Measure round-trip latency of a soundcard
alsa_delay playdev captdev fsamp frsize nfrags
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.
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)
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
alsa_delay is a port of jack_delay (by the same author) to ALSA.
zita-alsa-pcmi was written by Fons Adriaensen <[email protected]>.
This manual page was written by IOhannes m zmoelnig <[email protected]> for the Debian project (but may be used by others).