[R] Limitations of audio processing in R

[Spencer Graves]

Hi, Michael & Ulisses:


ULISSES:  If you haven't already, I suggest you look at the hexView 
package including the R News article cited below and the readRaw 
function in particular.  I just used readRaw(filename, offset=4, 
nbytes=8) to read bytes 5:12 in filename;  in this case, filename was 
*.wma created by the Windows 7 Sound Recorder.


MICHAEL:  Thanks.


       Spencer


On 9/21/2011 4:25 PM, Michael Sumner wrote:
> On Thu, Sep 22, 2011 at 8:08 AM, Spencer Graves
> <spencer.graves at 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.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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