heh...:)<br><br>maybe I´ll just answer "the number is 42". ;)<br><br>well... some guys did mixing using <strong>G.722 </strong>encoded frames... maybe we could ask them: 8P<br><a href="http://ieeexplore.ieee.org/Xplore/login.jsp?url=/iel5/4054516/4054517/04054870.pdf?isnumber=4054517&prod=CNF&arnumber=4054870&arSt=2045&ared=2048&arAuthor=G.+Agnello%3B+R.+M.+Dansereau" target="_blank">http://ieeexplore.ieee.org/Xplore/login.jsp?url=/iel5/4054516/4054517/04054870.pdf?isnumber=4054517&prod=CNF&arnumber=4054870&arSt=2045&ared=2048&arAuthor=G.+Agnello%3B+R.+M.+Dansereau</a><br>
<br>and a little off-topic, but fun for audio gurus like you, a very complicated way to mix two mp3 streams: <br><a href="http://www.freshpatents.com/Processing-of-encoded-signals-dt20060302ptan20060047523.php?type=description" target="_blank">http://www.freshpatents.com/Processing-of-encoded-signals-dt20060302ptan20060047523.php?type=description</a><br>
<br>[]s, gandhi<br><br><div class="gmail_quote">On Tue, Mar 25, 2008 at 10:01 PM, Jean-Marc Valin <<a href="mailto:jean-marc.valin@usherbrooke.ca">jean-marc.valin@usherbrooke.ca</a>> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div class="Ih2E3d">> ok, lets get to the point. :)<br>
> I would need to mix some audio streams realtime. After googling a little<br>
> I had only two answers:<br>
> 1 - decode,mix,encode<br>
> 2 - lower quality, send streams at the same time and mix at the client.<br>
><br>
> I didnt like either solutions.<br>
><br>
> I´m not an audio expert, so I´m just saying something silly. I readed<br>
> that speex uses a fixed "codebook". So I think that in a simplistic way<br>
> this means that the encoded data are indexes in this codebook and some<br>
> transformation information.<br>
> Is it possible to create a "mixing codebook"? the idea is to generate<br>
> all the mix combinations of each entry in the codebook., so two encoded<br>
> frames could be merged and point to this different codebook, maybe<br>
> selected in the rtp header.<br>
<br>
</div>Well, you *might* be able to do that at the frame level. Considering<br>
that 15 kbps corresponds to 300 bits. The the case of mixing two<br>
streams, you'd need a 600-bit codebook (2^600 entries). There's just a<br>
tiny implementation detail when it comes to storage. What you need to do<br>
to solve it is:<br>
1) Find a way to encode a (very very) large number of terabytes in<br>
every electron (or other fundamental particle)<br>
2) Manage to use every particle in the universe to store your codebook<br>
3) Prevent the whole thing from turning into a black hole.<br>
<br>
You do what you want, but I suggest you go with one of the two solutions<br>
you listed above (decode,mix,encode or multiple streams).<br>
<font color="#888888"><br>
Jean-Marc<br>
</font></blockquote></div><br>