开始使用 IMA DAI SDK

选择您感兴趣的 DAI 解决方案

Pod Serving DAI

IMA SDK 可简化将多媒体广告集成到您的网站和应用中的流程。

IMA SDK 可以从任何与 VAST 兼容的广告服务器请求广告，并管理应用中的广告播放。

借助 IMA DAI SDK，应用可以针对 VOD 或直播内容发出广告和内容视频的流式传输请求。然后，SDK 会返回一个合并的视频串流，这样您就不必在应用中管理广告视频和内容视频之间的切换。

本指南演示了如何使用适用于 CAF 的 IMA DAI SDK 播放 DAI Pod 服务流。

在使用本指南之前，请先熟悉 Chromecast 应用框架的 Web 接收器协议。本指南假定您对 CAF 接收器概念（例如消息拦截器和 mediaInformation 对象）有基本的了解，并且熟悉如何使用 Cast 命令和控制工具来模拟 CAF 发送器。

如需使用 IMA DAI Pod Serving，您必须与 Pod Serving 合作伙伴合作，并且必须拥有 Ad Manager 360 Advanced 账号。如果您有 Ad Manager 账号，请与您的客户经理联系以了解详情。如需了解如何注册 Ad Manager，请访问 Ad Manager 帮助中心。

如需了解如何与其他平台集成或如何使用 IMA 客户端 SDK，请参阅Interactive Media Ads SDK。

IMA DAI Pod Serving 概览

使用 IMA CAF DAI SDK 实现 Pod 广告投放涉及两个主要组件，本指南将对此进行演示：

• StreamRequest：用于定义对 Google 广告服务器的流式传输请求的对象。请求会指定广告联盟代码、自定义素材资源键和可选 API 密钥，以及其他可选参数。
• StreamManager：用于处理视频串流与 IMA DAI SDK 之间的通信的对象，例如触发跟踪 ping 和将串流事件转发给发布商。

前提条件

• 一个已注册测试设备的 Cast Developer Console 账号。
• 已在 Cast 开发者控制台中注册的托管网站接收器应用，该应用可修改为托管本指南提供的代码。
• 配置为使用 Web 接收器应用的发送应用。在本例中，请使用 Cast 命令和控制工具作为发送端。

配置发件人的 MediaInfo 对象

首先，配置发件人应用的 MediaInfo 对象，使其包含以下字段：

下面是一些代码示例，可帮助您开始使用：

// Create mediaInfo object
const mediaInfo = new chrome.cast.media.MediaInfo("CONTENT_ID");
mediaInfo.contentUrl = "BACKUP_STREAM_URL";
mediaInfo.contentType = "CONTENT_STREAM_MIMETYPE";
mediaInfo.streamType = chrome.cast.media.StreamType.LIVE;
mediaInfo.customData = {
  daiStreamType: "DAI_STREAM_TYPE",
  networkCode: "NETWORK-CODE",
  customAssetKey: "CUSTOM_ASSET_KEY",
  apiKey: "API_KEY"
};

// Make load request to cast web receiver
const castSession = cast.framework.CastContext.getInstance().getCurrentSession();
const request = new chrome.cast.media.LoadRequest(mediaInfo);
castSession.loadMedia(request).then(
  () => { console.log('Load succeed'); },
  (errorCode) => { console.log('Error code: ' + errorCode); });

JSONObject customData = new JSONObject()?
  .put("daiStreamType", "DAI_STREAM_TYPE")
  .put("networkCode", "NETWORK-CODE")
  .put("customAssetKey", "CUSTOM_ASSET_KEY")
  .put("apiKey", "API_KEY");
MediaInfo mediaInfo = MediaInfo.Builder("CONTENT_ID")
  .setContentUrl("BACKUP_STREAM_URL")
  .setContentType("CONTENT_STREAM_MIMETYPE")
  .setStreamType(MediaInfo.STREAM_TYPE_LIVE)
  .setCustomData(customData)
  .build();

RemoteMediaClient remoteMediaClient = mCastSession.getRemoteMediaClient();
remoteMediaClient.load(new MediaLoadRequestData.Builder().setMediaInfo(mediaInfo).build());

NSURL url = [NSURL URLWithString:@"BACKUP_STREAM_URL"];
NSDictionary *customData = @{
  @"daiStreamType": @"DAI_STREAM_TYPE",
  @"networkCode": @"NETWORK-CODE",
  @"customAssetKey": @"CUSTOM_ASSET_KEY",
  @"apiKey": @"API_KEY"};
mediaInfoBuilder.customData = customData;

