[opus] Exact audio position

[Ian Malone]

On 13 May 2013 09:45, Hermann Weber <hermie.weber at gmx.de> wrote:

> Hello!
>
> I need to extract audio data at a certain position in respect to the
> original audio data.
>
> Is the "-cbr" switch meant to ensure that data can be found on a
> specific position?
>
> I want to be able to predict where certain audio can be found in the
> encoded data.
>
> An example:
> If you put 10 apples into a box and then compress the box, you will not
> be able to predict where apple C can be found in the box.
> Perhaps apple B could be compressed more than apple C, and now the
> "position" of apple C is not predictable anymore.
> This is exactely NOT what I want :-)
>
>
>
(Oops, replied off-list by mistake)

The encapsulation records this information, for Opus in Ogg you want
'granule position':
http://tools.ietf.org/html/draft-ietf-codec-oggopus-00#section-4
https://wiki.xiph.org/GranulePosAndSeeking

I'm less familiar with RTP, but I think the RTP timestamp is probably the
equivalent thing:
http://tools.ietf.org/html/draft-spittka-payload-rtp-opus-03



-- 
imalone
http://ibmalone.blogspot.co.uk
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