0,0 → 1,172 |
/* |
* Copyright (c) 2011 Mina Nagy Zaki |
* Copyright (c) 2000 Edward Beingessner And Sundry Contributors. |
* This source code is freely redistributable and may be used for any purpose. |
* This copyright notice must be maintained. Edward Beingessner And Sundry |
* Contributors are not responsible for the consequences of using this |
* software. |
* |
* 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 |
*/ |
|
/** |
* @file |
* Stereo Widening Effect. Adds audio cues to move stereo image in |
* front of the listener. Adapted from the libsox earwax effect. |
*/ |
|
#include "libavutil/channel_layout.h" |
#include "avfilter.h" |
#include "audio.h" |
#include "formats.h" |
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#define NUMTAPS 64 |
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static const int8_t filt[NUMTAPS] = { |
/* 30° 330° */ |
4, -6, /* 32 tap stereo FIR filter. */ |
4, -11, /* One side filters as if the */ |
-1, -5, /* signal was from 30 degrees */ |
3, 3, /* from the ear, the other as */ |
-2, 5, /* if 330 degrees. */ |
-5, 0, |
9, 1, |
6, 3, /* Input */ |
-4, -1, /* Left Right */ |
-5, -3, /* __________ __________ */ |
-2, -5, /* | | | | */ |
-7, 1, /* .---| Hh,0(f) | | Hh,0(f) |---. */ |
6, -7, /* / |__________| |__________| \ */ |
30, -29, /* / \ / \ */ |
12, -3, /* / X \ */ |
-11, 4, /* / / \ \ */ |
-3, 7, /* ____V_____ __________V V__________ _____V____ */ |
-20, 23, /* | | | | | | | | */ |
2, 0, /* | Hh,30(f) | | Hh,330(f)| | Hh,330(f)| | Hh,30(f) | */ |
1, -6, /* |__________| |__________| |__________| |__________| */ |
-14, -5, /* \ ___ / \ ___ / */ |
15, -18, /* \ / \ / _____ \ / \ / */ |
6, 7, /* `->| + |<--' / \ `-->| + |<-' */ |
15, -10, /* \___/ _/ \_ \___/ */ |
-14, 22, /* \ / \ / \ / */ |
-7, -2, /* `--->| | | |<---' */ |
-4, 9, /* \_/ \_/ */ |
6, -12, /* */ |
6, -6, /* Headphones */ |
0, -11, |
0, -5, |
4, 0}; |
|
typedef struct { |
int16_t taps[NUMTAPS * 2]; |
} EarwaxContext; |
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static int query_formats(AVFilterContext *ctx) |
{ |
static const int sample_rates[] = { 44100, -1 }; |
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AVFilterFormats *formats = NULL; |
AVFilterChannelLayouts *layout = NULL; |
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ff_add_format(&formats, AV_SAMPLE_FMT_S16); |
ff_set_common_formats(ctx, formats); |
ff_add_channel_layout(&layout, AV_CH_LAYOUT_STEREO); |
ff_set_common_channel_layouts(ctx, layout); |
ff_set_common_samplerates(ctx, ff_make_format_list(sample_rates)); |
|
return 0; |
} |
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//FIXME: replace with DSPContext.scalarproduct_int16 |
static inline int16_t *scalarproduct(const int16_t *in, const int16_t *endin, int16_t *out) |
{ |
int32_t sample; |
int16_t j; |
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while (in < endin) { |
sample = 0; |
for (j = 0; j < NUMTAPS; j++) |
sample += in[j] * filt[j]; |
*out = av_clip_int16(sample >> 6); |
out++; |
in++; |
} |
|
return out; |
} |
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static int filter_frame(AVFilterLink *inlink, AVFrame *insamples) |
{ |
AVFilterLink *outlink = inlink->dst->outputs[0]; |
int16_t *taps, *endin, *in, *out; |
AVFrame *outsamples = ff_get_audio_buffer(inlink, insamples->nb_samples); |
int len; |
|
if (!outsamples) { |
av_frame_free(&insamples); |
return AVERROR(ENOMEM); |
} |
av_frame_copy_props(outsamples, insamples); |
|
taps = ((EarwaxContext *)inlink->dst->priv)->taps; |
out = (int16_t *)outsamples->data[0]; |
in = (int16_t *)insamples ->data[0]; |
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len = FFMIN(NUMTAPS, 2*insamples->nb_samples); |
// copy part of new input and process with saved input |
memcpy(taps+NUMTAPS, in, len * sizeof(*taps)); |
out = scalarproduct(taps, taps + len, out); |
|
// process current input |
if (2*insamples->nb_samples >= NUMTAPS ){ |
endin = in + insamples->nb_samples * 2 - NUMTAPS; |
scalarproduct(in, endin, out); |
|
// save part of input for next round |
memcpy(taps, endin, NUMTAPS * sizeof(*taps)); |
} else |
memmove(taps, taps + 2*insamples->nb_samples, NUMTAPS * sizeof(*taps)); |
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av_frame_free(&insamples); |
return ff_filter_frame(outlink, outsamples); |
} |
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static const AVFilterPad earwax_inputs[] = { |
{ |
.name = "default", |
.type = AVMEDIA_TYPE_AUDIO, |
.filter_frame = filter_frame, |
}, |
{ NULL } |
}; |
|
static const AVFilterPad earwax_outputs[] = { |
{ |
.name = "default", |
.type = AVMEDIA_TYPE_AUDIO, |
}, |
{ NULL } |
}; |
|
AVFilter avfilter_af_earwax = { |
.name = "earwax", |
.description = NULL_IF_CONFIG_SMALL("Widen the stereo image."), |
.query_formats = query_formats, |
.priv_size = sizeof(EarwaxContext), |
.inputs = earwax_inputs, |
.outputs = earwax_outputs, |
}; |