IMA SDK 可用于通过直播和视频点播创收。 对于直播,您需要为每个广告插播时间点发出新的广告请求。 错开这些请求,确保不会让所有观看者同时请求广告,导致广告服务器无法运行。
为帮助完成此任务,IMA SDK 具有 AdsRequest.liveStreamPrefetchSeconds
属性。此属性用于指定在您调用 AdsLoader.requestAds()
后,SDK 在与广告服务器通信之前应等待的最大秒数。实际请求时间是随机的。例如,如果您将 AdsRequest.liveStreamPrefetchSeconds
设置为 30,在您调用 AdsLoader.requestAds()
以实际向服务器发出请求后,SDK 会等待 0 到 30 秒。
直播预提取的实际运用
我们建议在广告插播结束后立即预提取下一个广告插播时间点。 这样可以确保预取窗口具有最长的时间长度。假设您的广告插播时间点之间有 5 分钟的间隔时间。广告插播结束后,您可以请求将预提取时长设置为 290 秒(5 分钟减去 10 秒,以确保在预提取窗口结束时发送的请求有足够的时间进行解析)的下一个广告插播时间点:
Objective-C
- (void)adsManager:(IMAAdsManager *)adsManager didReceiveAdEvent:(IMAAdEvent *)event {
...
switch (event.type) {
...
case kIMAAdEvent_ALL_ADS_COMPLETED:
IMAAdsRequest *request = [[IMAAdsRequest alloc]
initWithAdTagUrl: self.adTagUrl
adDisplayContainer: self.adDisplayContainer
avPlayerVideoDisplay: self.avPlayerVideoDisplay
pictureInPictureProxy: self.pictureInPictureProxy
userContext: nil];
// set a delay between the end of the last ad
// in the last request, and the first ad from
// the new request
Float64 adGap = 30;
// make sure the request occurs at least five
// seconds before starting the new set of ads
request.liveStreamPrefetchSeconds = adGap - 5;
[self.adsLoader requestAdsWithRequest:request];
// start new ads after adGap seconds have elapsed
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, adGap * NSEC_PER_SEC), dispatch_get_main_queue(), ^{
[adsManager start];
});
break;
...
}
...
}
Swift
func adsManager(_ adsManager: IMAAdsManager!, didReceive event: IMAAdEvent!) {
switch event.type {
...
case IMAAdEventType.ALL_ADS_COMPLETED:
let request = IMAAdsRequest(
adTagUrl: AdTagUrl,
adDisplayContainer: adDisplayContainer,
contentPlayhead: contentPlayhead,
userContext: nil)
// set a delay between the end of the last ad
// in the last request, and the first ad from
// the new request
let adGap = 30
// make sure the request occurs at least five
// seconds before starting the new set of ads
request.liveStreamPrefetchSeconds = adGap - 5
adsLoader.requestAds(with: request)
// start new ads after adGap seconds have elapsed
DispatchQueue.main.asyncAfter(deadline: .now() + adGap) {
adsManager.start()
}
break
...
}
}