开始使用 IMA DAI SDK

IMA SDK 可让您轻松地将多媒体广告集成到您的网站和应用中。IMA SDK 可以 向任意 <ph type="x-smartling-placeholder"></ph> 符合 VAST 标准的广告服务器，并管理应用中的广告播放。借助 IMA DAI SDK，应用 针对广告和内容视频（VOD 或直播内容）的视频流请求。然后，SDK 会返回 组合视频流，因此您无需管理在广告与内容视频之间的切换 。

选择您感兴趣的 DAI 解决方案

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本指南将演示如何使用 适用于 Roku 的 IMA DAI SDK。

IMA DAI Pod Serving 概览

使用 IMA DAI 实现广告连播投放涉及两个主要 SDK 组件： 具体说明如下：

此外，您还需要请求操纵清单 服务器检索数据流 以供您的应用显示具体流程可能会因视频技术而异 合作伙伴 (VTP) 迁移到 VTP。

前提条件

播放视频

示例视频 玩家 提供的开箱即用内容视频。将示例播放器部署到 Roku 设备，确保正确设置您的开发环境。

将视频播放器转换为 IMA DAI 流媒体播放器

请按照以下步骤实现流式播放器。

创建 Sdk.xml

向您的项目添加一个名为 Sdk.xml 的新文件以及 MainScene.xml， 添加以下样板：

Sdk.xml

<?xml version = "1.0" encoding = "utf-8" ?>

  <component name = "imasdk" extends = "Task">
  <interface>
  </interface>
  <script type = "text/brightscript">
  <![CDATA[
    ' Your code goes here.
  ]]>
  </script>
  </component>

您需要彻底修改这两个文件（MainScene.xml 和 Sdk.xml） 本指南。

加载 IMA DAI SDK 框架

如需加载框架，请将以下代码添加到 manifest 和 Sdk.xml：

清单

bs_libs_required=googleima3

Sdk.xml

<?xml version = "1.0" encoding = "utf-8" ?>

  <component name = "imasdk" extends = "Task">
  <interface>
  </interface>
  <script type = "text/brightscript">
  <![CDATA[
  Library "IMA3.brs"
  ]]>
  </script>
  </component>

初始化 IMA DAI SDK

加载 IMA 动态广告插播视频流的第一步是 初始化 IMA DAI SDK。以下代码会初始化 IMA DAI SDK 脚本。

Sdk.xml

<?xml version="1.0" encoding="utf-8" ?>

  <component name="IMASDKTask" extends="Task">
  <interface>
    <field id="IMASDKInitialized" type="Boolean" />
    <field id="errors" type="stringarray" />
  </interface>
  <script type = "text/brightscript">
  <![CDATA[
    Library "IMA3.brs"
    sub init()
      m.top.functionName = "runThread"
    end sub

    sub runThread()
      if not m.top.IMASDKInitialized
        initializeIMASDK()
      end if
    end sub

    sub initializeIMASDK()
        if m.sdk = invalid
          m.sdk = New_IMASDK()
        end if
        m.top.IMASDKInitialized = true
    end sub
  ]]>
  </script>
  </component>

现在，在 MainScene.xml 中启动此任务，并移除加载内容的调用 。

MainScene.xml

<?xml version="1.0" encoding="utf-8" ?>

<component extends="Scene" initialFocus="myVideo" name="MainScene">
  <script type="text/brightscript">
  <![CDATA[
  function init()
    m.video = m.top.findNode("myVideo")
    m.video.notificationinterval = 1
    runIMASDKTask()
  end function

  function runIMASDKTask()
    m.IMASDKTask = createObject("roSGNode", "IMASDKTask")
    m.IMASDKTask.observeField("IMASDKInitialized", "handleIMASDKInitialized")
    m.IMASDKTask.observeField("errors", "handleIMASDKErrors")

    m.IMASDKTask.control = "RUN"
  end function

  sub handleIMASDKInitialized()

    ' Follow your manifest manipulator (VTP) documentation to register a user
    ' streaming session if needed.

  end sub

  sub handleIMASDKErrors(message as object)
    print "------ IMA DAI SDK failed  ------"
    if message <> invalid and message.getData() <> invalid
      print "IMA DAI SDK Error ";message.getData()
    end if
  end sub
  ]]>
  </script>
  <children>
    <Video height="720" id="myVideo" visible="false" width="1280"/>
  </children>
</component>

