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Alex Bakaev

2005-Dec-21 15:45 UTC

[Speex-dev] Bitrate problem

But that's what a jitter buffer will do, eventually -
drop a packet. And it's better to drop a silence packet.

Cheers,
.a 

-----Original Message-----
From: Jean-Marc Valin
[mailto:jean-marc.valin@usherbrooke.ca] 
Sent: Wednesday, December 21, 2005 3:39 PM
To: Alex Bakaev
Cc: Shantanu Gramsci; speex-dev@xiph.org
Subject: RE: [Speex-dev] Bitrate problem

On Wed, 2005-12-21 at 15:29 -0800, Alex Bakaev wrote:> This is a common problem. Sound cards run at different
clock speeds > (but your difference seems kinda high).
> What I'd suggest is dropping silence packets once in awhile.

Or just use a decent jitter buffer!

	Jean-Marc
> .a
> 
> -----Original Message-----
> From: speex-dev-bounces@xiph.org
> [mailto:speex-dev-bounces@xiph.org] On Behalf Of
Shantanu Gramsci> Sent: Wednesday, December 21, 2005 2:05 PM
> To: speex-dev@xiph.org
> Subject: [Speex-dev] Bitrate problem
> 
> Hello all,
> 
> This is a bit off topic but I am sure many of you can
answer it.> 
> I use speex and speex-wb in my VOIP application. With
speex [at 8 KHz] > bitrate is arround 30KBPS, including UDP,RTP headers.
This is OK for > me and I get good quality audio.
> 
> Problem is, if call is made from a HIGH END machine
[like> P4 3.2 GHz with good soundcard] to a LOW END machine
[like P3 550 > MHz], high end pc sends at more bitrate than as usual
[arround > 31Kbps].And apparently low end PC receives this HIGH
bitrate.> 
> So, slow end PC receives audio packets at arround 8100
Hz but it is > confiured for 8000 Hz. So there are overflows in the
directsound > buffer at receiver end at periodic interval [in my case
after every 30 > sec], than I flush the buffer which makes some
distortion.> 
> What should be approapriate solution for this resynch
problem?> 
> 
> Thanks
> 
> Shantanu
> 
> 
> __________________________________________________
> Do You Yahoo!?
> Tired of spam?  Yahoo! Mail has the best spam
protection around > http://mail.yahoo.com
_______________________________________________> Speex-dev mailing list
> Speex-dev@xiph.org
> http://lists.xiph.org/mailman/listinfo/speex-dev
> _______________________________________________
> Speex-dev mailing list
> Speex-dev@xiph.org
> http://lists.xiph.org/mailman/listinfo/speex-dev
>

Shantanu Gramsci

2005-Dec-21 16:08 UTC

head link

[Speex-dev] Bitrate problem

Thanks all for your prompt reply.

I agree with Alex. I think jitter buffer will have to
drop packets if its input bitrate is higher than it is
configured for.

I never tried speex jitter buffer. What does it do
when input bitrate is higher or lower ?

As an alternate solution, I was thinking to play with
directsound playrate [using SetFrequency()]. Has
anyone used it to solve such problem?

Any comment is appreciated.

-- Shantanu


--- Alex Bakaev <Alex.Bakaev@citrix.com> wrote:
> But that's what a jitter buffer will do, eventually
> -
> drop a packet. And it's better to drop a silence
> packet.
> 
> Cheers,
> .a 
> 
> -----Original Message-----
> From: Jean-Marc Valin
> [mailto:jean-marc.valin@usherbrooke.ca] 
> Sent: Wednesday, December 21, 2005 3:39 PM
> To: Alex Bakaev
> Cc: Shantanu Gramsci; speex-dev@xiph.org
> Subject: RE: [Speex-dev] Bitrate problem
> 
> On Wed, 2005-12-21 at 15:29 -0800, Alex Bakaev
> wrote:
> > This is a common problem. Sound cards run at
> different
> clock speeds 
> > (but your difference seems kinda high).
> > What I'd suggest is dropping silence packets once
> in a
> while.
> 
> Or just use a decent jitter buffer!
> 
> 	Jean-Marc
> 
> > .a
> > 
> > -----Original Message-----
> > From: speex-dev-bounces@xiph.org
> > [mailto:speex-dev-bounces@xiph.org] On Behalf Of
> Shantanu Gramsci
> > Sent: Wednesday, December 21, 2005 2:05 PM
> > To: speex-dev@xiph.org
> > Subject: [Speex-dev] Bitrate problem
> > 
> > Hello all,
> > 
> > This is a bit off topic but I am sure many of you
> can
> answer it.
> > 
> > I use speex and speex-wb in my VOIP application.
> With
> speex [at 8 KHz] 
> > bitrate is arround 30KBPS, including UDP,RTP
> headers.
> This is OK for 
> > me and I get good quality audio.
> > 
> > Problem is, if call is made from a HIGH END
> machine
> [like
> > P4 3.2 GHz with good soundcard] to a LOW END
> machine
> [like P3 550 
> > MHz], high end pc sends at more bitrate than as
> usual
> [arround 
> > 31Kbps].And apparently low end PC receives this
> HIGH
> bitrate.
> > 
> > So, slow end PC receives audio packets at arround
> 8100
> Hz but it is 
> > confiured for 8000 Hz. So there are overflows in
> the
> directsound 
> > buffer at receiver end at periodic interval [in my
> case
> after every 30 
> > sec], than I flush the buffer which makes some
> distortion.
> > 
> > What should be approapriate solution for this
> resynch
> problem?
> > 
> > 
> > Thanks
> > 
> > Shantanu
> > 
> > 
> > __________________________________________________
> > Do You Yahoo!?
> > Tired of spam?  Yahoo! Mail has the best spam
> protection around 
> > http://mail.yahoo.com
> _______________________________________________
> > Speex-dev mailing list
> > Speex-dev@xiph.org
> > http://lists.xiph.org/mailman/listinfo/speex-dev
> > _______________________________________________
> > Speex-dev mailing list
> > Speex-dev@xiph.org
> > http://lists.xiph.org/mailman/listinfo/speex-dev
> > 
> 

