RE: liasion letter from Open IPTV Forum to W3C In-band Tracks Community Group

Brendan,

> This seems like an odd choice. Why not the PID?

In DVB networks, my (limited) understanding is that PIDs are changed as a TS passes through the distribution network but component tags remain unchanged. Certainly if you look in the DVB-SI specification, references from descriptors to elementary streams normally use a component tag and not a PID.

Jon

________________________________
From: Brendan Long [B.Long@cablelabs.com]
Sent: 12 November 2013 22:55
To: Jon Piesing; Giuseppe Pascale; team-liaisons@w3.org; public-inbandtracks@w3.org
Cc: liaisons@oipf.tv
Subject: RE: liasion letter from Open IPTV Forum to W3C In-band Tracks Community Group

I took a look at this spec and have some comments:

> MPEG-2 TS
> readonly attribute DOMString id;
> The contents of the component_tag  field in the stream_identifier_descriptor in PMT.

This seems like an odd choice. Why not the PID? Also, how are you mapping this value to a string?

I wonder if we can find labels to use for MPEG-TS or mp4. The only one I found was for debug purposes apparently, so maybe it just doesn't exist.

The language attributes seem reasonable, so maybe we can just adopt that.

________________________________
From: Jon Piesing [Jon.Piesing@tpvision.com]
Sent: Tuesday, November 12, 2013 2:06 PM
To: Giuseppe Pascale; team-liaisons@w3.org; public-inbandtracks@w3.org
Cc: liaisons@oipf.tv
Subject: liasion letter from Open IPTV Forum to W3C In-band Tracks Community Group

Dear W3C colleagues,

We note with interest your creation of the “In-band Tracks Community Group” to address how to expose information on in-band tracks through the HTML5 media element.

As part of our activity to update our specifications to use HTML5, we have made a very simple such definition based on our previous APIs. This mapping will be included in our R2 V2.3 specification to be published around the end of this year and a self-contained extract of this is included in the attached liaison letter in case it helps your work.

Comments on our mapping are welcome although due to process constraints, this mapping is now very hard to update before publication except for completely trivial changes or to fix clear and obvious errors.

Regards
Jon Piesing
Chair OIPF DAE Task Force