Need to split a very long .wav

[P]

I've recorded a long radio program using JetAudio, I used .wav for quality
reasons. The recording was started manually and the timer set for 7 hours.

The end result was a 4.5GB file which seemed fine, but every player or
program I've used recognises the file as 47min 11sec and will only play this
much. I am hoping the full recording is still trapped within the file
somewhere. Can anyone please give me some advice on this, or suggest a
program (preferably a freebie) that can split the file into smaller more
manageable - and hopefully playable - bits?

Thank you all.

(This post appeared in a different form in rec.audio.tech, apologies to
anyone offended by my multiple posting.)

[Mike O'Sullivan]

P wrote:
> I've recorded a long radio program using JetAudio, I used .wav for quality
> reasons. The recording was started manually and the timer set for 7 hours.
>
> The end result was a 4.5GB file which seemed fine, but every player or
> program I've used recognises the file as 47min 11sec and will only play this
> much. I am hoping the full recording is still trapped within the file
> somewhere. Can anyone please give me some advice on this, or suggest a
> program (preferably a freebie) that can split the file into smaller more
> manageable - and hopefully playable - bits?
>
> Thank you all.
>
> (This post appeared in a different form in rec.audio.tech, apologies to
> anyone offended by my multiple posting.)
>
>
I use Adobe Audition for dividing WAVE files into bite-sized chunks. Not
free though I'm afraid.

[P]

> I use Adobe Audition for dividing WAVE files into bite-sized chunks. Not
> free though I'm afraid.

Thanks... I tried Cool Edit Pro 2.1 which seems to have metamorphosed into
Adobe Audition (if I'm correct). The main problem seems to be that each of
these programs, whether a player or an editor, "thinks" the file runs 47min
11sec so they give me nothing longer than this either to play or edit. If I
could trick a program into believing the file was 7 hours (or even 4.5GB) we
might be getting somewhere. What information does a player use to base its
belief on the length of a .wav file, is there a header?

[Ron Hardin]

P wrote:
>
> > I use Adobe Audition for dividing WAVE files into bite-sized chunks. Not
> > free though I'm afraid.
>
> Thanks... I tried Cool Edit Pro 2.1 which seems to have metamorphosed into
> Adobe Audition (if I'm correct). The main problem seems to be that each of
> these programs, whether a player or an editor, "thinks" the file runs 47min
> 11sec so they give me nothing longer than this either to play or edit. If I
> could trick a program into believing the file was 7 hours (or even 4.5GB) we
> might be getting somewhere. What information does a player use to base its
> belief on the length of a .wav file, is there a header?

4gb is 32 bits worth of bytes. Perhaps they're using the 32 low bits of the
file length, so think it's a .5gb file

You can do the calculation more exactly with the exact file length you have
but (.5/4.5) * (7*60) = 46.2 minutes, in the ballpark of what you see

use the exact (file length) and (file length - 2^32 (=4294967296))
instead of (4.5) and (.5)

I don't know what change you'd have to make to get it to work; perhaps a
64-bit operating system is needed, at the worst end.

The .wav format itself may have only 32 bits for some length header word,
though. I don't know.

It's probably very simple to fix in C language, so don't destroy the file ;
a matter of breaking up the file and writing new headers for each half.

--
Ron Hardin


On the internet, nobody knows you're a jerk.

[Arny Krueger]

"P" > wrote in message

>> I use Adobe Audition for dividing WAVE files into
>> bite-sized chunks. Not free though I'm afraid.
>
> Thanks... I tried Cool Edit Pro 2.1 which seems to have
> metamorphosed into Adobe Audition (if I'm correct). The
> main problem seems to be that each of these programs,
> whether a player or an editor, "thinks" the file runs
> 47min 11sec so they give me nothing longer than this
> either to play or edit.

Your file must have one heck of a sample rate. What is it, 192/24?

I presume you're running XP or something like it to even have a file this
large.

>If I could trick a program into
> believing the file was 7 hours (or even 4.5GB) we might
> be getting somewhere. What information does a player use
> to base its belief on the length of a .wav file, is there
> a header?

There's a header to every .wav file, whose layout is well-documented on the
web. You've heard of goggle, right? ;-)

The major problem with .wav files is that the headers limit the maximum size
of the file. The short answer is that some counters in the header are 4
bytes long, which limits the file to about 4 billion elements. Most software
is limited to .wav files that are either 2 or 4 GB.

A few pieces of software support a .wav file format called wav64, which
doubles the size of some fields in the header. SoundForge is one of them.

You may have to chop the file up with a file splitter, which will create
headerless files. Programs like Audition can handle headerless files, if you
know the format of the file and can type it in when prompted for it.

[Greg Berchin]

On Mon, 26 Dec 2005 12:47:45 +1100, "P" > wrote:

>I used .wav for quality
>reasons. The recording was started manually and the timer set for 7 hours.
>
>The end result was a 4.5GB file which seemed fine, but every player or
>program I've used recognises the file as 47min 11sec and will only play this
>much.

