[FFmpeg-devel] [PATCH] avfilter: add dialogue enhance audio filter
Pierre-Anthony Lemieux
pal at sandflow.com
Sun Feb 6 22:49:25 EET 2022
On Sun, Feb 6, 2022 at 11:52 AM Paul B Mahol <onemda at gmail.com> wrote:
>
> Signed-off-by: Paul B Mahol <onemda at gmail.com>
> ---
> doc/filters.texi | 28 +++
> libavfilter/Makefile | 1 +
> libavfilter/af_dialoguenhance.c | 407 ++++++++++++++++++++++++++++++++
> libavfilter/allfilters.c | 1 +
> 4 files changed, 437 insertions(+)
> create mode 100644 libavfilter/af_dialoguenhance.c
>
> diff --git a/doc/filters.texi b/doc/filters.texi
> index 04c34cb1fb..10c11c1f55 100644
> --- a/doc/filters.texi
> +++ b/doc/filters.texi
> @@ -4178,6 +4178,34 @@ Default value is @var{o}.
>
> @end table
>
> + at section dialoguenhance
> +Enhance dialogue in stereo audio.
I suggest adding a link to an explainer/article and/or including an
overview description of the algorithm.
> +
> +This filter accepts stereo input and produce surround (3.0) channels output.
> +The newly produced front center channel have enhanced speech dialogue originally
> +available in both stereo channels.
> +This filter outputs front left and front right channels same as available in stereo input.
> +
> +The filter accepts the following options:
> +
> + at table @option
> + at item original
> +Set the original center factor to keep in front center channel output.
> +Allowed range is from 0 to 1. Default value is 1.
> +
> + at item enhance
> +Set the dialogue enhance factor to put in front center channel output.
> +Allowed range is from 0 to 3. Default value is 1.
> +
> + at item voice
> +Set the voice detection factor.
> +Allowed range is from 2 to 32. Default value is 2.
> + at end table
> +
> + at subsection Commands
> +
> +This filter supports the all above options as @ref{commands}.
> +
> @section drmeter
> Measure audio dynamic range.
>
> diff --git a/libavfilter/Makefile b/libavfilter/Makefile
> index 282967144b..56d33e6480 100644
> --- a/libavfilter/Makefile
> +++ b/libavfilter/Makefile
> @@ -124,6 +124,7 @@ OBJS-$(CONFIG_CROSSFEED_FILTER) += af_crossfeed.o
> OBJS-$(CONFIG_CRYSTALIZER_FILTER) += af_crystalizer.o
> OBJS-$(CONFIG_DCSHIFT_FILTER) += af_dcshift.o
> OBJS-$(CONFIG_DEESSER_FILTER) += af_deesser.o
> +OBJS-$(CONFIG_DIALOGUENHANCE_FILTER) += af_dialoguenhance.o
> OBJS-$(CONFIG_DRMETER_FILTER) += af_drmeter.o
> OBJS-$(CONFIG_DYNAUDNORM_FILTER) += af_dynaudnorm.o
> OBJS-$(CONFIG_EARWAX_FILTER) += af_earwax.o
> diff --git a/libavfilter/af_dialoguenhance.c b/libavfilter/af_dialoguenhance.c
> new file mode 100644
> index 0000000000..87cf131320
> --- /dev/null
> +++ b/libavfilter/af_dialoguenhance.c
> @@ -0,0 +1,407 @@
> +/*
> + * Copyright (c) 2022 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 "libavutil/tx.h"
> +#include "audio.h"
> +#include "avfilter.h"
> +#include "filters.h"
> +#include "internal.h"
> +#include "window_func.h"
> +
> +#include <float.h>
> +
> +typedef struct AudioDialogueEnhancementContext {
> + const AVClass *class;
> +
> + double original, enhance, voice;
> +
> + int fft_size;
> + int overlap;
> +
> + float *window;
> + float prev_vad;
> +
> + AVFrame *in;
