audio/filter: remove some useless filters

All of these filters are considered not useful anymore by us. Some have
replacements in libavfilter (useable through af_lavfi).

af_center, af_extrastereo, af_karaoke, af_sinesuppress, af_sub,
af_surround, af_sweep: pretty simple and useless filters which probably
nobody ever wants.

af_ladspa: has a replacement in libavfilter.

af_hrtf: the algorithm doesn't work properly on most sources, and the
implementation was buggy and complicated. (The filter was inherited from
MPlayer; but even in mpv times we had to apply fixes that fixed major
issues with added noise.) There is a ladspa filter if you still want to
use it.

af_export: I'm not even sure what this is supposed to do. Possibly it
was meant for GUIs rendering audio visualizations, but it couldn't
really work well. For example, the size of the audio depended on the
samplerate (fixed number of samples only), and it couldn't retrieve the
complete audio, only fragments. If this is really needed for GUIs, mpv
should add native visualization, or a proper API for it.

1 files changed, 0 insertions, 86 deletions

diff --git a/audio/filter/af_karaoke.c b/audio/filter/af_karaoke.c
deleted file mode 100644
index 0c8dc626d7..0000000000
--- a/audio/filter/af_karaoke.c
+++ /dev/null
@@ -1,86 +0,0 @@
-/*
- * simple voice removal filter
- *
- * copyright (c) 2006 Reynaldo H. Verdejo Pinochet
- * Based on code by Alex Beregszaszi for his 'center' filter.
- *
- * This file is part of mpv.
- *
- * mpv is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * mpv 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 General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License along
- * with mpv.  If not, see <http://www.gnu.org/licenses/>.
- */
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-
-#include "af.h"
-
-// Data for specific instances of this filter
-
-// Initialization and runtime control
-static int control(struct af_instance* af, int cmd, void* arg)
-{
-        switch(cmd){
-                case AF_CONTROL_REINIT:
-                mp_audio_copy_config(af->data, (struct mp_audio*)arg);
-                mp_audio_set_format(af->data, AF_FORMAT_FLOAT);
-                return af_test_output(af,(struct mp_audio*)arg);
-        }
-        return AF_UNKNOWN;
-}
-
-static int filter_frame(struct af_instance *af, struct mp_audio *c)
-{
-        if (!c)
-                return 0;
-        if (af_make_writeable(af, c) < 0) {
-                talloc_free(c);
-                return 0;
-        }
-
-        float*          a       = c->planes[0];  // Audio data
-        int                     nch     = c->nch;        // Number of channels
-        int                     len     = c->samples*nch;        // Number of samples in current audio block
-        register int  i;
-
-        /*
-                FIXME1 add a low band pass filter to avoid suppressing
-                centered bass/drums
-                FIXME2 better calculated* attenuation factor
-        */
-
-        for(i=0;i<len;i+=nch)
-        {
-                a[i] = (a[i] - a[i+1]) * 0.7;
-                a[i+1]=a[i];
-        }
-
-        af_add_output_frame(af, c);
-        return 0;
-}
-
-// Allocate memory and set function pointers
-static int af_open(struct af_instance* af){
-        af->control     = control;
-        af->filter_frame = filter_frame;
-        return AF_OK;
-}
-
-// Description of this filter
-const struct af_info af_info_karaoke = {
-        .info = "Simple karaoke/voice-removal audio filter",
-        .name = "karaoke",
-        .flags = AF_FLAGS_NOT_REENTRANT,
-        .open = af_open,
-};