[FFmpeg-devel] [RFC][WIP][PATCH] avfilter: add SOFAlizer audio filter

Paul B Mahol onemda at gmail.com
Thu Dec 10 00:43:58 CET 2015


Signed-off-by: Paul B Mahol <onemda at gmail.com>
---
 libavfilter/Makefile       |   1 +
 libavfilter/af_sofalizer.c | 816 +++++++++++++++++++++++++++++++++++++++++++++
 libavfilter/allfilters.c   |   1 +
 3 files changed, 818 insertions(+)
 create mode 100644 libavfilter/af_sofalizer.c

diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index 8884d1d..d7a3f61 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -87,6 +87,7 @@ OBJS-$(CONFIG_SIDECHAINCOMPRESS_FILTER)      += af_sidechaincompress.o
 OBJS-$(CONFIG_SIDECHAINGATE_FILTER)          += af_agate.o
 OBJS-$(CONFIG_SILENCEDETECT_FILTER)          += af_silencedetect.o
 OBJS-$(CONFIG_SILENCEREMOVE_FILTER)          += af_silenceremove.o
+OBJS-$(CONFIG_SOFALIZER_FILTER)              += af_sofalizer.o
 OBJS-$(CONFIG_STEREOTOOLS_FILTER)            += af_stereotools.o
 OBJS-$(CONFIG_STEREOWIDEN_FILTER)            += af_stereowiden.o
 OBJS-$(CONFIG_TREBLE_FILTER)                 += af_biquads.o
diff --git a/libavfilter/af_sofalizer.c b/libavfilter/af_sofalizer.c
new file mode 100644
index 0000000..8e4da74
--- /dev/null
+++ b/libavfilter/af_sofalizer.c
@@ -0,0 +1,816 @@
+/*****************************************************************************
+ * sofalizer.c : SOFAlizer filter for virtual binaural acoustics
+ *****************************************************************************
+ * Copyright (C) 2013-2015 Andreas Fuchs, Wolfgang Hrauda,
+ *                         Acoustics Research Institute (ARI), Vienna, Austria
+ *
+ * Authors: Andreas Fuchs <andi.fuchs.mail at gmail.com>
+ *          Wolfgang Hrauda <wolfgang.hrauda at gmx.at>
+ *
+ * SOFAlizer project coordinator at ARI, main developer of SOFA:
+ *          Piotr Majdak <piotr at majdak.at>
+ *
+ * This program 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.
+ *
+ * This program 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 this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
+ *****************************************************************************/
+
+#include <netcdf.h>
+
+#include "libavutil/opt.h"
+#include "avfilter.h"
+#include "internal.h"
+#include "audio.h"
+
+#define N_SOFA 3 /* no. SOFA files loaded (for instant comparison) */
+#define N_POSITIONS 4 /* no. virtual source positions (advanced settings) */
+
+typedef struct NCSofa { /* contains data of one SOFA file */
+   int i_ncid;          /* netCDF ID of the opened SOFA file */
+   int i_n_samples;     /* length of one impulse response (IR) */
+   int i_m_dim;         /* number of measurement positions */
+   int *pi_data_delay;  /* broadband delay of each IR */
+                        /* all measurement positions for each receiver (i.e. ear): */
+   float *pf_sp_a;      /* azimuth angles */
+   float *pf_sp_e;      /* elevation angles */
+   float *pf_sp_r;      /* radii */
+                        /* dataat at each measurement position for each receiver: */
+   float *pf_data_ir;   /* IRs (time-domain) */
+} NCSofa;
+
+typedef struct SOFAlizerContext {
+    const AVClass *class;
+
+    char *filename[N_SOFA];
+    struct NCSofa sofa[N_SOFA]; /* contains data of the SOFA files */
+
+    float *pf_speaker_pos; /* positions of the virtual loudspekaers */
+    float f_gain_lfe;
+
+    int i_n_conv; /* number of channels to convolute */
+    int i_n_clippings_l;
+    int i_n_clippings_r;
+
+    /* buffer variables (for convolution) */
+    float *pf_ringbuffer_l; /* buffers input samples, length of one buffer: */
+    float *pf_ringbuffer_r; /* no. input ch. (incl. LFE) x i_buffer_length */
+    int i_write_l; /* current write position to ringbuffer */
+    int i_write_r; /* current write position to ringbuffer */
+    int i_buffer_length; /* is: longest IR plus max. delay in all SOFA files */
