OrazioPirataDelloSpazio (Lorenzo) wrote: > Hi all, > I need to use a microphone input as a trigger. In other words my idea is > to connect a switch to the microphone input. In this way, when the > switch is turned on it generates a spike in the captured track. > I would like to create a program that trigger an event every spike it > receives.
one option is to rip some code from a ladspa gate plugin and use that to create a software event. or you could use a midi trigger and receive a midi event. > I succeed in capturing the mic input through a simple program that uses > alsa driver, but I don't know how to "parse" the raw data to search for > the spikes. Any hints? the easiest approach is to rms the data to get loudness information, and then generate an event if a certain threshold is reached. further refinements could be variable attack and hold times and a bandpass to filter out unwanted noise. take a look at any noise gate implementation. > Second question: on a "full duplex" sound card, can I capture at 8 bit, > mono, 22.050 bit/s , and on the same time playback at 16 bit, stereo, > 44.100 ? generally, no. but you can capture at 16bit/44k1. afterwards it is a trivial operation to resample and decimate if necessary. -- jörn nettingsmeier home://germany/45128 essen/lortzingstr. 11/ http://spunk.dnsalias.org phone://+49/201/491621 Kurt is up in Heaven now. _______________________________________________ Linux-audio-dev mailing list [email protected] http://lists.linuxaudio.org/mailman/listinfo/linux-audio-dev
