Re: AudioCodec questions
Re: AudioCodec questions
- Subject: Re: AudioCodec questions
- From: William Stewart <email@hidden>
- Date: Tue, 20 Sep 2005 12:21:41 -0700
On 19/09/2005, at 11:57 PM, Nathaniel Gray wrote:
Hello,
A few questions about the AudioCodec API.
The vorbis codec needs to know when it's seeing the first or last
packet of the stream. Is there a way for it to get that info?
No. Why? We have well defined behaviours for codec behaviours - have
a look at the CAF file documentation (developer.apple.com/audio) (it
looks like you have already!) - there are API in CoreAudio for both
converters and audio codecs to interact with these requirements.
Also, I'm not exactly sure what priming means specifically. Is
priming done at the beginning of playback, after seeking, or both?
Should be both - after seeking you are/should be reset, the re-primed.
Also, are leading frames those that come before or after a given frame
in time? Which would be used if audio output begins after the second
input frame is decoded?
Before - its how far you have to seek *back* in order to get valid
data out.
If a codec is used in a streaming context, how are dropped packets
handled? Are they treated the same way as seeks? I ask because a
vorbis codec needs to know if its stream has been interrupted.
Packets in vorbis overlap with their nearest neighbors in time.
This is dependent on different clients - ideally of course, this is
the behaviour you would expect, but you may not get it - I wouldn't
worry about this just at the moment.
Bill
Thanks,
-n8
--
-- Nathaniel Gray -- Caltech Computer Science ------>
-- Mojave Project -- http://mojave.cs.caltech.edu -->
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