Add prebid to amp-ima-video via rtc-config

[curseagain]

Description

Real Time Config was recently added to the amp-ad element via the rtc-config attribute. We would like to enable prebid for video ads as well. Possible to add the rtc-config attribute to the amp-ima-video element?

Additional Context

• Vamsee's RTC Config blog post
• AMP Real Time Config With Google Ad Manager

[curseagain]

@torch2424 here is that issue I mentioned. Let me know if you need any additional information!

[torch2424]

@curseagain Thanks for making this! Assigned this to both of us.

cc @jasti @lannka

Let me know If this has any large implications on the extension, or if it would be a simple implementation on our end. Thanks!

[jasti]

Thanks for submitting the issue.
I'm concerned a bit about the latency, given that the ad would block the prebid calls to resolve. It's different from the <amp-ad> case because the user can consume content while the ads take their own time but in the <amp-ima-video> case, the video content is blocked on the ad to finish.

@curseagain What do you think?
CC @ampproject/a4a

[curseagain]

@jasti that is a great point! It would probably be annoying to have to wait so long for an ad to load when the rest of the page loads instantly.

However, I think publishers who are trying to do AMP-only sites feel like their ability to fully monetize their site is limited when they don't have options like prebid for video ads.

I wonder what could be done..

If the delay really is too much for videos above the fold then maybe it's possible for mid-roll or post-roll ads?

Or in the case that you have to scroll to a video, I wonder if we could fetch the prebid data a bit earlier than we would make a normal ad call.

Maybe someone has a creative idea! :)

[jasti]

I'm happy with the mid-roll & post-roll only suggestion. The current RTC limit is at 1 second and could consider reducing that further?
@jeffkaufman do we have data on how many RTC callouts are timing out due to the 1 second limit?
@curseagain do you know if prebid works with IMA video?

[curseagain]

@jasti I guess we would have to do the bidding first and then include the results of bidding to the targeting set in the data-tag attribute. Maybe override cust_params like this: https://support.google.com/admanager/answer/7320899#override-the-default-ad-tag-using-the-ima-sdk

[jasti]

Pinging @jeffkaufman again & @keithwrightbos as well.

[jeffkaufman]

Sorry, missed the tag the first time! I don't have that data in general, since not all ad requests go to doubleclick, but I think @keithwrightbos or @bradfrizzell have calculated this for the traffic that does come to us?

[jasti]

I had a few more discussions about this and generally speaking, we are okay making an RTC callout when it's not blocking on content.
That translates to disabling the RTC callout if the ad is in a preroll spot and the video player is in the current viewport.
Note that RTC calls can be made if the ad request is in a mid or postroll location OR if the video player is at least one (as a starting point, but suggest other options) viewport below the current viewport.
@curseagain @torch2424 What do you think?
@keithwrightbos @jeffkaufman @bradfrizzell @robhazan do you have any concerns with this approach?

[torch2424]

@jasti I am in favor of this idea 😄 Pretty sure we can use some thing similar to isInViewport to accomplish this for pre-roll as well:

https://github.com/ampproject/amphtml/blob/master/src/custom-element.js#L1146