Re: ExtAudioFile 4GB file size limitation on WAV files
Re: ExtAudioFile 4GB file size limitation on WAV files
- Subject: Re: ExtAudioFile 4GB file size limitation on WAV files
- From: Richard Dobson <email@hidden>
- Date: Sat, 30 Apr 2011 18:01:06 +0100
On 30/04/2011 17:34, Paul Davis wrote:
On Sat, Apr 30, 2011 at 10:26 AM, Richard Dobson
<email@hidden> wrote:
Rather
a lot of developers (especially on Linux, for some reason!) think WAVE has a
fixed-length header! So when many people talk about "the WAVE format", a lot
of the time they have in mind a random mashup of incorrect and incomplete
information.
this is one of the reasons why libraries like libsndfile are so
incredibly important.
Agreed.
.
btw, there is nothing in the RIFF/WAVE spec that requires the "fmt "
header to come first. the only chunk that is required to be at the
front is the RIFF header.
Not so - the fmt chunk ~must~ precede the data chunk (but not
necessarily consecutive). That is clearly stated in the original
documentation (look for "riffmci.txt" or similar). That is what ensures
WAVE is a streamable file format - you can stream the file (e.g. through
a pipe, network, etc) and the required format info will always precede
the data. The format that allows chunks in any order is AIFF. And of
course in order to support floating-point samples they had to
define/adapt AIFF-C - there was no means of specifying floats in the
AIFF spec.
But it ~is ~ true that there can be other (non-data) chunks before the
fmt chunk. That is indeed one of the aspects most widely ignored by a
lot of parsers. There is no obvious reason why one would put anything
before the fmt chunk, but in principle it is possible.
Richard Dobson
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