On Thu, Sep 22, 2011 at 8:08 AM, Spencer Graves
<spencer.gra...@structuremonitoring.com> wrote:
> 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
>
?readBin and ?seek
Also see "Viewing Binary Files with the hexView Package" in RNews
Volume 7/1, April 2007.
http://www.r-project.org/doc/Rnews/Rnews_2007-1.pdf
Cheers, Mike.
>
> 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.hard...@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.cama...@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.hard...@wlandres.net>
>>> Fax-to-email: +44 (0)870 094 0861
>>> Date: 21-Sep-11 Time: 22:05:55
>>> ------------------------------ XFMail ------------------------------
>>>
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>>
>> ______________________________________________
>> R-help@r-project.org mailing list
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>
>
> --
> Spencer Graves, PE, PhD
> President and Chief Technology Officer
> Structure Inspection and Monitoring, Inc.
> 751 Emerson Ct.
> San José, CA 95126
> ph: 408-655-4567
> web: www.structuremonitoring.com
>
> ______________________________________________
> R-help@r-project.org mailing list
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> and provide commented, minimal, self-contained, reproducible code.
>
--
Michael Sumner
Institute for Marine and Antarctic Studies, University of Tasmania
Hobart, Australia
e-mail: mdsum...@gmail.com
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