Subject: Re: [ecasound] edi-18: removal of implicit resampling
From: Bill Allen (ballen_AT_mail.serve.com)
Date: Wed Jan 30 2002 - 12:52:48 EET
I haven't experienced the downside of implicit resampling but invoking
Occam's Razor, the reasoning behind removing it, the subsequent
simplification, plus making resampling explicit all sound like excellent
ideas to me.
Bill
On Wed, 30 Jan 2002, Kai Vehmanen wrote:
> Just came up with a solution candidate for...
>
> (edi-18) Intelligent system for setting the internal sample rate.
>
> What if we just removed implicit resampling altogether? My reasoning
> behind this is:
>
> - current resampling is not high-quality (mostly just causes
> bad pr for ecasound)
> - for any kind of realtime work, resampling should _not_
> be used (wastes cpu-resource for no good reason)
> - only real use for resampling is file format conversions
> - by removing the "resampling_needed()" check we
> make the common code path a little bit faster (although
> not much) and cleaner
> - we avoid problems with unexpected resampling
>
> As a result you could not execute a chainsetup, where sampling rate of
> one or more objects differs from engine's sampling rate.
>
> If this was done, implementation of 'edi-18' would be reduced to:
>
> - find the common sampling rate between audio objects
> - if found: set engine's rate to it
> - else: print an error message
>
> This would also make the -sr option obsolete.
>
> For cases where resampling is needed, a new audio object type could be
> added - something like:
>
> ecasound -f:16,2,44100 -i resample,22050hz_file.wav,44100 -o output.wav
>
> As a bonus, as now resampling would be a special-case operation, we are
> not limited to light resampling algorithms. In practise we could use a
> much more high-quality (=cpu-heavy) alternative (if someone has the time
> to do it).
>
> Comments?
>
>
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