iOS和Mac如何输出音视频数据_音视频通信(RTC)-阿里云帮助中心

通过阅读本文，您可以了解输出音视频数据的方法。

输出视频数据

注册视频裸数据。
接口方法如下：
```
- (void)registerVideoSampleObserver;
```
说明调用此接口后，即可开始订阅视频裸数据，裸数据通过回调接口给出。
如果想停止获取音频裸数据，调用以下接口：
```
- (void)unregisterVideoSampleObserver;
```

通过回调获取视频裸数据。

回调接口方法如下：

/**
* @brief 订阅的本地采集视频数据回调
* @param videoSource video source
* @param videoSample video sample
*/
- (void)onCaptureVideoSample:(AliRtcVideoSource)videoSource videoSample:(AliRtcVideoDataSample *)videoSample;

/**
* @brief 订阅的远端视频数据回调
* @param uid user id
* @param videoSource video source
* @param videoSample video sample
*/
- (void)onRemoteVideoSample:(NSString *)uid videoSource:(AliRtcVideoSource)videoSource videoSample:(AliRtcVideoDataSample *)videoSample;

说明

调用registerVideoSampleObserver接口后，通过以下两个回调获取对应的视频裸数据。

onCaptureVideoSample为预览数据回调，在开始预览之后可收到数据流。
onRemoteVideoSample为拉流数据回调，subscribe拉流成功后可收到数据流。

预览视频裸数据写入本地yuv文件。

{
// 开始订阅
[_engine registerVideoSampleObserver];
}

- (void)onCaptureVideoSample:(AliRtcVideoSource)videoSource videoSample:(AliRtcVideoDataSample *)videoSample {

    [self dumpVideoYuvData:@"" videoSource:videoSource videoSample:videoSample];
}

- (void)onRemoteVideoSample:(NSString *)uid videoSource:(AliRtcVideoSource)videoSource videoSample:(AliRtcVideoDataSample *)videoSample {
    [self dumpVideoYuvData:uid videoSource:videoSource videoSample:videoSample];
}

- (void)dumpVideoYuvData:(NSString *)uid videoSource:(AliRtcVideoSource)videoSource videoSample:(AliRtcVideoDataSample *)videoSample {
    //创建串行队列
       dispatch_queue_t testqueue = dispatch_queue_create("subVideo", NULL);

       //同步执行任务
       dispatch_sync(testqueue, ^{
           if(_dumpYUVVideoData || _remoteYUVVideoData){

               if (videoSource != AliRtcVideosourceCameraLargeType) {
                   return;
               }

               if (!_subDataMutableDic[uid]) {
                   NSString *time = [self getCurrentTimes];

                   NSString *filePath = [NSString stringWithFormat:@"Documents/yuv/%@/",uid];
                   if ([uid isEqualToString:@""]) {
                       filePath = [NSString stringWithFormat:@"Documents/yuv/self/"];
                   }

                   NSString *fileName = [NSString stringWithFormat:@"sub_%@_video_%d*%d_%@.yuv",uid,videoSample.width,videoSample.height,time];
                   if ([uid isEqualToString:@""]) {
                       fileName = [NSString stringWithFormat:@"pub_%@_video_%d*%d_%@.yuv",uid,videoSample.width,videoSample.height,time];
                   }

                   NSString * dataPath = [SubFilePath getSubDataFilePath:filePath FileName:fileName];

                   subYUVFile = fopen([dataPath UTF8String], "ab");

                   SubDataModel *cache = [[SubDataModel alloc] init];
                   cache.filePath = dataPath;
                   cache.outputFile = subYUVFile;
                   [_subDataMutableDic setObject:cache forKey:uid];
               }

               SubDataModel *cache = _subDataMutableDic[uid];
               subYUVFile = cache.outputFile;

               uint8_t *outputData = NULL;
               int32_t w = videoSample.width;
               int32_t h = videoSample.height;

               if (outputData == NULL) {
                   outputData = (uint8_t*)malloc(w*h*3/2);
               }

               if(videoSample.type == AliRtcBufferType_Raw_Data) {

                   if(videoSample.dataYPtr && videoSample.dataUPtr &&  videoSample.dataVPtr) {
                       memcpy(outputData, (uint8_t*)videoSample.dataYPtr,w*h*3/2);
                       memcpy(outputData + w*h, (uint8_t*)videoSample.dataUPtr, w*h/4);
                       memcpy(outputData + w*h*5/4, (uint8_t*)videoSample.dataVPtr, w*h/4);
                   }

