Subject: [ecasound] edi-18: removal of implicit resampling
From: Kai Vehmanen (kai.vehmanen_AT_wakkanet.fi)
Date: Wed Jan 30 2002 - 01:34:35 EET
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).
-- http://www.eca.cx Audio software for Linux!
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