diff options
author | Paul B Mahol <onemda@gmail.com> | 2015-09-05 06:55:47 +0300 |
---|---|---|
committer | Paul B Mahol <onemda@gmail.com> | 2015-09-08 13:43:17 +0300 |
commit | b31041adc32f9bb26a400903f13c2220fa6e08f5 (patch) | |
tree | c82d11ad2eeebb039ac910ef7951289b82b0b21d /libavfilter/af_extrastereo.c | |
parent | 9b2802f0d3296059a61b0f323ee0fc86eba48bf5 (diff) |
avfilter: add extrastereo filter
Signed-off-by: Paul B Mahol <onemda@gmail.com>
Diffstat (limited to 'libavfilter/af_extrastereo.c')
-rw-r--r-- | libavfilter/af_extrastereo.c | 128 |
1 files changed, 128 insertions, 0 deletions
diff --git a/libavfilter/af_extrastereo.c b/libavfilter/af_extrastereo.c new file mode 100644 index 0000000000..4877244a4f --- /dev/null +++ b/libavfilter/af_extrastereo.c @@ -0,0 +1,128 @@ +/* + * Copyright (c) 2015 The FFmpeg Project + * + * 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 + */ + +#include "libavutil/channel_layout.h" +#include "libavutil/opt.h" +#include "avfilter.h" +#include "audio.h" +#include "formats.h" + +typedef struct ExtraStereoContext { + const AVClass *class; + float mult; + int clip; +} ExtraStereoContext; + +#define OFFSET(x) offsetof(ExtraStereoContext, x) +#define A AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM + +static const AVOption extrastereo_options[] = { + { "m", "set the difference coefficient", OFFSET(mult), AV_OPT_TYPE_FLOAT, {.dbl=2.5}, -10, 10, A }, + { "c", "enable clipping", OFFSET(clip), AV_OPT_TYPE_INT, {.i64=1}, 0, 1, A }, + { NULL } +}; + +AVFILTER_DEFINE_CLASS(extrastereo); + +static int query_formats(AVFilterContext *ctx) +{ + AVFilterFormats *formats = NULL; + AVFilterChannelLayouts *layout = NULL; + + ff_add_format(&formats, AV_SAMPLE_FMT_FLT); + ff_set_common_formats(ctx, formats); + ff_add_channel_layout(&layout, AV_CH_LAYOUT_STEREO); + ff_set_common_channel_layouts(ctx, layout); + + formats = ff_all_samplerates(); + if (!formats) + return AVERROR(ENOMEM); + return ff_set_common_samplerates(ctx, formats); +} + +static int filter_frame(AVFilterLink *inlink, AVFrame *in) +{ + AVFilterContext *ctx = inlink->dst; + AVFilterLink *outlink = ctx->outputs[0]; + ExtraStereoContext *s = ctx->priv; + const float *src = (const float *)in->data[0]; + const float mult = s->mult; + AVFrame *out = NULL; + float *dst; + int n; + + if (av_frame_is_writable(in)) { + out = in; + } else { + AVFrame *out = ff_get_audio_buffer(inlink, in->nb_samples); + if (!out) { + av_frame_free(&in); + return AVERROR(ENOMEM); + } + av_frame_copy_props(out, in); + } + dst = (float *)out->data[0]; + + for (n = 0; n < in->nb_samples; n++) { + float average, left, right; + + left = src[n * 2 ]; + right = src[n * 2 + 1]; + average = (left + right) / 2.; + left = average + mult * (left - average); + right = average + mult * (right - average); + + if (s->clip) { + dst[n * 2 ] = av_clipf(left, -1, 1); + dst[n * 2 + 1] = av_clipf(right, -1, 1); + } + } + + if (out != in) + av_frame_free(&in); + return ff_filter_frame(outlink, out); +} + +static const AVFilterPad inputs[] = { + { + .name = "default", + .type = AVMEDIA_TYPE_AUDIO, + .filter_frame = filter_frame, + }, + { NULL } +}; + +static const AVFilterPad outputs[] = { + { + .name = "default", + .type = AVMEDIA_TYPE_AUDIO, + }, + { NULL } +}; + +AVFilter ff_af_extrastereo = { + .name = "extrastereo", + .description = NULL_IF_CONFIG_SMALL("Increase difference between stereo audio channels."), + .query_formats = query_formats, + .priv_size = sizeof(ExtraStereoContext), + .priv_class = &extrastereo_class, + .inputs = inputs, + .outputs = outputs, +}; |