[alsa-devel] [PATCH] Bugfix: Fix resampling when client and slave both use format float

[Takashi Iwai]

At Mon, 24 Feb 2014 14:19:15 +0100,
Takashi Iwai wrote:
> 
> > It would be easy to replace those functions with
> > pcm_src_convert_float (both resampler libraries have functions that take
> > float directly), but that will break the plugin ABI. Is that acceptable?
> > The same would have to be done for the channel remapping (route
> > conversion) plugin.
> 
> It's fine as long as the plugin is backward compatible.
> That is, pcm_rate.c checks the plugin version and uses the new ops
> only for objects advertising the newer version.  See pcm_extplug.c.
> There are some codes checking version numbers.

Looking at the code again, the PCM rate plugin version checks are done
slightly differently from ext-plugin or io-plugin; it's rather done in
the plugin side.  pcm_rate.c repeats to trying to hook a plugin until
it matches by degrading the version.  In the plugin side, it provides
additional ops depending on the version it's asked. 


Takashi