Pass some state to convert and channelmix functions. This makes it
possible to select per channel optimized convert functions but
also makes it possible to implement noise shaping later.
Pass the channelmix matrix and volume in the state.
Handle specialized 2 channel s16 -> f32 conversion
Add some const and SPA_RESTRICT to methods
When the input and output is the same, work in passthrough mode
where we simply copy place the input pointer onto the output buffer
without doing a memcpy.
Do memcpy when the resampler is not active.
Improve the allocators to always align the buffer memory to the
requested alignment
Use aligned read and writes for sse functions and check alignment,
optionally falling back to unaligned path.
Add more tests and benchmark cases
Check and warn for misaligned memory in plugins.
Make special format types for planar and interleaved instead of
having a field.
Add enum for audio channel positions
Add some default audio channel layouts
Place the channel layout in the audio format when possible
alsa: place audio channel positions in format
Add sse optimized channel mixing for some common cases
Remove name from port info, it's not mandatory and in the properties
Add direction to port info
Implement audioconvert as a complex element of fmtconver,
channelmix and resample.
Make copying resample just to test.
Plug the converter into pw_stream.
