最終更新:2026-04-14 (火) 07:49:26 (33d)
alsaloop
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command-line PCM loopback
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Usage: alsaloop [OPTION]... -h,--help help -g,--config configuration file (one line = one job specified) -d,--daemonize daemonize the main process and use syslog for errors -P,--pdevice playback device -C,--cdevice capture device -X,--pctl playback ctl device -Y,--cctl capture ctl device -l,--latency requested latency in frames -t,--tlatency requested latency in usec (1/1000000sec) -f,--format sample format -c,--channels channels -r,--rate rate -n,--resample resample in alsa-lib -A,--samplerate use converter (0=sincbest,1=sincmedium,2=sincfastest, 3=zerohold,4=linear) -B,--buffer buffer size in frames -E,--period period size in frames -s,--seconds duration of loop in seconds -b,--nblock non-block mode (very early process wakeup) -S,--sync sync mode(0=none,1=simple,2=captshift,3=playshift,4=samplerate, 5=auto) -a,--slave stream parameters slave mode (0=auto, 1=on, 2=off) -T,--thread thread number (-1 = create unique) -m,--mixer redirect mixer, argument is: SRC_SLAVE_ID(PLAYBACK)[@DST_SLAVE_ID(CAPTURE)] -O,--ossmixer rescan and redirect oss mixer, argument is: ALSA_ID@OSS_ID (for example: "Master@VOLUME") -e,--effect apply an effect (bandpass filter sweep) -v,--verbose verbose mode (more -v means more verbose) -w,--workaround use workaround (serialopen) -U,--xrun xrun profiling -W,--wake process wake timeout in ms -z,--syslog use syslog for errors Recognized sample formats are: S8 U8 S16_LE S16_BE U16_LE U16_BE S24_LE S24_BE U24_LE U24_BE S32_LE S32_BE U32_LE U32_BE FLOAT_LE FLOAT_BE FLOAT64_LE FLOAT64_BE IEC958_SUBFRAME_LE IEC958_SUBFRAME_BE MU_LAW A_LAW IMA_ADPCM MPEG GSM S20_LE S20_BE U20_LE U20_BE SPECIAL S24_3LE S24_3BE U24_3LE U24_3BE S20_3LE S20_3BE U20_3LE U20_3BE S18_3LE S18_3BE U18_3LE U18_3BE G723_24 G723_24_1B G723_40 G723_40_1B DSD_U8 DSD_U16_LE DSD_U32_LE DSD_U16_BE Tip #1 (usable 500ms latency, good CPU usage, superb xrun prevention): alsaloop -t 500000 Tip #2 (superb 1ms latency, but heavy CPU usage): alsaloop -t 1000
