/* Silence effect for SoX * by Heikki Leinonen (heilei@iki.fi) 25.03.2001 * Major Modifications by Chris Bagwell 06.08.2001 * Minor addition by Donnie Smith 13.08.2003 * * This effect can delete samples from the start of a sound file * until it sees a specified count of samples exceed a given threshold * (any of the channels). * This effect can also delete samples from the end of a sound file * when it sees a specified count of samples below a given threshold * (all channels). * It may also be used to delete samples anywhere in a sound file. * Thesholds can be given as either a percentage or in decibels. */ #include "sox_i.h" #include <string.h> /* Private data for silence effect. */ #define SILENCE_TRIM 0#define SILENCE_TRIM_FLUSH 1#define SILENCE_COPY 2#define SILENCE_COPY_FLUSH 3#define SILENCE_STOP 4 typedef struct { char start; int start_periods; char *start_duration_str; size_t start_duration; double start_threshold; char start_unit; /* "d" for decibels or "%" for percent. */ int restart; sox_sample_t *start_holdoff; size_t start_holdoff_offset; size_t start_holdoff_end; int start_found_periods; char stop; int stop_periods; char *stop_duration_str; size_t stop_duration; double stop_threshold; char stop_unit; sox_sample_t *stop_holdoff; size_t stop_holdoff_offset; size_t stop_holdoff_end; int stop_found_periods; double *window; double *window_current; double *window_end; size_t window_size; double rms_sum; char leave_silence; /* State Machine */ char mode;} priv_t; static void clear_rms(sox_effect_t * effp) { priv_t * silence = (priv_t *) effp->priv; memset(silence->window, 0, silence->window_size * sizeof(double)); silence->window_current = silence->window; silence->window_end = silence->window + silence->window_size; silence->rms_sum = 0;} static int sox_silence_getopts(sox_effect_t * effp, int argc, char **argv){ priv_t * silence = (priv_t *) effp->priv; int parse_count; uint64_t temp; const char *n; --argc, ++argv; /* check for option switches */ silence->leave_silence = sox_false; if (argc > 0) { if (!strcmp("-l", *argv)) { argc--; argv++; silence->leave_silence = sox_true; } } if (argc < 1) return lsx_usage(effp); /* Parse data related to trimming front side */ silence->start = sox_false; if (sscanf(argv[0], "%d", &silence->start_periods) != 1) return lsx_usage(effp); if (silence->start_periods < 0) { lsx_fail("Periods must not be negative"); return(SOX_EOF); } argv++; argc--; if (silence->start_periods > 0) { silence->start = sox_true; if (argc < 2) return lsx_usage(effp); /* We do not know the sample rate so we can not fully * parse the duration info yet. So save argument off * for future processing. */ silence->start_duration_str = lsx_strdup(argv[0]); /* Perform a fake parse to do error checking */ n = lsx_parsesamples(0.,silence->start_duration_str,&temp,'s'); if (!n || *n) return lsx_usage(effp); silence->start_duration = temp; parse_count = sscanf(argv[1], "%lf%c", &silence->start_threshold, &silence->start_unit); if (parse_count < 1) return lsx_usage(effp); else if (parse_count < 2) silence->start_unit = '%'; argv++; argv++; argc--; argc--; } silence->stop = sox_false; /* Parse data needed for trimming of backside */ if (argc > 0) { if (argc < 3) return lsx_usage(effp); if (sscanf(argv[0], "%d", &silence->stop_periods) != 1) return lsx_usage(effp); if (silence->stop_periods < 0) { silence->stop_periods = -silence->stop_periods; silence->restart = 1; } else silence->restart = 0; silence->stop = sox_true; argv++; argc--; /* We do not know the sample rate so we can not fully * parse the duration info yet. So save argument off * for future processing. */ silence->stop_duration_str = lsx_strdup(argv[0]); /* Perform a fake parse to do error checking */ n = lsx_parsesamples(0.,silence->stop_duration_str,&temp,'s'); if (!n || *n) return lsx_usage(effp); silence->stop_duration = temp; parse_count = sscanf(argv[1], "%lf%c", &silence->stop_threshold, &silence->stop_unit); if (parse_count < 1) return lsx_usage(effp); else if (parse_count < 2) silence->stop_unit = '%'; argv++; argv++; argc--; argc--; USED(argv); USED(argc); } /* Error checking */ if (silence->start) { if ((silence->start_unit != '%') && (silence->start_unit != 'd')) { lsx_fail("Invalid unit specified"); return lsx_usage(effp); } if ((silence->start_unit == '%') && ((silence->start_threshold < 0.0) || (silence->start_threshold > 100.0))) { lsx_fail("silence threshold should be between 0.0 and 100.0 %%"); return (SOX_EOF); } if ((silence->start_unit == 'd') && (silence->start_threshold >= 0.0)) { lsx_fail("silence threshold should be less than 0.0 dB"); return(SOX_EOF); } } if (silence->stop) { if ((silence->stop_unit != '%') && (silence->stop_unit != 'd')) { lsx_fail("Invalid unit specified"); return(SOX_EOF); } if ((silence->stop_unit == '%') && ((silence->stop_threshold < 0.0) || (silence->stop_threshold > 100.0))) { lsx_fail("silence threshold should be between 0.0 and 100.0 %%"); return (SOX_EOF); } if ((silence->stop_unit == 'd') && (silence->stop_threshold >= 0.0)) { lsx_fail("silence threshold should be less than 0.0 dB"); return(SOX_EOF); } } return(SOX_SUCCESS);} static int sox_silence_start(sox_effect_t * effp){ priv_t *silence = (priv_t *)effp->priv; uint64_t temp; /* When you want to remove silence, small window sizes are * better or else RMS will look like non-silence at * aburpt changes from load to silence. */ silence->window_size = (effp->in_signal.rate / 50) * effp->in_signal.channels; silence->window = lsx_malloc(silence->window_size * sizeof(double)); clear_rms(effp); /* Now that we know sample rate, reparse duration. */ if (silence->start) { if (lsx_parsesamples(effp->in_signal.rate, silence->start_duration_str, &temp, 's') == NULL) return lsx_usage(effp); silence->start_duration = temp * effp->in_signal.channels; } if (silence->stop) { if (lsx_parsesamples(effp->in_signal.rate,silence->stop_duration_str, &temp,'s') == NULL) return lsx_usage(effp); silence->stop_duration = temp * effp->in_signal.channels; } if (silence->start) silence->mode = SILENCE_TRIM; else silence->mode = SILENCE_COPY; silence->start_holdoff = lsx_malloc(sizeof(sox_sample_t)*silence->start_duration); silence->start_holdoff_offset = 0; silence->start_holdoff_end = 0; silence->start_found_periods = 0; silence->stop_holdoff = lsx_malloc(sizeof(sox_sample_t)*silence->stop_duration); silence->stop_holdoff_offset = 0; silence->stop_holdoff_end = 0; silence->stop_found_periods = 0; effp->out_signal.length = SOX_UNKNOWN_LEN; /* depends on input data */ return(SOX_SUCCESS);} static sox_bool aboveThreshold(sox_effect_t const * effp, sox_sample_t value /* >= 0 */, double threshold, int unit){ /* When scaling low bit data, noise values got scaled way up */ /* Only consider the original bits when looking for silence */ sox_sample_t masked_value = value & (-1 << (32 - effp->in_signal.precision)); double scaled_value = (double)masked_value / SOX_SAMPLE_MAX; if (unit == '%') scaled_value *= 100; else if (unit == 'd') scaled_value = linear_to_dB(scaled_value); return scaled_value > threshold;} static sox_sample_t compute_rms(sox_effect_t * effp, sox_sample_t sample){ priv_t * silence = (priv_t *) effp->priv; double new_sum; sox_sample_t rms; new_sum = silence->rms_sum; new_sum -= *silence->window_current; new_sum += ((double)sample * (double)sample); rms = sqrt(new_sum / silence->window_size); return (rms);} static void update_rms(sox_effect_t * effp, sox_sample_t sample){ priv_t * silence = (priv_t *) effp->priv; silence->rms_sum -= *silence->window_current; *silence->window_current = ((double)sample * (double)sample); silence->rms_sum += *silence->window_current; silence->window_current++; if (silence->window_current >= silence->window_end) silence->window_current = silence->window;} /* Process signed long samples from ibuf to obuf. *//* Return number of samples processed in isamp and osamp. */static int sox_silence_flow(sox_effect_t * effp, const sox_sample_t *ibuf, sox_sample_t *obuf, size_t *isamp, size_t *osamp){ priv_t * silence = (priv_t *) effp->priv; int threshold; size_t i, j; size_t nrOfTicks, /* sometimes wide, sometimes non-wide samples */ nrOfInSamplesRead, nrOfOutSamplesWritten; /* non-wide samples */ nrOfInSamplesRead = 0; nrOfOutSamplesWritten = 0; switch (silence->mode) { case