Channel distortion when converting S16_LE -> S32_LE ('plug' plugin)

alsa-project/alsa-lib issue #195 was opened from dh1dm:

When using a Terretec EWX2496 (ICE1712) a sample format conversion is required in some cases as S32_LE is the only supported format. This can be done by using the 'plug' plugin (e.g. 'plughw:0,0'). However, the left audio channel is distorted in a varying intensity, it sounds like a resolution loss in the lower bits. Applications with native S32_LE support (e.g. Audacity) do not show this effect. I'd suppose that the responsible code is in 'alsa-lib/src/pcm/pcm_plug.c', but up to now I could not track down this issue.

Issue URL : https://github.com/alsa-project/alsa-lib/issues/195 Repository URL: https://github.com/alsa-project/alsa-lib