[alsa-devel] alsa-lib: pcm_plug: fix float conversion for user specified ttable

[Sergey]

June 17 2014 Raymond Yau wrote:

>> Move custom ttable with equal channels case from a separate ttable_last
>> exception into a common plugins insertion loop.
>> Fixes plug with ttable for float pcms (jack, ladspa).
>> Example: aplay -fFLOAT_LE /dev/zero
>> pcm.!default {
>>     type plug
>>     slave.pcm { type null }
>>     ttable.0.0 1
>> }
> 
> Any reason to use type null in your test case since type null seem can
> support all format ?

It was the shortest test to reproduce the bug.

A more restricted config:
# aplay -fFLOAT_LE /dev/zero
pcm.!default {
    type plug
    slave.pcm { type null }
    slave.format FLOAT_LE
    ttable.0.0 1
}
But that test was enough to reproduce "Assertion failed" bug too.

Actually I've hit this bug with a complex ladspa upmixing code:
pcm.upmix {
    type plug
    slave.pcm {
        type ladspa
        slave.pcm {
            type plug
            slave.pcm "..."
            ttable { ... }
        }
        plugins [ ... ]
    }
    ttable { ... }
}
similar to this:
  http://forums.gentoo.org/viewtopic-p-4528619.html#4528619

This bug crashed the application for me (it generates SIGABRT)
so I thought that it should be fixed.

-- 
  Sergey