创建 IMA 流媒体播放器

接下来，您需要使用现有的 roVideoScreen 来创建 IMA 视频流 。

直播广告连播投放

对于直播视频流，此流播放器会实现三种回调方法： streamInitialized、adBreakStarted和adBreakEnded。

同时在加载视频流时停用特技播放。这会阻止用户 在前贴片广告开始播放的那一刻（广告插播时间点开始之前）跳过前贴片广告 事件。

Sdk.xml

<?xml version="1.0" encoding="utf-8" ?>

  <component name="IMASDKTask" extends="Task">
  <interface>
    <field id="IMASDKInitialized" type="Boolean" />
    <field id="errors" type="stringarray" />
    <field id="urlData" type="assocarray" />
    <field id="adPlaying" type="Boolean" />
    <field id="videoNode" type="Node" />
  </interface>

  <script type="text/brightscript">
  ...
  sub runThread()
    if not m.top.IMASDKInitialized
      initializeIMASDK()
    end if

    setupPlayerCallbacks()
  end sub
  ...
  sub initializeIMASDK()
    if m.ima = invalid
      ima = New_IMASDK()
      ima.initSdk()
      m.ima = ima
    end if
    m.top.IMASDKInitialized = true
  end sub

  sub setupPlayerCallbacks()
    m.player = m.ima.createPlayer()
    m.player.top = m.top

    m.player.streamInitialized = function(urlData)
      m.top.videoNode.enableTrickPlay = false
      m.top.urlData = urlData
    end function

    m.player.adBreakStarted = function(adBreakInfo)
      print "------ Ad break started ------"
      m.top.adPlaying = true
      m.top.videoNode.enableTrickPlay = false
    end function

    m.player.adBreakEnded = function(adBreakInfo)
      print "------ Ad break ended ------"
      m.top.adPlaying = false
      m.top.videoNode.enableTrickPlay = true
    end function

  end sub
  </script>
...
</component>

VOD 视频流广告连播投放

对于 VOD 视频流，该流播放器实现了以下四种回调方法： streamInitialized、loadUrl、adBreakStarted和adBreakEnded。在 streamInitialized 回调，请务必调用 StreamManager.loadThirdPartyStream()。否则会导致 SDK 未触发 loadUrl 函数。

在此步骤中，您还需要向您的视频技术合作伙伴请求直播网址 (VTP) 使用在 loadAdPodStream() 中获取的数据流 ID。然后，调用 将 StreamManager.loadThirdPartyStream() 替换为广告连播清单，以及任何 您的 VTP 返回的字幕。

同时在加载视频流时停用特技播放。这会阻止用户 在前贴片广告开始播放的那一刻（广告插播时间点开始之前）跳过前贴片广告 事件。

Sdk.xml

<?xml version="1.0" encoding="utf-8" ?>

  <component name="IMASDKTask" extends="Task">
  <interface>
    <field id="IMASDKInitialized" type="Boolean" />
    <field id="errors" type="stringarray" />
    <field id="adStitchedStreamInfo" type="assocarray" />
    <field id="adPlaying" type="Boolean" />
    <field id="videoNode" type="Node" />
    <field id="streamParameters" type="assocarray" />
  </interface>

  <script type="text/brightscript">
  ...
  sub runThread()
    if not m.top.IMASDKInitialized
      initializeIMASDK()
    end if

    setupPlayerCallbacks()
  end sub
  ...
  sub initializeIMASDK()
    if m.ima = invalid
      ima = New_IMASDK()
      ima.initSdk()
      m.ima = ima
    end if
    m.top.IMASDKInitialized = true
  end sub

  sub loadThirdPartyStream(adStitchedManifest as string, subtitleConfig as dynamic)
    m.streamManager.loadThirdPartyStream(adStitchedManifest, subtitleConfig)
  end sub

  sub setupPlayerCallbacks()
    m.player = m.ima.createPlayer()
    m.player.top = m.top

    m.player.streamInitialized = function(urlData)
      adStitchedManifest = m.top.streamParameters.VTPManifest.replace("[[STREAMID]]", urlData.streamId)
      loadThirdPartyStream(adStitchedManifest, m.top.streamParameters.subtitleConfig)
    end function

    m.player.loadUrl = function(streamInfo)
      m.top.adStitchedStreamInfo = streamInfo
    end function

    m.player.adBreakStarted = function(adBreakInfo)
      print "------ Ad break started ------"
      m.top.adPlaying = true
      m.top.videoNode.enableTrickPlay = false
    end function

    m.player.adBreakEnded = function(adBreakInfo)
      print "------ Ad break ended ------"
      m.top.adPlaying = false
      m.top.videoNode.enableTrickPlay = true
    end function

  end sub
  </script>
...
</component>

创建和执行直播或 VOD 广告连播投放视频流请求

有了流播放器后，您可以创建和执行流请求。 此示例包含存储在 m.testPodServingStream。

直播广告连播投放

在 m.testPodServingStream 对象中，存储 Google Ad 管理员需要确定相关视频流，例如广告联盟代码和 自定义素材资源键。同时存储用于访问清单的清单网址 操作服务器。在这种情况下，清单网址需要包含 在返回视频流请求后添加的数据流 ID。

