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Re: Re: 2GB limit, changing cards

Subject: Re: Re: 2GB limit, changing cards
From: Derek Holzer <>
Date: Thu, 22 Sep 2005 21:19:07 +0200
Hey Lou,

I correct myself! The max size of a WAV file is 4 GB (not 2 GB), and
this is due to the nature of the file spec itself. WAV uses a 32 bit
signed interger for its chunk size fields, and that limits the actual
size of the file as it can be described in the header.

However--many programs, especially on windoze, do not parse this
information properly and can only deal with 2 GB file sizes. So actually
the applications are often the bottleneck.

What applies to bit-depth in terms of sound resolution can also apply to
file length as represented in the header. Thus a 64 bit file can be
exponentially longer as well as have a higher dynamic range, so long as
the spec allows for it (WAV does not). W64 and AU format files use this
format, and are not subject to the 4 GB size limitation. Some docs in
case you're bored ;-)

http://mail.python.org/pipermail/python-dev/2005-July/054677.html

http://ccrma.stanford.edu/courses/422/projects/WaveFormat/
http://www.sonicspot.com/guide/wavefiles.html
http://www.borg.com/~jglatt/tech/wave.htm

Deepest apologies to those who find this kind of chat offensive ;-)
derek


Lou Judson wrote:
> I once did a four channel recording on my 744T in "poly" mode, and it
> made four channnel interleaved files of 3.8 gig each. I ended up
> transferring it realtime with two tracks going in analog, 2 digital to
> Protools - though the next day I found Audacity would open and export
> them as mono files. Had to learn the hard way.
>
> But it was the machine being set for 4 G files limit, not the Wav
> format that determined the size in this case.
>
> Lou
> On Sep 21, 2005, at 6:13 AM, Derek Holzer wrote:
>
>
>>The limitation is in the file format, AFAIK. You simply cannot create a
>>WAV file over a certain size, or it will be unreadable. Most HD
>>recorders handle this by automatically starting a new file once the
>>size limit is reached, and you can seamlessly splice them later (the
>>endpoint samples match up).
>>
>>The other way around the size limit is to use the newer w64 file
>>format,
>>although I'm not sure how many commercial DAW applications handle it. I
>>know Ardour does:
>>
>>http://ardour.org
>>
>>But it's still a bit rough around the edges.
>>
>>best,
>>d.

--
derek holzer ::: http://www.umatic.nl
---Oblique Strategy # 41:
"Define an area as `safe' and use it as an anchor"


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