+                         /* then choose next power of 2 */
+    int i_n_longest_filter; /* longest IR + max. delay in all SOFA files */
+    int i_output_buffer_length; /* remember no. samples in output buffer */
+
+    /* netCDF variables */
+    int i_sofa_id;  /* selected SOFA file */
+    int *pi_delay_l; /* broadband delay for each channel/IR to be convolved */
+    int *pi_delay_r;
+    float *pf_data_ir_l; /* IRs for all channels to be convolved */
+    float *pf_data_ir_r; /* (this excludes the LFE) */
+
+    /* control variables */
+    float f_gain; /* filter gain (in dB) */
+    float f_rotation; /* rotation of virtual loudspeakers (in degrees)  */
+    float f_elevation; /* elevation of virtual loudspeakers (in deg.) */
+    float f_radius; /* distance virtual loudspeakers to listener (in metres) */
+    int i_switch; /* 0: source positions according to input format plus */
+                  /* user's rotation and elevation settings, */
+                  /* 1-4: virtual source pos. defined in advanced settings */
+    /* - from advanced settings: virtual source positions: */
+    int pi_azimuth_array[N_POSITIONS]; /* azimuth angles (in deg.) */
+    int pi_elevation_array[N_POSITIONS]; /* elevation angles (in deg.) */
+
+    int lfe; /* whether or not the LFE channel is used */
+} SOFAlizerContext;
+
+static int close_sofa(struct NCSofa *sofa)
+{
+    av_freep(&sofa->pi_data_delay);
+    av_freep(&sofa->pf_sp_a);
+    av_freep(&sofa->pf_sp_e);
+    av_freep(&sofa->pf_sp_r);
+    av_freep(&sofa->pf_data_ir);
+    nc_close(sofa->i_ncid);
+    sofa->i_ncid = 0;
+    return 0;
+}
+
+static int load_sofa(AVFilterContext *ctx, char *filename,
+                    int i_sofa_id , int *samplingrate)
+{
+    struct SOFAlizerContext *s = ctx->priv;
+    /* variables associated with content of SOFA file: */
+    int i_ncid, i_n_dims, i_n_vars, i_n_gatts, i_n_unlim_dim_id, i_status;
+    unsigned int i_samplingrate;
+    int i_n_samples = 0;
+    int i_m_dim = 0;
+    s->sofa[i_sofa_id].i_ncid = 0;
+    i_status = nc_open( filename , NC_NOWRITE, &i_ncid); /* open SOFA file read-only */
+    if (i_status != NC_NOERR)
+    {
+        av_log(ctx, AV_LOG_ERROR, "Can't find SOFA-file '%s'\n", filename);
+        return -1;
+    }
+    /* get number of dimensions, vars, global attributes and Id of unlimited dimensions: */
+    nc_inq(i_ncid, &i_n_dims, &i_n_vars, &i_n_gatts, &i_n_unlim_dim_id);
+
+    /* -- get number of measurements ("M") and length of one IR ("N") -- */
+    char psz_dim_names[i_n_dims][NC_MAX_NAME];   /* names of netCDF dimensions */
+    size_t pi_dim_length[i_n_dims]; /* lengths of netCDF dimensions */
+    int i_m_dim_id = -1;
+    int i_n_dim_id = -1;
+    for( int i = 0; i < i_n_dims; i++ ) /* go through all dimensions of file */
+    {
+        nc_inq_dim( i_ncid, i, psz_dim_names[i], &pi_dim_length[i] ); /* get dimensions */
+        if ( !strncmp("M", psz_dim_names[i], 1 ) ) /* get ID of dimension "M" */
+            i_m_dim_id = i;
+        if ( !strncmp("N", psz_dim_names[i], 1 ) ) /* get ID of dimension "N" */
+            i_n_dim_id = i;
+    }
+    if( ( i_m_dim_id == -1 ) || ( i_n_dim_id == -1 ) ) /* dimension "M" or "N" couldn't be found */
+    {
+        av_log(ctx, AV_LOG_ERROR, "Can't find required dimensions in SOFA file.\n");
+        nc_close(i_ncid);
+        return -1;
+    }
+    i_n_samples = pi_dim_length[i_n_dim_id]; /* get number of measurements */
+    i_m_dim =  pi_dim_length[i_m_dim_id]; /* get length of one IR */
+
+    /* -- check file type -- */
+    size_t i_att_len; /* get length of attritube "Conventions" */
+    i_status = nc_inq_attlen(i_ncid, NC_GLOBAL, "Conventions", &i_att_len);
+    if (i_status != NC_NOERR)
+    {
+        av_log(ctx, AV_LOG_ERROR, "Can't get length of attribute \"Conventions\".\n");
+        nc_close(i_ncid);
+        return -1;
