Subject: RE: [AVT] Pointer for the IETF-for-pro-production folks ...

From: "Allison, Art" <[email-masked]>
Date: Fri, 14 Apr 2006 10:13:15 -0400

And lip synch is actually quite hard to maintain in the real world.
While ISO wrote down some tolerances, US broadcasters took exception.
See 
http://www.atsc.org/standards/isfindings/relative.html
This document was prepared before the issues of set-top-box to display
were fully understood. For example, if the internet receiver has an
output over HDMI, the display may insert a frame (or 2) delay in the
video before display occurs, making the audio appear 'early' to the
consumer unless there is an adjustment available to compensate.  If you
pop to http://www.atsc.org/standards/isfindings/ , you may find other
findings that are of interest.
Art

_____________
Art Allison
Director, Advanced Engineering
Science & Technology
National Association of Broadcasters
1771 N Street, NW
Washington, D.C. 20036
Phone: 202.429.5418
Fax: 202.777.4981
[email-masked]

The National Association of Broadcasters is a trade association that
advocates on behalf of more than 8,300 free, local radio and television
stations and also broadcast networks before Congress, the Federal
Communications Commission and the Courts.

-----Original Message-----
From: lazzaro [mailto:[email-masked]] 
Sent: Thursday, April 13, 2006 11:23 PM
To: [email-masked]
Cc: lazzaro
Subject: [AVT] Pointer for the IETF-for-pro-production folks ...

Hi everyone,

	Interesting article in Mix Magazine
this month:

http://mixonline.com/mag/audio_hidef_backbone/

	on the backbone networks that US
TV networks are putting into their production facilities in preparation
for the switch-over to digital TV terrestrial. Audio-centric given Mix's
orientation.

	By and large, store-and-forward media flows are going over IP,
but real-time media flows use mostly circuit-switched standards ... the
article gives a good sense of type and scale of problems we'd need to
solve in the IETF multimedia stack in order to be viable in this
application area.

---
John Lazzaro
http://www.cs.berkeley.edu/~lazzaro
lazzaro [at] cs [dot] berkeley [dot] edu
---

_______________________________________________
Audio/Video Transport Working Group
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_______________________________________________
Audio/Video Transport Working Group
[email-masked]
https://www1.ietf.org/mailman/listinfo/avt