ID3 and Metadata TextTrack Issues

Vega Open Beta Bug Reports
1

:backhand_index_pointing_right: ID3 and Metadata TextTrack Issues

1. Summary

When testing a DASH Live stream with in-band Emsg, the issues described below are observed

Bug Severity
Select one that applies

  • Impacts operation of app

3. Observed Behavior

Explain what actually happened, noting any discrepancies or malfunctions.

1) Shaka Metadata event issue

Emsg event
- Emsg events occur as expected, ie., they are received at parse time in 'raw' form

Metadata events
- Metadata events are intended to emerge at the PTS of a given ID3 Emsg, such that ID3 Emsg events may be ignored and only metadata need be listened to.
However, due to a flaw in shaka versions prior to 4.14.1, these emerge with incorrect times (using the start time of the segment within with the metadata was found, rather than the actual PTS of the metadata). 

The current 4.8.5 patched build of shaka exhibits this faulty behavior, which was corrected by this PR:

https://github.com/shaka-project/shaka-player/pull/8012


2). TextTrack Issue
On attempting to manually add metadata cues to the metadata TextTrack (obtained from `video.textTracks`, where `kind` = 'metadata'), an exception is thrown intermittently.

i.e., invoking `track.addCue(cue)`, where `cue` is `VTTCue` instance with a valid `startTime` property, intermittently produces this error: "Cannot read property 'startTime' of undefined"

4.a Possible Root Cause & Temporary Workaround

Fill out anything you have tried. If you don’t know, N/A is acceptable

See shaka PR

6. Environment

Please fill out the fields related to your bug below:

  • SDK Version: 0.20.3154
  • App State: Foreground

:backhand_index_pointing_right: Playback Issues

arm7.

Please share the following details in addition:_

  • Player SDK: Shaka
  • Player SDK Version: 4.8.5
3

Hi @Douglas_Loftus ,

Could you please share logs for this please?

Thanks,
Rohit

4

Sure, Rohit. I’ve included a good chunk of time here (it’s from a live stream). The locations of interest will contain “MDS” in the lines, as in

MDS addId3Metadata @ [time]: adding cue PTS [time] to track (track exists = true)

Nearby lines containing “SHAKA” indicate the point of receipt of an Emsg event.

-Doug

log-dash-emsg.txt (1.4 MB)

5

Hi Rohit, we are looking for a status on this please. We have two major issues with (ID3 or timeline region) signaling to monetize successfully. Do you need more info? This ticket is for ID3 issue only.

Here is the upstream shaka fix for this issue.

6

Hi @Daniel , @Douglas_Loftus ,

Our team is still looking into this and will get back to you once we have an update.

Thanks,
Rohit

9

This issue appears to be resolved with the Shaka v4.16.13 update.