ref: d8c8e7b910b05f6e13d4ffb5baa634b13d06afaa
dir: /src/silence.c/
/* * silence - effect to detect periods of silence in audio data and * use this to clip data before and after. * * Written by Chris Bagwell (cbagwell@sprynet.com) - January 10, 1999 * * Copyright 1999 Chris Bagwell And Sundry Contributors * This source code is freely redistributable and may be used for * any purpose. This copyright notice must be maintained. * Chris Bagwell And Sundry Contributors are not responsible for * the consequences of using this software. */ #include "st.h" /* Private data for SKEL file */ typedef struct silencestuff { int threshold; int threshold_length; int threshold_count; int begin; int begin_skip; int begin_count; int end; int end_skip; int end_count; } *silenc_t; /* * Process options * * Don't do initialization now. * The 'info' fields are not yet filled in. */ void silence_getopts(effp, n, argv) eff_t effp; int n; char **argv; { if (n) fail("Silence effect takes no options."); } /* * Prepare processing. * Do all initializations. */ silence_start(effp) eff_t effp; { silence_t silence = (silence_t) effp->priv; silence.threshold = 5; silence.thres_length = 1000; silence.thres_count = 0; silence.begin = silence.end = 0; silence.begin_skip = silence.end_skip = 0; silence.begin_count = silence.end_count = 0; } /* * Processed signed long samples from ibuf to obuf. * Return number of samples processed. */ void silence_flow(effp, ibuf, obuf, isamp, osamp) eff_t effp; LONG *ibuf, *obuf; LONG *isamp, *osamp; { silence_t silence = (silence_t) effp->priv; int len, done; len = ((*isamp > *osamp) ? *osamp : *isamp); for(done = 0; done < len; done++) { if (silence.threshold_count >= silence.threshold_length) { if no more samples break get a sample l = sample converted to signed long *buf++ = l; } *isamp = *osamp = } /* * Drain out remaining samples if the effect generates any. */ void skel_drain(effp, obuf, osamp) LONG *obuf; LONG *osamp; { *osamp = 0; } /* * Do anything required when you stop reading samples. * (free allocated memory, etc.) */ void skel_stop(effp) eff_t effp; { /* nothing to do */ }