The header in the .wav file uses a 32 bit field for file length (in
bytes). If you recorded in stereo, 16 bits per sample, 48 kHz sampling
rate, then 4,294,967,295 bytes will be used in 22,369 seconds, or 6.2
hours. So by recording for ~7 hours it appears that you overflowed the
32 bit number in the header by a little over 543,000,000 samples.

>I am hoping the full recording is still trapped within the file
>somewhere.

It is! This file could be split up into smaller pieces with a very
simple program. You might even be able to do it with a file editor, if
you can find one that will open a file in hexadecimal mode instead of
ASCII. You'll have to understand the structure of the .wav header, and
modify values.

Greg

[Greg Berchin]

Here's an even easier method to try.

Make a copy of the file, and rename it as "filename.pcm" instead of
"filename.wav". Open it in your favorite audio editor as a "raw pcm"
file. Tell the editor that it's 16 bit, 48 kHz stereo.

You'll see 11 bad samples in each channel at the beginning of the file.
That's the .wav header. Edit it out. Now trim the file into smaller
pieces (less than 6.2 hours each), and save the pieces in .wav format.

Greg

[mc]

I wonder if you could open it as a "raw" file with SoundForge.

"Greg Berchin" > wrote in message
...
> On Mon, 26 Dec 2005 12:47:45 +1100, "P" > wrote:
>
>>I used .wav for quality
>>reasons. The recording was started manually and the timer set for 7
>>hours.
>>
>>The end result was a 4.5GB file which seemed fine, but every player or
>>program I've used recognises the file as 47min 11sec and will only play
>>this
>>much.
>
> The header in the .wav file uses a 32 bit field for file length (in
> bytes). If you recorded in stereo, 16 bits per sample, 48 kHz sampling
> rate, then 4,294,967,295 bytes will be used in 22,369 seconds, or 6.2
> hours. So by recording for ~7 hours it appears that you overflowed the
> 32 bit number in the header by a little over 543,000,000 samples.
>
>>I am hoping the full recording is still trapped within the file
>>somewhere.
>
> It is! This file could be split up into smaller pieces with a very
> simple program. You might even be able to do it with a file editor, if
> you can find one that will open a file in hexadecimal mode instead of
> ASCII. You'll have to understand the structure of the .wav header, and
> modify values.
>
> Greg

[P]

Thanks for the suggestion fellas. Nothing has worked. Every player and
editor still reads the header no matter what I call the bloody thing. Also,
unfortunately I'm not sufficiently versed in computer programming (or file
writing/rewriting) to tackle changes to the header in the manner Greg
suggested.

When I try and open it as a .pcm in Sound Forge it still sees it as 47'11".
When I hit the "More" button it gives me the following properties:

File size: 4,725.23 MB (4,838,630,446 bytes)
File attributes: - --a- ----
Last saved: 2005-12-25 16:56:54
File type: Wave (Microsoft)
Audio format: Uncompressed
Audio attributes: 48,000 Hz, 16-bit, Stereo
Audio Length 00:47:11:579 (135,915,776 samples)

At this point I scream something along the lines of "you KNOW it's
4.whatever gig and yet you STILL think it's 47 minutes! ^#(*#@!"

About to give up. All I really need is a file splitter that will only look
at the length of the file, not what the file is. I suspect a program like
Sound Forge would still recognise unrelated, unheadered pieces of this file
without actually "knowing" it's in .wav format.

[Greg Berchin]

On Thu, 29 Dec 2005 14:12:12 +1100, "P" > wrote:

>Nothing has worked. Every player and
>editor still reads the header no matter what I call the bloody thing.

Here's a longshot. Make a copy of the file. Try opening the copy in
Notepad (NOT Wordpad; I think that Wordpad adds a <LF> byte every time
it finds a <CR> byte). You will be able to read much of the header at
the beginning of the file. Delete everything from the beginning of the
file up to and including the word "data". Save and close the file as
"filename.pcm" or "filename.raw". (Save as type: "All Files", or
Notepad will append ".txt" to the filename, and may also add a <CR> to
every <LF> -- I'm not sure.) Now try to open it as a raw pcm file in
Sound Forge.

(Versions of Notepad that came with Windows 9x had a file size limit
that was very small, but a quick check on the Web indicates that Windows
2000 / XP Notepad has no file size limit.)

Good luck,
Greg

[mc]

"P" > wrote in message ...
> Thanks for the suggestion fellas. Nothing has worked. Every player and
> editor still reads the header no matter what I call the bloody thing.

Isn't there a RAW option in Sound Forge?

Or find an undergraduate who is taking a programming course.

[Jürgen Schöpf]

mc schrieb:
> "P" > wrote in message ...
>
>>Thanks for the suggestion fellas. Nothing has worked. Every player and
>>editor still reads the header no matter what I call the bloody thing.
>
>
> Isn't there a RAW option in Sound Forge?
>
> Or find an undergraduate who is taking a programming course.
>
>

.... or try the suggested procedure with Cool Edit instead of SoundForge...

:-J