blob: 24146ff1df0068f5b46a46b0305969b1340fc0f9
| 1 | /* |
| 2 | * Copyright (C) 2012 VLC authors and VideoLAN |
| 3 | * Author : Sukrit Sangwan < sukritsangwan at gmail dot com > |
| 4 | * |
| 5 | * This file is part of FFmpeg. |
| 6 | * |
| 7 | * FFmpeg is free software; you can redistribute it and/or |
| 8 | * modify it under the terms of the GNU Lesser General Public |
| 9 | * License as published by the Free Software Foundation; either |
| 10 | * version 2.1 of the License, or (at your option) any later version. |
| 11 | * |
| 12 | * FFmpeg is distributed in the hope that it will be useful, |
| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 15 | * Lesser General Public License for more details. |
| 16 | * |
| 17 | * You should have received a copy of the GNU Lesser General Public |
| 18 | * License along with FFmpeg; if not, write to the Free Software |
| 19 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| 20 | */ |
| 21 | |
| 22 | #include "libavutil/channel_layout.h" |
| 23 | #include "libavutil/opt.h" |
| 24 | #include "avfilter.h" |
| 25 | #include "audio.h" |
| 26 | #include "formats.h" |
| 27 | |
| 28 | typedef struct StereoWidenContext { |
| 29 | const AVClass *class; |
| 30 | |
| 31 | float delay; |
| 32 | float feedback; |
| 33 | float crossfeed; |
| 34 | float drymix; |
| 35 | |
| 36 | float *buffer; |
| 37 | float *cur; |
| 38 | int length; |
| 39 | } StereoWidenContext; |
| 40 | |
| 41 | #define OFFSET(x) offsetof(StereoWidenContext, x) |
| 42 | #define A AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM |
| 43 | |
| 44 | static const AVOption stereowiden_options[] = { |
| 45 | { "delay", "set delay time", OFFSET(delay), AV_OPT_TYPE_FLOAT, {.dbl=20}, 1, 100, A }, |
| 46 | { "feedback", "set feedback gain", OFFSET(feedback), AV_OPT_TYPE_FLOAT, {.dbl=.3}, 0, 0.9, A }, |
| 47 | { "crossfeed", "set cross feed", OFFSET(crossfeed), AV_OPT_TYPE_FLOAT, {.dbl=.3}, 0, 0.8, A }, |
| 48 | { "drymix", "set dry-mix", OFFSET(drymix), AV_OPT_TYPE_FLOAT, {.dbl=.8}, 0, 1.0, A }, |
| 49 | { NULL } |
| 50 | }; |
| 51 | |
| 52 | AVFILTER_DEFINE_CLASS(stereowiden); |
| 53 | |
| 54 | static int query_formats(AVFilterContext *ctx) |
| 55 | { |
| 56 | AVFilterFormats *formats = NULL; |
| 57 | AVFilterChannelLayouts *layout = NULL; |
| 58 | int ret; |
| 59 | |
| 60 | if ((ret = ff_add_format (&formats, AV_SAMPLE_FMT_FLT )) < 0 || |
| 61 | (ret = ff_set_common_formats (ctx , formats )) < 0 || |
| 62 | (ret = ff_add_channel_layout (&layout , AV_CH_LAYOUT_STEREO)) < 0 || |
| 63 | (ret = ff_set_common_channel_layouts (ctx , layout )) < 0) |
| 64 | return ret; |
| 65 | |
| 66 | formats = ff_all_samplerates(); |
| 67 | return ff_set_common_samplerates(ctx, formats); |
| 68 | } |
| 69 | |
| 70 | static int config_input(AVFilterLink *inlink) |
| 71 | { |
| 72 | AVFilterContext *ctx = inlink->dst; |
| 73 | StereoWidenContext *s = ctx->priv; |
| 74 | |
| 75 | s->length = s->delay * inlink->sample_rate / 1000; |
| 76 | s->length *= 2; |
| 77 | s->buffer = av_calloc(s->length, sizeof(*s->buffer)); |
| 78 | if (!s->buffer) |
| 79 | return AVERROR(ENOMEM); |
| 80 | s->cur = s->buffer; |
| 81 | |
| 82 | return 0; |
| 83 | } |
| 84 | |
| 85 | static int filter_frame(AVFilterLink *inlink, AVFrame *in) |
| 86 | { |
| 87 | AVFilterContext *ctx = inlink->dst; |
| 88 | AVFilterLink *outlink = ctx->outputs[0]; |
| 89 | StereoWidenContext *s = ctx->priv; |
| 90 | const float *src = (const float *)in->data[0]; |
| 91 | const float drymix = s->drymix; |
| 92 | const float crossfeed = s->crossfeed; |
| 93 | const float feedback = s->feedback; |
| 94 | AVFrame *out; |
| 95 | float *dst; |
| 96 | int n; |
| 97 | |
| 98 | if (av_frame_is_writable(in)) { |
| 99 | out = in; |
| 100 | } else { |
| 101 | out = ff_get_audio_buffer(inlink, in->nb_samples); |
| 102 | if (!out) { |
| 103 | av_frame_free(&in); |
| 104 | return AVERROR(ENOMEM); |
| 105 | } |
| 106 | av_frame_copy_props(out, in); |
| 107 | } |
| 108 | dst = (float *)out->data[0]; |
| 109 | |
| 110 | for (n = 0; n < in->nb_samples; n++, src += 2, dst += 2, s->cur += 2) { |
| 111 | const float left = src[0], right = src[1]; |
| 112 | |
| 113 | if (s->cur == s->buffer + s->length) |
| 114 | s->cur = s->buffer; |
| 115 | |
| 116 | dst[0] = drymix * left - crossfeed * right - feedback * s->cur[1]; |
| 117 | dst[1] = drymix * right - crossfeed * left - feedback * s->cur[0]; |
| 118 | |
| 119 | s->cur[0] = left; |
| 120 | s->cur[1] = right; |
| 121 | } |
| 122 | |
| 123 | if (out != in) |
| 124 | av_frame_free(&in); |
| 125 | return ff_filter_frame(outlink, out); |
| 126 | } |
| 127 | |
| 128 | static av_cold void uninit(AVFilterContext *ctx) |
| 129 | { |
| 130 | StereoWidenContext *s = ctx->priv; |
| 131 | |
| 132 | av_freep(&s->buffer); |
| 133 | } |
| 134 | |
| 135 | static const AVFilterPad inputs[] = { |
| 136 | { |
| 137 | .name = "default", |
| 138 | .type = AVMEDIA_TYPE_AUDIO, |
| 139 | .filter_frame = filter_frame, |
| 140 | .config_props = config_input, |
| 141 | }, |
| 142 | { NULL } |
| 143 | }; |
| 144 | |
| 145 | static const AVFilterPad outputs[] = { |
| 146 | { |
| 147 | .name = "default", |
| 148 | .type = AVMEDIA_TYPE_AUDIO, |
| 149 | }, |
| 150 | { NULL } |
| 151 | }; |
| 152 | |
| 153 | AVFilter ff_af_stereowiden = { |
| 154 | .name = "stereowiden", |
| 155 | .description = NULL_IF_CONFIG_SMALL("Apply stereo widening effect."), |
| 156 | .query_formats = query_formats, |
| 157 | .priv_size = sizeof(StereoWidenContext), |
| 158 | .priv_class = &stereowiden_class, |
| 159 | .uninit = uninit, |
| 160 | .inputs = inputs, |
| 161 | .outputs = outputs, |
| 162 | }; |
| 163 |