Question about MEI Pre-seeding behavior and muted autoplay policy

[Taehyun Park]

Hello,

I have a question regarding the "Autoplay Pre-seeding in Chrome"  Chromium blog article about autoplay policy.

The pre-seeding list mentioned in the blog appears to come from the "MEI Preload" component.
In that list, YouTube is included, but Twitch, TikTok, and Instagram are not.

I’ve noticed that in browsers without the "MEI Preload" component, YouTube fails to autoplay when user engagement data(in media-engagement) is unavailable.
However, domains not included in the pre-seeding domain list (such as Twitch, TikTok, Instagram) seem to attempt muted autoplay when autoplay fails in such environments.

My question is: in the MEI pre-seeding criteria described as “site visitors permit autoplay”, does muted autoplay count as user engagement?
In other words, if a site autoplays muted video and the user later unmutes it, does that action contribute to MEI scoring or not?

Thank you for your time and clarification.

Best regards,
Taehyun

[Dale Curtis]

@Evan Liu 

- dale

--
You received this message because you are subscribed to the Google Groups "media-dev" group.
To unsubscribe from this group and stop receiving emails from it, send an email to media-dev+...@chromium.org.
To view this discussion visit https://groups.google.com/a/chromium.org/d/msgid/media-dev/3d6f798c-11eb-47fe-9c26-303046c78a87n%40chromium.org.

[Taehyun Park]

Hi Evan,

Thank you for the clear explanation about how MEI scoring works.

I had a follow-up specifically about how the pre-seeding list is made.

Before I begin, just to avoid any misunderstanding: the domains I mentioned earlier and this mail were simply common media platforms used as examples. I don’t work for (and haven’t worked for) any of those companies, and I’m not raising a complaint about a specific domain’s absence.

In the blog post on pre-seeding, the condition is described as "if a sizable majority of site visitors permit autoplay on it."  
Given that some major video platforms are not on the list, I was wondering if there are additional criteria beyond the MEI scoring conditions you described.

My assumption is that platforms like Instagram or TikTok might see a higher share of <7s viewing or muted autoplay, which could affect MEI. But for Twitch, it seems harder to explain by “fewer real users,” especially since a comparatively smaller live-streaming platform like Rumble appears on pre-seeding list. That made me think there might be other signals or heuristics involved.

If there are criteria other than “site visitors permit autoplay” that influence inclusion on the pre-seeding list, I would really appreciate any clarification or pointers to documentation.

Thank you again for your time and help.

Best regards,
Taehyun

2025년 10월 23일 (목) 오전 3:01, Evan Liu <ev...@google.com>님이 작성:

Hi Taehyun,

Yes, that action does contribute to the Media Engagement Index (MEI) scoring, provided the user continues to watch the video after unmuting it.

Here is a breakdown of how the MEI scoring works based on Chrome's autoplay policy:

• Muted Autoplay is Always Allowed: As you observed, Chrome's policy always permits muted autoplay, regardless of a site's MEI score. This is why sites not on the pre-seeding list (like Twitch or TikTok) can still start a video without sound.

• MEI Score Calculation: The MEI score is calculated based on "significant media playback events." For an event to be counted towards the score, it must meet several criteria:

  1. The media (audio or video) must be consumed for more than 7 seconds.

  2. Audio must be present and unmuted.

  3. The tab containing the video must be active.

  4. The video's size must be greater than 200x140 pixels.

Therefore, a muted video playing by itself does not contribute to the MEI score.

When a user clicks the "unmute" button, they are providing the user interaction. If they then keep the video unmuted and active for more than 7 seconds, that entire event now meets all the criteria and will be counted as a "significant media playback event," increasing the MEI score for that domain. This is precisely the engagement strategy that sites without pre-seeding permission rely on.Hi Taehyun,

This blogpost has some more info about the autoplay policy in Chrome: https://developer.chrome.com/blog/autoplay

Thanks,

Evan