ALSABAT(1) General Commands Manual ALSABAT(1) (NAME) alsabat - nj ALSA (SYNOPSIS) alsabat [] (DESCRIPTION) ALSABAT(ALSA Basic Audio Tester) . ALSABAT nj nj (PM) . ALSABAT . ALSABAT nj nj. nj (FFT) nj . ALSABAT nj nj ( - standalone) / njnj alsabat nj . / nj nj nj . nj nj nj nj nj . nj nj nj "line in" "line out" . ( combo) nj nj : https://source.android.com/devices/audio/loopback.html tinyalsa nj "--enable-alsabat-backend-tiny" tinyalsa nj (backend) . (OPTIONS) -h, --help : . -D . -P PCM. -C PCM. -f nj (Sample format). nj nj nj : U8 S16_LE S24_3LE S32_LE nj nj . nj : -f cd (16 bit little endian, 44100, stereo) [-f S16_LE -c2 -r44100] -f dat (16 bit little endian, 48000, stereo) [-f S16_LE -c2 -r48000] S16_LE nj. -c nj. nj . . -r nj . nj . nj . -n . nj : . nj nj . 's' nj. nj . -k (Sigma k) . nj WAV nj FFT nj nj nj. nj: threshold = k * standard_deviation + mean_value nj nj (peak) nj nj njnj nj. ALSABAT nj nj . nj . -F . nj . (DC_THRESHOLD, 40% * Sampling rate). -p nj (periods) . --log=# stderr stdout . --file=# WAV . --saveplay=# WAV nj. --local nj . ALSABAT nj. nj nj ALSABAT ALSABAT nj. --standalone ALSABAT . nj nj . ALSABAT libfftw3 . ALSABAT nj "--standalone" nj . --roundtriplatency (Round trip latency). nj. . . --snr-db=# SNR (nj). 26dB nj . SNR ALSABAT nj. --snr-pc=# (). ALSABAT nj. (EXAMPLES) alsabat -P plughw:0,0 -C plughw:0,0 -c 2 -f S32_LE -F 250 S32_LE . alsabat -P plughw:0,0 -C plughw:0,0 --file 500Hz.wav RIFF WAV "500Hz.wav" nj LPCM . (RETURN VALUE) nj. 1001- nj DC 1002- nj 1003- nj. (SEE ALSO) aplay(1) (BUGS) RIFF WAV nj PCM nj. alsa-devel . (AUTHORS) alsabat Liam Girdwood Bernard Gautier Han Lu . Liam Girdwood Han Lu . 20th October 2015 ALSABAT(1)