ref: 080b6c7cb5a24ae80477e441b75ba6f3bdfc2cab
dir: /src/silence.c/
/* 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. * Theshold's can be given as either a percentage or in decibels. */ #include <string.h> #include <math.h> #include "st_i.h" #ifndef TRUE #define TRUE 1 #endif #ifndef FALSE #define FALSE 0 #endif #ifndef min #define min(s1,s2) ((s1)<(s2)?(s1):(s2)) #endif /* 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 silencestuff { char start; int start_periods; char *start_duration_str; st_size_t start_duration; double start_threshold; char start_unit; /* "d" for decibels or "%" for percent. */ int restart; st_sample_t *start_holdoff; st_size_t start_holdoff_offset; st_size_t start_holdoff_end; int start_found_periods; char stop; int stop_periods; char *stop_duration_str; st_size_t stop_duration; double stop_threshold; char stop_unit; st_sample_t *stop_holdoff; st_size_t stop_holdoff_offset; st_size_t stop_holdoff_end; int stop_found_periods; double *window; double *window_current; double *window_end; st_size_t window_size; double rms_sum; /* State Machine */ char mode; } *silence_t; #define SILENCE_USAGE "Usage: silence above_periods [ duration thershold[d | %% ] ] [ below_periods duration threshold[ d | %% ]]" int st_silence_getopts(eff_t effp, int n, char **argv) { silence_t silence = (silence_t) effp->priv; int parse_count; if (n < 1) { st_fail(SILENCE_USAGE); return (ST_EOF); } /* Parse data related to trimming front side */ silence->start = FALSE; if (sscanf(argv[0], "%d", &silence->start_periods) != 1) { st_fail(SILENCE_USAGE); return(ST_EOF); } if (silence->start_periods < 0) { st_fail("Periods must not be negative"); return(ST_EOF); } argv++; n--; if (silence->start_periods > 0) { silence->start = TRUE; if (n < 2) { st_fail(SILENCE_USAGE); return ST_EOF; } /* 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 = (char *)malloc(strlen(argv[0])+1); if (!silence->start_duration_str) { st_fail("Could not allocate memory"); return(ST_EOF); } strcpy(silence->start_duration_str,argv[0]); /* Perform a fake parse to do error checking */ if (st_parsesamples(0,silence->start_duration_str, &silence->start_duration,'s') != ST_SUCCESS) { st_fail(SILENCE_USAGE); return(ST_EOF); } parse_count = sscanf(argv[1], "%lf%c", &silence->start_threshold, &silence->start_unit); if (parse_count < 1) { st_fail(SILENCE_USAGE); return ST_EOF; } else if (parse_count < 2) silence->start_unit = '%'; argv++; argv++; n--; n--; } silence->stop = FALSE; /* Parse data needed for trimming of backside */ if (n > 0) { if (n < 3) { st_fail(SILENCE_USAGE); return ST_EOF; } if (sscanf(argv[0], "%d", &silence->stop_periods) != 1) { st_fail(SILENCE_USAGE); return ST_EOF; } if (silence->stop_periods < 0) { silence->stop_periods = -silence->stop_periods; silence->restart = 1; } else silence->restart = 0; silence->stop = TRUE; argv++; n--; /* 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 = (char *)malloc(strlen(argv[0])+1); if (!silence->stop_duration_str) { st_fail("Could not allocate memory"); return(ST_EOF); } strcpy(silence->stop_duration_str,argv[0]); /* Perform a fake parse to do error checking */ if (st_parsesamples(0,silence->stop_duration_str, &silence->stop_duration,'s') != ST_SUCCESS) { st_fail(SILENCE_USAGE); return(ST_EOF); } parse_count = sscanf(argv[1], "%lf%c", &silence->stop_threshold, &silence->stop_unit); if (parse_count < 1) { st_fail(SILENCE_USAGE); return ST_EOF; } else if (parse_count < 2) silence->stop_unit = '%'; argv++; argv++; n--; n--; } /* Error checking */ if (silence->start) { if ((silence->start_unit != '%') && (silence->start_unit != 'd')) { st_fail("Invalid unit specified"); st_fail(SILENCE_USAGE); return(ST_EOF); } if ((silence->start_unit == '%') && ((silence->start_threshold < 0.0) || (silence->start_threshold > 100.0))) { st_fail("silence threshold should be between 0.0 and 100.0 %%"); return (ST_EOF); } if ((silence->start_unit == 'd') && (silence->start_threshold >= 0.0)) { st_fail("silence threshold should be less than 0.0 dB"); return(ST_EOF); } } if (silence->stop) { if ((silence->stop_unit != '%') && (silence->stop_unit != 'd')) { st_fail("Invalid unit specified"); return(ST_EOF); } if ((silence->stop_unit == '%') && ((silence->stop_threshold < 0.0) || (silence->stop_threshold > 100.0))) { st_fail("silence threshold should be between 0.0 and 100.0 %%"); return (ST_EOF); } if ((silence->stop_unit == 'd') && (silence->stop_threshold >= 0.0)) { st_fail("silence threshold should be less than 0.0 dB"); return(ST_EOF); } } return(ST_SUCCESS); } int st_silence_start(eff_t effp) { silence_t silence = (silence_t) effp->priv; silence->window_size = (effp->ininfo.rate / 10) * effp->ininfo.channels; silence->window = (double *)malloc(silence->window_size * sizeof(double)); if (!silence->window) { st_fail("Unable to allocate memory"); return(ST_EOF); } 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; /* Now that we now sample rate, reparse duration. */ if (silence->start) { if (st_parsesamples(effp->ininfo.rate, silence->start_duration_str, &silence->start_duration, 's') != ST_SUCCESS) { st_fail(SILENCE_USAGE); return(ST_EOF); } } if (silence->stop) { if (st_parsesamples(effp->ininfo.rate,silence->stop_duration_str, &silence->stop_duration,'s') != ST_SUCCESS) { st_fail(SILENCE_USAGE); return(ST_EOF); } } if (silence->start) silence->mode = SILENCE_TRIM; else silence->mode = SILENCE_COPY; silence->start_holdoff = (st_sample_t *)malloc(sizeof(st_sample_t)*silence->start_duration); if (!silence->start_holdoff) { st_fail("Could not allocate memory"); return(ST_EOF); } silence->start_holdoff_offset = 0; silence->start_holdoff_end = 0; silence->start_found_periods = 0; silence->stop_holdoff = (st_sample_t *)malloc(sizeof(st_sample_t)*silence->stop_duration); if (!silence->stop_holdoff) { st_fail("Could not allocate memory"); return(ST_EOF); } silence->stop_holdoff_offset = 0; silence->stop_holdoff_end = 0; silence->stop_found_periods = 0; return(ST_SUCCESS); } int aboveThreshold(eff_t effp, st_sample_t value, double threshold, char unit) { double ratio; int rc; /* When scaling low bit data, noise values got scaled way up */ /* Only consider the original bits when looking for silence */ switch(effp->ininfo.size) { case ST_SIZE_BYTE: value = ST_SAMPLE_TO_SIGNED_BYTE(value); ratio = (double)abs(value) / (double)ST_INT8_MAX; break; case ST_SIZE_WORD: value = ST_SAMPLE_TO_SIGNED_WORD(value); ratio = (double)abs(value) / (double)ST_INT16_MAX; break; case ST_SIZE_DWORD: value = ST_SAMPLE_TO_SIGNED_DWORD(value); ratio = (double)labs(value) / (double)ST_INT32_MAX; break; default: ratio = 0; } if (unit == '%') ratio *= 100.0; else if (unit == 'd') ratio = log10(ratio) * 20.0; rc = (ratio >= threshold); return rc; } st_sample_t compute_rms(eff_t effp, st_sample_t sample) { silence_t silence = (silence_t) effp->priv; double new_sum; st_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); } void update_rms(eff_t effp, st_sample_t sample) { silence_t silence = (silence_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. */ int st_silence_flow(eff_t effp, st_sample_t *ibuf, st_sample_t *obuf, st_size_t *isamp, st_size_t *osamp) { silence_t silence = (silence_t) effp->priv; int threshold, j; st_size_t i; st_size_t nrOfTicks, nrOfInSamplesRead, nrOfOutSamplesWritten; 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 = min((*isamp), (*osamp)) / effp->ininfo.channels; for(i = 0; i < nrOfTicks; i++) { threshold = 0; for (j = 0; j < effp->ininfo.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->ininfo.