From 870baf207a74d3700954ba4c07a25f85a3730989 Mon Sep 17 00:00:00 2001
From: Sanchit Sinha <sanchit15083@iiitd.ac.in>
Date: Sat, 18 Mar 2017 15:11:50 +0530
Subject: [PATCH] added: lavf/af_ambisonic.c makefile allfilters.c changelog
Signed-off-by: Sanchit Sinha <sanchit15083@iiitd.ac.in>
---
Changelog | 1 +
libavfilter/Makefile | 1 +
libavfilter/af_ambisonic.c | 122 +++++++++++++++++++++++++++++++++++++++++++++
libavfilter/allfilters.c | 1 +
4 files changed, 125 insertions(+)
create mode 100644 libavfilter/af_ambisonic.c
@@ -26,6 +26,7 @@ version <next>:
- native Opus encoder
- ScreenPressor decoder
- incomplete ClearVideo decoder
+- Ambisonic Decoder
version 3.2:
- libopenmpt demuxer
@@ -44,6 +44,7 @@ OBJS-$(CONFIG_AINTERLEAVE_FILTER) += f_interleave.o
OBJS-$(CONFIG_ALIMITER_FILTER) += af_alimiter.o
OBJS-$(CONFIG_ALLPASS_FILTER) += af_biquads.o
OBJS-$(CONFIG_ALOOP_FILTER) += f_loop.o
+OBJS-$(CONFIG_AMBISONIC_FILTER) += af_ambisonic.o
OBJS-$(CONFIG_AMERGE_FILTER) += af_amerge.o
OBJS-$(CONFIG_AMETADATA_FILTER) += f_metadata.o
OBJS-$(CONFIG_AMIX_FILTER) += af_amix.o
new file mode 100644
@@ -0,0 +1,122 @@
+/*
+ * Copyright (c) 2017 Sanchit Sinha
+ * Copyright (c) 2017 Paul B Mahol
+ * 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 <stdio.h>
+#include "libavutil/avstring.h"
+#include "libavutil/channel_layout.h"
+#include "libavutil/opt.h"
+#include "audio.h"
+#include "avfilter.h"
+#include "formats.h"
+#include <math.h>
+
+typedef struct AmbisonicContext {
+ const AVClass *class;
+} AmbisonicContext;
+
+static const AVOption ambisonic_options[] = {
+ {NULL}
+};
+
+AVFILTER_DEFINE_CLASS(ambisonic);
+
+static int query_formats(AVFilterContext *ctx)
+{
+ AVFilterFormats *formats = NULL;
+ AVFilterChannelLayouts *layout = NULL;
+ int ret;
+
+ if ((ret = ff_add_format (&formats, AV_SAMPLE_FMT_FLTP )) < 0 ||
+ (ret = ff_set_common_formats (ctx , formats )) < 0 ||
+ (ret = ff_add_channel_layout (&layout , AV_CH_LAYOUT_4POINT0)) < 0 ||
+ (ret = ff_set_common_channel_layouts (ctx , layout )) < 0)
+ return ret;
+
+ formats = ff_all_samplerates();
+ return ff_set_common_samplerates(ctx, formats);
+}
+static int filter_frame(AVFilterLink *inlink, AVFrame *in)
+{
+ AVFilterContext *ctx = inlink->dst;
+ AVFilterLink *outlink = ctx->outputs[0];
+ AVFrame *out;
+ int itr;
+ float *w,*x,*y,*c1,*c2,*c3,*c4;
+ float root8 = sqrt(8);
+ float lf=0,lb=0,rb=0,rf=0;
+
+ if (av_frame_is_writable(in)) {
+ out = in;
+ } else {
+ out = ff_get_audio_buffer(inlink, in->nb_samples);
+ if (!out){
+ av_frame_free(&in);
+ return AVERROR(ENOMEM);
+ }
+ av_frame_copy_props(out, in);
+ }
+
+ w=(float *)in->extended_data[0];
+ x=(float *)in->extended_data[1];
+ y=(float *)in->extended_data[2];
+ c1=(float *)out->extended_data[0];
+ c2=(float *)out->extended_data[1];
+ c3=(float *)out->extended_data[2];
+ c4=(float *)out->extended_data[3];
+
+ for(itr=0;itr<in->nb_samples;itr++){
+ lf = root8 * (2*(w[itr])+x[itr]+y[itr]);
+ lb = root8 * (2*(w[itr])-x[itr]+y[itr]);
+ rb = root8 * (2*(w[itr])-x[itr]-y[itr]);
+ rf = root8 * (2*(w[itr])+x[itr]-y[itr]);
+ c1[itr] = lf;
+ c2[itr] = rf;
+ c3[itr] = lb;
+ c4[itr] = rb;
+ }
+
+ 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_ambisonic = {
+ .name = "ambisonic",
+ .description = NULL_IF_CONFIG_SMALL("An ambisonic filter"),
+ .query_formats = query_formats,
+ .priv_size = sizeof(AmbisonicContext),
+ .priv_class = &ambisonic_class,
+ .inputs = inputs,
+ .outputs = outputs,
+};
\ No newline at end of file
@@ -56,6 +56,7 @@ static void register_all(void)
REGISTER_FILTER(ALIMITER, alimiter, af);
REGISTER_FILTER(ALLPASS, allpass, af);
REGISTER_FILTER(ALOOP, aloop, af);
+ REGISTER_FILTER(AMBISONIC, ambisonic, af);
REGISTER_FILTER(AMERGE, amerge, af);
REGISTER_FILTER(AMETADATA, ametadata, af);
REGISTER_FILTER(AMIX, amix, af);
--
2.7.4