From 2fc12f4971a788acbd42861af90858cc0981417a Mon Sep 17 00:00:00 2001 From: Paul B Mahol Date: Tue, 17 Apr 2018 11:31:34 +0200 Subject: avfilter: add lowshelf and highshelf filters These are old bass and treble filters. Make bass and treble filters better at boosting. Signed-off-by: Paul B Mahol --- libavfilter/af_biquads.c | 78 ++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 69 insertions(+), 9 deletions(-) (limited to 'libavfilter/af_biquads.c') diff --git a/libavfilter/af_biquads.c b/libavfilter/af_biquads.c index d5c3823e64..9dfc16cef6 100644 --- a/libavfilter/af_biquads.c +++ b/libavfilter/af_biquads.c @@ -78,6 +78,8 @@ enum FilterType { allpass, highpass, lowpass, + lowshelf, + highshelf, }; enum WidthType { @@ -245,7 +247,7 @@ static int config_filter(AVFilterLink *outlink, int reset) AVFilterLink *inlink = ctx->inputs[0]; double A = exp(s->gain / 40 * log(10.)); double w0 = 2 * M_PI * s->frequency / inlink->sample_rate; - double alpha; + double alpha, beta; if (w0 > M_PI) { av_log(ctx, AV_LOG_ERROR, @@ -277,6 +279,8 @@ static int config_filter(AVFilterLink *outlink, int reset) av_assert0(0); } + beta = 2 * sqrt(A); + switch (s->filter_type) { case biquad: break; @@ -289,20 +293,24 @@ static int config_filter(AVFilterLink *outlink, int reset) s->b2 = 1 - alpha * A; break; case bass: - s->a0 = (A + 1) + (A - 1) * cos(w0) + 2 * sqrt(A) * alpha; + beta = sqrt((A * A + 1) - (A - 1) * (A - 1)); + case lowshelf: + s->a0 = (A + 1) + (A - 1) * cos(w0) + beta * alpha; s->a1 = -2 * ((A - 1) + (A + 1) * cos(w0)); - s->a2 = (A + 1) + (A - 1) * cos(w0) - 2 * sqrt(A) * alpha; - s->b0 = A * ((A + 1) - (A - 1) * cos(w0) + 2 * sqrt(A) * alpha); + s->a2 = (A + 1) + (A - 1) * cos(w0) - beta * alpha; + s->b0 = A * ((A + 1) - (A - 1) * cos(w0) + beta * alpha); s->b1 = 2 * A * ((A - 1) - (A + 1) * cos(w0)); - s->b2 = A * ((A + 1) - (A - 1) * cos(w0) - 2 * sqrt(A) * alpha); + s->b2 = A * ((A + 1) - (A - 1) * cos(w0) - beta * alpha); break; case treble: - s->a0 = (A + 1) - (A - 1) * cos(w0) + 2 * sqrt(A) * alpha; + beta = sqrt((A * A + 1) - (A - 1) * (A - 1)); + case highshelf: + s->a0 = (A + 1) - (A - 1) * cos(w0) + beta * alpha; s->a1 = 2 * ((A - 1) - (A + 1) * cos(w0)); - s->a2 = (A + 1) - (A - 1) * cos(w0) - 2 * sqrt(A) * alpha; - s->b0 = A * ((A + 1) + (A - 1) * cos(w0) + 2 * sqrt(A) * alpha); + s->a2 = (A + 1) - (A - 1) * cos(w0) - beta * alpha; + s->b0 = A * ((A + 1) + (A - 1) * cos(w0) + beta * alpha); s->b1 =-2 * A * ((A - 1) + (A + 1) * cos(w0)); - s->b2 = A * ((A + 1) + (A - 1) * cos(w0) - 2 * sqrt(A) * alpha); + s->b2 = A * ((A + 1) + (A - 1) * cos(w0) - beta * alpha); break; case bandpass: if (s->csg) { @@ -459,6 +467,8 @@ static int process_command(AVFilterContext *ctx, const char *cmd, const char *ar if ((!strcmp(cmd, "frequency") || !strcmp(cmd, "f")) && (s->filter_type == equalizer || + s->filter_type == lowshelf || + s->filter_type == highshelf || s->filter_type == bass || s->filter_type == treble || s->filter_type == bandpass || @@ -476,6 +486,8 @@ static int process_command(AVFilterContext *ctx, const char *cmd, const char *ar s->frequency = freq; } else if ((!strcmp(cmd, "gain") || !strcmp(cmd, "g")) && (s->filter_type == equalizer || + s->filter_type == lowshelf || + s->filter_type == highshelf || s->filter_type == bass || s->filter_type == treble)) { double gain; @@ -488,6 +500,8 @@ static int process_command(AVFilterContext *ctx, const char *cmd, const char *ar s->gain = gain; } else if ((!strcmp(cmd, "width") || !strcmp(cmd, "w")) && (s->filter_type == equalizer || + s->filter_type == lowshelf || + s->filter_type == highshelf || s->filter_type == bass || s->filter_type == treble || s->filter_type == bandpass || @@ -505,6 +519,8 @@ static int process_command(AVFilterContext *ctx, const char *cmd, const char *ar s->width = width; } else if ((!strcmp(cmd, "width_type") || !strcmp(cmd, "t")) && (s->filter_type == equalizer || + s->filter_type == lowshelf || + s->filter_type == highshelf || s->filter_type == bass || s->filter_type == treble || s->filter_type == bandpass || @@ -784,6 +800,50 @@ static const AVOption allpass_options[] = { DEFINE_BIQUAD_FILTER(allpass, "Apply a two-pole all-pass filter."); #endif /* CONFIG_ALLPASS_FILTER */ +#if CONFIG_LOWSHELF_FILTER +static const AVOption lowshelf_options[] = { + {"frequency", "set central frequency", OFFSET(frequency), AV_OPT_TYPE_DOUBLE, {.dbl=100}, 0, 999999, FLAGS}, + {"f", "set central frequency", OFFSET(frequency), AV_OPT_TYPE_DOUBLE, {.dbl=100}, 0, 999999, FLAGS}, + {"width_type", "set filter-width type", OFFSET(width_type), AV_OPT_TYPE_INT, {.i64=QFACTOR}, HERTZ, NB_WTYPE-1, FLAGS, "width_type"}, + {"t", "set filter-width type", OFFSET(width_type), AV_OPT_TYPE_INT, {.i64=QFACTOR}, HERTZ, NB_WTYPE-1, FLAGS, "width_type"}, + {"h", "Hz", 0, AV_OPT_TYPE_CONST, {.i64=HERTZ}, 0, 0, FLAGS, "width_type"}, + {"q", "Q-Factor", 0, AV_OPT_TYPE_CONST, {.i64=QFACTOR}, 0, 0, FLAGS, "width_type"}, + {"o", "octave", 0, AV_OPT_TYPE_CONST, {.i64=OCTAVE}, 0, 0, FLAGS, "width_type"}, + {"s", "slope", 0, AV_OPT_TYPE_CONST, {.i64=SLOPE}, 0, 0, FLAGS, "width_type"}, + {"k", "kHz", 0, AV_OPT_TYPE_CONST, {.i64=KHERTZ}, 0, 0, FLAGS, "width_type"}, + {"width", "set