> + AVFrame *in_frame;
> + AVFrame *out_dist_frame;
> + AVFrame *windowed_frame;
> + AVFrame *windowed_out;
> + AVFrame *windowed_prev;
> + AVFrame *center_frame;
> +
> + AVTXContext *tx_ctx[2], *itx_ctx;
> + av_tx_fn tx_fn, itx_fn;
> +} AudioDialogueEnhanceContext;
> +
> +#define OFFSET(x) offsetof(AudioDialogueEnhanceContext, x)
> +#define FLAGS AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_FILTERING_PARAM | AV_OPT_FLAG_RUNTIME_PARAM
> +
> +static const AVOption dialoguenhance_options[] = {
> + { "original", "set original center factor", OFFSET(original), AV_OPT_TYPE_DOUBLE, {.dbl=1}, 0, 1, FLAGS },
> + { "enhance", "set dialog enhance factor", OFFSET(enhance), AV_OPT_TYPE_DOUBLE, {.dbl=1}, 0, 3, FLAGS },
> + { "voice", "set voice detection factor", OFFSET(voice), AV_OPT_TYPE_DOUBLE, {.dbl=2}, 2,32, FLAGS },
> + {NULL}
> +};
> +
> +AVFILTER_DEFINE_CLASS(dialoguenhance);
> +
> +static int query_formats(AVFilterContext *ctx)
> +{
> + AVFilterFormats *formats = NULL;
> + AVFilterChannelLayouts *in_layout = NULL, *out_layout = NULL;
> + int ret;
> +
> + if ((ret = ff_add_format (&formats, AV_SAMPLE_FMT_FLTP )) < 0 ||
> + (ret = ff_set_common_formats (ctx , formats )) < 0 ||
> + (ret = ff_add_channel_layout (&in_layout , AV_CH_LAYOUT_STEREO)) < 0 ||
> + (ret = ff_channel_layouts_ref(in_layout, &ctx->inputs[0]->outcfg.channel_layouts)) < 0 ||
> + (ret = ff_add_channel_layout (&out_layout , AV_CH_LAYOUT_SURROUND)) < 0 ||
> + (ret = ff_channel_layouts_ref(out_layout, &ctx->outputs[0]->incfg.channel_layouts)) < 0)
> + return ret;
> +
> + return ff_set_common_all_samplerates(ctx);
> +}
> +
> +static int config_input(AVFilterLink *inlink)
> +{
> + AVFilterContext *ctx = inlink->dst;
> + AudioDialogueEnhanceContext *s = ctx->priv;
> + float scale = 1.f, iscale, overlap;
> + int ret;
> +
> + s->fft_size = inlink->sample_rate > 100000 ? 8192 : inlink->sample_rate > 50000 ? 4096 : 2048;
> + s->overlap = s->fft_size / 4;
> +
> + s->window = av_calloc(s->fft_size, sizeof(*s->window));
> + if (!s->window)
> + return AVERROR(ENOMEM);
> +
> + s->in_frame = ff_get_audio_buffer(inlink, s->fft_size * 4);
> + s->center_frame = ff_get_audio_buffer(inlink, s->fft_size * 4);
> + s->out_dist_frame = ff_get_audio_buffer(inlink, s->fft_size * 4);
> + s->windowed_frame = ff_get_audio_buffer(inlink, s->fft_size * 4);
> + s->windowed_out = ff_get_audio_buffer(inlink, s->fft_size * 4);
> + s->windowed_prev = ff_get_audio_buffer(inlink, s->fft_size * 4);
> + if (!s->in_frame || !s->windowed_out || !s->windowed_prev ||
> + !s->out_dist_frame || !s->windowed_frame || !s->center_frame)
> + return AVERROR(ENOMEM);
> +
> + generate_window_func(s->window, s->fft_size, WFUNC_SINE, &overlap);
> +
> + iscale = 1.f / s->fft_size;
> +
> + ret = av_tx_init(&s->tx_ctx[0], &s->tx_fn, AV_TX_FLOAT_RDFT, 0, s->fft_size, &scale, 0);
> + if (ret < 0)
> + return ret;
> +
> + ret = av_tx_init(&s->tx_ctx[1], &s->tx_fn, AV_TX_FLOAT_RDFT, 0, s->fft_size, &scale, 0);
> + if (ret < 0)
> + return ret;
> +
> + ret = av_tx_init(&s->itx_ctx, &s->itx_fn, AV_TX_FLOAT_RDFT, 1, s->fft_size, &iscale, 0);
> + if (ret < 0)
> + return ret;
> +
> + return 0;
> +}
> +
