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8. 完成了IAudioPlay和SLAudioPlay的音频播放环境初始化~1

发布时间：2021-06-11 21:37:06编辑：雪饮阅读（）

 利用IAudioPlay和SLAudioPlay完成的音频播放环境初始化需要先在cpp/CMakeLists.txt中引入這兩個家夥：

# 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
            SLAudioPlay
            IAudioPlay
        )

# 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} )
然後在cpp/XParameter.h中先聲明下通道和樣率：

#ifndef XPLAY_XPARAMETER_H
#define XPLAY_XPARAMETER_H



struct AVCodecParameters;
class XParameter
{
public:
    AVCodecParameters *para = 0;
    int channels = 2;
    int sample_rate = 44100;
};


#endif //XPLAY_XPARAMETER_H

那麽在cpp/FFResample.cpp中音頻重采樣需要再次優化下： 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(out.channels),
                              AV_SAMPLE_FMT_S16,out.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;
}

然後對於入口cpp/native-lib.cpp中就可以調用這個IAudioPlay和SLAudioPlay的音频播放環境了。： #include <jni.h>
#include <string>
#include <android/native_window_jni.h>

#include "FFDemux.h"
#include "XLog.h"
#include "FFDecode.h"
#include "XEGL.h"
#include "XShader.h"
#include "IVideoView.h"
#include "GLVideoView.h"
#include "FFResample.h"
#include "IAudioPlay.h"
#include "SLAudioPlay.h"

class TestObs:public IObserver
{
public:
    void Update(XData d)
    {
        //XLOGI("TestObs Update data size is %d",d.size);
    }
};


IVideoView *view = NULL;
extern "C"
JNIEXPORT jstring

JNICALL
Java_com_example_xplay_MainActivity_stringFromJNI(
        JNIEnv *env,
        jobject /* this */) {
    std::string hello = "Hello from C++";

    //XLOGI("S begin!");
    //XSleep(3000);
    //XLOGI("S end!");
    //return env->NewStringUTF(hello.c_str());

    ///////////////////////////////////
    ///测试用代码
    TestObs *tobs = new TestObs();
    IDemux *de = new FFDemux();
    //de->AddObs(tobs);
    de->Open("/sdcard/1080.mp4");

    IDecode *vdecode = new FFDecode();
    vdecode->Open(de->GetVPara());

    IDecode *adecode = new FFDecode();
    adecode->Open(de->GetAPara());
    de->AddObs(vdecode);
    de->AddObs(adecode);

    view = new GLVideoView();
    vdecode->AddObs(view);

    IResample *resample = new FFResample();
    XParameter outPara = de->GetAPara();

    resample->Open(de->GetAPara(),outPara);
    adecode->AddObs(resample);

    IAudioPlay *audioPlay = new SLAudioPlay();
    audioPlay->StartPlay(outPara);
    resample->AddObs(audioPlay);


    //vdecode->Open();
    de->Start();
    vdecode->Start();
    adecode->Start();

    //XSleep(3000);
    //de->Stop();
    /*for(;;)
    {
        XData d = de->Read();
        XLOGI("Read data size is %d",d.size);


    }*/

    return env->NewStringUTF(hello.c_str());
}
extern "C"
JNIEXPORT void JNICALL
Java_com_example_xplay_XPlay_InitView(JNIEnv *env, jobject instance, jobject surface) {

    // TODO
    ANativeWindow *win = ANativeWindow_fromSurface(env,surface);
    view->SetRender(win);
    //XEGL::Get()->Init(win);
    //XShader shader;
    //shader.Init();


}

不，別急這裏還沒有在cpp/IAudioPlay.cpp中進行相關實現： #include "IAudioPlay.h"
void IAudioPlay::Update(XData data)
{
    //压入缓冲队列
}

雖然是個空實現，為後面做鋪墊唄。

以及在cpp/SLAudioPlay.h中的相關聲明：
#ifndef XPLAY_SLAUDIOPLAY_H
#define XPLAY_SLAUDIOPLAY_H


#include "IAudioPlay.h"

class SLAudioPlay: public IAudioPlay
{
public:
    virtual bool StartPlay(XParameter out);
    void PlayCall(void *bufq);
};


