:Implement RTS-based stream pulling on iOS

Create a player

This section explains how to play videos using the SDK. Playback can be manual or autoplay.

1. Create an AliPlayer instance.

   setTraceID determines which monitoring and event tracing features you can use later. For more information, see Create a player.

   // Create a player.
   self.player = [[AliPlayer alloc] init];
   // We recommend that you specify the traceId.
   [play setTraceID:@"xxxxxx"];

   Note

   The event tracking logs are uploaded to nodes in the China (Shanghai) region.

2. Configure listeners.

   • The prepare method must be set for manual playback, as it requires calling the start method in the prepare callback to begin playback.

   • The onPlayerEvent and onError methods are crucial for handling player events and errors. We recommend that you set them up.

   @interface SimplePlayerViewController ()<AVPDelegate>
   @end
   - (void)viewDidLoad {
       self.player = [[AliPlayer alloc] init];
       self.player.playerView = self.avpPlayerView.playerView;
       self.player.delegate = self;
       //...
   }
   /**
    @brief Error delegate callback.
    @param player Pointer to the player instance.
    @param errorModel Error description. For details, see AliVcPlayerErrorModel.
    */
   - (void)onError:(AliPlayer*)player errorModel:(AVPErrorModel *)errorModel {
       // Display the error message and implement actions such as stopping playback.
   }
   /**
    @brief Callback for player events.
    @param player Pointer to the player instance.
    @param eventType Event type. For details, see AVPEventType.
    */
   -(void)onPlayerEvent:(AliPlayer*)playereventType:(AVPEventType)eventType{
       switch(eventType){
           caseAVPEventPrepareDone:{
               // The preparation is complete.
               // When autoPlay is set to NO, call the start method in the prepare callback.
               [self.playerstart];
           }
               break;
           case AVPEventAutoPlayStart:
               // Autoplay started.
               break;
           case AVPEventFirstRenderedStart:
               // First frame rendered. 
               break;
           case AVPEventCompletion:
               // Playback completed.
               break;
           case AVPEventLoadingStart:
               // Buffering started.
               break;
           case AVPEventLoadingEnd:
               // Buffering ended.
               break;
           case AVPEventSeekEnd:
               // Seeking completed.
               break;
           case AVPEventLoopingStart:
               // Looping started.
               break;
           default:
               break;
       }
   }
   /**
    @brief Callback for the current playback position. 
    @param player Pointer to the player instance.
    @param position The current playback position.
    */
   - (void)onCurrentPositionUpdate:(AliPlayer*)player position:(int64_t)position {
       // Update the progress bar.
   }
   /**
    @brief Callback for buffer position. 
    @param player Pointer to the player instance.
    @param position The current buffer position.
    */
   - (void)onBufferedPositionUpdate:(AliPlayer*)player position:(int64_t)position {
       // Update the buffer progress.
   }
   /**
    @brief Callback for track information.
    @param player Pointer to the player instance.
    @param info For track information, see AVPTrackInfo.
    */
   - (void)onTrackReady:(AliPlayer*)player info:(NSArray<AVPTrackInfo*>*)info {
       // Obtain multi-bitrate and track information. 
   }
   /**
    @brief Callback for subtitle display.
    @param player Pointer to the player instance.
    @param index The index of the subtitle being displayed. 
    @param subtitle The content of the displayed subtitle, which is a string.
    */
   - (void)onSubtitleShow:(AliPlayer*)player index:(int)index subtitle:(NSString *)subtitle {
       // Display the subtitles.
   }
   /**
    @brief Callback for subtitle removal.
    @param player Pointer to the player instance.
    @param index The index of the subtitle being displayed.
    */
   - (void)onSubtitleHide:(AliPlayer*)player index:(int)index {
       // Remove subtitles from display.
   }
   /**
    @brief Callback for screenshot.
    @param player Pointer to the player instance.
    @param image Screenshot image.
    */
   - (void)onCaptureScreen:(AliPlayer *)player image:(UIImage *)image {
       // Preview or save the screenshot.
   }
   /**
    @brief Callback for switching tracks.
    @param player Pointer to the player instance.
    @param info For updated track information, see AVPTrackInfo.
    */
   - (void)onTrackChanged:(AliPlayer*)player info:(AVPTrackInfo*)info {
       // The notification on bitrate switching.
   }

3. Create a data source.

   ApsaraVideo Player supports four types of sources: VidSts, VidAuth, VidMps, and UrlSource. For RTS service, set the protocol to artc:// if you use UrlSource.

