Subject: [AVT] Re: Draft minutes for first IETF56 AVT session

From: John Lazzaro <[email-masked]>
Date: Sun, 13 Apr 2003 15:13:51 -0700

> Stephen Casner <[email-masked]> writes:
>
> Audio/Video Transport Working Group Minutes [...]
>
> RTP Payload Format for uncompressed video [...]
>
> The last question was whether there should be a means 
> to independently represent SMPTE timecodes [...]
>
> Stephan advised we need input on real usage cases in
> order to produce anything useful. 

I'd recommend this paper -- it was very useful in helping me
think through how MTC (MIDI Time Code, i.e. SMPTE 12M over
MIDI 1.0 DIN cables) sent over MWPP could end up being used
in multi-stream RTP sessions:

Terry K, Todd C. An open model for audio elementary stream encoding
in a DTV distribution chain. [Journal Paper] SMPTE Journal-Society of
Motion Picture & Television Engineers, vol.107, no.11, Nov. 1998,
pp.950-60. Publisher: Soc. Motion Picture & Telev. Eng, USA.

Abstract

This paper addresses issues of audio distribution for modern digital
television (DTV) systems focusing on digital broadcast systems. In
particular, a model is described for handling audio and video
elementary streams in existing distribution networks. The model
supports new system architectures that allow audio and video coding to
take place at many points in the distribution chain. It covers both
physical and logical interface formats, synchronization with
associated video signals, and carriage of metadata associated with the
audio. The model also demonstrates that many audio features of new
digital delivery formats can be exploited by existing broadcast
systems with minimal additional equipment investment. It makes use of
existing AES and SMPTE standards; however, new standards and
recommended practices to support the open model may be desired by the
industry. Specific recommendations are discussed. In addition,
examples of systems applying the model to DTV broadcast facilities are
described including examples of products that implement the audio
coding function using the model.

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John Lazzaro -- Research Specialist -- CS Division -- EECS -- UC Berkeley
lazzaro [at] cs [dot] berkeley [dot] edu     www.cs.berkeley.edu/~lazzaro
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