[vorbis-dev] 22khz strangeness?

[vorbis at fuchs.offl.uni-jena.de]

On Tue, Jul 16, 2002 at 02:37:20PM -0400, Monty wrote:
> 
> 
> 
> On Tue, Jul 16, 2002 at 10:03:27AM -0700, HJ wrote:
> > I'm not sure if this is intended or broken (but the quality rocks
> > anyway so I hardly mind) -- 
> > 
> > As I understand, if just a nominal bitrate is set, oggenc (or
> > similar) would attempt to keep the bitrate hovering at approximately
> > that value.
> 
> Let's eliminate the oggenc possibility:
> 
> rc4 and 1.0 go back to the pre-rc3 behavior of -b mapping directly to
> a -q mode and not, by default, activating bitrate management.  You
> only get true ABR with --managed (or if you also use one of -m/-M).
> 
> if you're using ogginfo, 'nominal' bitrate is the bitrate it was
> shooting for, 'average' bitrate is the real rate the file ended up as.
> If using -q or -b alone, nominal and average can diverge by quite a
> bit.  If using -b --managed, they should agree very closely.
> 
> If all of this looks the way you'd expect, we can look at Winamp
> a bit further.  ogginfo and chaining_example both return accurate
> average bitrate numbers (oggenc reports a bit high becuase it includes
> the headers in calculation)
> 
--managed should be combined with a time constant.
A short time constant managed the bitrate heavily, a long only very
slightly.

  oggenc -b 128 --managed 4 input.wav - | oggstreamer 

Generate a bitstream which can be send using a 128 kbps line with a
pre-buffering of 4 seconds. Receiver collects 4 seconds of Ogg Vorbis stream
and then starts decoding. As long as the 128 kbps line really transports 128
kbps there's no gap while decoding. Best would be when the 4 seconds are
also encoded in the stream so the decoder knows the needed prebuffering
time.

radio streaming with 5 seconds latency over 2xISDN using raw IP:

  oggenc -b 128 --managed 5 input.wav - | oggstreamer 

radio streaming using a 56K modem

  oggenc -b 30 --managed 10 input.wav - | oggstreamer 

realtime streaming using 2xISDN:

  oggenc -b 30 --managed 0.042 input.wav - | oggstreamer 

<p>
-- 
Frank Klemm

<p>--- >8 ----
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