+    }
+    char psz_conventions[i_att_len + 1]; /* check whether file is SOFA file */
+    nc_get_att_text(i_ncid , NC_GLOBAL, "Conventions", psz_conventions);
+    *( psz_conventions + i_att_len ) = 0;
+    if ( strncmp( "SOFA" , psz_conventions, 4 ) )
+    {
+        av_log(ctx, AV_LOG_ERROR, "Not a SOFA file!\n");
+        nc_close(i_ncid);
+        return -1;
+    }
+
+    /* -- check if attribute "SOFAConventions" is "SimpleFreeFieldHRIR": -- */
+    nc_inq_attlen (i_ncid, NC_GLOBAL, "SOFAConventions", &i_att_len );
+    char psz_sofa_conventions[i_att_len + 1];
+    nc_get_att_text(i_ncid, NC_GLOBAL, "SOFAConventions", psz_sofa_conventions);
+    *( psz_sofa_conventions + i_att_len ) = 0;
+    if ( strncmp( "SimpleFreeFieldHRIR" , psz_sofa_conventions, i_att_len ) )
+    {
+       av_log(ctx, AV_LOG_ERROR, "Not a SimpleFreeFieldHRIR file!\n");
+       nc_close(i_ncid);
+       return -1;
+    }
+
+    /* -- get sampling rate of HRTFs -- */
+    int i_samplingrate_id; /* read ID, then value */
+    i_status = nc_inq_varid( i_ncid, "Data.SamplingRate", &i_samplingrate_id);
+    i_status += nc_get_var_uint( i_ncid, i_samplingrate_id, &i_samplingrate );
+    if (i_status != NC_NOERR)
+    {
+        av_log(ctx, AV_LOG_ERROR, "Couldn't read Data.SamplingRate.\n");
+        nc_close(i_ncid);
+        return -1;
+    }
+    *samplingrate = i_samplingrate; /* remember sampling rate */
+
+    /* -- allocate memory for one value for each measurement position: -- */
+    float *pf_sp_a = s->sofa[i_sofa_id].pf_sp_a = av_malloc(sizeof(float) * i_m_dim);
+    float *pf_sp_e = s->sofa[i_sofa_id].pf_sp_e = av_malloc(sizeof(float) * i_m_dim);
+    float *pf_sp_r = s->sofa[i_sofa_id].pf_sp_r = av_malloc(sizeof(float) * i_m_dim);
+    /* delay and IR values required for each ear and measurement position: */
+    int *pi_data_delay = s->sofa[i_sofa_id].pi_data_delay =
+        av_calloc (i_m_dim * 2, sizeof(int));
+    float *pf_data_ir = s->sofa[i_sofa_id].pf_data_ir =
+        av_malloc(sizeof(float) * 2 * i_m_dim * i_n_samples);
+
+    if (!pi_data_delay || !pf_sp_a || !pf_sp_e || !pf_sp_r || !pf_data_ir) {
+        /* if memory could not be allocated */
+        close_sofa( &s->sofa[i_sofa_id] );
+        return AVERROR(ENOMEM);
+    }
+
+    /* get impulse responses (HRTFs): */
+    int i_data_ir_id; /* get corresponding ID */
+    i_status = nc_inq_varid( i_ncid, "Data.IR", &i_data_ir_id);
+    i_status += nc_get_var_float( i_ncid, i_data_ir_id, pf_data_ir); /* read and store IRs */
+    if (i_status != NC_NOERR) {
+        av_log( ctx, AV_LOG_ERROR, "Couldn't read Data.IR!" );
+        goto error;
+    }
+
+    /* get source positions of the HRTFs in the SOFA file: */
+    int i_sp_id;
+    i_status = nc_inq_varid(i_ncid, "SourcePosition", &i_sp_id); /* get corresponding ID */
+    i_status += nc_get_vara_float (i_ncid, i_sp_id, (size_t[2]){ 0 , 0 } ,
+                (size_t[2]){ i_m_dim , 1 } , pf_sp_a ); /* read & store azimuth angles */
+    i_status += nc_get_vara_float (i_ncid, i_sp_id, (size_t[2]){ 0 , 1 } ,
+                (size_t[2]){ i_m_dim , 1 } , pf_sp_e ); /* read & store elevation angles */
+    i_status += nc_get_vara_float (i_ncid, i_sp_id, (size_t[2]){ 0 , 2 } ,
+                (size_t[2]){ i_m_dim , 1 } , pf_sp_r ); /* read & store radii */
+    if (i_status != NC_NOERR) { /* if any source position variable coudn't be read */
+        av_log(ctx, AV_LOG_ERROR, "Couldn't read SourcePosition.\n");
+        goto error;
+    }
+
+    /* read Data.Delay, check for errors and fit it to pi_data_delay */
+    int i_data_delay_id;
+    int pi_data_delay_dim_id[2];
+    char psz_data_delay_dim_name[NC_MAX_NAME];
+
+    i_status = nc_inq_varid(i_ncid, "Data.Delay", &i_data_delay_id);
+    i_status += nc_inq_vardimid ( i_ncid, i_data_delay_id, &pi_data_delay_dim_id[0]);
