File size: 4,401 Bytes
8ead80b |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 |
/*
* Copyright (c) 2000 Chris Ausbrooks <[email protected]>
* Copyright (c) 2000 Fabien COELHO <[email protected]>
*
* 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/opt.h"
#include "libavutil/samplefmt.h"
#include "avfilter.h"
#include "audio.h"
#include "internal.h"
typedef struct DCShiftContext {
const AVClass *class;
double dcshift;
double limiterthreshold;
double limitergain;
} DCShiftContext;
#define OFFSET(x) offsetof(DCShiftContext, x)
#define A AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
static const AVOption dcshift_options[] = {
{ "shift", "set DC shift", OFFSET(dcshift), AV_OPT_TYPE_DOUBLE, {.dbl=0}, -1, 1, A },
{ "limitergain", "set limiter gain", OFFSET(limitergain), AV_OPT_TYPE_DOUBLE, {.dbl=0}, 0, 1, A },
{ NULL }
};
AVFILTER_DEFINE_CLASS(dcshift);
static av_cold int init(AVFilterContext *ctx)
{
DCShiftContext *s = ctx->priv;
s->limiterthreshold = INT32_MAX * (1.0 - (fabs(s->dcshift) - s->limitergain));
return 0;
}
static int filter_frame(AVFilterLink *inlink, AVFrame *in)
{
AVFilterContext *ctx = inlink->dst;
AVFilterLink *outlink = ctx->outputs[0];
AVFrame *out;
DCShiftContext *s = ctx->priv;
int i, j;
double dcshift = s->dcshift;
if (av_frame_is_writable(in)) {
out = in;
} else {
out = ff_get_audio_buffer(outlink, in->nb_samples);
if (!out) {
av_frame_free(&in);
return AVERROR(ENOMEM);
}
av_frame_copy_props(out, in);
}
if (s->limitergain > 0) {
for (i = 0; i < inlink->ch_layout.nb_channels; i++) {
const int32_t *src = (int32_t *)in->extended_data[i];
int32_t *dst = (int32_t *)out->extended_data[i];
for (j = 0; j < in->nb_samples; j++) {
double d;
d = src[j];
if (d > s->limiterthreshold && dcshift > 0) {
d = (d - s->limiterthreshold) * s->limitergain /
(INT32_MAX - s->limiterthreshold) +
s->limiterthreshold + dcshift;
} else if (d < -s->limiterthreshold && dcshift < 0) {
d = (d + s->limiterthreshold) * s->limitergain /
(INT32_MAX - s->limiterthreshold) -
s->limiterthreshold + dcshift;
} else {
d = dcshift * INT32_MAX + d;
}
dst[j] = av_clipl_int32(d);
}
}
} else {
for (i = 0; i < inlink->ch_layout.nb_channels; i++) {
const int32_t *src = (int32_t *)in->extended_data[i];
int32_t *dst = (int32_t *)out->extended_data[i];
for (j = 0; j < in->nb_samples; j++) {
double d = dcshift * (INT32_MAX + 1.) + src[j];
dst[j] = av_clipl_int32(d);
}
}
}
if (out != in)
av_frame_free(&in);
return ff_filter_frame(outlink, out);
}
static const AVFilterPad dcshift_inputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_AUDIO,
.filter_frame = filter_frame,
},
};
const AVFilter ff_af_dcshift = {
.name = "dcshift",
.description = NULL_IF_CONFIG_SMALL("Apply a DC shift to the audio."),
.priv_size = sizeof(DCShiftContext),
.priv_class = &dcshift_class,
.init = init,
FILTER_INPUTS(dcshift_inputs),
FILTER_OUTPUTS(ff_audio_default_filterpad),
FILTER_SINGLE_SAMPLEFMT(AV_SAMPLE_FMT_S32P),
.flags = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC,
};
|