GCKMediaInformationBuilder *mediaInfoBuilder =
  [[GCKMediaInformationBuilder alloc] initWithContentID: @"CONTENT_ID"];
mediaInfoBuilder.contentURL = url;
mediaInfoBuilder.contentType = @"CONTENT_STREAM_MIMETYPE";
mediaInfoBuilder.streamType = GCKMediaStreamTypeLive;
mediaInfoBuilder.customData = customData;
self.mediaInformation = [mediaInfoBuilder build];

GCKRequest *request = [self.sessionManager.currentSession.remoteMediaClient loadMedia:self.mediaInformation];
if (request != nil) {
  request.delegate = self;
}

let url = URL.init(string: "BACKUP_STREAM_URL")
guard let mediaURL = url else {
  print("invalid mediaURL")
  return
}

let customData = [
  "daiStreamType": "DAI_STREAM_TYPE",
  "networkCode": "NETWORK-CODE",
  "customAssetKey": "CUSTOM_ASSET_KEY",
  "region": "API_KEY"
]

let mediaInfoBuilder = GCKMediaInformationBuilder.init(contentId: "CONTENT_ID")
mediaInfoBuilder.contentURL = mediaUrl
mediaInfoBuilder.contentType = @"CONTENT_STREAM_MIMETYPE"
mediaInfoBuilder.streamType = GCKMediaStreamType.Live
mediaInfoBuilder.customData = customData
mediaInformation = mediaInfoBuilder.build()

guard let mediaInfo = mediaInformation else {
  print("invalid mediaInformation")
  return
}

if let request = sessionManager.currentSession?.remoteMediaClient?.loadMedia
(mediaInfo) {
  request.delegate = self
}

{
  "media": {
    "contentId": "CONTENT_ID",
    "contentUrl": "BACKUP_STREAM_URL",
    "contentType": ""CONTENT_STREAM_MIMETYPE"",
    "streamType": "LIVE",
    "customData": {
      "daiStreamType": "DAI_STREAM_TYPE",
      "networkCode": "NETWORK-CODE",
      "customAssetKey": "CUSTOM_ASSET_KEY",
      "oAuthToken": "API_KEY"
    }
  }
}

此自定义加载请求可发送给接收器，以测试其余步骤。

创建基本 CAF 接收器

创建自定义 Web 接收器，如 CAF SDK 自定义 Web 接收器指南中所述。

接收器的代码应如下所示：

<html>
<head>
  <script
      src="//www.gstatic.com/cast/sdk/libs/caf_receiver/v3/cast_receiver_framework.js">
  </script>
</head>
<body>
  <cast-media-player></cast-media-player>
  <script>
    // ...
  </script>
</body>
</html>

导入 IMA DAI SDK 并获取 Player Manager

在脚本加载 CAF 后，添加一个脚本标记，以将适用于 CAF 的 IMA DAI SDK 导入到您的 Web 接收器。在脚本标记中，将接收器上下文和播放器管理器存储为常量，然后再启动接收器。

<html>
<head>
  <script
      src="//www.gstatic.com/cast/sdk/libs/caf_receiver/v3/cast_receiver_framework.js"></script>
  <script src="//imasdk.googleapis.com/js/sdkloader/cast_dai.js"></script>
</head>
<body>
  <cast-media-player></cast-media-player>
  <script>
    const castContext = cast.framework.CastReceiverContext.getInstance();
    const playerManager = castContext.getPlayerManager();

    castContext.start();
  </script>
</body>
</html>

初始化 IMA 串流管理器

初始化 IMA 串流管理器。

<html>
<head>
  <script type="text/javascript"
      src="//www.gstatic.com/cast/sdk/libs/caf_receiver/v3/cast_receiver_framework.js"></script>
  <script src="//imasdk.googleapis.com/js/sdkloader/cast_dai.js"></script>
</head>
<body>
  <cast-media-player></cast-media-player>
  <script>
    const castContext = cast.framework.CastReceiverContext.getInstance();
    const playerManager = castContext.getPlayerManager();
    const streamManager = new google.ima.cast.dai.api.StreamManager();

    castContext.start();
  </script>
</body>
</html>

创建 Stream Manager 加载拦截器

在媒体内容传递给 CAF 之前，请在 LOAD 消息拦截器中创建流式传输请求。

    const castContext = cast.framework.CastReceiverContext.getInstance();
    const playerManager = castContext.getPlayerManager();
    const streamManager = new google.ima.cast.dai.api.StreamManager();

