Hi,
I've been interested in using Linear Predictive Coding for a good while. Having had a few problems compiling some of the older examples from the CSound Book, I discovered that quite a bit has changed with the lpc opcodes along with adsyn opcodes as well. While my .lpa analysis files seem to work okay in some cases (cool and interesting results but for 'predictive coding' its pretty damn unpredicatable ;)) I took an interest in the 'lpinterp' opcode with the related 'lpslot' opcode only to be unsuccessful in working it.
Heres what I get trying to use a normal .lpa file...
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INIT ERROR in instr 1: lpinterpol works only with poles files..
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Fair enough, yet how do I go about making them? I know you can make .SDIR files with the hetro utility as far as I understand but what utility makes these .pol files?
If anyone could shed light on this I'd be very grateful :)
cheers
-dave
Well heres what I've found
Well heres what I've found using CSound 5.12's lpinterp opcode...
First off, the lpanal does apparantly give the option to create "Poles" files as the help tells you the following...
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-a -- [alternate storage] asks lpanal to write a file with filter poles values rather than the usual filter coefficient files. When lpread / lpreson are used with pole files, automatic stabilization is performed and the filter should not get wild. (This is the default in the Windows GUI) - Changed by Marc Resibois.
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While I can ONLY assume that this works to an extent, the file it spits out doesnt have a .pol extension nor will it work with 'lpread/lpinterp' if given one. Every time lpanal analyses a file with the '-a' flag it says it can't find enough poles and the file exported is ALWAYS 1KB.
Stranger is the fact that, when I add an .lpa extension at the end of the exported 1kb "pole" file and use it with 'lpread/lpinterp' it DOES compile no trouble (without the message below**) However all you can hear is a very high pitched noise.
Someone must know some details about these opcodes a least. Could anyone just confirm to me that they are broke?
-dave
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INIT ERROR in instr 1: lpinterpol works only with poles files..
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me too i have problems with
me too i have problems with the LPC opcodes, sometimes they just don't work.
I have done a feature request for new, streamimg, LPC opcodes and they are on the list for Csound6: http://sourceforge.net/apps/mediawiki/csound/index.php?title=Notes_from_...
Further i recommend you do your postings on http://csound.1045644.n5.nabble.com/ Lots more Csound people go there for their Q&A
Menno
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