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->ininfo.channels; j++) { update_rms(effp, ibuf[j]); } ibuf += effp->ininfo.channels; nrOfInSamplesRead += effp->ininfo.channels; } } /* for nrOfTicks */ break; case SILENCE_TRIM_FLUSH: silence_trim_flush: nrOfTicks = min((silence->start_holdoff_end - silence->start_holdoff_offset), (*osamp-nrOfOutSamplesWritten)); 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. If not * looking for silence to terminate copy then blindly * copy data into output buffer. * * If looking for silence, then see if input sample is above * threshold. If found then flush out hold off buffer * and copy over to output buffer. Tell user about * input and output processing. * * If not above threshold then store in hold off buffer * and do not write to output buffer. Tell user input * was processed. * * If hold off buffer is full then stop copying data and * discard data in hold off buffer. */ silence_copy: nrOfTicks = min((*isamp-nrOfInSamplesRead), (*osamp-nrOfOutSamplesWritten)) / effp->ininfo.channels; if (silence->stop) { for(i = 0; i < nrOfTicks; i++) { threshold = 1; for (j = 0; j < effp->ininfo.channels; j++) { threshold &= aboveThreshold(effp, compute_rms(effp, ibuf[j]), silence->stop_threshold, silence->stop_unit); } /* 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 (threshold && silence->stop_holdoff_end) { silence->mode = SILENCE_COPY_FLUSH; goto silence_copy_flush; } else if (threshold) { /* Not holding off so copy into output buffer */ for (j = 0; j < effp->ininfo.channels; j++) { update_rms(effp, *ibuf); *obuf++ = *ibuf++; nrOfInSamplesRead++; nrOfOutSamplesWritten++; } } else if (!threshold) { /* Add to holdoff buffer */ for (j = 0; j < effp->ininfo.channels; j++) { update_rms(effp, *ibuf); silence->stop_holdoff[ silence->stop_holdoff_end++] = *ibuf++; nrOfInSamplesRead++; } /* Check if holdoff buffer is greater than duration */ if (silence->stop_holdoff_end >= silence->stop_duration) { /* Increment found counter and see if this * is the last period. If so then exit. */ if (++silence->stop_found_periods >= silence->stop_periods) { silence->stop_holdoff_offset = 0; silence->stop_holdoff_end = 0; if (!silence->restart) { silence->mode = SILENCE_STOP; *isamp = nrOfInSamplesRead; *osamp = nrOfOutSamplesWritten; /* Return ST_EOF since no more processing */ return (ST_EOF); } else { silence->mode = SILENCE_TRIM; return (ST_SUCCESS); } } else { /* Flush this buffer and start * looking again. */ silence->mode = SILENCE_COPY_FLUSH; goto silence_copy_flush; } break; } /* Filled holdoff buffer */ } /* Detected silence */ } /* For # of samples */ } /* Trimming off backend */ else /* !(silence->stop) */ { memcpy(obuf, ibuf, sizeof(st_sample_t)*nrOfTicks* effp->ininfo.channels); nrOfInSamplesRead += (nrOfTicks*effp->ininfo.channels); nrOfOutSamplesWritten += (nrOfTicks*effp->ininfo.channels); } break; case SILENCE_COPY_FLUSH: silence_copy_flush: nrOfTicks = min((silence->stop_holdoff_end - silence->stop_holdoff_offset), (*osamp-nrOfOutSamplesWritten)); for(i = 0; i < nrOfTicks; i++) { *obuf++ = silence->stop_holdoff[silence->stop_holdoff_offset++]; nrOfOutSamplesWritten++; } /* If fully drained holdoff then return to copy mode */ if (silence->stop_holdoff_offset == silence->stop_holdoff_end) { silence->stop_holdoff_offset = 0; silence->stop_holdoff_end = 0; silence->mode = SILENCE_COPY; goto silence_copy; } break; case SILENCE_STOP: nrOfInSamplesRead = *isamp; break; } *isamp = nrOfInSamplesRead; *osamp = nrOfOutSamplesWritten; return (ST_SUCCESS); } int st_silence_drain(eff_t effp, st_sample_t *obuf, st_size_t *osamp) { silence_t silence = (silence_t) effp->priv; st_size_t i; st_size_t nrOfTicks, nrOfOutSamplesWritten = 0; /* Only if in flush mode will there be possible samples to write * out during drain() call. */ if (silence->mode == SILENCE_COPY_FLUSH || silence->mode == SILENCE_COPY) { nrOfTicks = min((silence->stop_holdoff_end - silence->stop_holdoff_offset), *osamp); for(i = 0; i < nrOfTicks; i++) { *obuf++ = silence->stop_holdoff[silence->stop_holdoff_offset++]; nrOfOutSamplesWritten++; } /* If fully drained holdoff then stop */ if (silence->stop_holdoff_offset == silence->stop_holdoff_end) { silence->stop_holdoff_offset = 0; silence->stop_holdoff_end = 0; silence->mode = SILENCE_STOP; } } *osamp = nrOfOutSamplesWritten; return(ST_SUCCESS); } int st_silence_stop(eff_t effp) { silence_t silence = (silence_t) effp->priv; if (silence->window) free(silence->window); if (silence->start_holdoff) free(silence->start_holdoff); if (silence->stop_holdoff) free(silence->stop_holdoff); return(ST_SUCCESS); }