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Re: Won't Read Entire Soundfile; Why?

• To: mathgroup at smc.vnet.net
• Subject: [mg7523] Re: [mg7388] Won't Read Entire Soundfile; Why?
• From: tornberg at primenet.com (Neal E. Tornberg)
• Date: Tue, 10 Jun 1997 23:17:57 -0400 (EDT)
• Organization: Primenet Services for the Internet
• Sender: owner-wri-mathgroup at wolfram.com

Hi, Mark

On 31 May 1997 20:17:29 GMT, you wrote:


>The code for ReadSoundfile in Miscellaneous`Audio` is buggy.  Although
>it parses the header for all WAV formats, it only works for 8-bit
>formats.
>
>My suggestion is to take a look at the module definition, and make your
>own version that reads 16-bit, taking into account little-endian vs.
>big-endian issues, or to settle for using 8-bit WAV files only.
>
>It was very surprising to me that WRI let this package out the door...it
>seems as though it was only partially finished.  They really ought to
>post a bug-fix version on MathSource.

Sorry it took a while to get back to you on this.  I haven't had all the time
in the world and I originally wanted to use the package Miscellaneous`Audio`
to avoid spending a lot of time on learning file formats and some of the
arcana of MMA programming.

Hah!

Now, one file format and much programming arcana later, I find that if I
replace
sf = OpenRead[name] ;    (* quit if file not found *)

with

sf = OpenRead[name,DOSTextFormat->False] ;    (* quit if file not found *)

near the end of the package it works.  I'm not certain this is the final word
on the subject - the documentation in that package is atrocious - but I did
discover that OpenRead[] is defaulting with DOSTextFormat->True.  It was
probably seeing a 01Ah and interpreting it as an end-of-file.  I'm not certain
why it would work OK on 8-bit sound formats, but I didn't even try that.
Still haven't.  NOTE that I haven't yet attempted to retain generality with
other operating systems.  Probably won't since I have no way to test under
them.

I really appreciate your reply.  It helped spur me into greater effort which
resulted in advancing my MMA skills.


Neal E. Tornberg
tornberg at primenet.com