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Hi Gregory, hi Jean-Marc,<br>
<br>
I found the cause of the problem. The bug is in the llcon softare, not
in the CELT library.<br>
<br>
In case of a network error, I do not only call the CELT decoder with
data=NULL but sometimes with an all zero data vector (caused by a bug
in my socket buffer implementation).<br>
<br>
Thank you for your support,<br>
Best Regards,<br>
Volker<br>
<br>
<br>
<pre wrap="">>When I use CELT in the llcon software, I noticed that in the case of a
>network trouble, I get a constant tone back from the CELT decoder (audio
>is not muted after some audio frames as I would expect). What I do in
>case of network trouble is that I use a NULL pointer instead of putting
>actual coded data to the decoder to force the "error resilience" in the
>decoder.
>
>I wonder if I am doing something wrong using the CELT library or if this
>is a bug.</pre>
<br>
Gregory Maxwell schrieb:
<blockquote
cite="mid:e692861c0908202214x36dbd9dey195e0a6c0725fff5@mail.gmail.com"
type="cite">
<pre wrap="">On Fri, Aug 21, 2009 at 1:12 AM, Gregory Maxwell<a class="moz-txt-link-rfc2396E" href="mailto:gmaxwell@gmail.com"><gmaxwell@gmail.com></a> wrote:
</pre>
<blockquote type="cite">
<pre wrap="">On Fri, Aug 21, 2009 at 1:07 AM, Volker<a class="moz-txt-link-rfc2396E" href="mailto:v.fischer@nt.tu-darmstadt.de"><v.fischer@nt.tu-darmstadt.de></a> wrote:
</pre>
<blockquote type="cite">
<pre wrap="">Gregory Maxwell schrieb:
</pre>
<blockquote type="cite">
<pre wrap="">Hm? If you call celt_decode with a null pointer in place of the data
it should fade out the audio after consecutive losses.
The relevant code is around line 1286 in celt.c:
for (i=0;i<C*N;i++)
freq[i] = ADD32(EPSILON, MULT16_32_Q15(QCONST16(.9f,15),freq[i]));
</pre>
</blockquote>
<pre wrap="">If I interpret your code correctly, you use an exponential decay for the
fade out. In previous software projects I did something similar and got
strange effects when I applied a multiplication to very small floating point
values. I guess the same happens here, too. You should introduce a bound for
the floating point values. If the signal is below the bound, set the
floating point value to zero and the problems should disapear (I guess ;-)
).
</pre>
</blockquote>
<pre wrap="">The addition of EPSILON prevents the creation of denormals and is more
efficient than the compare and branch required for zeroizing.
</pre>
</blockquote>
<pre wrap=""><!---->
This makes me think however.. are you applying any gain control the
the output which might be making a quiet tone loud?</pre>
</blockquote>
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