Hello. I needed a tool to test if anything loud is playing right now. So I wrote "ahwmon" - alsa hw monitoring tool. It's based on dmix idea: it gets "hw" shared playback buffer, but reads from the buffer instead of writing. Code is mostly copied from alsa-lib, but it uses kernel /dev/snd/pcm* files directly and doesn't depend on alsa-lib or dmix. May work for other apps playing to "hw", including pulseaudio and jackd. What do you think about it? Can something like this get into alsa-lib or alsa-utils or alsa-plugins? It could be a capture side of "dmix" plugin, which has no capture now. Maybe someone with strong dmix knowledge can port it to dmix? Build: gcc -o ahwmon ahwmon.c Usage: ./ahwmon [-v] [-v] <card_index> <device_index> [<subdevice_index>] subdevice 0 is used by default it outputs .wav stream to stdout Use cases: * Card VUmeter: ./ahwmon 0 0 | aplay -V stereo -D null * Dump what you hear: ./ahwmon 0 0 > audiodump.wav * Duplicate output of one card to another: ./ahwmon 0 0 | aplay -D plughw:1,0 * Stream what you hear to another pc: ./ahwmon 0 0 | nc 192.168.1.10 12345 Known limitations: * supports S16_LE and S32_LE only. * breaks clients attempting to close and reopen "hw" Any ideas are welcome! -- Sergey
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