               }else if(videoSample.type == AliRtcBufferType_CVPixelBuffer) {
                   if(videoSample.pixelBuffer) {
                       CVPixelBufferRef newBuffer = videoSample.pixelBuffer;
                       if(newBuffer) {
                           CVReturn cvRet = CVPixelBufferLockBaseAddress(newBuffer, 0);
                            if ( cvRet != kCVReturnSuccess ) {
                                return;
                            }
                            void*  src_y = CVPixelBufferGetBaseAddressOfPlane(newBuffer, 0);
                            void*  src_uv = CVPixelBufferGetBaseAddressOfPlane(newBuffer, 1);

                            size_t src_y_stride = CVPixelBufferGetBytesPerRowOfPlane(newBuffer, 0);
                            size_t src_uv_stride = CVPixelBufferGetBytesPerRowOfPlane(newBuffer, 1);

                            uint8_t *destData = outputData;

                            for (int row = 0; row < h; ++row) {
                                memcpy(destData, (uint8_t*)src_y + row * src_y_stride,w);
                                destData += w;
                            }

                            for (int row = 0; row < (h + 1) / 2; ++row) {
                                memcpy(destData, (uint8_t*)src_uv + row * src_uv_stride,w);
                                destData += w;
                            }

                            CVPixelBufferUnlockBaseAddress(newBuffer, 0);
                       }
                   }
               }

               fwrite(outputData, 1, w*h*3/2, subYUVFile);

               if (outputData) {
                   free(outputData);
                   outputData = NULL;
               }
           }
       });
}

输出音频裸数据

设置入会模式为音乐模式。

接口方法：

+ (instancetype)sharedInstance:(id<AliRtcEngineDelegate>)delegate extras:(NSString *)extras;

通过设置extras参数来控制是否为音乐模式。

{
  "user_specified_scene_mode" : "SCENE_MUSIC_MODE",
}

说明 extras为JSON字符串，如果当前使用了其他key值的extras配置，可以共存。

音乐模式示例代码如下所示。

NSMutableDictionary *extrasDic = [[NSMutableDictionary alloc] init];
[extrasDic setValue:@"ENGINE_BASIC_QUALITY_MODE" forKey:@"user_specified_engine_mode"];
[extrasDic setValue:@"SCENE_MUSIC_MODE" forKey:@"user_specified_scene_mode"];
NSError *parseError = nil;
NSData *jsonData = [NSJSONSerialization dataWithJSONObject:extrasDic options:NSJSONWritingPrettyPrinted error:&parseError];
NSString *extras = [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];

AliRtcEngine *engine = [AliRtcEngine sharedInstance:self extras:extras];

获取音频推流裸数据。

注册音频裸数据。

接口方法如下：

- (void)subscribeAudioData:(AliRtcAudioSource)audioSource;

说明该接口必须在音频流发布成功之后调用才能生效；调用此接口后，即可开始订阅音频裸数据，裸数据通过回调接口返回。

参数说明如下：


参数	说明
AliRtcAudioSource	AliRtcAudiosourcePub：推流端数据。 AliRtcAudiosourceSub：拉流端数据。

如果您想停止获取音频裸数据，调用以下接口：

- (void)unSubscribeAudioData:(AliRtcAudioSource)audioSource;

通过回调获取对应的音频裸数据。

回调接口如下：

- (void)onAudioSampleCallback:(AliRtcAudioSource)audioSource audioSample:(AliRtcAudioDataSample *)audioSample;

说明调用subscribeAudioData接口后，通过此回调获取对应的音频裸数据。

AliRtcAudioDataSample参数说明如下：


参数	类型	描述
dataPtr	long	裸数据。
numOfSamples	int	音频样本点数。
bytesPerSample	int	量化位数。
numOfChannels	int	声道数。
samplesPerSec	int	采样率。

推流音频裸数据写入本地pcm文件。

{
// 开始订阅（在音频流publish成功之后）
[self.engine subscribeAudioData:(AliRtcAudiosourcePub)];
}

// 订阅的音频数据回调
- (void)onAudioSampleCallback:(AliRtcAudioSource)audioSource audioSample:(AliRtcAudioDataSample *)audioSample {

    if (audioSample.dataPtr == 0) {
        //没有音频订阅数据
        return;
    }

    if (audioSource == AliRtcAudiosourcePub) {
        // pub数据回调
    }

    // 获取buffer 和 bufferSize
    int bufferSize = audioSample.numOfSamples * audioSample.bytesPerSample * audioSample.numOfChannels;
    void *audioSampleBufferPtr = NULL;

    if(bufferSize) {
        audioSampleBufferPtr = malloc(bufferSize);
        if(audioSampleBufferPtr) {
            memcpy(audioSampleBufferPtr, (void *)audioSample.dataPtr, bufferSize);
        }
    }

    // 写入文件（此处省略FILE对象的初始化和销毁等，请写在外部）    
    fwrite(audioSampleBufferPtr, 1, bufferSize, file);

    if (audioSampleBufferPtr) {
        free(audioSampleBufferPtr);
        audioSampleBufferPtr = NULL;
    }
}