Re: [Audacity-devel] Truncate Silence leaves minimum residualsilenceof 2 ms, not 1 ms

[Gale A. <ga...@au...>]

| From "Philip Van Baren" <pdv...@vi...> 
| Sat, 8 Aug 2009 23:12:25 -0400
| Subject: [Audacity-devel] Truncate Silence leaves minimum residualsilenceof 2 ms, not 1 ms
> I've submitted a change which reduces BlendFrameCount if the requested 
> minimum silence is less than the default BlendFrameCount.  Now you can get 
> 1ms minimum duration with TruncateSilence.

Thanks, Phil, it seems fine (tried at 11025 and 96000 Hz).


Gale

 
> --------------------------------------------------
> From: "Gale Andrews" <ga...@au...>
> Sent: Wednesday, August 05, 2009 3:51 AM
> To: <aud...@li...>
> Subject: Re: [Audacity-devel] Truncate Silence leaves minimum 
> residualsilenceof 2 ms, not 1 ms
> 
> >
> > | From "Philip Van Baren" <pdv...@vi...>
> > | Mon, 3 Aug 2009 22:51:33 -0400
> > | Subject: [Audacity-devel] Truncate Silence leaves minimum residual 
> > silenceof 2 ms, not 1 ms
> >> The minimum duration is limited by the cross-fade length of 100 samples. 
> >> At
> >> 44.1kHz this would be 2.27ms.
> >>
> >> The cross-fade time is set by the registry parameter
> >> /CsPresets/BlendFrameCount  This value is not made available to the user
> >> interface, but if you know where these things get stored (in the registry
> >> somewhere?) the value could be changed.
> >
> > I see the note in TruncSilence.cpp:
> >
> > " \todo mBlendFrameCount only retrieved from prefs ... not using dialog
> >        Only way to change (for windows) is thru registry
> >       The values should be figured dynamically ... too many frames
> >       could be invalid"
> >
> > but my XP Registry does not seem to have any such parameter that is
> > findable by searching.
> >
> >
> >> If this is objectionable, I see a couple options:
> >
> > "Objectionable" is too strong, however the fact remains that at its
> > default sample rate (44100 Hz) Audacity is no longer providing the
> > "Max Silence duration" indicated if it is set to 1ms (but 1.3.7 did).
> >
> >
> >> 1) change the default cross-fade to 44 samples which would allow for a
> >> minimum 1ms silence
> >>
> >> 2) When short silences are requested, ignore the BlendFrameCount 
> >> parameter,
> >> and use the minimum silence duration as the cross-fade time.
> >
> > I presume 1) would still give in excess of requested 1 ms at sample
> > rates below 44100 Hz, though? If so, and if you feel there are no
> > audible problems with solution 2), do that?
> >
> >
> >> As for the clicks, when you insert silence into a sine tone it will 
> >> produce
> >> clicks (depending on the phase of the sine tone at the point of the 
> >> insert).
> >> The insert doesn't do any cross-fade.  The truncate silence effect 
> >> doesn't
> >> change the full-level signal, so it leaves any clicks as they were.
> >
> > I understand the user was working with music, but she did not have
> > an example file. I wasn't testing with tones as I agree inserting
> > silences in sine tones will create clicks. I don't find any audible
> > problem with the truncation in 1.3.8 if I choose a region in some
> > arbitrary 44100 Hz music track, Edit > Silence it then truncate
> > the silence with "Max Silence Duration" set to 1 ms.
> >
> >
> >
> > Thanks
> >
> >
> > Gale
> >
> >
> >
> >> --------------------------------------------------
> >> From: <ga...@au...>
> >> Sent: Monday, August 03, 2009 12:29 AM
> >> To: <aud...@li...>
> >> Subject: [Audacity-devel] Truncate Silence leaves minimum residual 
> >> silenceof
> >> 2 ms, not 1 ms
> >>
> >> >
> >> > 1. Generate a tone of 30 seconds
> >> > 2. Click at 15 seconds and overwrite the next
> >> >     5 seconds with silence
> >> > 3  Select All and apply the effect
> >> >
> >> > If I set "Max silence duration" to 1 ms,  the residual silence always
> >> > seems to be 2 ms. In 1.3.7 you get the requested 1 ms residual
> >> > silence in the same scenario.
> >> >
> >> > A couple of users have pointed this out, one of whom claims clicks
> >> > as a result of the 2 ms ("truncate the exact same audio in 1.3.7 down
> >> > to 1 ms and there are no clicks").
> >> >
> >> > The most common (novice) use case of this effect is (I think) to
> >> > "remove as much silence as possible". Is there a reason for the
> >> > 2 ms residual? Other residual durations I tried appeared to be
> >> > accurate in 1.3.8.
> >> >
> >> >
> >> >
> >> >
> >> > Gale
> >> >
> >> >
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