shelf transition steep", OFFSET(width), AV_OPT_TYPE_DOUBLE, {.dbl=0.5}, 0, 99999, FLAGS}, + {"w", "set shelf transition steep", OFFSET(width), AV_OPT_TYPE_DOUBLE, {.dbl=0.5}, 0, 99999, FLAGS}, + {"gain", "set gain", OFFSET(gain), AV_OPT_TYPE_DOUBLE, {.dbl=0}, -900, 900, FLAGS}, + {"g", "set gain", OFFSET(gain), AV_OPT_TYPE_DOUBLE, {.dbl=0}, -900, 900, FLAGS}, + {"channels", "set channels to filter", OFFSET(channels), AV_OPT_TYPE_CHANNEL_LAYOUT, {.i64=-1}, INT64_MIN, INT64_MAX, FLAGS}, + {"c", "set channels to filter", OFFSET(channels), AV_OPT_TYPE_CHANNEL_LAYOUT, {.i64=-1}, INT64_MIN, INT64_MAX, FLAGS}, + {NULL} +}; + +DEFINE_BIQUAD_FILTER(lowshelf, "Apply a low shelf filter."); +#endif /* CONFIG_LOWSHELF_FILTER */ +#if CONFIG_HIGHSHELF_FILTER +static const AVOption highshelf_options[] = { + {"frequency", "set central frequency", OFFSET(frequency), AV_OPT_TYPE_DOUBLE, {.dbl=3000}, 0, 999999, FLAGS}, + {"f", "set central frequency", OFFSET(frequency), AV_OPT_TYPE_DOUBLE, {.dbl=3000}, 0, 999999, FLAGS}, + {"width_type", "set filter-width type", OFFSET(width_type), AV_OPT_TYPE_INT, {.i64=QFACTOR}, HERTZ, NB_WTYPE-1, FLAGS, "width_type"}, + {"t", "set filter-width type", OFFSET(width_type), AV_OPT_TYPE_INT, {.i64=QFACTOR}, HERTZ, NB_WTYPE-1, FLAGS, "width_type"}, + {"h", "Hz", 0, AV_OPT_TYPE_CONST, {.i64=HERTZ}, 0, 0, FLAGS, "width_type"}, + {"q", "Q-Factor", 0, AV_OPT_TYPE_CONST, {.i64=QFACTOR}, 0, 0, FLAGS, "width_type"}, + {"o", "octave", 0, AV_OPT_TYPE_CONST, {.i64=OCTAVE}, 0, 0, FLAGS, "width_type"}, + {"s", "slope", 0, AV_OPT_TYPE_CONST, {.i64=SLOPE}, 0, 0, FLAGS, "width_type"}, + {"k", "kHz", 0, AV_OPT_TYPE_CONST, {.i64=KHERTZ}, 0, 0, FLAGS, "width_type"}, + {"width", "set shelf transition steep", OFFSET(width), AV_OPT_TYPE_DOUBLE, {.dbl=0.5}, 0, 99999, FLAGS}, + {"w", "set shelf transition steep", OFFSET(width), AV_OPT_TYPE_DOUBLE, {.dbl=0.5}, 0, 99999, FLAGS}, + {"gain", "set gain", OFFSET(gain), AV_OPT_TYPE_DOUBLE, {.dbl=0}, -900, 900, FLAGS}, + {"g", "set gain", OFFSET(gain), AV_OPT_TYPE_DOUBLE, {.dbl=0}, -900, 900, FLAGS}, + {"channels", "set channels to filter", OFFSET(channels), AV_OPT_TYPE_CHANNEL_LAYOUT, {.i64=-1}, INT64_MIN, INT64_MAX, FLAGS}, + {"c", "set channels to filter", OFFSET(channels), AV_OPT_TYPE_CHANNEL_LAYOUT, {.i64=-1}, INT64_MIN, INT64_MAX, FLAGS}, + {NULL} +}; + +DEFINE_BIQUAD_FILTER(highshelf, "Apply a high shelf filter."); +#endif /* CONFIG_HIGHSHELF_FILTER */ #if CONFIG_BIQUAD_FILTER static const AVOption biquad_options[] = { {"a0", NULL, OFFSET(a0), AV_OPT_TYPE_DOUBLE, {.dbl=1}, INT32_MIN, INT32_MAX, FLAGS}, -- cgit v1.2.3