NAME

       alsa_delay - measure round-trip latency of a soundcard

SYNOPSIS

       alsa_delay playdev captdev fsamp frsize nfrags

DESCRIPTION

       This tool can be used to measure the round-trip latency of a soundcard.  To do this, start
       the program and connect like this:
         alsa_delay -> playdev -> cable from soundcard output to input -> captdev -> alsa_delay

       alsa_delay should be able to measure the round-trip latency with  an  accuracy  of  around
       1/1000  of  a  sample.  The assumption is, that the latency is more or less independent of
       frequency, and that the cable between  soundcard  output  and  input  has  virtually  zero
       latency.

ARGUMENTS

       playdev
              ALSA playback device (e.g.: hw:0)

       captdev
              ALSA capture device (e.g.: hw:0)

       fsamp  Sample rate (e.g.: 48000)

       frsize Period size (e.g.: 256)

       nfrags Number of fragments (e.g.: 2)

EXAMPLES

       This  will  measure  and  display  the  round-trip  latency  of soundcard hw:0 using 48kHz
       samplerate, and 10 fragments each 2048 samples.
         alsa_delay hw:0 hw:0 48000 2048 10

NOTES

       alsa_delay is a port of jack_delay (by the same author) to ALSA.

AUTHOR

       zita-alsa-pcmi was written by Fons Adriaensen <fons@linuxaudio.org>.

       This manual page was written by IOhannes  m  zmoelnig  <zmoelnig@iem.at>  for  the  Debian
       project (but may be used by others).

                                            July 2013                           zita-alsa-pcmi(1)