#endif //XPLAY_SLAUDIOPLAY_H

最後關於混音器和緩衝隊列這些，咱們可以參考之前面嚮過程時期的那個代碼然後調整于cpp/SLAudioPlay.cpp: #include "SLAudioPlay.h"
#include <SLES/OpenSLES.h>
#include <SLES/OpenSLES_Android.h>
#include "XLog.h"
static SLObjectItf engineSL = NULL;
static SLEngineItf eng = NULL;
static SLObjectItf mix = NULL;
static SLObjectItf player = NULL;
static SLPlayItf iplayer = NULL;
static SLAndroidSimpleBufferQueueItf pcmQue = NULL;
static SLEngineItf CreateSL()
{
    SLresult re;
    SLEngineItf en;
    re = slCreateEngine(&engineSL,0,0,0,0,0);
    if(re != SL_RESULT_SUCCESS) return NULL;
    re = (*engineSL)->Realize(engineSL,SL_BOOLEAN_FALSE);
    if(re != SL_RESULT_SUCCESS) return NULL;
    re = (*engineSL)->GetInterface(engineSL,SL_IID_ENGINE,&en);
    if(re != SL_RESULT_SUCCESS) return NULL;
    return en;
}

void SLAudioPlay::PlayCall(void *bufq)
{
    if(!bufq)return;
    SLAndroidSimpleBufferQueueItf bf = (SLAndroidSimpleBufferQueueItf)bufq;
    XLOGE("SLAudioPlay::PlayCall");
}

static void PcmCall(SLAndroidSimpleBufferQueueItf bf,void *contex)
{
    SLAudioPlay *ap = (SLAudioPlay *)contex;
    if(!ap)
    {
        XLOGE("PcmCall failed contex is null!");
        return;
    }
    ap->PlayCall((void *)bf);
}

bool SLAudioPlay::StartPlay(XParameter out)
{

    //1 创建引擎
    eng = CreateSL();
    if(eng)
    {
        XLOGI("CreateSL success！ ");
    }
    else
    {
        XLOGE("CreateSL failed！ ");
        return false;
    }

    //2 创建混音器

    SLresult re = 0;
    re = (*eng)->CreateOutputMix(eng,&mix,0,0,0);
    if(re !=SL_RESULT_SUCCESS )
    {
        XLOGE("SL_RESULT_SUCCESS failed!");
        return false;
    }
    re = (*mix)->Realize(mix,SL_BOOLEAN_FALSE);
    if(re !=SL_RESULT_SUCCESS )
    {
        XLOGE("(*mix)->Realize failed!");
        return false;
    }
   SLDataLocator_OutputMix outmix = {SL_DATALOCATOR_OUTPUTMIX,mix};
    SLDataSink audioSink= {&outmix,0};

    //3 配置音频信息
    //缓冲队列
    SLDataLocator_AndroidSimpleBufferQueue que = {SL_DATALOCATOR_ANDROIDSIMPLEBUFFERQUEUE,10};
    //音频格式
    SLDataFormat_PCM pcm = {
            SL_DATAFORMAT_PCM,
            (SLuint32) out.channels,//    声道数
            (SLuint32) out.sample_rate*1000,
            SL_PCMSAMPLEFORMAT_FIXED_16,
            SL_PCMSAMPLEFORMAT_FIXED_16,
            SL_SPEAKER_FRONT_LEFT|SL_SPEAKER_FRONT_RIGHT,
            SL_BYTEORDER_LITTLEENDIAN //字节序，小端
    };
    SLDataSource ds = {&que,&pcm};


    //4 创建播放器
    const SLInterfaceID ids[] = {SL_IID_BUFFERQUEUE};
    const SLboolean req[] = {SL_BOOLEAN_TRUE};
    re = (*eng)->CreateAudioPlayer(eng,&player,&ds,&audioSink,sizeof(ids)/sizeof(SLInterfaceID),ids,req);
    if(re !=SL_RESULT_SUCCESS )
    {
        XLOGE("CreateAudioPlayer failed!");
        return false;
    } else{
        XLOGI("CreateAudioPlayer success!");
    }
   (*player)->Realize(player,SL_BOOLEAN_FALSE);
    //获取player接口
    re = (*player)->GetInterface(player,SL_IID_PLAY,&iplayer);
    if(re !=SL_RESULT_SUCCESS )
    {
        XLOGE("GetInterface SL_IID_PLAY failed!");
        return false;
    }
    re = (*player)->GetInterface(player,SL_IID_BUFFERQUEUE,&pcmQue);
    if(re !=SL_RESULT_SUCCESS )
    {
        XLOGE("GetInterface SL_IID_BUFFERQUEUE failed!");
        return false;
    }

    //设置回调函数，播放队列空调用
    (*pcmQue)->RegisterCallback(pcmQue,PcmCall,this);

    //设置为播放状态
    (*iplayer)->SetPlayState(iplayer,SL_PLAYSTATE_PLAYING);

    //启动队列回调
    (*pcmQue)->Enqueue(pcmQue,"",1);
    XLOGI("SLAudioPlay::StartPlay success!");
    return true;
}

果然還是老師的v1080.mp4可以播放，但是沒有聲音，在這個雷電4中