[pulseaudio-discuss] Pulseaudio Mixing & DSP Mixing

tieg tie.ge at access-company.com
Tue Dec 22 22:04:36 PST 2009

Many people has ever suspect on pulseaudio software mixing. If you have
hardware mixing why using software mixing. Lennart argue that "hardware
mixing is a thing of the past, modern soundcards don't do it anymore",
and modern CPU with necessary SIMD commands is the trend to solve mixing
performance issue.

Now I'd like to discuss the mixing issue in DSP area. I have the
background of working with TI OMAP 3430, which is a high level handset
device platform. On this platform, TI provide a DASF (DSP Audio System
Framework) solution. DASF support multiple stream encoder/decoder,
resample, mixing and volume control for each stream. All these work can
be done with DSP core. TI OMAP3430 has two core: one is general ARM
core, the other is DSP core.

Recently, I am considering to port pulseaudio to TI OMAP 3430. However,
pulseaudio framework does not take DSP solution into consideration. It
is trouble for me to decide mixing with DSP or pulseaudio. If with DSP,
pulseaudio seems nonsense. If with pulseaudio, the DSP potential can not
be fully used, and there will be performance issue.

Does any one encounter the same situation as me? Any suggestion or idea
is welcome!


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