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			241 lines
		
	
	
		
			8.1 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			241 lines
		
	
	
		
			8.1 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /*
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|  * Copyright (c) 2011 Mina Nagy Zaki
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|  * Copyright (c) 2000 Edward Beingessner And Sundry Contributors.
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|  * This source code is freely redistributable and may be used for any purpose.
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|  * This copyright notice must be maintained.  Edward Beingessner And Sundry
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|  * Contributors are not responsible for the consequences of using this
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|  * software.
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|  *
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|  * This file is part of FFmpeg.
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|  *
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|  * FFmpeg is free software; you can redistribute it and/or
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|  * modify it under the terms of the GNU Lesser General Public
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|  * License as published by the Free Software Foundation; either
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|  * version 2.1 of the License, or (at your option) any later version.
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|  *
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|  * FFmpeg is distributed in the hope that it will be useful,
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|  * but WITHOUT ANY WARRANTY; without even the implied warranty of
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|  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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|  * Lesser General Public License for more details.
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|  *
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|  * You should have received a copy of the GNU Lesser General Public
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|  * License along with FFmpeg; if not, write to the Free Software
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|  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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|  */
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| 
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| /**
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|  * @file
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|  * Stereo Widening Effect. Adds audio cues to move stereo image in
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|  * front of the listener. Adapted from the libsox earwax effect.
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|  */
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| 
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| #include "libavutil/channel_layout.h"
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| #include "avfilter.h"
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| #include "audio.h"
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| #include "formats.h"
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| 
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| #define NUMTAPS 32
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| 
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| static const int8_t filt[NUMTAPS * 2] = {
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| /* 30°  330° */
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|     4,   -6,     /* 32 tap stereo FIR filter. */
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|     4,  -11,     /* One side filters as if the */
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|    -1,   -5,     /* signal was from 30 degrees */
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|     3,    3,     /* from the ear, the other as */
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|    -2,    5,     /* if 330 degrees. */
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|    -5,    0,
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|     9,    1,
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|     6,    3,     /*                         Input                         */
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|    -4,   -1,     /*                   Left         Right                  */
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|    -5,   -3,     /*                __________   __________                */
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|    -2,   -5,     /*               |          | |          |               */
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|    -7,    1,     /*           .---|  Hh,0(f) | |  Hh,0(f) |---.           */
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|     6,   -7,     /*          /    |__________| |__________|    \          */
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|    30,  -29,     /*         /                \ /                \         */
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|    12,   -3,     /*        /                  X                  \        */
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|   -11,    4,     /*       /                  / \                  \       */
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|    -3,    7,     /*  ____V_____   __________V   V__________   _____V____  */
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|   -20,   23,     /* |          | |          |   |          | |          | */
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|     2,    0,     /* | Hh,30(f) | | Hh,330(f)|   | Hh,330(f)| | Hh,30(f) | */
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|     1,   -6,     /* |__________| |__________|   |__________| |__________| */
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|   -14,   -5,     /*      \     ___      /           \      ___     /      */
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|    15,  -18,     /*       \   /   \    /    _____    \    /   \   /       */
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|     6,    7,     /*        `->| + |<--'    /     \    `-->| + |<-'        */
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|    15,  -10,     /*           \___/      _/       \_      \___/           */
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|   -14,   22,     /*               \     / \       / \     /               */
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|    -7,   -2,     /*                `--->| |       | |<---'                */
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|    -4,    9,     /*                     \_/       \_/                     */
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|     6,  -12,     /*                                                       */
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|     6,   -6,     /*                       Headphones                      */
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|     0,  -11,
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|     0,   -5,
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|     4,    0};
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| 
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| typedef struct EarwaxContext {
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|     int16_t filter[2][NUMTAPS];
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|     int16_t taps[4][NUMTAPS * 2];
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| 
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|     AVFrame *frame[2];
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| } EarwaxContext;
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| 
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| static int query_formats(AVFilterContext *ctx)
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| {
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|     static const int sample_rates[] = { 44100, -1 };
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|     int ret;
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| 
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|     AVFilterFormats *formats = NULL;
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|     AVFilterChannelLayouts *layout = NULL;
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| 
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|     if ((ret = ff_add_format                 (&formats, AV_SAMPLE_FMT_S16P                )) < 0 ||
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|         (ret = ff_set_common_formats         (ctx     , formats                           )) < 0 ||
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|         (ret = ff_add_channel_layout         (&layout , &(AVChannelLayout)AV_CHANNEL_LAYOUT_STEREO)) < 0 ||
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|         (ret = ff_set_common_channel_layouts (ctx     , layout                            )) < 0 ||
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|         (ret = ff_set_common_samplerates_from_list(ctx, sample_rates)) < 0)
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|         return ret;
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| 
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|     return 0;
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| }
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| 
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| //FIXME: replace with DSPContext.scalarproduct_int16
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| static inline int16_t *scalarproduct(const int16_t *in, const int16_t *endin,
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|                                      const int16_t *filt, int16_t *out)
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| {
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|     int32_t sample;
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|     int16_t j;
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| 
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|     while (in < endin) {
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|         sample = 0;
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|         for (j = 0; j < NUMTAPS; j++)
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|             sample += in[j] * filt[j];
