Speex dev - Apr 2005 - speex voice seems to be bit breaking over long distance.

Hi Jean,
> Actually, Speex has Packet Loss Concealment (PLC)
> builtin. If a packet
> is missing, instead of repeating the previous one,
> just try decoding by
> passing NULL instead of the SpeexBits struct.
> 
Thanks, I have made the above changes and the effect
seems to be better now.
> > I think jitter buffering is more correct way to
> solve
> > this problem but I think this is not so easy. Is
> there
> > got any source code to reference from?
> 
> Look for the speex_jitter.h header.
I tried to implement it but I don't really understand
the parameters for the speex_jitter_get() and
speex_jitter_put() function.  I have the following
questions:

Since the second parameter of speex_jitter_put() is a
char* and the second parameter of speex_jitter_get()
is a short*, does it mean that these two function will
actually replace speex_bits_read_from() and
speex_decode_int()?  

Also, which timestamp should I use for the third
parameter of speex_jitter_put(), should I use the
GetTickCount() value at the point when I first receive
a voice packet from the microphone?

Finally, what is the use of the third parameter
(timestamp) of speex_jitter_get()? 

Thanks very much. Hopes my question is not too many.

Regards,
YueWeng


		
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> I tried to implement it but I don't really understand
> the parameters for the speex_jitter_get() and
> speex_jitter_put() function.  I have the following
> questions:
> 
> Since the second parameter of speex_jitter_put() is a
> char* and the second parameter of speex_jitter_get()
> is a short*, does it mean that these two function will
> actually replace speex_bits_read_from() and
> speex_decode_int()?  
Yes, it does the decoding internally.
> Also, which timestamp should I use for the third
> parameter of speex_jitter_put(), should I use the
> GetTickCount() value at the point when I first receive
> a voice packet from the microphone?
The third parameter of speex_jitter_put() actually *returns* the
timestamp you got. You can also pass NULL if you're not interested in
the value.
> Finally, what is the use of the third parameter
> (timestamp) of speex_jitter_get()? 
This one tells the jitter buffer what timestamp the packet you're giving
it corresponds to.

	Jean-Marc

-- 
Jean-Marc Valin <Jean-Marc.Valin@USherbrooke.ca>
Universit? de Sherbrooke