为了能够支持广告界面（例如广告选择图标），您还必须传递 请求中包含您的内容视频的节点。

MainScene.xml

function init()
  m.video = m.top.findNode("myVideo")
  m.video.notificationinterval = 1
  m.testPodServingStream = {
    title: "Test live stream for DAI Pod Serving",
    assetKey: "test-live-stream",
    networkCode: "your-network-code",
    manifest: "https://.../master.m3u8?stream_id=[[STREAMID]]",
    apiKey: ""
  }
  runIMASDKTask()
end function

function runIMASDKTask()
  m.IMASDKTask = createObject("roSGNode", "IMASDKTask")

  m.IMASDKTask.streamParameters = m.testPodservingStream
  m.IMASDKTask.videoNode = m.video

  m.IMASDKTask.observeField("IMASDKInitialized", "handleIMASDKInitialized")
  m.IMASDKTask.observeField("errors", "handleIMASDKErrors")

  m.IMASDKTask.control = "RUN"
end function

Sdk.xml

<interface>
  <field id="IMASDKInitialized" type="Boolean" />
  <field id="errors" type="stringarray" />
  <field id="urlData" type="assocarray" />
  <field id="adPlaying" type="Boolean" />
  <field id="videoNode" type="Node" />
  <field id="streamParameters" type="assocarray" />
</interface>

...

sub runThread()
  if not m.top.IMASDKInitialized
    initializeIMASDK()
  end if

  setupPlayerCallbacks()
  loadAdPodStream()
end sub

sub loadAdPodStream()
  request = m.ima.CreatePodLiveStreamRequest(m.top.streamParameters.assetKey, m.top.streamParameters.networkCode, m.top.streamParameters.apiKey)

  ' Set the player object so that the request can trigger the player's
  ' callbacks at stream initialization or playback events.
  request.player = m.player

  ' Set the video node for the IMA DAI SDK to create ad UI as its child nodes.
  request.adUiNode = m.top.video

  requestResult = m.ima.requestStream(request)
  if requestResult <> invalid
    print "Error requesting stream ";requestResult
    return
  end if

  m.streamManager = invalid
  while m.streamManager = invalid
    sleep(50)
    m.streamManager = m.ima.getStreamManager()
  end while

  if m.streamManager = invalid
    errors = CreateObject("roArray", 1, True)
    invalidStreamManagerError = "Invalid stream manager"
    print invalidStreamManagerError
    errors.push(invalidStreamManagerError)
    m.top.errors = errors
    return
  end if

  if m.streamManager["type"] <> invalid and m.streamManager["type"] = "error"
    errors = CreateObject("roArray", 1, True)
    print "Stream request returns an error. " ; m.streamManager["info"]
    errors.push(m.streamManager["info"])
    m.top.errors = errors
    return
  end if

  setupStreamManager()
  m.streamManager.start()
end sub

VOD 视频流广告连播投放

在 m.testPodServingStream 对象中，您将存储 视频流请求，以便 Google Ad Manager 可以提供视频流 ID。同时存储 用于访问您清单中的用户特定清单的清单网址 操作服务器。

为了能够支持广告界面（例如广告选择图标），您还必须将 节点。

MainScene.xml

sub init()
  m.video = m.top.findNode("myVideo")
  m.video.notificationinterval = 1
  m.testPodServingStream = {
    title: "Pod Serving VOD Stream",
    networkCode: "your-network-code",
    VTPManifest: "https://.../manifest.m3u8?gam-stream-id=[[STREAMID]]",
    subtitleConfig: []
  }
  runIMASDKTask()
end sub

sub runIMASDKTask()
  m.IMASDKTask = createObject("roSGNode", "IMASDKTask")

  m.IMASDKTask.streamParameters = m.testPodservingStream
  m.IMASDKTask.videoNode = m.video

  m.IMASDKTask.observeField("IMASDKInitialized", "handleIMASDKInitialized")
  m.IMASDKTask.observeField("errors", "handleIMASDKErrors")

  m.IMASDKTask.control = "RUN"
end sub

Sdk.xml

sub runThread()
  if not m.top.IMASDKInitialized
    initializeIMASDK()
  end if

  setupPlayerCallbacks()
  loadAdPodStream()
end sub

sub loadAdPodStream()
  request = m.ima.CreatePodVodStreamRequest(m.top.streamParameters.networkCode)

