/* * Copyright (c) 2001 Heikki Leinonen * Copyright (c) 2001 Chris Bagwell * Copyright (c) 2003 Donnie Smith * Copyright (c) 2014 Paul B Mahol * * This file is part of FFmpeg. * * FFmpeg is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * FFmpeg is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #include <float.h> /* DBL_MAX */ #include "libavutil/opt.h" #include "libavutil/timestamp.h" #include "audio.h" #include "formats.h" #include "avfilter.h" #include "internal.h" enum SilenceMode { SILENCE_TRIM, SILENCE_TRIM_FLUSH, SILENCE_COPY, SILENCE_COPY_FLUSH, SILENCE_STOP }; typedef struct SilenceRemoveContext { const AVClass *class; enum SilenceMode mode; int start_periods; int64_t start_duration; double start_threshold; int stop_periods; int64_t stop_duration; double stop_threshold; double *start_holdoff; size_t start_holdoff_offset; size_t start_holdoff_end; int start_found_periods; double *stop_holdoff; size_t stop_holdoff_offset; size_t stop_holdoff_end; int stop_found_periods; double *window; double *window_current; double *window_end; int window_size; double rms_sum; int leave_silence; int restart; int64_t next_pts; } SilenceRemoveContext; #define OFFSET(x) offsetof(SilenceRemoveContext, x) #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_AUDIO_PARAM static const AVOption silenceremove_options[] = { { "start_periods", NULL, OFFSET(start_periods), AV_OPT_TYPE_INT, {.i64=0}, 0, 9000, FLAGS }, { "start_duration", NULL, OFFSET(start_duration), AV_OPT_TYPE_DURATION, {.i64=0}, 0, 9000, FLAGS }, { "start_threshold", NULL, OFFSET(start_threshold), AV_OPT_TYPE_DOUBLE, {.dbl=0}, 0, DBL_MAX, FLAGS }, { "stop_periods", NULL, OFFSET(stop_periods), AV_OPT_TYPE_INT, {.i64=0}, -9000, 9000, FLAGS }, { "stop_duration", NULL, OFFSET(stop_duration), AV_OPT_TYPE_DURATION, {.i64=0}, 0, 9000, FLAGS }, { "stop_threshold", NULL, OFFSET(stop_threshold), AV_OPT_TYPE_DOUBLE, {.dbl=0}, 0, DBL_MAX, FLAGS }, { "leave_silence", NULL, OFFSET(leave_silence), AV_OPT_TYPE_BOOL, {.i64=0}, 0, 1, FLAGS }, { NULL } }; AVFILTER_DEFINE_CLASS(silenceremove); static av_cold int init(AVFilterContext *ctx) { SilenceRemoveContext *s = ctx->priv; if (s->stop_periods < 0) { s->stop_periods = -s->stop_periods; s->restart = 1; } return 0; } static void clear_rms(SilenceRemoveContext *s) { memset(s->window, 0, s->window_size * sizeof(*s->window)); s->window_current = s->window; s->window_end = s->window + s->window_size; s->rms_sum = 0; } static int config_input(AVFilterLink *inlink) { AVFilterContext *ctx = inlink->dst; SilenceRemoveContext *s = ctx->priv; s->window_size = (inlink->sample_rate / 50) * inlink->channels; s->window = av_malloc_array(s->window_size, sizeof(*s->window)); if (!s->window) return AVERROR(ENOMEM); clear_rms(s); s->start_duration = av_rescale(s->start_duration, inlink->sample_rate, AV_TIME_BASE); s->stop_duration = av_rescale(s->stop_duration, inlink->sample_rate, AV_TIME_BASE); s->start_holdoff = av_malloc_array(FFMAX(s->start_duration, 1), sizeof(*s->start_holdoff) * inlink->channels); if (!s->start_holdoff) return AVERROR(ENOMEM); s->start_holdoff_offset = 0; s->start_holdoff_end = 0; s->start_found_periods = 0; s->stop_holdoff = av_malloc_array(FFMAX(s->stop_duration, 1), sizeof(*s->stop_holdoff) * inlink->channels); if (!s->stop_holdoff) return AVERROR(ENOMEM); s->stop_holdoff_offset = 0; s->stop_holdoff_end = 0; s->stop_found_periods = 0; if (s->start_periods) s->mode = SILENCE_TRIM; else s->mode = SILENCE_COPY; return 