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|         *out = av_clip_int16(sample >> 7);
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|         out++;
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|         in++;
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|     }
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| 
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|     return out;
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| }
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| 
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| static int config_input(AVFilterLink *inlink)
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| {
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|     EarwaxContext *s = inlink->dst->priv;
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| 
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|     for (int i = 0; i < NUMTAPS; i++) {
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|         s->filter[0][i] = filt[i * 2];
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|         s->filter[1][i] = filt[i * 2 + 1];
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|     }
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| 
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|     return 0;
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| }
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| 
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| static void convolve(AVFilterContext *ctx, AVFrame *in,
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|                      int input_ch, int output_ch,
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|                      int filter_ch, int tap_ch)
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| {
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|     EarwaxContext *s = ctx->priv;
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|     int16_t *taps, *endin, *dst, *src;
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|     int len;
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| 
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|     taps  = s->taps[tap_ch];
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|     dst   = (int16_t *)s->frame[input_ch]->data[output_ch];
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|     src   = (int16_t *)in->data[input_ch];
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| 
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|     len = FFMIN(NUMTAPS, in->nb_samples);
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|     // copy part of new input and process with saved input
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|     memcpy(taps+NUMTAPS, src, len * sizeof(*taps));
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|     dst = scalarproduct(taps, taps + len, s->filter[filter_ch], dst);
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| 
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|     // process current input
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|     if (in->nb_samples >= NUMTAPS) {
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|         endin = src + in->nb_samples - NUMTAPS;
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|         scalarproduct(src, endin, s->filter[filter_ch], dst);
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| 
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|         // save part of input for next round
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|         memcpy(taps, endin, NUMTAPS * sizeof(*taps));
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|     } else {
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|         memmove(taps, taps + in->nb_samples, NUMTAPS * sizeof(*taps));
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|     }
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| }
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| 
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| static void mix(AVFilterContext *ctx, AVFrame *out,
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|                 int output_ch, int f0, int f1, int i0, int i1)
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| {
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|     EarwaxContext *s = ctx->priv;
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|     const int16_t *srcl = (const int16_t *)s->frame[f0]->data[i0];
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|     const int16_t *srcr = (const int16_t *)s->frame[f1]->data[i1];
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|     int16_t *dst = (int16_t *)out->data[output_ch];
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| 
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|     for (int n = 0; n < out->nb_samples; n++)
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|         dst[n] = av_clip_int16(srcl[n] + srcr[n]);
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| }
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| 
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| static int filter_frame(AVFilterLink *inlink, AVFrame *in)
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| {
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|     AVFilterContext *ctx = inlink->dst;
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|     EarwaxContext *s = ctx->priv;
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|     AVFilterLink *outlink = ctx->outputs[0];
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|     AVFrame *out = ff_get_audio_buffer(outlink, in->nb_samples);
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| 
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|     for (int ch = 0; ch < 2; ch++) {
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|         if (!s->frame[ch] || s->frame[ch]->nb_samples < in->nb_samples) {
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|             av_frame_free(&s->frame[ch]);
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|             s->frame[ch] = ff_get_audio_buffer(outlink, in->nb_samples);
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|             if (!s->frame[ch]) {
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|                 av_frame_free(&in);
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|                 av_frame_free(&out);
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|                 return AVERROR(ENOMEM);
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|             }
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|         }
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|     }
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| 
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|     if (!out) {
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|         av_frame_free(&in);
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|         return AVERROR(ENOMEM);
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|     }
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|     av_frame_copy_props(out, in);
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| 
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|     convolve(ctx, in, 0, 0, 0, 0);
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|     convolve(ctx, in, 0, 1, 1, 1);
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|     convolve(ctx, in, 1, 0, 0, 2);
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|     convolve(ctx, in, 1, 1, 1, 3);
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| 
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|     mix(ctx, out, 0, 0, 1, 1, 0);
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|     mix(ctx, out, 1, 0, 1, 0, 1);
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| 
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|     av_frame_free(&in);
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|     return ff_filter_frame(outlink, out);
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| }
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| 
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| static av_cold void uninit(AVFilterContext *ctx)
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| {
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|     EarwaxContext *s = ctx->priv;
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| 
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|     av_frame_free(&s->frame[0]);
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|     av_frame_free(&s->frame[1]);
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| }
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| 
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| static const AVFilterPad earwax_inputs[] = {
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|     {
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|         .name         = "default",
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|         .type         = AVMEDIA_TYPE_AUDIO,
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|         .filter_frame = filter_frame,
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|         .config_props = config_input,
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|     },
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| };
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| 
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| static const AVFilterPad earwax_outputs[] = {
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|     {
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|         .name = "default",
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|         .type = AVMEDIA_TYPE_AUDIO,
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|     },
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| };
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| 
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| const AVFilter ff_af_earwax = {
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|     .name           = "earwax",
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|     .description    = NULL_IF_CONFIG_SMALL("Widen the stereo image."),
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|     .priv_size      = sizeof(EarwaxContext),
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|     .uninit         = uninit,
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|     FILTER_INPUTS(earwax_inputs),
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|     FILTER_OUTPUTS(earwax_outputs),
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|     FILTER_QUERY_FUNC(query_formats),
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| };
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