mirror of
https://github.com/FFmpeg/FFmpeg.git
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134 lines
4.0 KiB
C
134 lines
4.0 KiB
C
/*
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* Copyright (c) 2015 The FFmpeg Project
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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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#include "libavutil/channel_layout.h"
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#include "libavutil/opt.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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typedef struct ExtraStereoContext {
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const AVClass *class;
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float mult;
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int clip;
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} ExtraStereoContext;
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#define OFFSET(x) offsetof(ExtraStereoContext, x)
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#define A AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_RUNTIME_PARAM
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static const AVOption extrastereo_options[] = {
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{ "m", "set the difference coefficient", OFFSET(mult), AV_OPT_TYPE_FLOAT, {.dbl=2.5}, -10, 10, A },
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{ "c", "enable clipping", OFFSET(clip), AV_OPT_TYPE_BOOL, {.i64=1}, 0, 1, A },
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{ NULL }
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};
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AVFILTER_DEFINE_CLASS(extrastereo);
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static int query_formats(AVFilterContext *ctx)
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{
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AVFilterFormats *formats = NULL;
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AVFilterChannelLayouts *layout = NULL;
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int ret;
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if ((ret = ff_add_format (&formats, AV_SAMPLE_FMT_FLT )) < 0 ||
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(ret = ff_set_common_formats (ctx , formats )) < 0 ||
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(ret = ff_add_channel_layout (&layout , AV_CH_LAYOUT_STEREO)) < 0 ||
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(ret = ff_set_common_channel_layouts (ctx , layout )) < 0)
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return ret;
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formats = ff_all_samplerates();
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return ff_set_common_samplerates(ctx, formats);
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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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AVFilterLink *outlink = ctx->outputs[0];
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ExtraStereoContext *s = ctx->priv;
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const float *src = (const float *)in->data[0];
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const float mult = s->mult;
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AVFrame *out;
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float *dst;
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int n;
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if (av_frame_is_writable(in)) {
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out = in;
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} else {
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out = ff_get_audio_buffer(outlink, in->nb_samples);
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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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dst = (float *)out->data[0];
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for (n = 0; n < in->nb_samples; n++) {
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float average, left, right;
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left = src[n * 2 ];
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right = src[n * 2 + 1];
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average = (left + right) / 2.;
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left = average + mult * (left - average);
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right = average + mult * (right - average);
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if (s->clip) {
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left = av_clipf(left, -1, 1);
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right = av_clipf(right, -1, 1);
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}
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dst[n * 2 ] = left;
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dst[n * 2 + 1] = right;
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}
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if (out != in)
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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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static const AVFilterPad 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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},
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{ NULL }
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};
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static const AVFilterPad 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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{ NULL }
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};
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AVFilter ff_af_extrastereo = {
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.name = "extrastereo",
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.description = NULL_IF_CONFIG_SMALL("Increase difference between stereo audio channels."),
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.query_formats = query_formats,
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.priv_size = sizeof(ExtraStereoContext),
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.priv_class = &extrastereo_class,
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.inputs = inputs,
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.outputs = outputs,
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.flags = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC,
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.process_command = ff_filter_process_command,
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};
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