getPlayheadTimeAsDate() differs from program time (X-EXT-PROGRAM-DATE-TIME)

[bbert]

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

If the problem is related to FairPlay, have you read the tutorial?

Yes

What version of Shaka Player are you using?

4.6.2

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

Can you reproduce the issue with the latest code from main?
Yes

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

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

What browser and OS are you using?
Chrome/Windows

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

What are the manifest and license server URIs?

Sent by email

What configuration are you using? What is the output of player.getConfiguration()?

Default

What did you do?

1. Load the live manifest
2. Pause afters some time after playback has started
3. Open the console and call the getPlayheadTimeAsDate() API method

document.querySelector('video').ui.player_.getPlayheadTimeAsDate()

What did you expect to happen?

The playlist contains the X-EXT-PROGRAM-DATE-TIME tag, and the live content's video displays a timecode synchronized with the X-EXT-PROGRAM-DATE-TIME tag.

The getPlayheadTimeAsDate() should return the same time value as the one displayed on the video.

What actually happened?

The getPlayheadTimeAsDate() returns a value that differs by a few seconds from the real time value displayed on the video, 13 seconds in the following snapshot.

As a comparison, here is a snaphost of hls.js (Windows/Chrome):

And a snapshot of AVPlayer on iOS:

Maybe the problem is related to the issue #4330

[avelad]

@bbert are you interested on send a PR to fix it? Thanks! (see: https://github.com/shaka-project/shaka-player/blob/main/lib/player.js#L4417)

[bbert]

@avelad I'm not aware enough of source code to try to fix it without introducing any regression.

I had a look but don't understand this part of code:

shaka-player/lib/media/presentation_timeline.js

Line 303 in 6102060

this.presentationStartTime_ =

#X-EXT-PROGRAM-DATE-TIME seems not be considered to compute timeline presentationStartTime_ used by getPlayheadTimeAsDate().

[avelad]

@bbert Can you check if #6059 resolves your issue? Thanks!

[bbert]

Hi @avelad, I confirm PR #6059 resolves the issue.
Thanks!

[joeyparrish]

We are reverting the fix, which caused additional issues.