[R] Limitations of audio processing in R

[Spencer Graves]

A more general question:  What tools are available in R for reading 
parts of binary files?  'scan' allows you to 'skip' a certain number of 
records and read the next 'nlines'.  Unfortunately, scan only seems to 
work for text files not binary, and I cannot find a comparable function 
that would work for binary files.  I tried library(sos);  (rb <- 
findFn('read binary')).  This produced 299 matches.  Something there 
might solve the problem, but I haven't taken the time to study it 
carefully.  I hope someone else will know.


       Spencer


On 9/21/2011 2:15 PM, Ken wrote:
> Also with Linux you can add more swap memory(which I'm pretty sure R spills into if it hasn't reached it's  internal limits on 32 bit installations). Windows pagefile is kind of obnoxious.
>     Ken Hutchison
>
> On Sep 21, 2554 BE, at 5:05 PM, (Ted Harding)<ted.harding at wlandres.net>  wrote:
>
>> Hi Ulisses!
>> Yes, "get more creative" -- or "get more memory"!
>>
>> On the "creative" side, it may be worth thinking about
>> using an independent (non-R) audio file editor. I'm
>> writing from the standpoint of a Linux/Unixoid user
>> here -- I wouldn;t know how to set ebout this in WIndows.
>>
>> You could use R to create a shell script which would run
>> the editor in such a way as to extract your 6 random samples,
>> and save them, where the script would be fed with the
>> randomly-chosen 5-minute intervals decided by R. This
>> could be done under the control of R, so you could set
>> it up for your 1500 or so sets of samples, which (with
>> the right editing program) could be done quite quickly.
>>
>> On Linux (also available for Windows) a flexible audio
>> editor is 'sox' -- see:
>>
>>   http://en.wikipedia.org/wiki/SoX
>>
>> To take, say, a 5-minute sample starting at 1 hour,
>> 10 min and 35sec into the audio file "infile.wav",
>> and save this as "outfile.wav", you can execute
>>
>>   sox infile.wav outfile.wav trim 01:10:35 00:05:00
>>
>> and such a command could easily be generated by R and
>> fed to a shell script (or simply executed from R by
>> using the system() command). My test just now with
>> a 5-minute long sample from a .wav file was completed
>> in about 5 seconds, so it is quite efficient.
>>
>> There is a huge number of options for 'sox', allowing
>> you to manipulate almost any aspect of the editing.
>>
>> Hoping this helps,
>> Ted.
>>
>>
>> On 21-Sep-11 19:55:22, R. Michael Weylandt wrote:
>>> If you are running Windows it may be as simple as using
>>> memory.limit() to allow R more memory -- if you are on
>>> another OS, it may be possible to get the needed memory
>>> by deleting various things in your workspace and running
>>> gc()
>>>
>>> Of course, if your computer's memory is<3GB, you are
>>> probably going to have trouble with R's keeping all objects
>>> in memory and will have to get more creative.
>>>
>>> Michael
>>>
>>> On Wed, Sep 21, 2011 at 3:43 PM, Ulisses.Camargo<
>>> moliterno.camargo at gmail.com>  wrote:
>>>
>>>> Hello everybody
>>>>
>>>> I am trying to process audio files in R and had some problems
>>>> with files size. I´m using R packages 'audio' and 'sound'.
>>>> I´m trying a really simple thing and it is working well with
>>>> small sized .wav files. When I try to open huge audio files
>>>> I received this error message: "cannot allocate vector of
>>>> size 2.7 Gb". My job is open in R a 3-hour .wav file, make six
>>>> 5-minute random audio subsamples, and than save these new files.
>>>> I have to do the same process +1500 times. My problems is not
>>>> in build the function to do the job, but in oppening the 3-hour
>>>> files. Does anybody knows how to handle big audio files in R?
>>>> Another package that allows me to do this work? I believe
>>>> this is a really simple thing, but I really don´t know what
>>>> to do to solve that memory problem.
>>>>
>>>> Thank you very much for your answers,
>>>> all the best!
>>>>
>>>> Ulisses
>> --------------------------------------------------------------------
>> E-Mail: (Ted Harding)<ted.harding at wlandres.net>
>> Fax-to-email: +44 (0)870 094 0861
>> Date: 21-Sep-11                                       Time: 22:05:55
>> ------------------------------ XFMail ------------------------------
>>
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-- 
Spencer Graves, PE, PhD
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