[Pkg-alsa-devel] Bug#277542: libasound2: better resampling methods for rate plugin

[Tobias Diedrich]

Package: libasound2
Version: 1.0.6-3
Severity: wishlist
Tags: upstream

As far as I understand it all resampling in alsa is done by the rate
plugin, which is automatically inserted by "plug" into the processing
chain.  I recently started playing with dmix and noticed audible
resampling artifacts when using it.  Now dmix itself can only be
configured to a fixed rate, so I assume that if the client application
(e.g. mplayer) requests a different rate, rate will be used to resample.

The sourcecode suggests that it is currently implementing only linear
interpolation, but polyphase and bandlimited methods are planned
(Although IMHO the artifacts sound more like nearest neighbour
resampling to me, Maybe because it was downsampling from 48000Hz to
44100Hz.  So it might be sufficient to improve the downsampler).

-- System Information:
Debian Release: 3.1
  APT prefers unstable
  APT policy: (3000, 'unstable')
Architecture: i386 (i686)
Kernel: Linux 2.6.8.1-ruby
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8

Versions of packages libasound2 depends on:
ii  libc6                       2.3.2.ds1-18 GNU C Library: Shared libraries an

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