SILENCE_TRIM: /* Reads and discards all input data until it detects a * sample that is above the specified threshold. Turns on * copy mode when detected. * Need to make sure and copy input in groups of "channels" to * prevent getting buffers out of sync. * nrOfTicks counts wide samples here. */silence_trim: nrOfTicks = min((*isamp-nrOfInSamplesRead), (*osamp-nrOfOutSamplesWritten)) / effp->in_signal.channels; for(i = 0; i < nrOfTicks; i++) { threshold = 0; for (j = 0; j < effp->in_signal.channels; j++) { threshold |= aboveThreshold(effp, compute_rms(effp, ibuf[j]), silence->start_threshold, silence->start_unit); } if (threshold) { /* Add to holdoff buffer */ for (j = 0; j < effp->in_signal.channels; j++) { update_rms(effp, *ibuf); silence->start_holdoff[ silence->start_holdoff_end++] = *ibuf++; nrOfInSamplesRead++; } if (silence->start_holdoff_end >= silence->start_duration) { if (++silence->start_found_periods >= silence->start_periods) { silence->mode = SILENCE_TRIM_FLUSH; goto silence_trim_flush; } /* Trash holdoff buffer since its not * needed. Start looking again. */ silence->start_holdoff_offset = 0; silence->start_holdoff_end = 0; } } else /* !above Threshold */ { silence->start_holdoff_end = 0; for (j = 0; j < effp->in_signal.channels; j++) { update_rms(effp, ibuf[j]); } ibuf += effp->in_signal.channels; nrOfInSamplesRead += effp->in_signal.channels; } } /* for nrOfTicks */ break; case SILENCE_TRIM_FLUSH: /* nrOfTicks counts non-wide samples here. */silence_trim_flush: nrOfTicks = min((silence->start_holdoff_end - silence->start_holdoff_offset), (*osamp-nrOfOutSamplesWritten)); nrOfTicks -= nrOfTicks % effp->in_signal.channels; for(i = 0; i < nrOfTicks; i++) { *obuf++ = silence->start_holdoff[silence->start_holdoff_offset++]; nrOfOutSamplesWritten++; } /* If fully drained holdoff then switch to copy mode */ if (silence->start_holdoff_offset == silence->start_holdoff_end) { silence->start_holdoff_offset = 0; silence->start_holdoff_end = 0; silence->mode = SILENCE_COPY; goto silence_copy; } break; case SILENCE_COPY: /* Attempts to copy samples into output buffer. * * Case B: * If not looking for silence to terminate copy then * blindly copy data into output buffer. * * Case A: * * Case 1a: * If previous silence was detect then see if input sample is * above threshold. If found then flush out hold off buffer * and copy over to output buffer. * * Case 1b: * If no previous silence detect then see if input sample * is above threshold. If found then copy directly * to output buffer. * * Case 2: * If not above threshold then silence is detect so * store in hold off buffer and do not write to output * buffer. Even though it wasn't put in output * buffer, inform user that input was consumed. * * If hold off buffer is full after this then stop * copying data and discard data in hold off buffer. * * Special leave_silence logic: * * During this mode, go ahead and copy input * samples to output buffer instead of holdoff buffer * Then also short ciruit any flushes that would occur * when non-silence is detect since samples were already * copied. This has the effect of always leaving * holdoff[] amount of silence but deleting any * beyond that amount. * * nrOfTicks counts wide samples here. */silence_copy: nrOfTicks = min((*isamp-nrOfInSamplesRead), (*osamp-nrOfOutSamplesWritten)) / effp->in_signal.channels; if (silence->stop) { /* Case A */ for(i = 0; i < nrOfTicks; i++) { threshold = 1; for (j = 0; j < effp->in_signal.channels; j++) { threshold &= aboveThreshold(effp, compute_rms(effp, ibuf[j]), silence->stop_threshold, silence->stop_unit); } /* Case 1a * If above threshold, check to see if we where holding * off previously. If so then flush this buffer. * We haven't incremented any pointers yet so nothing * is lost. * * If user wants to leave_silence, then we * were already copying the data and so no * need to flush the old data. Just resume * copying as if we were not holding off. */ if (threshold && silence->stop_holdoff_end && !silence->leave_silence) { silence->mode = SILENCE_COPY_FLUSH; goto silence_copy_flush; } /* Case 1b */ else if (threshold) {Lines 1–500 of 691. Load more