> +static void apply_window(AudioDialogueEnhanceContext *s,
> + const float *in_frame, float *out_frame, const int add_to_out_frame)
> +{
> + const float *window = s->window;
> +
> + if (add_to_out_frame) {
> + for (int i = 0; i < s->fft_size; i++)
> + out_frame[i] += in_frame[i] * window[i];
> + } else {
> + for (int i = 0; i < s->fft_size; i++)
> + out_frame[i] = in_frame[i] * window[i];
> + }
> +}
> +
> +static float sqrf(float x)
> +{
> + return x * x;
> +}
> +
> +static void get_centere(AVComplexFloat *left, AVComplexFloat *right,
> + AVComplexFloat *center, int N)
> +{
> + for (int i = 0; i < N; i++) {
> + const float l_re = left[i].re;
> + const float l_im = left[i].im;
> + const float r_re = right[i].re;
> + const float r_im = right[i].im;
> + const float a = 0.5f * (1.f - sqrtf((sqrf(l_re - r_re) + sqrf(l_im - r_im))/
> + (sqrf(l_re + r_re) + sqrf(l_im + r_im) + FLT_EPSILON)));
> +
> + center[i].re = a * (l_re + r_re);
> + center[i].im = a * (l_im + r_im);
> + }
> +}
> +
> +static float flux(float *curf, float *prevf, int N)
> +{
> + AVComplexFloat *cur = (AVComplexFloat *)curf;
> + AVComplexFloat *prev = (AVComplexFloat *)prevf;
> + float sum = 0.f;
> +
> + for (int i = 0; i < N; i++) {
> + float c_re = cur[i].re;
> + float c_im = cur[i].im;
> + float p_re = prev[i].re;
> + float p_im = prev[i].im;
> +
> + sum += sqrf(hypotf(c_re, c_im) - hypotf(p_re, p_im));
> + }
> +
> + return sum;
> +}
> +
> +static float fluxlr(float *lf, float *lpf,
> + float *rf, float *rpf,
> + int N)
> +{
> + AVComplexFloat *l = (AVComplexFloat *)lf;
> + AVComplexFloat *lp = (AVComplexFloat *)lpf;
> + AVComplexFloat *r = (AVComplexFloat *)rf;
> + AVComplexFloat *rp = (AVComplexFloat *)rpf;
> + float sum = 0.f;
> +
> + for (int i = 0; i < N; i++) {
> + float c_re = l[i].re - r[i].re;
> + float c_im = l[i].im - r[i].im;
> + float p_re = lp[i].re - rp[i].re;
> + float p_im = lp[i].im - rp[i].im;
> +
> + sum += sqrf(hypotf(c_re, c_im) - hypotf(p_re, p_im));
> + }
> +
> + return sum;
> +}
> +
> +static float calc_vad(float fc, float flr, float a)
> +{
> + const float vad = a * (fc / (fc + flr) - 0.5f);
> +
> + return av_clipf(vad, 0.f, 1.f);
> +}
> +
> +static void get_final(float *c, float *l,
> + float *r, float vad, int N,
> + float original, float enhance)
> +{
> + AVComplexFloat *center = (AVComplexFloat *)c;
> + AVComplexFloat *left = (AVComplexFloat *)l;
> + AVComplexFloat *right = (AVComplexFloat *)r;
> +
> + for (int i = 0; i < N; i++) {
> + float cP = sqrf(center[i].re) + sqrf(center[i].im);
> + float lrP = sqrf(left[i].re - right[i].re) + sqrf(left[i].im - right[i].im);
> + float G = cP / (cP + lrP + FLT_EPSILON);
> + float re, im;
> +
> + re = center[i].re * (original + vad * G * enhance);
> + im = center[i].im * (original + vad * G * enhance);
> +
> + center[i].re = re;
> + center[i].im = im;
> + }
> +}
> +
> +static int de_stereo(AVFilterContext *ctx, AVFrame *out)
> +{
> + AudioDialogueEnhanceContext *s = ctx->priv;
> + float *center = (float *)s->center_frame->extended_data[0];
> + float *center_prev = (float *)s->center_frame->extended_data[1];
> + float *left_in = (float *)s->in_frame->extended_data[0];
