[speex-dev] de-essing into speex?

Tony & Amanda Benik benikajal at mcihispeed.net
Thu Dec 4 21:47:39 PST 2003

Representative of Olav,

>like if you say "someone said the sun is shining", there is a lot of
>ess sounds, and these will sound "computer-ish" at vbr qualities below

  I don't mean to be rude but what bit rate is windows media encoder
encoding at and what encoder (type) are you using...  Unless its low
(32kbps-8kbps) it doesn't compare to speex (spx).  The "ess" sound
you are hearing are most likely generated because the entire frame
(bit of sound) has been striped of all but it most mathematically
pure and simplest (smallest) representation.

  I know a bit about text2speech and speech2text, and though a de-ess
filter on the speex decoder would be 'pleasant' to the human ear
(if one finds pure tones unpleasant rather than unhuman).  It would
make subsequent mixing and encoding of speex streams (VoIP phone
lines) less effective and more costly in a resource sense.

  It is a good idea, though I would consider a luxury filter, that's
just me being overly assertive.

  If anyone is interested from my knowledge of speech recognition all
human phonemes when converted from power vs. time to power vs. freq
exibit 2 characteristic spikes.  The primary spike defines the base
for recognizing the phoneme and the next highest spikes relative
location and power give a program a good probability match as to
which phoneme it is.

Humanizing spx audio derived solely from pure human voices could be
accomplished by reconstructing the secondary peak but would introduce
a minimum latency far larger than several frame sizes (ie the length
of a human phoneme i.e. vowel consonant).

The filter also will most likely foul up the speech alittle cause
like most voice recognition software it can guess wrong an 
reconstuct the wrong secondary peak onto the frames.  (I'm guessing)

The filter also will most likely eat up a lot of cpu power like most
voice recognition software.  (I'm guessing)


To conclude:
  I may be very wrong so please correct me but I am dilligent to keep
  up on these things.

-- Benikus Rex
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