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Re: [payload] new draft - RTP Payload for TTML Timed Text

Kjetil Oftedal <oftedal@gmail.com> Thu, 17 January 2019 18:53 UTC

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From: Kjetil Oftedal <oftedal@gmail.com>
Date: Thu, 17 Jan 2019 19:53:45 +0100
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To: James Sandford <james.sandford@bbc.co.uk>
Cc: "payload@ietf.org" <payload@ietf.org>
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Subject: Re: [payload] new draft - RTP Payload for TTML Timed Text
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On 17/01/2019, James Sandford <james.sandford@bbc.co.uk> wrote:
> I have uploaded a draft specifying an RTP payload format for TTML Timed Text
> https://datatracker.ietf.org/doc/draft-sandford-payload-rtp-ttml/
>

Hi,

Can you please elaborate a bit on the RTP Timestamping requirements
outlined here?
As far as I can see TTML already specifies the timing of the text in
relation to some epoch.
Will the processing of the RTP packet require the receiver/sender to
rewrite the timing data in TTML-information in relation to the RTP
timestamp? Or written another way: Is the RTP Timestamp considered the
epoch of the TTML document?

Best regards,
Kjetil Oftedal

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