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Hi,<br>
<br>
I've been working on multichannel celt support myself for FMOD, and
just wanted to confirm some things.<br>
<br>
I am finding that for n channel streams, I need to have n decoder
instances, one decoder instance for each channel. If I try to decode
all channels with just one decoder instance, I get audio corruption.<br>
<br>
I always thought that each decode was completely independant and didn't
rely on any state built up from previous decodes or anything like that
(i have interframe prediction and pitch prediction turned off during
encoding), but this seems to show the contrary?<br>
<br>
<br>
<br>
<div class="moz-signature"><span
style="font-size: 10pt; font-family: "Arial","sans-serif"; color: rgb(102, 102, 102);"><font
color="#000000"><b>Chen-Po Sun</b></font> | Programmer <br>
Firelight Technologies Pty Ltd. <br>
FMOD Sound System | <a class="moz-txt-link-abbreviated" href="http://www.fmod.org">www.fmod.org</a> <br>
PH: <font color="#000000">+61 3 96635947</font> Fax: <font
color="#000000">+61 3 96635951</font> <br>
</span>
</div>
<br>
<br>
Jean-Marc Valin wrote:
<blockquote cite="mid:1255617090.4ad7324276652@www.usherbrooke.ca"
type="cite">
<pre wrap="">Quoting Dirk Griffioen <a class="moz-txt-link-rfc2396E" href="mailto:dirk.griffioen@barcelonamedia.org"><dirk.griffioen@barcelonamedia.org></a>:
</pre>
<blockquote type="cite">
<pre wrap="">I would like to encode multiple channels of audio, the input being for
instance
- a multichannel (wav) file
- n jack sources
And in the end stream low latency over RTP (for instance in a Gstreamer
pipeline); currently I use vorbis, and although it is very convenient
channelwise, the added latency is too high to be of use and I need
compression to keep the bandwith reasonable.
As I understand it now I will have to write both the interleaving bit
and the celt n channel rtp payloader.
</pre>
</blockquote>
<pre wrap=""><!---->
The RTP payload format defines everything you need to do to stream multi-channel
CELT audio. You happen to need more than one encoder state, but that's just an
implementation detail. The only thing that doesn't support >2 channels (for
now) is the Ogg software (celtenc/celtdec), but then again they're mostly toys
because there's no real reason to use CELT for encoding files.
Cheers,
Jean-Marc
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</pre>
</blockquote>
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