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Want WAV editor allows cutting without changing remaining ..

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Anonymous
May 7, 2005 6:10:41 PM

Archived from groups: comp.multimedia,rec.audio.tech (More info?)

I have some WAV recordings that I would like to trim to remove extra
material
at the beginning/end. I am looking for a wav file editor that will let
me do
simple edits like this, without changing the remaining audio.

>From cursory examination of the .WAV file format, I would have thought
this was simple to do. Yet the programs I have tried so far (Audacity,
Nero WAV editor) can't even manage the even simpler operations of
Opening and saving a .WAV file, without changing the contents.

i.e., If I open a .WAV file, do nothing to it, then save/export it with
a new name, then compare the result to my original (fc /b), there are
lots of changes reported (not just at the beginning of the file). (And
each subsequent save/export produces yet a different variant of the
file.)

Are there portions of a .WAV file given over to garbage? If so, it
would
make life easier if the tool would repeat the same garbage
consistently.
(e.g. so that file compare routines could recognize when files are
identical.)
Is there generational information embedded in wav files? If so, are
there
comparison programs that will extract this information, or at least
ignore it
and tell you when the audio portions of two wav files are identical?

Looking for something low cost or free. (Don't need lots of bells and
whistles, just something simple and fast to do some basic operations.)

Thank you
Sorry, the e-mail address above is no longer valid, if you wish to
respond by e-mail, please use zzxjoanw at hotmail period com. I will
post a summary of relevant e-mail responses.
Anonymous
May 8, 2005 4:10:05 AM

Archived from groups: comp.multimedia,rec.audio.tech (More info?)

<scdr@my-deja.com> wrote in message
news:1115500241.095884.112830@f14g2000cwb.googlegroups.com...

> i.e., If I open a .WAV file, do nothing to it, then save/export it with
> a new name, then compare the result to my original (fc /b), there are
> lots of changes reported (not just at the beginning of the file). (And
> each subsequent save/export produces yet a different variant of the
> file.)
>

The .wav format specification allows some variability in the way data is
stored; that is, the same audio data can be stored in different ways.
Here's oe description and commentary on the spec

http://www.borg.com/~jglatt/tech/wave.htm

I guess each program will have its own methods of storing the data (eg,
order of the .wav file components)

Anyway, I tried what you suggested - I took an existing .wav file, created
by a Tascam 788 recorder, and opened and saved it with Goldwave. The input
and output files differed. I then opened the output file in Goldwave, and
saved it as a second output fiole. The two output files were identical.

Tim
Anonymous
May 9, 2005 6:28:27 PM

Archived from groups: comp.multimedia,rec.audio.tech (More info?)

scdr@my-deja.com wrote:

>I have some WAV recordings that I would like to trim to remove extra
>material
>at the beginning/end. I am looking for a wav file editor that will let
>me do
>simple edits like this, without changing the remaining audio.

Most audio editors should allow to select a portion of the file and
offer Save Highlighted Part.
>
>>From cursory examination of the .WAV file format, I would have thought
>this was simple to do. Yet the programs I have tried so far (Audacity,
>Nero WAV editor) can't even manage the even simpler operations of
>Opening and saving a .WAV file, without changing the contents.
>
>i.e., If I open a .WAV file, do nothing to it, then save/export it with
>a new name, then compare the result to my original (fc /b), there are
>lots of changes reported (not just at the beginning of the file). (And
>each subsequent save/export produces yet a different variant of the
>file.)

The problem lies with fc as it doesn't know anything about the structure
of a wav file. It consists of several chunks, one of them is headed
DATA. That's shouldn't change unless you change the music i.e. by
deleting/inserting, changing the amplitude, EQ.

Anything else ususally changes because the INFO chunk may contain the
name of the program that stored the file. Even the header of the wave
file will change because it stores the length of the file and the
displacement of the next chunk. As the position of the chunks are
not fixed, some program will store the DATA chunk before the INFO
chunk while some other program will store INFO before DATA.

Norbert
Anonymous
May 9, 2005 6:28:28 PM

Archived from groups: comp.multimedia,rec.audio.tech (More info?)

Norbert Hahn wrote:
> scdr@my-deja.com wrote:
>
>> I have some WAV recordings that I would like to trim to
remove extra
>> material
>> at the beginning/end. I am looking for a wav file editor
that will
>> let me do
>> simple edits like this, without changing the remaining
audio.
>
> Most audio editors should allow to select a portion of the
file and
> offer Save Highlighted Part.
>>
>>> From cursory examination of the .WAV file format, I
would have
>>> thought
>> this was simple to do. Yet the programs I have tried so
far
>> (Audacity, Nero WAV editor) can't even manage the even
simpler
>> operations of Opening and saving a .WAV file, without
changing the
>> contents.
>>
>> i.e., If I open a .WAV file, do nothing to it, then
save/export it
>> with a new name, then compare the result to my original
(fc /b),
>> there are lots of changes reported (not just at the
beginning of the
>> file). (And each subsequent save/export produces yet a
different
>> variant of the file.)
>
> The problem lies with fc as it doesn't know anything about
the
> structure of a wav file. It consists of several chunks,
one of them
> is headed DATA. That's shouldn't change unless you change
the music
> i.e. by deleting/inserting, changing the amplitude, EQ.
>
> Anything else ususally changes because the INFO chunk may
contain the
> name of the program that stored the file. Even the header
of the wave
> file will change because it stores the length of the file
and the
> displacement of the next chunk. As the position of the
chunks are
> not fixed, some program will store the DATA chunk before
the INFO
> chunk while some other program will store INFO before
DATA.

Good point. There are .wav file comparison tools in CDEX and
EAC (both free downloads) that do know about the structure
of .wav files and report only differences that could be
sonically relevant.
Anonymous
May 11, 2005 5:46:55 PM

Archived from groups: comp.multimedia,rec.audio.tech (More info?)

Norbert Hahn wrote:
> scdr@my-deja.com wrote:
>
> >
> >>From cursory examination of the .WAV file format, I would have
thought
> >this was simple to do. Yet the programs I have tried so far
(Audacity,
> >Nero WAV editor) can't even manage the even simpler operations of
> >Opening and saving a .WAV file, without changing the contents.
> >
> >i.e., If I open a .WAV file, do nothing to it, then save/export it
with
> >a new name, then compare the result to my original (fc /b), there
are
> >lots of changes reported (not just at the beginning of the file).
(And
> >each subsequent save/export produces yet a different variant of the
> >file.)
>
> The problem lies with fc as it doesn't know anything about the
structure
> of a wav file. It consists of several chunks, one of them is headed
> DATA. That's shouldn't change unless you change the music i.e. by
> deleting/inserting, changing the amplitude, EQ.

No, the programs are changing the audio data (not just the header).
I have since confirmed this using a WAV editor. I inverted one of
the files and then added it to one of the others. If the audio had
been identical, this should have resulted in a .WAV file of all 0's.
It doesn't. (I did this before I found out about the .WAV compare
features mentioned by others in this thread.)

So the programs (Audacity, Nero Wave Editor) are adding their own noise
to the WAV files.

--
In response to other messages - thanks for the pointers on WAV compare
features, and for the suggestion of GoldWave. It doesn't seem to have
this problem.
!