From: Paul Winkler <pw_lists@xxxxxxxxxx>
Reply-To: A list for linux audio users
<linux-audio-user@xxxxxxxxxxxxxxxxxx>
To: linux-audio-user@xxxxxxxxxxxxxxxxxx
Subject: Re: Stretching with very high accuracy
Date: Thu, 8 Jun 2006 17:42:36 -0400
On Thu, Jun 08, 2006 at 11:15:03PM +0200, Nick Copeland wrote:
> What is the format of the files? Raw audio, WAV, etc? What is the rough
> content - if the signal is constant than sample insertion is not easy
since
> you may not have periods of silence. If the signal does have silent
periods
> then the solution may be a noise gate that inserts samples - this would
be
> all but inaudible. There is no reason why this should not work from file
to
> file with 'cat oldfile | <program> > newfile so should not need to have
the
> lot in memory.
Given the very small amount of drift (53 ms / hour), we're talking about
inserting maybe 1 sample per 30000. I submit that nobody will notice
if you just insert a copy of an adjacent sample, and if you
want better than that, interpolation between two adjacent
samples would be even smoother.
You dont think that there may be issues with sample insertion at regular
locations? They can become noticable as they are cyclic - I tried it with
SLab, and for a while with bristol before deciding it needed resampling.
Perhaps going half way would be to duplicate a sample at zero crossing
rather than during silence. This would be a little more random and hence
less noticable.
Perhaps somebody should just fix sox - its such a cool tool that a fix might
be in order. Is it still maintained? I also thinks sox had a few different
options for resampling (binary/quadrature?), perhaps it just needs a
different option for the algorithm?
Nick
_________________________________________________________________
Express yourself instantly with MSN Messenger! Download today it's FREE!
http://messenger.msn.click-url.com/go/onm00200471ave/direct/01/
