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author | Paul B Mahol <onemda@gmail.com> | 2023-01-08 13:53:39 +0100 |
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committer | Paul B Mahol <onemda@gmail.com> | 2023-01-16 09:59:31 +0100 |
commit | ac7d21284bd3c2b7f7c6d15db450e4c58e93fef8 (patch) | |
tree | a1e448e970921b329db9124ee56021db0db5bb66 /libavfilter/asrc_afdelaysrc.c | |
parent | 1ab0f83b0a243c635d77f8b116646bb7594988d4 (diff) | |
download | ffmpeg-ac7d21284bd3c2b7f7c6d15db450e4c58e93fef8.tar.gz |
avfilter: add fractional delay IR source filter
Diffstat (limited to 'libavfilter/asrc_afdelaysrc.c')
-rw-r--r-- | libavfilter/asrc_afdelaysrc.c | 173 |
1 files changed, 173 insertions, 0 deletions
diff --git a/libavfilter/asrc_afdelaysrc.c b/libavfilter/asrc_afdelaysrc.c new file mode 100644 index 0000000000..2fc57cee4d --- /dev/null +++ b/libavfilter/asrc_afdelaysrc.c @@ -0,0 +1,173 @@ +/* + * 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/avassert.h" +#include "libavutil/channel_layout.h" +#include "libavutil/opt.h" + +#include "audio.h" +#include "avfilter.h" +#include "filters.h" +#include "internal.h" + +typedef struct AFDelaySrcContext { + const AVClass *class; + + double delay; + int sample_rate; + int nb_samples; + int nb_taps; + AVChannelLayout chlayout; + char *chlayout_str; + + int64_t pts; +} AFDelaySrcContext; + +static av_cold int init(AVFilterContext *ctx) +{ + AFDelaySrcContext *s = ctx->priv; + int ret; + + ret = ff_parse_channel_layout(&s->chlayout, NULL, s->chlayout_str, ctx); + if (ret < 0) + return ret; + + return 0; +} + +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, + }, +}; + +static av_cold void uninit(AVFilterContext *ctx) +{ + AFDelaySrcContext *s = ctx->priv; + + av_channel_layout_uninit(&s->chlayout); +} + +#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_str),AV_OPT_TYPE_STRING,{.str="stereo"},0, 0, AF }, + { "c", "set channel layout", OFFSET(chlayout_str),AV_OPT_TYPE_STRING,{.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, + .init = init, + .activate = activate, + .uninit = uninit, + .inputs = NULL, + FILTER_OUTPUTS(afdelaysrc_outputs), + FILTER_QUERY_FUNC(query_formats), +}; |