Re: [GnomeMeeting-list] speex-8kps using > 24kbs?

[Damien Sandras <dsandras seconix com>]

Le mer 10/12/2003 à 19:51, Joost Witteveen a écrit :
> When I tried the speex-8k codec, it turns out that gnomemeeting
> sends each speex frame (20ms, 20 bytes) in a single UDP package 
> (with >= 28 bytes overhead), and somewhere also adding another 
> 12 bytes (ogg headers??)

See previous comment from Craig. 8k is the estimated bandwidth for raw
data.

> 
> So, for every 20 bytes of speex data, a IP package of 60 bytes
> is sent, using 24kbps of IP traffic (and 26kbps ppp traffic,
> if sent over a ppp link)
> 
> I've increased the "minumum jitter buffer" setting to 100ms,
> even 500 ms, on both ends, hoping that the higher latency may
> persuade gnomemeeting to put more frames in each UDP package,
> but gnomemeeting still sends a package every 20ms.
> 

Yes, the jitter buffer is the bufferisation of audio that you receive.

> The phoneline I would like to use gnomemeeting over really
> doesn't handle 24kbps. And, after using gnomemeeting 
> during some time with a round-trip-time of about 
> 1 second (I guess a result of a link getting saturated),
> I found it quite usable.
> So, it seems I begin able to be able to get more speex 
> frames in each IP package would really help me.
> 
> When I saw that ohphone had the same behaviour (using >24kbps
> for speex-8k), I (wrongly) concluded that this was a speex
> limitation, but I was quickly corrected:
> 
> http://www.xiph.org/archives/speex-dev/200312/0011.html
> http://www.xiph.org/archives/speex-dev/200312/0012.html
> 
> Are there any plans on making the number of speex frames
> in each package custumisable? Would patches be appreciated?

No plans, patches accepted.
Notice other codecs like GSM and G.711 do have customizable (through
gconf because changing defaults is not recommended) frames per packet
counts.

> (I've tried looking at the source, but, really, up until
> now I haven't been able to really figure out where to begin).
> 
> 
> Oh, and about me suppozing that gnomemeeting puts ogg headers
> in each package sent. This was based on theses observations
>   - 20ms of 8kbps data is 20 bytes, each IP package was
>     60 bytes long, with 28 bytes of IP/UDP headers, that
>     leaves still 12 bytes unaccounted for. 12 bytes happens
>     to be the size of the ogg headers.
>   - when looking at tcpdump -x output, I noticed that more
>     than the first 28 bytes were static (except checksums),
>     and attribute those to ogg headers.
> Anyway, does gnomemeeting add ogg headers?
> 


No...

> 
> Thanks,
> joostje
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-- 
 _      Damien Sandras
(o-     
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