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MathGroup Archive 1996

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Windows WAV File Bug & Compiled File Routines

  • To: mathgroup at smc.vnet.net
  • Subject: [mg5088] Windows WAV File Bug & Compiled File Routines
  • From: Mark Evans <evans at gte.net>
  • Date: Wed, 30 Oct 1996 22:03:36 -0500
  • Organization: None
  • Sender: owner-wri-mathgroup at wolfram.com

I'm very impressed by 3.0, but Mathematica is still a real bear when it comes 
to working with data files.  I think WRI should implement some compiled C code 
to read and write the most common file formats that exist on PCs and Macs, 
instead of forcing everyone to rely on Read[] and its family of functions.  
Will anyone second the motion?

Here is the latest file reading bug:  The package Miscellaneous`Audio` does not 
read all Windows .WAV files correctly.  It reads 8-bit files, albeit at a 
snail's pace, but has problems reading 16-bit files.  It will interpret the 
header correctly, but then fail to read the actual data.

I had to truncate my 12.5 second, 44100 Hz, 16-bit mono file to 8 bits, and 
then wait a long time, to get it into Mathematica.  It took at least 60 seconds 
on a P166 machine.  By contrast, some of the freeware sound utilities that I 
downloaded from the Internet take about a tenth of a second to read in this 
same file.

Of course, the package does not offer a way to write .WAV files back to disk.  
This omission is in itself a great deficiency.

If you look at the file-reading code in Audio.m you begin to understand why (1) 
reading files into Mathematica is slow, and (2) error-prone.  There are all 
kinds of flips and flops relating to byte ordering, scaling and the like that 
cry out for compiled routines instead of interpreted execution.

I love Mathematica, and yes it can do everything, but in cases like these I 
request compiled code.  I respect the work that has gone into many of these 
file-reading utilities, and I am thankful for what I have; but it seems to me 
that if the freebies I pull down from ftp sites can read and write .WAV files, 
then a mammoth like Mathematica should be able to pull it off with ease.

Mark Evans
evans at gte.net



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