Subject: Re: [ecasound] skipping unwanted portions of an audio file.
From: S. Massy (theanaloguekid@tak.net.dhis.org)
Date: Sat Mar 03 2001 - 21:30:35 EET
On Sat, 03 Mar 2001, Kai Vehmanen wrote:
> On Sat, 3 Mar 2001, Bill Kenworthy wrote:
>
> > appears that it is possible to manually extract and then recombine parts
> > of an audiofile only by a number of manual cut & paste operations. Have
> > I missed something or is it possible to play for a predermined period,
> > skip forward a few thousand seconds and then start playing again,
> > possibly a number of times. This would not be for live play, but would
>
> This kind of cutting and pasting is possible, but not with a single
> ecasound operation. In theory, the ewf-format could be extended to include
> support for selecting multiple ranges from a single (or perhaps multiple?)
> big audio file, but at the moment, this is not possible. However, it's
I remember we discussed cutting waves in a single pass, support for
that in ewf would be quite welcome.
Anyway, wouldn't it be possible to do that in IAM? Like two chains:
-a:1,2 -i:bigthing.wav
-a:1 -o:/dev/dsp
-a:2 -o:newthing.wav
Where you'd have the second chain disconnected and set your position
in bigthing with aio-setpos, then connect chain 2 to copy a certain
portion of audio before disconnecting it and skipping to the next
position in the wave file. Would that sort of editing work?
> quite easy to put together a bash script to do the necessary steps:
>
> ecasound -i big-file.wav -o target.wav -y:0 -t:20
> ecasound -i big-file.wav -y:40 -o target.wav -y:20 -t:10
> ecasound -i big-file.wav -y:100 -o target.wav -y:30 -t:40
> ecasound -i big-file.wav -y:500 -o target.wav -y:70 -t:100
>
> ... so this cuts ranges [0,20], [40,50], [100,140] and [500,600] to file
> 'target.wav'. After the last operation, 'target.wav' should be
> 20+10+40+100=170sec long. If you need to do this a lot, it might be easier
> to write a shell script or a small program that takes the wanted ranges as
> its input, and translates them into a ecasound script. Basicly you just
> need to calculate the -y:x values for 'target.wav' at different stages...
> 0+20=20 -> 20+10=30 -> 30+40=70 ... and so on.
>
> > in picking up the new start point is irrelevant. I have tried stacking
> > -y:seconds -t:seconds commands, but unless I have the wrong syntax, this
> > doesnt work.
>
> This is not possible.
>
> --
> . http://www.eca.cx ... [ audio software for linux ] /\ .
> . http://www.eca.cx/sculpscape [ my armchair-tunes mp3/ra/wav ]
>
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