[Ffmpeg-devel] Degraded G.726 quality with pops and clicks

Plotky, Jon Jon.Plotky
Thu Mar 1 16:02:14 CET 2007


RFC 2422 specifies a packing order for the 32kbps mode of G.726.  This is the order used for VPIM (RFC 2421) messages.

Only wrinkle I see is that RFC 2422 specifies discarding the last codeword if there is  an odd number of codewords.  Since RFC 3551 covers streaming it doesn't mention this case.


> -----Original Message-----
> From: ffmpeg-devel-bounces at mplayerhq.hu
> [mailto:ffmpeg-devel-bounces at mplayerhq.hu]On Behalf Of Brain Lai
> Sent: Thursday, March 01, 2007 1:30 AM
> To: FFmpeg development discussions and patches
> Subject: Re: [Ffmpeg-devel] Degraded G.726 quality with pops 
> and clicks
> 
> 
> Actually I find nothing to do with the bitstream packing 
> order in ITU specs
> for G.726.
> However, section 4.5.4 in RFC 3551 demonstrates the packing scheme for
> streaming.
> 
> BTW, one can refer to awave studi 
> <http://www.fmjsoft.com/awframe.html>o at
> http://www.fmjsoft.com/awframe.html which
> supports hundreds of audio formats including G.726 in 
> streaming packing
> order.
> 
> Regards
> Brain Lai
> 
> 2007/3/1, Roman Shaposhnik <rvs at sun.com>:
> >
> > On Thu, 2007-03-01 at 11:08 +0800, Brain Lai wrote:
> >
> >   Now here's the deal -- I know of at least one hardware device that
> > agrees on the order that ffmpeg has. That is, in fact how the order
> > was determined. I don't have the ITU spec handy but I don't 
> think that
> > it actually defined a particular order. Just the coding principles.
> > I'll check it tmr. in the office, but so far all I can say is that
> > it might very well be the case that we would need 2 flavors of
> > G726 to take the order into account.
> >
> > Thanks,
> > Roman.
> >
> > P.S. What's Awave Studio ?
> >
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> >
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