0; } static double compute_rms(SilenceRemoveContext *s, double sample) { double new_sum; new_sum = s->rms_sum; new_sum -= *s->window_current; new_sum += sample * sample; return sqrt(new_sum / s->window_size); } static void update_rms(SilenceRemoveContext *s, double sample) { s->rms_sum -= *s->window_current; *s->window_current = sample * sample; s->rms_sum += *s->window_current; s->window_current++; if (s->window_current >= s->window_end) s->window_current = s->window; } static void flush(AVFrame *out, AVFilterLink *outlink, int *nb_samples_written, int *ret) { if (*nb_samples_written) { out->nb_samples = *nb_samples_written / outlink->channels; *ret = ff_filter_frame(outlink, out); *nb_samples_written = 0; } else { av_frame_free(&out); } } static int filter_frame(AVFilterLink *inlink, AVFrame *in) { AVFilterContext *ctx = inlink->dst; AVFilterLink *outlink = ctx->outputs[0]; SilenceRemoveContext *s = ctx->priv; int i, j, threshold, ret = 0; int nbs, nb_samples_read, nb_samples_written; double *obuf, *ibuf = (double *)in->data[0]; AVFrame *out; nb_samples_read = nb_samples_written = 0; switch (s->mode) { case SILENCE_TRIM: silence_trim: nbs = in->nb_samples - nb_samples_read / inlink->channels; if (!nbs) break; for (i = 0; i < nbs; i++) { threshold = 0; for (j = 0; j < inlink->channels; j++) { threshold |= compute_rms(s, ibuf[j]) > s->start_threshold; } if (threshold) { for (j = 0; j < inlink->channels; j++) { update_rms(s, *ibuf); s->start_holdoff[s->start_holdoff_end++] = *ibuf++; nb_samples_read++; } if (s->start_holdoff_end >= s->start_duration * inlink->channels) { if (++s->start_found_periods >= s->start_periods) { s->mode = SILENCE_TRIM_FLUSH; goto silence_trim_flush; } s->start_holdoff_offset = 0; s->start_holdoff_end = 0; } } else { s->start_holdoff_end = 0; for (j = 0; j < inlink->channels; j++) update_rms(s, ibuf[j]); ibuf += inlink->channels; nb_samples_read += inlink->channels; } } break; case SILENCE_TRIM_FLUSH: silence_trim_flush: nbs = s->start_holdoff_end - s->start_holdoff_offset; nbs -= nbs % inlink->channels; if (!nbs) break; out = ff_get_audio_buffer(inlink, nbs / inlink->channels); if (!out) { av_frame_free(&in); return AVERROR(ENOMEM); } memcpy(out->data[0], &s->start_holdoff[s->start_holdoff_offset], nbs * sizeof(double)); s->start_holdoff_offset += nbs; ret = ff_filter_frame(outlink, out); if (s->start_holdoff_offset == s->start_holdoff_end) { s->start_holdoff_offset = 0; s->start_holdoff_end = 0; s->mode = SILENCE_COPY; goto silence_copy; } break; case SILENCE_COPY: silence_copy: nbs = in->nb_samples - nb_samples_read / inlink->channels; if (!nbs) break; out = ff_get_audio_buffer(inlink, nbs); if (!out) { av_frame_free(&in); return AVERROR(ENOMEM); } obuf = (double *)out->data[0]; if (s->stop_periods) { for (i = 0; i < nbs; i++) { threshold = 1; for (j = 0; j < inlink->channels; j++) threshold &= compute_rms(s, ibuf[j]) > s->stop_threshold; if (threshold && s->stop_holdoff_end && !s->leave_silence) { s->mode = SILENCE_COPY_FLUSH; flush(out, outlink, &nb_samples_written, &ret); goto silence_copy_flush; } else if (threshold) { for (j = 0; j < inlink->channels; j++) { update_rms(s, *ibuf); *obuf++ = *ibuf++; nb_samples_read++; nb_samples_written++; } } else if (!threshold) { for (j = 0; j < inlink->channels; j++) { update_rms(s, *ibuf); if (s->leave_silence) { *obuf++ = *ibuf; nb_samples_written++; } s->stop_holdoff[s->stop_holdoff_end++] = *ibuf++; nb_samples_read++; } if (s->stop_holdoff_end >= s->stop_duration * inlink->channels) { if (++s->stop_found_periods >= s->stop_periods) { s->stop_holdoff_offset = 0; s->stop_holdoff_end = 0; if (!s->restart) { s->mode = SILENCE_STOP; flush(out, outlink, &nb_samples_written, &ret); goto silence_stop; } else { s->stop_found_periods = 0; s->start_found_periods = 0; s->start_holdoff_offset = 0; s->start_holdoff_end = 0; clear_rms(s); s->mode = SILENCE_TRIM; flush(out, outlink, &nb_samples_written, &ret); goto silence_trim; } } s->mode = SILENCE_COPY_FLUSH; flush(out, outlink, &nb_samples_written, &ret); goto silence_copy_flush; } } } flush(out, outlink, &nb_samples_written, &ret); } else { memcpy(obuf, ibuf, sizeof(double) * nbs * inlink->channels); ret = ff_filter_frame(outlink, out); } break; case SILENCE_COPY_FLUSH: silence_copy_flush: nbs = s->stop_holdoff_end - s->stop_holdoff_offset; nbs -= nbs % inlink->channels; if (!nbs) break; out = ff_get_audio_buffer(inlink, nbs / inlink->channels); if (!out) { av_frame_free(&in); return AVERROR(ENOMEM); } memcpy(out->data[0], &s->stop_holdoff[s->stop_holdoff_offset], nbs * sizeof(double)); s->stop_holdoff_offset += nbs; ret = ff_filter_frame(outlink, out); if (s->stop_holdoff_offset == s->stop_holdoff_end) { s->stop_holdoff_offset = 0; s->stop_holdoff_end = 0; s->mode = SILENCE_COPY; goto silence_copy; } break; case SILENCE_STOP: silence_stop: break; } av_frame_free(&in); return ret; } static int request_frame(AVFilterLink *outlink) { AVFilterContext *ctx = outlink->src; SilenceRemoveContext *s = ctx->priv; int ret; ret = ff_request_frame(ctx->inputs[0]); if (ret == AVERROR_EOF && (s->mode == SILENCE_COPY_FLUSH || s->mode == SILENCE_COPY)) { int nbs = s->stop_holdoff_end - s->stop_holdoff_offset; if (nbs) { AVFrame *frame; frame = ff_get_audio_buffer(outlink, nbs / outlink->channels); if (!frame) return AVERROR(ENOMEM); memcpy(frame->data[0], &s->stop_holdoff[s->stop_holdoff_offset], nbs * sizeof(double)); ret = ff_filter_frame(ctx->inputs[0], frame); } s->mode = SILENCE_STOP; } return ret; } static int query_formats(AVFilterContext *ctx) { AVFilterFormats *formats = NULL; AVFilterChannelLayouts *layouts = NULL; static const enum AVSampleFormat sample_fmts[] = { AV_SAMPLE_FMT_DBL, AV_SAMPLE_FMT_NONE }; int ret; layouts = ff_all_channel_counts(); if (!layouts) return AVERROR(ENOMEM); ret = ff_set_common_channel_layouts(ctx, layouts); if (ret < 0) return ret; formats = ff_make_format_list(sample_fmts); if (!formats) return AVERROR(ENOMEM); ret = ff_set_common_formats(ctx, formats); if (ret < 0) return ret; formats = ff_all_samplerates(); if (!formats) return AVERROR(ENOMEM); return ff_set_common_samplerates(ctx, formats); } static av_cold void uninit(AVFilterContext *ctx) { SilenceRemoveContext *s = ctx->priv; av_freep(&s->start_holdoff); av_freep(&s->stop_holdoff); av_freep(&s->window); } static const AVFilterPad silenceremove_inputs[] = { { .name = "default", .type = AVMEDIA_TYPE_AUDIO, .config_props = config_input, .filter_frame = filter_frame, }, { NULL } }; static const AVFilterPad silenceremove_outputs[] = { { .name = "default", .type = AVMEDIA_TYPE_AUDIO, .request_frame = request_frame, }, { NULL } }; AVFilter ff_af_silenceremove = { .name = "silenceremove", .description = NULL_IF_CONFIG_SMALL("Remove silence."), .priv_size = sizeof(SilenceRemoveContext), .priv_class = &silenceremove_class, .init = init, .uninit = uninit, .query_formats = query_formats, .inputs = silenceremove_inputs, .outputs = silenceremove_outputs, };