   AVPUrlSource *urlSource = [[AVPUrlSource alloc] 
   urlWithString:"artc://<streaming URL>"]; 
   [self.player setUrlSource:urlSource];

4. Set the display view.

   If the source has video content, configure the UI view to display content in the player.

   self.player.playerView = self.avpPlayerView.playerView;// Set the player view. 

5. Configure playback parameters.

   ApsaraVideo Player SDK V6.3.0 and later support automatically configuring the optimal ultra-low latency. If the playback URL starts with artc:// and MaxDelayTime, HighBufferDuration, or StartBufferDuration in AVPConfig has not been manually modified, the SDK automatically set MaxDelayTime to 1000 ms, HighBufferDuration to 10 ms, and StartBufferDuration to 10 ms.

   If you want to customize these parameters, the following code shows how to retrieve and modify the configuration:

   //1. Obtain and modify the configuration.
   AVPConfig *config = self.aliPlayer.getConfig;
   
   if ([playUrl hasPrefix:@"artc://"]) {
       // The maximum latency. Unit: milliseconds. In this example, the value is set to 1000, which indicates 1 second.
       [config setMaxDelayTime:1000];
       // The buffer duration for playback startup.
       [config setStartBufferDuration:10];
       // The buffer duration for stuttering recovery.
       [config setHighBufferDuration:10];
   } else {
       // You can use default configuration or specify custom values.
   }
   
   //2. Apply the configuration.
   [_aliPlayer setConfig:config];
   

6. Optional.Enable autoplay, which is disabled by default.

   self.player.autoPlay = YES;

7. Prepare for playback.

   Initiate data reading and parsing by calling [self.player prepare].

   [self.player prepare];

8. Start playback.

   • If autoplay is disabled, call the start method after the AVPEventPrepareDone callback is triggered.

   • If autoplay is enabled, you do not need to call the start method. The video will automatically play when data parsing is complete.

   Important

   During autoplay, the AVPEventPrepareDone callback is not triggered. Instead, the AVPEventAutoPlayStart callback occurs.

   [self.player start];

Control playback

ApsaraVideo Player SDK provides various controls for media playback, such as starting and pausing. Video seeking is not supported for RTS.

 [self.player start];

[self.player stop];

// Synchronous disposal. The system automatically calls the stop method.
[self.player destroy];
// Asynchronous disposal. The system automatically calls the stop method.
[self.player destroyAsync];

Use auxiliary features

1. Logging

   // Enable logging.
   [AliPlayer setEnableLog:YES];
   [AliPlayer setLogCallbackInfo:LOG_LEVEL_TRACE callbackBlock:nil];
   
   // Disable logging.
   [AliPlayer setEnableLog:NO];
   [AliPlayer setLogCallbackInfo:LOG_LEVEL_NONE callbackBlock:nil];

2. RTS downgrade

   1. Automatic downgrade

      If no specific streaming URL is configured for downgrade, the system automatically switches to an FLV-based streaming URL when RTS stream pulling fails.

      // 1 means enabling the feature. 0 means disabling the feature. By default, it is enabled.
      [AliPlayerGlobalSettings setOption:ALLOW_PRE_RENDER valueInt:1];

   2. Custom downgrade

      You can specify an alternative URL, such as an HLS or FLV-based URL for downgrade. If RTS stream pulling fails, the video from the alternative URL will be played automatically.

      //Set the downgrade URL.
      AVPUrlSource *urlSource = [[AVPUrlSource alloc] urlWithString:downgradeUrl];
      //Optional. Set other parameters.
      AVPConfig *config = [self.player getConfig];
      //Enable downgrade.
      [self.player enableDowngrade:urlSource config:config];

3. Obtain the TraceID

   Each low-latency playback generates a TraceID, which can be used for troubleshooting. Retrieve the TraceID from the player event callback.

   // Listen to the onPlayerEvent callback and parse the DemuxerTraceID message.
   - (void)onPlayerEvent:(AliPlayer*)player eventWithString:(AVPEventWithString)eventWithString description:(NSString *)description {
       switch (eventWithString) {
           case EVENT_PLAYER_DEMUXER_TRACE_ID:
               {
                   NSString *traceId = description;
               }
                   break;
               default:
                   break;
       }
   }