    /**
     * Creates a livestream request object for a Pod Serving stream.
     * @param {!LoadRequestData} castRequest The request object from the cast sender
     * @return {StreamRequest} an IMA stream request
     */
    const createStreamRequest = (castRequest) => { /* ... */};

    /**
     * Initates a DAI stream request for the final stream manifest.
     * @param {!LoadRequestData} castRequest The request object from the cast sender
     * @return {Promise<LoadRequestData>} a promise that resolves to an updated castRequest, containing the DAI stream manifest
     */
    const createDAICastRequest = (castRequest) => {
        return streamManager.requestStream(castRequest, createStreamRequest(castRequest))
          .then((castRequestWithPodStreamData) => {
            console.log('Successfully made DAI stream request.');
            // ...
            return castRequestWithPodStreamData;
          })
          .catch((error) => {
            console.log('Failed to make DAI stream request.');
            // CAF will automatically fallback to the content URL
            // that it can read from the castRequest object.
            return castRequest;
          });
    };

    playerManager.setMessageInterceptor(
        cast.framework.messages.MessageType.LOAD, createDAICastRequest);

    castContext.start();

创建数据流请求

完成 createStreamRequest 函数，以根据 CAF 加载请求创建 Pod 服务流。

    /**
     * Creates a livestream request object for a Pod Serving stream.
     * @param {!LoadRequestData} castRequest The request object from the cast sender
     * @return {StreamRequest} an IMA stream request
     */
    const createStreamRequest = (castRequest) => {
      const customData = castRequest.media.customData;
      let streamRequest;
      if (customData.daiStreamType == "LIVE") {
        streamRequest = new google.ima.cast.dai.api.PodStreamRequest();
        streamRequest.customAssetKey = customData.customAssetKey;
        streamRequest.networkCode = customData.networkCode;
        streamRequest.apiKey = customData.apiKey;
      } else if (customData.daiStreamType == "VOD") {
        streamRequest = new google.ima.cast.dai.api.PodVodStreamRequest();
        streamRequest.networkCode = customData.networkCode;
        streamRequest.apiKey = customData.apiKey;
      }
      return streamRequest;
    };

从 VTP 检索拼接的清单

如果您的数据流请求成功，请使用 streamManager.getStreamId() 检索数据流的 ID。您的视频技术合作伙伴 (VTP) 或自定义清单操作程序将提供使用此串流 ID 检索清单网址的说明。

检索到清单网址后，请将现有的 contentUrl 替换为新的 manifestUrl。

最后，在返回经过修改的直播清单之前，请对 streamManager 调用 loadStreamMetadata 方法，以告知 IMA SDK 可以安全地请求直播元数据。只有 VOD 串流才需要执行此调用。

    /**
     * Initates a DAI stream request for the final stream manifest.
     * @param {!LoadRequestData} castRequest The request object from the cast sender
     * @return {Promise<LoadRequestData>} a promise that resolves to an updated castRequest, containing the DAI stream manifest
     */
    const createDAICastRequest = (castRequest) => {
        return streamManager.requestStream(castRequest, createStreamRequest(castRequest))
          .then((castRequestWithPodStreamData) => {
            console.log('Successfully made DAI stream request.');

            // This is a sample VTP integration. Consult your VTP documentation
            // for how to retrieve an ad-stitched stream manifest URL.
            const manifestTemplate = "https://.../manifest.m3u8?gam_stream_id=[[STREAMID]]";
            const streamId = streamManager.getStreamId();
            const manifestUrl = manifestTemplate.replace('[[STREAMID]]', streamId)
            // Assign your manifestUrl to the request's content URL.
            castRequestWithPodStreamData.media.contentUrl = manifestUrl;

            // After generating the manifest URL, VOD streams must notify the
            // IMA SDK that it is safe to request ad pod metadata.
            // This is only necessary for VOD streams. It is a no-op for
            // livestreams, so no conditional is needed.
            streamManager.loadStreamMetadata();

            return castRequestWithPodStreamData;
          })
          .catch((error) => {
            console.log('Failed to make DAI stream request.');
            // CAF will automatically fallback to the content URL
            // that it can read from the castRequest object.
            return castRequest;
          });
    };

现在，您可以使用 Cast 应用框架和适用于 CAF 的 IMA DAI SDK 请求和播放 Pod Serving 广告连播。