| /* |
| * Copyright (c) 2023 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 "libavutil/channel_layout.h" |
| #include "libavutil/opt.h" |
| |
| #include "audio.h" |
| #include "avfilter.h" |
| #include "filters.h" |
| #include "formats.h" |
| #include "internal.h" |
| |
| typedef struct AFDelaySrcContext { |
| const AVClass *class; |
| |
| double delay; |
| int sample_rate; |
| int nb_samples; |
| int nb_taps; |
| AVChannelLayout chlayout; |
| |
| int64_t pts; |
| } AFDelaySrcContext; |
| |
| static float sincf(float x) |
| { |
| if (x == 0.f) |
| return 1.f; |
| return sinf(M_PI * x) / (M_PI * x); |
| } |
| |
| static int activate(AVFilterContext *ctx) |
| { |
| AVFilterLink *outlink = ctx->outputs[0]; |
| AFDelaySrcContext *s = ctx->priv; |
| AVFrame *frame = NULL; |
| int nb_samples; |
| float *dst; |
| |
| if (!ff_outlink_frame_wanted(outlink)) |
| return FFERROR_NOT_READY; |
| |
| nb_samples = FFMIN(s->nb_samples, s->nb_taps - s->pts); |
| if (nb_samples <= 0) { |
| ff_outlink_set_status(outlink, AVERROR_EOF, s->pts); |
| return 0; |
| } |
| |
| if (!(frame = ff_get_audio_buffer(outlink, nb_samples))) |
| return AVERROR(ENOMEM); |
| |
| dst = (float *)frame->extended_data[0]; |
| for (int n = 0; n < nb_samples; n++) { |
| float x = s->pts + n; |
| dst[n] = sincf(x - s->delay) * cosf(M_PI * (x - s->delay) / s->nb_taps) / sincf((x - s->delay) / s->nb_taps); |
| } |
| |
| for (int ch = 1; ch < frame->ch_layout.nb_channels; ch++) |
| memcpy(frame->extended_data[ch], dst, sizeof(*dst) * nb_samples); |
| |
| frame->pts = s->pts; |
| s->pts += nb_samples; |
| |
| return ff_filter_frame(outlink, frame); |
| } |
| |
| static int query_formats(AVFilterContext *ctx) |
| { |
| AFDelaySrcContext *s = ctx->priv; |
| AVChannelLayout chlayouts[] = { s->chlayout, { 0 } }; |
| int sample_rates[] = { s->sample_rate, -1 }; |
| static const enum AVSampleFormat sample_fmts[] = { AV_SAMPLE_FMT_FLTP, |
| AV_SAMPLE_FMT_NONE }; |
| int ret = ff_set_common_formats_from_list(ctx, sample_fmts); |
| if (ret < 0) |
| return ret; |
| |
| ret = ff_set_common_channel_layouts_from_list(ctx, chlayouts); |
| if (ret < 0) |
| return ret; |
| |
| return ff_set_common_samplerates_from_list(ctx, sample_rates); |
| } |
| |
| static int config_output(AVFilterLink *outlink) |
| { |
| AVFilterContext *ctx = outlink->src; |
| AFDelaySrcContext *s = ctx->priv; |
| |
| outlink->sample_rate = s->sample_rate; |
| s->pts = 0; |
| if (s->nb_taps <= 0) |
| s->nb_taps = s->delay * 8 + 1; |
| |
| return 0; |
| } |
| |
| static const AVFilterPad afdelaysrc_outputs[] = { |
| { |
| .name = "default", |
| .type = AVMEDIA_TYPE_AUDIO, |
| .config_props = config_output, |
| }, |
| }; |
| |
| #define AF AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM |
| #define OFFSET(x) offsetof(AFDelaySrcContext, x) |
| |
| static const AVOption afdelaysrc_options[] = { |
| { "delay", "set fractional delay", OFFSET(delay), AV_OPT_TYPE_DOUBLE,{.dbl=0}, 0, INT16_MAX, AF }, |
| { "d", "set fractional delay", OFFSET(delay), AV_OPT_TYPE_DOUBLE,{.dbl=0}, 0, INT16_MAX, AF }, |
| { "sample_rate", "set sample rate", OFFSET(sample_rate), AV_OPT_TYPE_INT, {.i64=44100}, 1, INT_MAX, AF }, |
| { "r", "set sample rate", OFFSET(sample_rate), AV_OPT_TYPE_INT, {.i64=44100}, 1, INT_MAX, AF }, |
| { "nb_samples", "set the number of samples per requested frame", OFFSET(nb_samples), AV_OPT_TYPE_INT, {.i64=1024}, 1, INT_MAX, AF }, |
| { "n", "set the number of samples per requested frame", OFFSET(nb_samples), AV_OPT_TYPE_INT, {.i64=1024}, 1, INT_MAX, AF }, |
| { "taps", "set number of taps for delay filter", OFFSET(nb_taps), AV_OPT_TYPE_INT, {.i64=0}, 0, 32768, AF }, |
| { "t", "set number of taps for delay filter", OFFSET(nb_taps), AV_OPT_TYPE_INT, {.i64=0}, 0, 32768, AF }, |
| { "channel_layout", "set channel layout", OFFSET(chlayout), AV_OPT_TYPE_CHLAYOUT,{.str="stereo"},0, 0, AF }, |
| { "c", "set channel layout", OFFSET(chlayout), AV_OPT_TYPE_CHLAYOUT,{.str="stereo"},0, 0, AF }, |
| { NULL } |
| }; |
| |
| AVFILTER_DEFINE_CLASS(afdelaysrc); |
| |
| const AVFilter ff_asrc_afdelaysrc = { |
| .name = "afdelaysrc", |
| .description = NULL_IF_CONFIG_SMALL("Generate a Fractional delay FIR coefficients."), |
| .priv_size = sizeof(AFDelaySrcContext), |
| .priv_class = &afdelaysrc_class, |
| .activate = activate, |
| .inputs = NULL, |
| FILTER_OUTPUTS(afdelaysrc_outputs), |
| FILTER_QUERY_FUNC(query_formats), |
| }; |