Dash.js: Support for DASHEventMessageBox Version 1

[damienlevin]

The latest 2.9.0 version doesn't seems to support DASHEventMessageBox version 1 (version 0 is supported)

See:
https://github.com/Dash-Industry-Forum/dash.js/blob/36baa49b658bf385384f39e7e621cd596644f70b/src/streaming/vo/IsoBox.js#L66

Format is:

aligned(8) class DASHEventMessageBox extends FullBox(‘emsg’, version, flags = 0){
if (version==0) {
string scheme_id_uri;
string value;
unsigned int(32) timescale;
unsigned int(32) presentation_time_delta;
unsigned int(32) event_duration;
unsigned int(32) id;
} else if (version==1) {
unsigned int(32) timescale;
unsigned int(64) presentation_time;
unsigned int(32) event_duration;
unsigned int(32) id;
string scheme_id_uri;
string value;
}
unsigned int(8) message_data[];

[epiclabsDASH]

This change requires changes in codem-isoboxer (the lib used by dash.js to parse isobmff files) so it supports emsg version 1. Changes sent in PR https://github.com/madebyhiro/codem-isoboxer/pull/36

[epiclabsDASH]

@damienlevin, do you have any sample dash stream that uses EMSG boxes version 1?

[damienlevin]

I'm having playback issues with this stream that might be unrelated but you can look at the following URL where you should have an emsg v1 in the first segment (with message_data = "hi").
https://storage.googleapis.com/dlevin/dash_id3/manifest_id3_v1.mpd

[epiclabsDASH]

@damienlevin, emsg box version 1 support has been added in #2739. I could also reproduce some playback issues although they are not related with emsg support. I am doing some research, seems to be related with some timing issues after switching to the second period but can't confirm yet.

I am closing this issue (related with emsg box support) and will keep you updated about any progress related with your stream playback issue.

[damienlevin]

Awesome, thanks a lot.
Very curious about those playback issues, thanks for looking into it.

[damienlevin]

@epiclabsDASH any update on the playback issue ? Is this a reported issue ?

Thanks

[jeoliva]

It is something related with the new multi period management algorithm we put in place since v2.8.0. Almost isolated :). I will let you know when it is fixed.

Thanks

[damienlevin]

Awesome ! Thanks for the update.

[damienlevin]

Out of curiosity, is this the same issue as #2681 or #2741 ?

[epiclabsDASH]

yep, same source although slightly different. We are preparing a PR that will fix these issues. It will be ready this week. Thanks!

[damienlevin]

@jeoliva,@epiclabsDASH any updates on those issues ?

Thanks.

[epiclabsDASH]

Close to have it ready :). The fix should be released this week.

[damienlevin]

Awesome, thanks !

[epiclabsDASH]

sorry for the delay. Still working on this. Should be ready very soon.....

[epiclabsDASH]

@damienlevin, issue should be fixed in #2778. To be merged by tomorrow and released in dash.js v2.9.1 (next Monday).

[damienlevin]

@epiclabsDASH Great news, It looks fine from our initial round of testing, I'll keep you posted if we find more playback issues !

Cheers !