TTML subtitles - ttp:tickRate is ignored

[Karmel0x]

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

What version of Shaka Player are you using?
3.0.6 (latest) release and master

Can you reproduce the issue with our latest release version?
yes

Can you reproduce the issue with the latest code from master?
yes

Are you using the demo app or your own custom app?
both

If custom app, can you reproduce the issue using our demo app?
yes

What browser and OS are you using?
Firefox 83.0 (latest) / Chrome 87.0 (latest)

For embedded devices (smart TVs, etc.), what model and firmware version are you using?

What are the manifest and license server URIs?
https://gist.githubusercontent.com/Karmel0x/fc4b648a69ca999a3a2e3ae3c3fd914e/raw/c2df87918308bcf5dbd0d9b225242c7cf4fd8208/wwww.mpd

What did you do?
Go to this link and choose english captions: demo link

What did you expect to happen?
(subtitles link) tickRate is set to 10, subtitles are on 10t and 30t
so subtitles should appear on 1 second and 3 second

What actually happened?
Subtitles appears on 10 second and 30 second

[Karmel0x]

Probably it's bad solution but it's fixing the problem using this trick:

At /lib/text/ttml_text_parser.js#L87 insert this piece of code:

ttpNs = tt.attributes.find(element => element.value.indexOf('#parameter') != -1)?.value || ttpNs;

[joeyparrish]

It seems that the root cause is your TTML using a different namespace URI than what we are expecting. Can you give us any context on that?

If you load the namespace URIs in your browser, you'll see the following:

https://www.w3.org/ns/ttml/

This is a placeholder for a namespace document that permits dereferencing the Timed Text Markup Language (TTML) 1.0 namespace URIs:

...

This namespace is stable!

https://www.w3.org/2006/10/ttaf1/

This is a placeholder for a namespace document that permits dereferencing the Timed Text (TT) Authoring Format V1.0 Distribution Format Exchange Profile namespace URIs:

...

This namespace is not stable!

Is TTAF a predecessor to TTML?

[Karmel0x]

I've already provided links, demo, manifest and subtitles.
Subtitles are ttaf1