Re: [Audacity-nyquist] Spectrum Analysis
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Re: [Audacity-nyquist] Spectrum Analysis
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From: George J. <geo...@gm...> - 2009-06-09 22:28:54
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Richard We do a similar thing to what you're trying to do (I think) of many recordings of train passbys. It might be easily adapted to manatees. Thing is I was too slow doing it in Nyquist so someone else in my office wrote it in Gnu Octave. Octave is an opensource program similar to Matlab. Uses its own language but it's not too hard. http://www.gnu.org/software/octave/ Anyway since I'm immediately off topic contact me off list if you want to know more. George On Wed, Jun 10, 2009 at 2:32 AM, RICHARD HAMILTON <r_...@ma...> wrote: > David- > > Thank you, and sorry for the delayed response. I am beginning to think > that I will have to do the coding directly in Audacity and recompile. If > anyone on the developers' list has any guidance I would appreciate hearing > from them. > > Richard > > > > On Thursday, May 28, 2009, at 04:45AM, "David R. Sky" < > dav...@sh...> wrote: > >Hi Richard, > > > >I'm not sure about your Nyquist request, but am cc'ing this to the > >Audacity development list, perhaps someone here can help you. > > > >David > > > >-- > >David R. Sky > >http://www.shellworld.net/~davidsky/<http://www.shellworld.net/%7Edavidsky/> > > > > > >On Wed, 27 May 2009, REH wrote: > > > >> Good Morning All- > >> > >> I am NOT new to studio sound processing nor traditional scientific > >> programming (including LISP), but I AM new to both Audacity and > >> Nyquist. I have need to (batch) parse large amounts of streamed audio > >> data from natural and artificial manatee habitats to isolate and > >> analyze vocalization (call) data. Rather than start from scratch, I > >> was hoping to use Audacity to provide some of the base processing, > >> particularly the Fourier transformation (I presume this is what is > >> being done) to get a spectrum analysis, which is what I need. > >> > >> If I could write a "macro" (term used loosely) perhaps using Nyquist, > >> it would look something like the following (even more loosely, in > >> pseudo-code): > >> > >> OPEN FILE (SPECIFIED MP3 SAMPLE) > >> EXECUTE "EFFECT/AMPLIFY" > /* EXISTING MENU COMMAND > >> > >> WHILE NOT EOF DO > >> SELECT FIRST/NEXT 0.5 SECONDS OF SAMPLE > >> EXECUTE "ANALYZE/PLOT SPECTRUM" /* > EXISTING MENU COMMAND > >> (EXPORT) > >> (SAVE AS (SPECIFIED FILE NAME)) > >> (WHERE (SPECIFIED LOCATION)) > >> (SAVE) > >> (CLOSE) > >> END DO > >> > >> CLOSE FILE > >> > >> What would result, unless I have made a silly mistake above, is a > >> series of spectra output files, one for each 0.5 second of the sample. > >> > >> A couple (to say the least!) of problems/issues present themselves: > >> > >> 1. I REALLY want all of the spectra for a given sample (typically 30 > >> minutes) to go into the SAME spectrum output file, i.e. to append at > >> each iteration of the loop, otherwise I would have 3600 (!) separate > >> output spectra files per audio sample. > >> > >> 2. For reasons of simplicity, I would prefer to do this with a plug- > >> in instead of having to modify the Audacity source code and re-build. > >> (I am NOT an object-oriented programmer.) > >> > >> 3. I intend to process this spectrum data OUTSIDE of Audacity, > >> because it appears that the spectrum tools are limited and I need to > >> extract time stamp, duration, fundamental pitch, harmonics, etc. which > >> I can do easily enough out of the "ANALYZE/PLOT SPECTRUM" output file > >> (which is a simple text file with two column of numbers; frequency > >> (Hz) v. level (dB)). > >> > >> I have downloaded the complete Nyquist implementation from Carnegie- > >> Melon University, noting that Audacity can ONLY use the LISP flavor > >> (my preference anyway). I am confident that I could navigate the file- > >> append issues and so forth, but I would NOT want to have to replicate > >> the production of the spectra themselves, unless that task would be a > >> LOT easier than I am thinking. > >> > >> >>>There may be an alternate approach that I have come across: There > >> is a "Spectrum" display on the "Track" drop-down. This would be > >> perfect if I could export it into a format similar to "ANALYZE/PLOT > >> SPECTRUM"... > >> > >> ANY guidance getting started would be appreciated. (I may have missed > >> much simpler approaches entirely.) I can noodle my way through the > >> details, I just would like to avoid making a plethora of false starts > >> with the wrong tool or strategy. > >> > >> Best Regards, > >> > >> Richard > >> > >> - - - - - - - - - - > >> > >> Richard Hamilton, B.S., M.S. > >> > >> Research Scientist, > >> Midwest Manatee Research Project > >> Xavier University > >> > >> Visiting Assistant Professor, > >> Departments of Mathematics and Physics > >> Xavier University > >> > >> HamiltonR@Xavier.edu > >> R_E_H@Mac.com > >> 513.484.6284 > >> > >> > >> > ------------------------------------------------------------------------------ > >> Register Now for Creativity and Technology (CaT), June 3rd, NYC. CaT > >> is a gathering of tech-side developers & brand creativity professionals. > Meet > >> the minds behind Google Creative Lab, Visual Complexity, Processing, & > >> iPhoneDevCamp as they present alongside digital heavyweights like > Barbarian > >> Group, R/GA, & Big Spaceship. http://p.sf.net/sfu/creativitycat-com > >> _______________________________________________ > >> Audacity-nyquist mailing list > >> Aud...@li... > >> https://lists.sourceforge.net/lists/listinfo/audacity-nyquist > >> > >> > > > > > > > ------------------------------------------------------------------------------ > Crystal Reports - New Free Runtime and 30 Day Trial > Check out the new simplified licensing option that enables unlimited > royalty-free distribution of the report engine for externally facing > server and web deployment. > http://p.sf.net/sfu/businessobjects > _______________________________________________ > Audacity-nyquist mailing list > Aud...@li... > https://lists.sourceforge.net/lists/listinfo/audacity-nyquist > |