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Re: [codec] #15: Efficiently combine pre-encoded audio

Stephan Wenger <stewe@stewe.org> Sun, 11 April 2010 19:04 UTC

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Date: Sun, 11 Apr 2010 12:03:56 -0700
From: Stephan Wenger <stewe@stewe.org>
To: stephen botzko <stephen.botzko@gmail.com>
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Thread-Topic: [codec] #15: Efficiently combine pre-encoded audio
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Subject: Re: [codec] #15: Efficiently combine pre-encoded audio
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True, with the notable exception of Vorbis (whose codebook concept is very
similar to H.264¹s parameter set concept, and the codebooks can be sent
out-of-band‹that¹s actually recommended for many applications).  See RFC
5215 how this is done.
Combining vorbis streams in a box that receives codebooks via SDP in
SIP-reinvite or something, and without in band codebooks, is an interesting
task from a synchronization viewpoint, but not impossible.
Stephan


On 4.11.2010 11:13 , "stephen botzko" <stephen.botzko@gmail.com> wrote:

> A related question is encoder-decoder synchronization time.  Generally audio
> codecs are designed so that even if they start decoding with unknown state,
> the encoder and decoder synchronize automatically and very quickly.
> 
> (Video codecs generally do not have this property BTW).
> 
> Stephen Botzko
> 
> 
> On Sun, Apr 11, 2010 at 11:07 AM, codec issue tracker <trac@tools.ietf.org>
> wrote:
>> #15: Efficiently combine pre-encoded audio
>> ------------------------------------+---------------------------------------
>>  Reporter:  hoene@Š                 |       Owner:
>>      Type:  enhancement             |      Status:  new
>>  Priority:  minor                   |   Milestone:
>> Component:  requirements            |     Version:
>>  Severity:  Active WG Document      |    Keywords:
>> ------------------------------------+---------------------------------------
>>  Ability to efficiently combine pre-encoded audio into a single stream. For
>>  instance, if a server needs to play an announcement it would be nice to be
>>  able to send pre-encoded, cached audio data to the client in such a way
>>  that decoder will reset its state and decode this audio properly. Or, in
>>  case of conference server, to switch to another audio source without the
>>  need to decode and encode the audio again
>> 
>> --
>> Ticket URL: <http://trac.tools.ietf.org/wg/codec/trac/ticket/15>
>> codec <http://tools.ietf.org/codec/>
>> 
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