avfilter: add arbitrary audio FIR filter

Signed-off-by: Paul B Mahol <onemda@gmail.com>

configure

@@ -3083,6 +3083,8 @@ unix_protocol_select="network"
 # filters
 afftfilt_filter_deps="avcodec"
 afftfilt_filter_select="fft"
+afir_filter_deps="avcodec"
+afir_filter_select="fft"
 amovie_filter_deps="avcodec avformat"
 aresample_filter_deps="swresample"
 ass_filter_deps="libass"
@@ -6476,6 +6478,7 @@ enabled zlib && add_cppflags -DZLIB_CONST
 
 # conditional library dependencies, in linking order
 enabled afftfilt_filter     && prepend avfilter_deps "avcodec"
+enabled afir_filter         && prepend avfilter_deps "avcodec"
 enabled amovie_filter       && prepend avfilter_deps "avformat avcodec"
 enabled aresample_filter    && prepend avfilter_deps "swresample"
 enabled atempo_filter       && prepend avfilter_deps "avcodec"

doc/filters.texi

@@ -878,6 +878,49 @@ afftfilt="1-clip((b/nb)*b,0,1)"
 @end example
 @end itemize
 
+@section afir
+
+Apply an arbitrary Frequency Impulse Response filter.
+
+This filter is designed for applying long FIR filters,
+up to 30 seconds long.
+
+It can be used as component for digital crossover filters,
+room equalization, cross talk cancellation, wavefield synthesis,
+auralization, ambiophonics and ambisonics.
+
+This filter uses second stream as FIR coefficients.
+If second stream holds single channel, it will be used
+for all input channels in first stream, otherwise
+number of channels in second stream must be same as
+number of channels in first stream.
+
+It accepts the following parameters:
+
+@table @option
+@item dry
+Set dry gain. This sets input gain.
+
+@item wet
+Set wet gain. This sets final output gain.
+
+@item length
+Set Impulse Response filter length. Default is 1, which means whole IR is processed.
+
+@item again
+Enable applying gain measured from power of IR.
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+Apply reverb to stream using mono IR file as second input, complete command using ffmpeg:
+@example
+ffmpeg -i input.wav -i middle_tunnel_1way_mono.wav -lavfi afir output.wav
+@end example
+@end itemize
+
 @anchor{aformat}
 @section aformat
 

libavfilter/Makefile

@@ -37,6 +37,7 @@ OBJS-$(CONFIG_AEMPHASIS_FILTER)              += af_aemphasis.o
 OBJS-$(CONFIG_AEVAL_FILTER)                  += aeval.o
 OBJS-$(CONFIG_AFADE_FILTER)                  += af_afade.o
 OBJS-$(CONFIG_AFFTFILT_FILTER)               += af_afftfilt.o window_func.o
+OBJS-$(CONFIG_AFIR_FILTER)                   += af_afir.o
 OBJS-$(CONFIG_AFORMAT_FILTER)                += af_aformat.o
 OBJS-$(CONFIG_AGATE_FILTER)                  += af_agate.o
 OBJS-$(CONFIG_AINTERLEAVE_FILTER)            += f_interleave.o

libavfilter/af_afir.h

+/*
+ * 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
+ */
+
+#ifndef  AVFILTER_AFIR_H
+#define  AVFILTER_AFIR_H
+
+#include "libavutil/audio_fifo.h"
+#include "libavutil/common.h"
+#include "libavutil/float_dsp.h"
+#include "libavutil/opt.h"
+#include "libavcodec/avfft.h"
+
+#include "audio.h"
+#include "avfilter.h"
+#include "formats.h"
+#include "internal.h"
+
+#define MAX_IR_DURATION 30
+
+typedef struct AudioFIRContext {
+    const AVClass *class;
+
+    float wet_gain;
+    float dry_gain;
+    float length;
+    int again;
+
+    float gain;
+
+    int eof_coeffs;
+    int have_coeffs;
+    int nb_coeffs;
+    int nb_taps;
+    int part_size;
+    int part_index;
+    int coeff_size;
+    int block_size;
+    int nb_partitions;
+    int nb_channels;
+    int ir_length;
+    int fft_length;
+    int nb_coef_channels;
+    int one2many;
+    int nb_samples;
+    int want_skip;
+    int need_padding;
+
+    RDFTContext **rdft, **irdft;
+    float **sum;
+    float **block;
+    FFTComplex **coeff;
+
+    AVAudioFifo *fifo[2];
+    AVFrame *in[2];
+    AVFrame *buffer;
+    int64_t pts;
+    int index;
+
+    AVFloatDSPContext *fdsp;
+    void (*fcmul_add)(float *sum, const float *t, const float *c,
+                      ptrdiff_t len);
+} AudioFIRContext;
+
+void ff_afir_init_x86(AudioFIRContext *s);
+
+#endif /* AVFILTER_AFIR_H */

