so)
add_library( # Sets the name of the library.
             native-lib

             # Sets the library as a shared library.
             SHARED

             # Provides a relative path to your source file(s).
            #src/main/cpp/native-lib.cpp
            IDemux
            FFDemux
            XData
            XLog
            native-lib.cpp
            XThread
            IObserver
            FFDecode
            IDecode
            XParameter
            IVideoView
            GLVideoView
            XTexture
            XEGL
            XShader
            FFResample
            IResample
        )

# Searches for a specified prebuilt library and stores the path as a
# variable. Because CMake includes system libraries in the search path by
# default, you only need to specify the name of the public NDK library
# you want to add. CMake verifies that the library exists before
# completing its build.

find_library( # Sets the name of the path variable.
              log-lib

              # Specifies the name of the NDK library that
              # you want CMake to locate.
              log )

# Specifies libraries CMake should link to your target library. You
# can link multiple libraries, such as libraries you define in this
# build script, prebuilt third-party libraries, or system libraries.

target_link_libraries( # Specifies the target library.
                       native-lib
                       GLESv2 EGL
                       OpenSLES
                       android
                       avcodec avformat avutil swscale swresample
                       # Links the target library to the log library
                       # included in the NDK.
                       ${log-lib} )

 

此时不必说，自然还是不能运行成功


Alloc暂时先不用实现。