  ' Set the player object so that the request can trigger the player
  ' callbacks at stream initialization or playback events.
  request.player = m.player

  ' Set the video node for the IMA DAI SDK to create ad UI as its child nodes.
  request.adUiNode = m.top.video

  requestResult = m.ima.requestStream(request)
  if requestResult <> invalid
    print "Error requesting stream ";requestResult
    return
  end if

  m.streamManager = invalid
  while m.streamManager = invalid
    sleep(50)
    m.streamManager = m.ima.getStreamManager()
  end while

  if m.streamManager = invalid
    errors = CreateObject("roArray", 1, True)
    invalidStreamManagerError = "Invalid stream manager"
    print invalidStreamManagerError
    errors.push(invalidStreamManagerError)
    m.top.errors = errors
    return
  end if

  if m.streamManager["type"] <> invalid and m.streamManager["type"] = "error"
    errors = CreateObject("roArray", 1, True)
    print "Stream request returns an error. " ; m.streamManager["info"]
    errors.push(m.streamManager["info"])
    m.top.errors = errors
    return
  end if

  setupStreamManager()
  m.streamManager.start()
end sub

添加事件监听器并启动数据流

直播广告连播投放

请求直播后，最后还有几个步骤要做：添加 事件监听器来跟踪广告进度并将 Roku 消息转发到 SDK。 请务必将所有消息转发给 SDK，以确保广告正确无误 。否则，会导致广告观看次数被错误报告。

在此步骤中，您还将添加一个函数以将 [[STREAMID]] 宏替换为 视频流 ID 并将已完成的清单请求网址传递给视频播放器。 此实现会在此步骤中获取视频流 ID，但具体取决于您的 VTP 集成，则可能在此步骤之前就已可用。

MainScene.xml

function runIMASDKTask()
  m.IMASDKTask = createObject("roSGNode", "IMASDKTask")

  m.IMASDKTask.streamParameters = m.testPodservingStream
  m.IMASDKTask.videoNode = m.video

  m.IMASDKTask.observeField("IMASDKInitialized", "handleIMASDKInitialized")
  m.IMASDKTask.observeField("errors", "handleIMASDKErrors")
  m.sdkTask.observeField("adStitchedStreamInfo", "loadAdStitchedStream")

  m.sdkTask.control = "RUN"
end function

sub loadAdStitchedStream(message as object)
  print "Ad pod stream information ";message
  adPodStreamInfo = message.getData()
  manifest = m.testPodservingStream.manifest.Replace("[[STREAMID]]", adPodStreamInfo.streamId)
  playStream(manifest, adPodStreamInfo.format)
end sub

sub playStream(url as string, format as string)
  vidContent = createObject("RoSGNode", "ContentNode")
  vidContent.url = url
  vidContent.title = m.testPodservingStream.title
  vidContent.streamformat = format
  m.video.content = vidContent
  m.video.setFocus(true)
  m.video.visible = true
  m.video.control = "play"
  m.video.EnableCookies()
end sub

Sdk.xml

sub runThread()
  if not m.top.IMASDKInitialized
    initializeIMASDK()
  end if

  setupPlayerCallbacks()
  loadAdPodStream()
  if m.streamManager <> invalid
    runLoop()
  end if
end sub

sub runLoop()
  m.top.videoNode.timedMetaDataSelectionKeys = ["*"]

  ' IMPORTANT: Failure to listen to the position and timedmetadata fields
  ' could result in ad impressions not being reported.
  m.port = CreateObject("roMessagePort")
  m.top.videoNode.observeField("position", m.port)
  m.top.videoNode.observeField("timedMetaData", m.port)
  m.top.videoNode.observeField("timedMetaData2", m.port)
  m.top.videoNode.observeField("state", m.port)

  while True
    msg = wait(1000, m.port)
    if m.top.videoNode = invalid
      print "exiting"
      exit while
    end if

    m.streamManager.onMessage(msg)
    currentTime = m.top.videoNode.position
    if currentTime > 3 And not m.top.adPlaying
      m.top.videoNode.enableTrickPlay = true
    end if
  end while
end sub

sub setupStreamManager()
  m.streamManager.addEventListener(m.sdk.AdEvent.ERROR, errorCallback)
  m.streamManager.addEventListener(m.sdk.AdEvent.START, startCallback)
  m.streamManager.addEventListener(m.sdk.AdEvent.FIRST_QUARTILE, firstQuartileCallback)
  m.streamManager.addEventListener(m.sdk.AdEvent.MIDPOINT, midpointCallback)
  m.streamManager.addEventListener(m.sdk.AdEvent.THIRD_QUARTILE, thirdQuartileCallback)
  m.streamManager.addEventListener(m.sdk.AdEvent.COMPLETE, completeCallback)
end sub