/* Silence effect for SoX * by Heikki Leinonen (heilei@iki.fi) 25.03.2001 * Major Modifications by Chris Bagwell 06.08.2001 * Minor addition by Donnie Smith 13.08.2003 * * This effect can delete samples from the start of a sound file * until it sees a specified count of samples exceed a given threshold * (any of the channels). * This effect can also delete samples from the end of a sound file * when it sees a specified count of samples below a given threshold * (all channels). * It may also be used to delete samples anywhere in a sound file. * Thesholds can be given as either a percentage or in decibels. */ #include "sox_i.h" #include <string.h> /* Private data for silence effect. */ #define SILENCE_TRIM 0 #define SILENCE_TRIM_FLUSH 1 #define SILENCE_COPY 2 #define SILENCE_COPY_FLUSH 3 #define SILENCE_STOP 4 typedef struct { char start; int start_periods; char *start_duration_str; size_t start_duration; double start_threshold; char start_unit; /* "d" for decibels or "%" for percent. */ int restart; sox_sample_t *start_holdoff; size_t start_holdoff_offset; size_t start_holdoff_end; int start_found_periods; char stop; int stop_periods; char *stop_duration_str; size_t stop_duration; double stop_threshold; char stop_unit; sox_sample_t *stop_holdoff; size_t stop_holdoff_offset; size_t stop_holdoff_end; int stop_found_periods; double *window; double *window_current; double *window_end; size_t window_size; double rms_sum; char leave_silence; /* State Machine */ char mode; } priv_t; static void clear_rms(sox_effect_t * effp) { priv_t * silence = (priv_t *) effp->priv; memset(silence->window, 0, silence->window_size * sizeof(double)); silence->window_current = silence->window; silence->window_end = silence->window + silence->window_size; silence->rms_sum = 0; } static int sox_silence_getopts(sox_effect_t * effp, int argc, char **argv) { priv_t * silence = (priv_t *) effp->priv; int parse_count; uint64_t temp; const char *n; --argc, ++argv; /* check for option switches */ silence->leave_silence = sox_false; if (argc > 0) { if (!strcmp("-l", *argv)) { argc--; argv++; silence->leave_silence = sox_true; } } if (argc < 1) return lsx_usage(effp); /* Parse data related to trimming front side */ silence->start = sox_false; if (sscanf(argv[0], "%d", &silence->start_periods) != 1) return lsx_usage(effp); if (silence->start_periods < 0) { lsx_fail("Periods must not be negative"); return(SOX_EOF); } argv++; argc--; if (silence->start_periods > 0) { silence->start = sox_true; if (argc < 2) return lsx_usage(effp); /* We do not know the sample rate so we can not fully * parse the duration info yet. So save argument off * for future processing. */ silence->start_duration_str = lsx_strdup(argv[0]); /* Perform a fake parse to do error checking */ n = lsx_parsesamples(0.,silence->start_duration_str,&temp,'s'); if (!n || *n) return lsx_usage(effp); silence->start_duration = temp; parse_count = sscanf(argv[1], "%lf%c", &silence->start_threshold, &silence->start_unit); if (parse_count < 1) return lsx_usage(effp); else if (parse_count < 2) silence->start_unit = '%'; argv++; argv++; argc--; argc--; } silence->stop = sox_false; /* Parse data needed for trimming of backside */ if (argc > 0) { if (argc < 3) return lsx_usage(effp); if (sscanf(argv[0], "%d", &silence->stop_periods) != 1) return lsx_usage(effp); if (silence->stop_periods < 0) { silence->stop_periods = -silence->stop_periods; silence->restart = 1; } else silence->restart = 0; silence->stop = sox_true; argv++; argc--; /* We do not know the sample rate so we can not fully * parse the duration info yet. So save argument off * for future processing. */ silence->stop_duration_str = lsx_strdup(argv[0]); /* Perform a fake parse to do error checking */ n = lsx_parsesamples(0.,silence->stop_duration_str,&temp,'s'); if (!n || *n) return lsx_usage(effp); silence->stop_duration = temp; parse_count = sscanf(argv[1], "%lf%c", &silence->stop_threshold, &silence->stop_unit); if (parse_count < 1) return lsx_usage(effp); else if (parse_count < 2) silence->stop_unit = '%'; argv++; argv++; argc--; argc--; USED(argv); USED(argc); } /* Error checking */ if (silence->start) { if ((silence->start_unit != '%') && (silence->start_unit != 'd')) { lsx_fail("Invalid unit specified"); return lsx_usage(effp); } if ((silence->start_unit == '%') && ((silence->start_threshold < 0.0) || (silence->start_threshold > 100.0))) { lsx_fail("silence threshold should be between 0.0 and 100.0 %%"); return (SOX_EOF); } if ((silence->start_unit == 'd') && (silence->start_threshold >= 0.0)) { lsx_fail("silence threshold should be less than 0.0 dB"); return(SOX_EOF); } } if (silence->stop) { if ((silence->stop_unit != '%') && (silence->stop_unit != 'd')) { lsx_fail("Invalid unit specified"); return(SOX_EOF); } if ((silence->stop_unit == '%') && ((silence->stop_threshold < 0.0) || (silence->stop_threshold > 100.0))) { lsx_fail("silence threshold should be between 0.0 and 100.0 %%"); return (SOX_EOF); } if ((silence->stop_unit == 'd') && (silence->stop_threshold >= 0.0)) { lsx_fail("silence threshold should be less than 0.0 dB"); return(SOX_EOF); } } return(SOX_SUCCESS); } static int sox_silence_start(sox_effect_t * effp) { priv_t *silence = (priv_t *)effp->priv; uint64_t temp; /* When you want to remove silence, small window sizes are * better or else RMS will look like non-silence at * aburpt changes from load to silence. */ silence->window_size = (effp->in_signal.rate / 50) * effp->in_signal.channels; silence->window = lsx_malloc(silence->window_size * sizeof(double)); clear_rms(effp); /* Now that we know sample rate, reparse duration. */ if (silence->start) { if (lsx_parsesamples(effp->in_signal.rate, silence->start_duration_str, &temp, 's') == NULL) return lsx_usage(effp); silence->start_duration = temp * effp->in_signal.channels; } if (silence->stop) { if (lsx_parsesamples(effp->in_signal.rate,silence->stop_duration_str, &temp,'s') == NULL) return lsx_usage(effp); silence->stop_duration = temp * effp->in_signal.channels; } if (silence->start) silence->mode = SILENCE_TRIM; else silence->mode = SILENCE_COPY; silence->start_holdoff = lsx_malloc(sizeof(sox_sample_t)*silence->start_duration); silence->start_holdoff_offset = 0; silence->start_holdoff_end = 0; silence->start_found_periods = 0; silence->stop_holdoff = lsx_malloc(sizeof(sox_sample_t)*silence->stop_duration); silence->stop_holdoff_offset = 0; silence->stop_holdoff_end = 0; silence->stop_found_periods = 0; effp->out_signal.length = SOX_UNKNOWN_LEN; /* depends on input data */ return(SOX_SUCCESS); } static sox_bool aboveThreshold(sox_effect_t const * effp, sox_sample_t value /* >= 0 */, double threshold, int unit) { /* When scaling low bit data, noise values got scaled way up */ /* Only consider the original bits when looking for silence */ sox_sample_t masked_value = value & (-1 << (32 - effp->in_signal.precision)); double scaled_value = (double)masked_value / SOX_SAMPLE_MAX; if (unit == '%') scaled_value *= 100; else if (unit == 'd') scaled_value = linear_to_dB(scaled_value); return scaled_value > threshold; } static sox_sample_t compute_rms(sox_effect_t * effp, sox_sample_t sample) { priv_t * silence = (priv_t *) effp->priv; double new_sum; sox_sample_t rms; new_sum = silence->rms_sum; new_sum -= *silence->window_current; new_sum += ((double)sample * (double)sample); rms = sqrt(new_sum / silence->window_size); return (rms); } static void update_rms(sox_effect_t * effp, sox_sample_t sample) { priv_t * silence = (priv_t *) effp->priv; silence->rms_sum -= *silence->window_current; *silence->window_current = ((double)sample * (double)sample); silence->rms_sum += *silence->window_current; silence->window_current++; if (silence->window_current >= silence->window_end) silence->window_current = silence->window; } /* Process signed long samples from ibuf to obuf. */ /* Return number of samples processed in isamp and osamp. */ static int sox_silence_flow(sox_effect_t * effp, const sox_sample_t *ibuf, sox_sample_t *obuf, size_t *isamp, size_t *osamp) { priv_t * silence = (priv_t *) effp->priv; int threshold; size_t i, j; size_t nrOfTicks, /* sometimes wide, sometimes non-wide samples */ nrOfInSamplesRead, nrOfOutSamplesWritten; /* non-wide samples */ nrOfInSamplesRead = 0; nrOfOutSamplesWritten = 0; switch (silence->mode) { case SILENCE_TRIM: /* Reads and discards all input data until it detects a * sample that is above the specified threshold. Turns on * copy mode when detected. * Need to make sure and copy input in groups of "channels" to * prevent getting buffers out of sync. * nrOfTicks counts wide samples here. */ silence_trim: nrOfTicks = min((*isamp-nrOfInSamplesRead), (*osamp-nrOfOutSamplesWritten)) / effp->in_signal.channels; for(i = 0; i < nrOfTicks; i++) { threshold = 0; for (j = 0; j < effp->in_signal.channels; j++) { threshold |= aboveThreshold(effp, compute_rms(effp, ibuf[j]), silence->start_threshold, silence->start_unit); } if (threshold) { /* Add to holdoff buffer */ for (j = 0; j < effp->in_signal.channels; j++) { update_rms(effp, *ibuf); silence->start_holdoff[ silence->start_holdoff_end++] = *ibuf++; nrOfInSamplesRead++; } if (silence->start_holdoff_end >= silence->start_duration) { if (++silence->start_found_periods >= silence->start_periods) { silence->mode = SILENCE_TRIM_FLUSH; goto silence_trim_flush; } /* Trash holdoff buffer since its not * needed. Start looking again. */ silence->start_holdoff_offset = 0; silence->start_holdoff_end = 0; } } else /* !above Threshold */ { silence->start_holdoff_end = 0; for (j = 0; j < effp->in_signal.channels; j++) { update_rms(effp, ibuf[j]); } ibuf += effp->in_signal.channels; nrOfInSamplesRead += effp->in_signal.channels; } } /* for nrOfTicks */ break; case SILENCE_TRIM_FLUSH: /* nrOfTicks counts non-wide samples here. */ silence_trim_flush: nrOfTicks = min((silence->start_holdoff_end - silence->start_holdoff_offset), (*osamp-nrOfOutSamplesWritten)); nrOfTicks -= nrOfTicks % effp->in_signal.channels; for(i = 0; i < nrOfTicks; i++) { *obuf++ = silence->start_holdoff[silence->start_holdoff_offset++]; nrOfOutSamplesWritten++; } /* If fully drained holdoff then switch to copy mode */ if (silence->start_holdoff_offset == silence->start_holdoff_end) { silence->start_holdoff_offset = 0; silence->start_holdoff_end = 0; silence->mode = SILENCE_COPY; goto silence_copy; } break; case SILENCE_COPY: /* Attempts to copy samples into output buffer. * * Case B: * If not looking for silence to terminate copy then * blindly copy data into output buffer. * * Case A: * * Case 1a: * If previous silence was detect then see if input sample is * above threshold. If found then flush out hold off buffer * and copy over to output buffer. * * Case 1b: * If no previous silence detect then see if input sample * is above threshold. If found then copy directly * to output buffer. * * Case 2: * If not above threshold then silence is detect so * store in hold off buffer and do not write to output * buffer. Even though it wasn't put in output * buffer, inform user that input was consumed. * * If hold off buffer is full after this then stop * copying data and discard data in hold off buffer. * * Special leave_silence logic: * * During this mode, go ahead and copy input * samples to output buffer instead of holdoff buffer * Then also short ciruit any flushes that would occur * when non-silence is detect since samples were already * copied. This has the effect of always leaving * holdoff[] amount of silence but deleting any * beyond that amount. * * nrOfTicks counts wide samples here. */ silence_copy: nrOfTicks = min((*isamp-nrOfInSamplesRead), (*osamp-nrOfOutSamplesWritten)) / effp->in_signal.channels; if (silence->stop) { /* Case A */ for(i = 0; i < nrOfTicks; i++) { threshold = 1; for (j = 0; j < effp->in_signal.channels; j++) { threshold &= aboveThreshold(effp, compute_rms(effp, ibuf[j]), silence->stop_threshold, silence->stop_unit); } /* Case 1a * If above threshold, check to see if we where holding * off previously. If so then flush this buffer. * We haven't incremented any pointers yet so nothing * is lost. * * If user wants to leave_silence, then we * were already copying the data and so no * need to flush the old data. Just resume * copying as if we were not holding off. */ if (threshold && silence->stop_holdoff_end && !silence->leave_silence) { silence->mode = SILENCE_COPY_FLUSH; goto silence_copy_flush; } /* Case 1b */ else if (threshold) {