> + float *right_in = (float *)s->in_frame->extended_data[1];
> + float *left_out = (float *)s->out_dist_frame->extended_data[0];
> + float *right_out = (float *)s->out_dist_frame->extended_data[1];
> + float *left_samples = (float *)s->in->extended_data[0];
> + float *right_samples = (float *)s->in->extended_data[1];
> + float *windowed_left = (float *)s->windowed_frame->extended_data[0];
> + float *windowed_right = (float *)s->windowed_frame->extended_data[1];
> + float *windowed_oleft = (float *)s->windowed_out->extended_data[0];
> + float *windowed_oright = (float *)s->windowed_out->extended_data[1];
> + float *windowed_pleft = (float *)s->windowed_prev->extended_data[0];
> + float *windowed_pright = (float *)s->windowed_prev->extended_data[1];
> + float *left_osamples = (float *)out->extended_data[0];
> + float *right_osamples = (float *)out->extended_data[1];
> + float *center_osamples = (float *)out->extended_data[2];
> + const int offset = s->fft_size - s->overlap;
> + float vad;
> +
> + // shift in/out buffers
> + memmove(left_in, &left_in[s->overlap], offset * sizeof(float));
> + memmove(right_in, &right_in[s->overlap], offset * sizeof(float));
> + memmove(left_out, &left_out[s->overlap], offset * sizeof(float));
> + memmove(right_out, &right_out[s->overlap], offset * sizeof(float));
> +
> + memcpy(&left_in[offset], left_samples, s->overlap * sizeof(float));
> + memcpy(&right_in[offset], right_samples, s->overlap * sizeof(float));
> + memset(&left_out[offset], 0, s->overlap * sizeof(float));
> + memset(&right_out[offset], 0, s->overlap * sizeof(float));
> +
> + apply_window(s, left_in, windowed_left, 0);
> + apply_window(s, right_in, windowed_right, 0);
> +
> + s->tx_fn(s->tx_ctx[0], windowed_oleft, windowed_left, sizeof(float));
> + s->tx_fn(s->tx_ctx[1], windowed_oright, windowed_right, sizeof(float));
> +
> + get_centere((AVComplexFloat *)windowed_oleft,
> + (AVComplexFloat *)windowed_oright,
> + (AVComplexFloat *)center,
> + s->fft_size / 2 + 1);
> +
> + vad = calc_vad(flux(center, center_prev, s->fft_size / 2 + 1),
> + fluxlr(windowed_oleft, windowed_pleft,
> + windowed_oright, windowed_pright, s->fft_size / 2 + 1), s->voice);
> + vad = vad * 0.1 + 0.9 * s->prev_vad;
> + s->prev_vad = vad;
> +
> + memcpy(center_prev, center, s->fft_size * sizeof(float));
> + memcpy(windowed_pleft, windowed_oleft, s->fft_size * sizeof(float));
> + memcpy(windowed_pright, windowed_oright, s->fft_size * sizeof(float));
> +
> + get_final(center, windowed_oleft, windowed_oright, vad, s->fft_size / 2 + 1,
> + s->original, s->enhance);
> +
> + s->itx_fn(s->itx_ctx, windowed_oleft, center, sizeof(float));
> +
> + apply_window(s, windowed_oleft, left_out, 1);
> +
> + for (int i = 0; i < s->overlap; i++) {
> + // 4 times overlap with squared hanning window results in 1.5 time increase in amplitude
> + if (!ctx->is_disabled)
> + center_osamples[i] = left_out[i] / 1.5f;
> + else
> + center_osamples[i] = 0.f;
> + left_osamples[i] = left_in[i];
> + right_osamples[i] = right_in[i];
> + }
> +
> + return 0;
> +}
> +
> +static int filter_frame(AVFilterLink *inlink, AVFrame *in)
> +{
> + AVFilterContext *ctx = inlink->dst;
