EMSG events in Google DAI

[avelad]

Have you read the Tutorials? Yes

Have you read the FAQ and checked for duplicate open issues? Yes

What version of Shaka Player are you using? 3.0.10

Please ask your question
I have seen that in the Google DAI project they have uploaded an example of integration with the Shaka Player, in the example they use EMSG events to notify the stream manager. Should the same be done in the internal integration of the Shaka Player?
https://github.com/googleads/googleads-ima-html5-dai/blob/master/shaka/dai.js#L410-L412

I have also seen that the timelineregionenter (example) event is used instead of timelineregionadded (library), what is correct?

@ismena , I think this is of your interest :)

[ismena]

Ahh! How come I know so little about the whole emsg event business?!
If it's working then I probably either wrote or reviewed it, but my mind id just going blank!

So, emsg events signal current ad state, is that right?

[avelad]

Well, precisely this part I did not know, that's why I asked you ...

Do you know someone within Google to ask about this?

[TheModMaker]

EMSG events are things for signaling events in the media, they are not necessarily associated with ads. We fire an event when an EMSG is parsed from the media, giving the app the data about it. An EMSG data indicates something happens at some time within the media. This can cover a range of times, or just be a point in time. This can be used to signal the start of an ad, or it could be used for anything.

We also have a separate thing for the <EventStream> elements in DASH. We fire a timelineregionadded event when one of these events is added. This usually happens during manifest parsing or updates. While playing, we fire a timelineregionenter and timelineregionexit events when we enter or exit one of these regions respectively. I don't remember if we map the EMSG events to timeline regions.

[ismena]

Ah, ok. Sorry, I didn't look at the IMA sample code closely when I wrote the first comment.

I need to sync with the IMA team on that - that example is based on our code from before our IMA integration. If you're using our integration, it shouldn't be relevant for you.

Tl;Dr: We're doing the same thing they are and this is already part of the library.

Regarding the way it currently works with library (I did write that code, thanks @TheModMaker for refreshing my memory!)
This is the part where we handle ad-related EMSG events. There are two ways to communicate timed metadata to the IMA SDK: processMetaData and onTimedMetaData. We use the first one and pass the region start time through it, thus delegating it to the IMA to track when the region was entered. In their example, they're likely using the second one which signals that a region is being entered now. Hence the discrepancy between the events we listen to, but
either way is fine.

Does this make sense?

[avelad]

It makes sense to me, but a double check with the IMA team wouldn't be bad.

[ismena]

The part about EMSG events is in sync with the IMA team.
I'll reach out to them about using our updated code in their examples.

[avelad]

@ismena I've been thinking about this. How would DAI work with HLS using mp4? Right now we process events for DASH, src = (HLS Apple devices), and HLS using mux.js, but there is no ID3 parsing in HLS using mp4, how should it work?

Can you reopen the issue while my question is resolved?

[ismena]

Looks like it's possible to embed ID3 in mp4, although we don't parse/use mux to parse them at the moment.

We'll need to do it to support DAI with HLS/mp4. Let me file a separate issue for that. We might have to hunt down some content for testing, though as the IMA team doesn't seem to have any at the moment.

Re: DASH events - the IMA team is working on fixing their samples to reflect our built-in IMA integration.

[ismena]

Created #3351

[avelad]

Thanks @ismena !