libavfilter/allfilters.c

@@ -50,6 +50,7 @@ static void register_all(void)
     REGISTER_FILTER(AEVAL,          aeval,          af);
     REGISTER_FILTER(AFADE,          afade,          af);
     REGISTER_FILTER(AFFTFILT,       afftfilt,       af);
+    REGISTER_FILTER(AFIR,           afir,           af);
     REGISTER_FILTER(AFORMAT,        aformat,        af);
     REGISTER_FILTER(AGATE,          agate,          af);
     REGISTER_FILTER(AINTERLEAVE,    ainterleave,    af);

libavfilter/version.h

@@ -30,7 +30,7 @@
 #include "libavutil/version.h"
 
 #define LIBAVFILTER_VERSION_MAJOR   6
-#define LIBAVFILTER_VERSION_MINOR  88
+#define LIBAVFILTER_VERSION_MINOR  89
 #define LIBAVFILTER_VERSION_MICRO 100
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \

libavfilter/x86/Makefile

+OBJS-$(CONFIG_AFIR_FILTER)                   += x86/af_afir_init.o
 OBJS-$(CONFIG_BLEND_FILTER)                  += x86/vf_blend_init.o
 OBJS-$(CONFIG_BWDIF_FILTER)                  += x86/vf_bwdif_init.o
 OBJS-$(CONFIG_COLORSPACE_FILTER)             += x86/colorspacedsp_init.o
@@ -23,6 +24,7 @@ OBJS-$(CONFIG_VOLUME_FILTER)                 += x86/af_volume_init.o
 OBJS-$(CONFIG_W3FDIF_FILTER)                 += x86/vf_w3fdif_init.o
 OBJS-$(CONFIG_YADIF_FILTER)                  += x86/vf_yadif_init.o
 
+YASM-OBJS-$(CONFIG_AFIR_FILTER)              += x86/af_afir.o
 YASM-OBJS-$(CONFIG_BLEND_FILTER)             += x86/vf_blend.o
 YASM-OBJS-$(CONFIG_BWDIF_FILTER)             += x86/vf_bwdif.o
 YASM-OBJS-$(CONFIG_COLORSPACE_FILTER)        += x86/colorspacedsp.o

libavfilter/x86/af_afir.asm

+;*****************************************************************************
+;* x86-optimized functions for afir filter
+;* 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 "libavutil/x86/x86util.asm"
+
+SECTION .text
+
+;------------------------------------------------------------------------------
+; void ff_fcmul_add(float *sum, const float *t, const float *c, int len)
+;------------------------------------------------------------------------------
+
+INIT_XMM sse3
+cglobal fcmul_add, 4,4,6, sum, t, c, len
+    shl       lend, 3
+    add       lend, mmsize*2
+    add         tq, lenq
+    add         cq, lenq
+    add       sumq, lenq
+    neg       lenq
+ALIGN 16
+.loop:
+    movsldup  m0, [tq + lenq]
+    movsldup  m3, [tq + lenq+mmsize]
+    movaps    m1, [cq + lenq]
+    movaps    m4, [cq + lenq+mmsize]
+    mulps     m0, m1
+    mulps     m3, m4
+    shufps    m1, m1, 0xb1
+    shufps    m4, m4, 0xb1
+    movshdup  m2, [tq + lenq]
+    movshdup  m5, [tq + lenq+mmsize]
+    mulps     m2, m1
+    mulps     m5, m4
+    addsubps  m0, m2
+    addsubps  m3, m5
+    addps     m0, [sumq + lenq]
+    addps     m3, [sumq + lenq+mmsize]
+    movaps    [sumq + lenq], m0
+    movaps    [sumq + lenq+mmsize], m3
+    add       lenq, mmsize*2
+    jl .loop
+    REP_RET

libavfilter/x86/af_afir_init.c

+/*
+ * 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 "config.h"
+#include "libavutil/attributes.h"
+#include "libavutil/cpu.h"
+#include "libavutil/x86/cpu.h"
+#include "libavfilter/af_afir.h"
+
+void ff_fcmul_add_sse3(float *sum, const float *t, const float *c,
+                       ptrdiff_t len);
+
+av_cold void ff_afir_init_x86(AudioFIRContext *s)
+{
+    int cpu_flags = av_get_cpu_flags();
+
+    if (EXTERNAL_SSE3(cpu_flags)) {
+        s->fcmul_add = ff_fcmul_add_sse3;
+    }
+}