sub startCallback(ad as object)
  print "Callback from SDK -- Start called - "
end sub

sub firstQuartileCallback(ad as object)
  print "Callback from SDK -- First quartile called - "
end sub

sub midpointCallback(ad as object)
  print "Callback from SDK -- Midpoint called - "
end sub

sub thirdQuartileCallback(ad as object)
  print "Callback from SDK -- Third quartile called - "
end sub

sub completeCallback(ad as object)
  print "Callback from SDK -- Complete called - "
end sub

function errorCallback(error as object)
  print "Callback from SDK -- Error called - " ; error
  m.errorState = True
end function

VOD 视频流广告连播投放

请求直播后，最后还有几个步骤要做：添加 事件监听器来跟踪广告进度并将 Roku 消息转发到 SDK。它 请务必将所有消息都转发给 SDK 。否则，会导致广告观看次数报告不正确。

MainScene.xml

sub runIMASDKTask()
  m.IMASDKTask = createObject("roSGNode", "IMASDKTask")

  m.IMASDKTask.streamParameters = m.testPodservingStream
  m.IMASDKTask.videoNode = m.video

  m.IMASDKTask.observeField("IMASDKInitialized", "handleIMASDKInitialized")
  m.IMASDKTask.observeField("errors", "handleIMASDKErrors")
  m.sdkTask.observeField("adStitchedStreamInfo", "loadAdStitchedStream")

  m.sdkTask.control = "RUN"
end sub

sub loadAdStitchedStream(message as object)
  print "Ad pod stream information ";message
  adPodStreamInfo = message.getData()
end sub

sub playStream(url as string, format as string, subtitleConfig as object)
  vidContent = createObject("RoSGNode", "ContentNode")
  vidContent.title = m.testPodservingStream.title
  vidContent.url = url
  vidContent.subtitleConfig = subtitleConfig
  vidContent.streamformat = format
  m.video.content = vidContent
  m.video.setFocus(true)
  m.video.visible = true
  m.video.control = "play"
  m.video.EnableCookies()
end sub

Sdk.xml

sub runThread()
  if not m.top.IMASDKInitialized
    initializeIMASDK()
  end if

  setupPlayerCallbacks()
  loadAdPodStream()
  if m.streamManager <> invalid
    runLoop()
  end if
end sub

sub runLoop()
  m.top.videoNode.timedMetaDataSelectionKeys = ["*"]

  ' IMPORTANT: Failure to listen to the position and timedmetadata fields
  ' could result in ad impressions not being reported.
  m.port = CreateObject("roMessagePort")
  m.top.videoNode.observeField("position", m.port)
  m.top.videoNode.observeField("timedMetaData", m.port)
  m.top.videoNode.observeField("timedMetaData2", m.port)
  m.top.videoNode.observeField("state", m.port)

  while True
    msg = wait(1000, m.port)
    if m.top.videoNode = invalid
      exit while
    end if

    m.streamManager.onMessage(msg)
    currentTime = m.top.videoNode.position
    if currentTime > 3 and not m.top.adPlaying
      m.top.videoNode.enableTrickPlay = true
    end if
  end while
end sub

sub setupStreamManager()
  m.streamManager.addEventListener(m.sdk.AdEvent.ERROR, errorCallback)
  m.streamManager.addEventListener(m.sdk.AdEvent.START, startCallback)
  m.streamManager.addEventListener(m.sdk.AdEvent.FIRST_QUARTILE, firstQuartileCallback)
  m.streamManager.addEventListener(m.sdk.AdEvent.MIDPOINT, midpointCallback)
  m.streamManager.addEventListener(m.sdk.AdEvent.THIRD_QUARTILE, thirdQuartileCallback)
  m.streamManager.addEventListener(m.sdk.AdEvent.COMPLETE, completeCallback)
end sub

sub startCallback(ad as object)
  print "Callback from SDK -- Start called - "
end sub

sub firstQuartileCallback(ad as object)
  print "Callback from SDK -- First quartile called - "
end sub

sub midpointCallback(ad as object)
  print "Callback from SDK -- Midpoint called - "
end sub

sub thirdQuartileCallback(ad as object)
  print "Callback from SDK -- Third quartile called - "
end sub

sub completeCallback(ad as object)
  print "Callback from SDK -- Complete called - "
end sub

sub errorCallback(error as object)
  print "Callback from SDK -- Error called - " ; error
  m.errorState = True
end sub