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.
ALSA playback device (e.g.: hw:0)
ALSA capture device (e.g.: hw:0)
Sample rate (e.g.: 48000)
Period size (e.g.: 256)
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.