> + AVFilterLink *outlink = ctx->outputs[0];
> + AudioDialogueEnhanceContext *s = ctx->priv;
> + AVFrame *out;
> + int ret;
> +
> + out = ff_get_audio_buffer(outlink, s->overlap);
> + if (!out) {
> + ret = AVERROR(ENOMEM);
> + goto fail;
> + }
> +
> + s->in = in;
> + de_stereo(ctx, out);
> +
> + out->pts = in->pts;
> + out->nb_samples = in->nb_samples;
> + ret = ff_filter_frame(outlink, out);
> +fail:
> + av_frame_free(&in);
> + s->in = NULL;
> + return ret < 0 ? ret : 0;
> +}
> +
> +static int activate(AVFilterContext *ctx)
> +{
> + AVFilterLink *inlink = ctx->inputs[0];
> + AVFilterLink *outlink = ctx->outputs[0];
> + AudioDialogueEnhanceContext *s = ctx->priv;
> + AVFrame *in = NULL;
> + int ret = 0, status;
> + int64_t pts;
> +
> + FF_FILTER_FORWARD_STATUS_BACK(outlink, inlink);
> +
> + ret = ff_inlink_consume_samples(inlink, s->overlap, s->overlap, &in);
> + if (ret < 0)
> + return ret;
> +
> + if (ret > 0) {
> + return filter_frame(inlink, in);
> + } else if (ff_inlink_acknowledge_status(inlink, &status, &pts)) {
> + ff_outlink_set_status(outlink, status, pts);
> + return 0;
> + } else {
> + if (ff_inlink_queued_samples(inlink) >= s->overlap) {
> + ff_filter_set_ready(ctx, 10);
> + } else if (ff_outlink_frame_wanted(outlink)) {
> + ff_inlink_request_frame(inlink);
> + }
> + return 0;
> + }
> +}
> +
> +static av_cold void uninit(AVFilterContext *ctx)
> +{
> + AudioDialogueEnhanceContext *s = ctx->priv;
> +
> + av_freep(&s->window);
> +
> + av_frame_free(&s->in_frame);
> + av_frame_free(&s->center_frame);
> + av_frame_free(&s->out_dist_frame);
> + av_frame_free(&s->windowed_frame);
> + av_frame_free(&s->windowed_out);
> + av_frame_free(&s->windowed_prev);
> +
> + av_tx_uninit(&s->tx_ctx[0]);
> + av_tx_uninit(&s->tx_ctx[1]);
> + av_tx_uninit(&s->itx_ctx);
> +}
> +
> +static const AVFilterPad inputs[] = {
> + {
> + .name = "default",
> + .type = AVMEDIA_TYPE_AUDIO,
> + .config_props = config_input,
> + },
> +};
> +
> +static const AVFilterPad outputs[] = {
> + {
> + .name = "default",
> + .type = AVMEDIA_TYPE_AUDIO,
> + },
> +};
> +
> +const AVFilter ff_af_dialoguenhance = {
> + .name = "dialoguenhance",
> + .description = NULL_IF_CONFIG_SMALL("Audio Dialogue Enhancement."),
> + .priv_size = sizeof(AudioDialogueEnhanceContext),
> + .priv_class = &dialoguenhance_class,
> + .uninit = uninit,
> + FILTER_INPUTS(inputs),
> + FILTER_OUTPUTS(outputs),
> + FILTER_QUERY_FUNC(query_formats),
> + .flags = AVFILTER_FLAG_SUPPORT_TIMELINE_INTERNAL,
> + .activate = activate,
> + .process_command = ff_filter_process_command,
> +};
> diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
> index 714468afce..f5caee3a62 100644
> --- a/libavfilter/allfilters.c
> +++ b/libavfilter/allfilters.c
> @@ -115,6 +115,7 @@ extern const AVFilter ff_af_crossfeed;
> extern const AVFilter ff_af_crystalizer;
> extern const AVFilter ff_af_dcshift;
> extern const AVFilter ff_af_deesser;
> +extern const AVFilter ff_af_dialoguenhance;
> extern const AVFilter ff_af_drmeter;
> extern const AVFilter ff_af_dynaudnorm;
> extern const AVFilter ff_af_earwax;
> --
> 2.33.0
>
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