__________________________________________________
Do You Yahoo!?
Tired of spam?  Yahoo! Mail has the best spam protection around 
http://mail.yahoo.com

wu xudong

2005-Dec-21 18:27 UTC

head link

回复： RE: [Speex-dev] Bitrate problem

We use speex-vad to solve this problem.That's means we
only send voice packets at send part.Though it can't
really solve the sampling rate distortion.I have
tested different sample frequency and the result data
rate is different.


--- Shantanu Gramsci <shantanu_khan@yahoo.com>??:
> 
> Thanks all for your prompt reply.
> 
> I agree with Alex. I think jitter buffer will have
> to
> drop packets if its input bitrate is higher than it
> is
> configured for.
> 
> I never tried speex jitter buffer. What does it do
> when input bitrate is higher or lower ?
> 
> As an alternate solution, I was thinking to play
> with
> directsound playrate [using SetFrequency()]. Has
> anyone used it to solve such problem?
> 
> Any comment is appreciated.
> 
> -- Shantanu
> 
> 
> --- Alex Bakaev <Alex.Bakaev@citrix.com> wrote:
> 
> > But that's what a jitter buffer will do,
> eventually
> > -
> > drop a packet. And it's better to drop a silence
> > packet.
> > 
> > Cheers,
> > .a 
> > 
> > -----Original Message-----
> > From: Jean-Marc Valin
> > [mailto:jean-marc.valin@usherbrooke.ca] 
> > Sent: Wednesday, December 21, 2005 3:39 PM
> > To: Alex Bakaev
> > Cc: Shantanu Gramsci; speex-dev@xiph.org
> > Subject: RE: [Speex-dev] Bitrate problem
> > 
> > On Wed, 2005-12-21 at 15:29 -0800, Alex Bakaev
> > wrote:
> > > This is a common problem. Sound cards run at
> > different
> > clock speeds 
> > > (but your difference seems kinda high).
> > > What I'd suggest is dropping silence packets
> once
> > in a
> > while.
> > 
> > Or just use a decent jitter buffer!
> > 
> > 	Jean-Marc
> > 
> > > .a
> > > 
> > > -----Original Message-----
> > > From: speex-dev-bounces@xiph.org
> > > [mailto:speex-dev-bounces@xiph.org] On Behalf Of
> > Shantanu Gramsci
> > > Sent: Wednesday, December 21, 2005 2:05 PM
> > > To: speex-dev@xiph.org
> > > Subject: [Speex-dev] Bitrate problem
> > > 
> > > Hello all,
> > > 
> > > This is a bit off topic but I am sure many of
> you
> > can
> > answer it.
> > > 
> > > I use speex and speex-wb in my VOIP application.
> > With
> > speex [at 8 KHz] 
> > > bitrate is arround 30KBPS, including UDP,RTP
> > headers.
> > This is OK for 
> > > me and I get good quality audio.
> > > 
> > > Problem is, if call is made from a HIGH END
> > machine
> > [like
> > > P4 3.2 GHz with good soundcard] to a LOW END
> > machine
> > [like P3 550 
> > > MHz], high end pc sends at more bitrate than as
> > usual
> > [arround 
> > > 31Kbps].And apparently low end PC receives this
> > HIGH
> > bitrate.
> > > 
> > > So, slow end PC receives audio packets at
> arround
> > 8100
> > Hz but it is 
> > > confiured for 8000 Hz. So there are overflows in
> > the
> > directsound 
> > > buffer at receiver end at periodic interval [in
> my
> > case
> > after every 30 
> > > sec], than I flush the buffer which makes some
> > distortion.
> > > 
> > > What should be approapriate solution for this
> > resynch
> > problem?
> > > 
> > > 
> > > Thanks
> > > 
> > > Shantanu
> > > 
> > > 
> > >
> __________________________________________________
> > > Do You Yahoo!?
> > > Tired of spam?  Yahoo! Mail has the best spam
> > protection around 
> > > http://mail.yahoo.com
> > _______________________________________________
> > > Speex-dev mailing list
> > > Speex-dev@xiph.org
> > > http://lists.xiph.org/mailman/listinfo/speex-dev
> > > _______________________________________________
> > > Speex-dev mailing list
> > > Speex-dev@xiph.org
> > > http://lists.xiph.org/mailman/listinfo/speex-dev
> > > 
> > 
> 
> 
> __________________________________________________
> Do You Yahoo!?
> Tired of spam?  Yahoo! Mail has the best spam
> protection around 
> http://mail.yahoo.com 
> _______________________________________________
> Speex-dev mailing list
> Speex-dev@xiph.org
> http://lists.xiph.org/mailman/listinfo/speex-dev
> 

__________________________________________________
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http://cn.mail.yahoo.com

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