!3622 新增 opensles 音频播放资料

Merge pull request !3622 from 杨帅/master

zh-cn/application-dev/media/Readme-CN.md

@@ -6,6 +6,7 @@
     - [音频录制开发指导](audio-recorder.md)
     - [音频渲染开发指导](audio-renderer.md)
     - [音频采集开发指导](audio-capturer.md)
+    - [OpenSL ES播放开发指导](opensles-playback.md)
 - 视频
 
   - [视频播放开发指导](video-playback.md)

zh-cn/application-dev/media/opensles-playback.md

+# OpenSL ES音频播放开发指导
+
+ 
+
+## 场景介绍
+
+开发者可以通过本文了解到在**OpenHarmony**如何使用**OpenSL ES**进行音频播放相关操作；当前仅实现了部分[**OpenSL ES**接口](https://gitee.com/openharmony/third_party_opensles/blob/master/api/1.0.1/OpenSLES.h)，未实现接口调用后会返回**SL_RESULT_FEATURE_UNSUPPORTED**
+
+ 
+
+## 开发步骤
+
+以下步骤描述了在**OpenHarmony**如何使用**OpenSL ES**开发音频播放功能：
+
+1. 添加头文件
+
+    ```c++
+    #include <OpenSLES.h>
+    #include <OpenSLES_OpenHarmony.h>
+    #include <OpenSLES_Platform.h>
+    ```
+
+    
+
+2. 使用 **slCreateEngine** 接口和获取 **engine** 实例。
+
+    ```c++
+    SLObjectItf engineObject = nullptr;
+    slCreateEngine(&engineObject, 0, nullptr, 0, nullptr, nullptr);
+    (*engineObject)->Realize(engineObject, SL_BOOLEAN_FALSE);
+    ```
+
+    
+
+3. 获取接口 **SL_IID_ENGINE** 的 **engineEngine** 实例
+
+    ```c++
+    SLEngineItf engineEngine = nullptr;
+    (*engineObject)->GetInterface(engineObject, SL_IID_ENGINE, &engineEngine);
+    ```
+
+    
+
+4. 配置播放器信息，创建 **AudioPlayer** 。
+
+    ```c++
+    SLDataLocator_BufferQueue slBufferQueue = {
+        SL_DATALOCATOR_BUFFERQUEUE,
+        0
+    };
+    
+    //具体参数需要根据音频文件格式进行适配
+    SLDataFormat_PCM pcmFormat = {
+        SL_DATAFORMAT_PCM,
+        2,
+        48000,
+        16,
+        0,
+        0,
+        0
+    };
+    SLDataSource slSource = {&slBufferQueue, &pcmFormat};
+    
+    SLObjectItf pcmPlayerObject = nullptr;
+    (*engineEngine)->CreateAudioPlayer(engineEngine, &pcmPlayerObject, &slSource, null, 0, nullptr, nullptr);
+    (*pcmPlayerObject)->Realize(pcmPlayerObject, SL_BOOLEAN_FALSE);
+    ```
+
+    
+
+5. 获取接口 **SL_IID_OH_BUFFERQUEUE** 的 **bufferQueueItf** 实例
+
+    ```
+    SLOHBufferQueueItf bufferQueueItf;
+    (*pcmPlayerObject)->GetInterface(pcmPlayerObject, SL_IID_OH_BUFFERQUEUE, &bufferQueueItf);
+    ```
+
+    
+
+6. 打开音频文件，注册 **BuqqerQueueCallback** 回调
+
+    ```c++
+    FILE *wavFile_ = nullptr;
+    
+    static void BuqqerQueueCallback (SLOHBufferQueueItf bufferQueueItf, void *pContext, SLuint32 size)
+    {
+        FILE *wavFile = (FILE *)pContext;
+        if (!feof(wavFile)) {
+            SLuint8 *buffer = nullptr;
+            SLuint32 pSize = 0;
+            (*bufferQueueItf)->GetBuffer(bufferQueueItf, &buffer, pSize);
+            //从文件读取数据
+            fread(buffer, 1, size, wavFile);
+            (*bufferQueueItf)->Enqueue(bufferQueueItf, buffer, size);
+        }
+        return;
+    }
+    
+    //wavFile_ 需要设置为用户想要播放的文件描述符
+    wavFile_ = fopen(path, "rb");
+    (*bufferQueueItf)->RegisterCallback(bufferQueueItf, BuqqerQueueCallback, wavFile_);
+    ```
+
+    
+
+7. 获取接口 **SL_PLAYSTATE_PLAYING** 的 **playItf** 实例，开始播放
+
+    ```c++
+    SLPlayItf playItf = nullptr;
+    (*pcmPlayerObject)->GetInterface(pcmPlayerObject, SL_IID_PLAY, &playItf);
+    (*playItf)->SetPlayState(playItf, SL_PLAYSTATE_PLAYING);
+    ```
+
+    
+
+8. 结束音频播放
+
+    ```c++
+    (*playItf)->SetPlayState(playItf, SL_PLAYSTATE_STOPPED);
+    (*pcmPlayerObject)->Destroy(pcmPlayerObject);
+    (*engineObject)->Destroy(engineObject);
+    ```
+