Subject: Re: [ecasound] filesize limitations
From: S. Massy (theanaloguekid_AT_tak.net.dhis.org)
Date: Wed Oct 10 2001 - 17:54:19 EEST
On Wed, 10 Oct 2001, Kai Vehmanen <k_AT_eca.cx> wrote:
> A few people have asked me about filesize limitations in ecasound and
> ecawave. At the moment the two closest ones are:
Also, there was this discussion on alsa-user a while back about how
the length is specified in a wave file header. It appears some
programs use unsigned ints thereafter shrinking the maximum size a
wave file might have to something like 1Gb. Sometimes it's
fascinating to see how the computing world has to catch up with its
own progresses; anyway, ecasound handles all lengths with longs,
> 1. Ecasound and ecawave use long ints for storing position_in_samples
> and length_in_samples. On many 32bit platforms long int is 32bit. This
> means that with 44100Hz sample rate, ecasound and ecawave can handle upto
> 13 hours (--> 8GB files). (*)
> 2. As far as I know, ext2 still has the 2GB upper limit for
> filesizes. With cd-quality this means 3 hours of audio. (**)
> 3. ftell(), fseek() and other standard file access routines in glibc also
> use long ints (--> 2GB limit for filesizes with 32bit platforms). There
> are 64bit variants of these functions, but support must be explicitly
> added to ecasound before this helps. (**)
> So for very long recordings, it's better to encode directly to ogg or mp3,
> or split material into multiple files. Of course, upgrading to a 64bit
> platform or possibly a different filesystem also helps.
> (*) Affects all files types.
> (**) Doesn't necessarily affect externally handled file types like
> aif&snd (libaudiofile), ogg, mp3, mikmod-modules, etc.
> Audio software for Linux!
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