In 2005, xine-lib 1.1.1 added the following change:
xine-lib (1.1.1) 2005-11-15
* Improve sound quality when using alsa 1.0.9 or above.
When playing a 44.1khz stream on a 48khz only capable sound card.
It bypasses alsa-lib resampler and uses xine's
That made sense when Alsa's resampling was the worst thing ever. But now,
if one installs alsa-plugins-1.0.25 and puts this in ~/.asoundrc:
Alsa then does markedly better resampling (using libsamplerate) than
xine-lib (using its own algorithm). The bypass added in 2005 is therefore
preventing the use of a higher-quality algorithm and blocking the ability to
tune that algorithm in ~/.asoundrc, and no longer seems to have any