Thread: help ALSA

os ubuntu 12.10
works: arecord, aplay, audacity, solfege---these work!
developer installed: furthermore, found source , can build aplay.

i'm struggling alsa docs write application visualize sound. pcm data reading pipe arecord . on loaded computer @ high data rate program lags miserably. use memory map directly libasound. failing i'd example command line arecord --mmap , including commands set mapped file.

assume alsa cyclically write map without checking see if data read. use data on schedule. application needs run small lag, , capture high frequencies. losing contiguous chunks of data ok long can capture of data in contiguous chunks.

code in post 3 of thread
http://forums.devshed.com/python-pro...rs-926301.html
after program designed plan write in compiled language.

also, what, please, devices in /dev/snd ? sound devices seem different ubuntu release of 2010.
controlc0
controlc29
hwc0d0
pcmc0d0c
pcmc0d0p
pcmc0d1p
seq
timer

appreciate time , guidance,
dave.

ps. see pulse audio , jack may options. haven't understood these, either.


update, maybe --mmap doesn't work yet?

$ alsa-utils-1.0.26.6.gf2826/aplay/arecord --mmap /tmp/buffer'
recording wave '/tmp/buffer' : unsigned 8 bit, rate 8000 hz, mono
arecord: set_params:1192: access type not available

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