+    i_status += nc_inq_dimname ( i_ncid, pi_data_delay_dim_id[0], psz_data_delay_dim_name );
+    if (i_status != NC_NOERR) {
+        av_log(ctx, AV_LOG_ERROR, "Couldn't read Data.Delay.\n");
+        goto error;
+    }
+
+    /* Data.Delay dimension check */
+    /* dimension of Data.Delay is [I R]: */
+    if (!strncmp(psz_data_delay_dim_name, "I", 2)) {
+      /* check 2 characters to assure string is 0-terminated after "I" */
+        int pi_Delay[2]; /* delays get from SOFA file: */
+        av_log ( ctx, AV_LOG_DEBUG, "Data.Delay has dimension [I R]\n" );
+        i_status = nc_get_var_int( i_ncid, i_data_delay_id, &pi_Delay[0] );
+        if ( i_status != NC_NOERR )
+        {
+            av_log(ctx, AV_LOG_ERROR, "Couldn't read Data.Delay\n");
+            goto error;
+        }
+        int *pi_data_delay_r = pi_data_delay + i_m_dim;
+        for ( int i = 0 ; i < i_m_dim ; i++ ) /* extend given dimension [I R] to [M R] */
+        { /* assign constant delay value for all measurements to data_delay fields */
+            *( pi_data_delay + i ) = pi_Delay[0];
+            *( pi_data_delay_r + i ) = pi_Delay[1];
+        }
+      /* dimension of Data.Delay is [M R] */
+    } else if (!strncmp(psz_data_delay_dim_name, "M", 2)) {
+        av_log( ctx, AV_LOG_ERROR, "Data.Delay in dimension [M R]\n");
+        /* get delays from SOFA file: */
+        i_status = nc_get_var_int( i_ncid, i_data_delay_id, pi_data_delay );
+        if (i_status != NC_NOERR)
+        {
+            av_log(ctx, AV_LOG_ERROR, "Couldn't read Data.Delay\n");
+            goto error;
+        }
+    } else { /* dimension of Data.Delay is neither [I R] nor [M R] */
+        av_log ( ctx, AV_LOG_ERROR,
+        "Data.Delay does not have the required dimensions [I R] or [M R].\n");
+        goto error;
+    }
+
+    /* save information in SOFA struct: */
+    s->sofa[i_sofa_id].i_m_dim = i_m_dim; /* no. measurement positions */
+    s->sofa[i_sofa_id].i_n_samples = i_n_samples; /* length on one IR */
+    s->sofa[i_sofa_id].i_ncid = i_ncid; /* netCDF ID of SOFA file */
+    nc_close(i_ncid); /* close SOFA file */
+
+    return 0;
+
+error:
+    close_sofa( &s->sofa[i_sofa_id] );
+    return -1;
+}
+
+static int get_speaker_pos(AVFilterContext *ctx, float *pf_speaker_pos )
+{
+    /* get input channel configuration: */
+    uint64_t i_physical_channels = ctx->inputs[0]->channel_layout;
+    float *pf_pos_temp;
+    int i_input_nb = ctx->inputs[0]->channels; /* get no. input channels */
+    int i_n_conv = i_input_nb;
+    if (i_physical_channels & AV_CH_LOW_FREQUENCY) { /* if LFE is used */
+        /* decrease number of channels to be convolved: */
+        i_n_conv = i_input_nb - 1;
+    }
+
+    /* set speaker positions according to input channel configuration: */
+    switch (i_physical_channels) {
+    case AV_CH_LAYOUT_MONO:
+                            pf_pos_temp = (float[1]){ 0 };
+                            break;
+    case AV_CH_LAYOUT_STEREO:
+    case AV_CH_LAYOUT_2_1:
+                            pf_pos_temp = (float[2]){ 30 , 330 };
+                            break;
+    case AV_CH_LAYOUT_SURROUND:
+    case AV_CH_LAYOUT_3POINT1:
+                            pf_pos_temp = (float[3]){ 30 , 330 , 0 };
+                            break;
+    case AV_CH_LAYOUT_4POINT0:
+    case AV_CH_LAYOUT_4POINT1:    pf_pos_temp = (float[4]){ 30 , 330 , 120 , 240 };
+                            break;
+    case AV_CH_LAYOUT_5POINT0:
+    case AV_CH_LAYOUT_5POINT1:
+                            pf_pos_temp = (float[5]){ 30 , 330 , 120 , 240 , 0 };
+                            break;
+    case AV_CH_LAYOUT_6POINT0:
+                            pf_pos_temp = (float[6]){ 30 , 330 , 90 , 270 , 150 , 210 };
+                            break;
+    case AV_CH_LAYOUT_7POINT0:
+    case AV_CH_LAYOUT_7POINT1:
+                            pf_pos_temp = (float[7]){ 30 , 330 , 90 , 270 , 150 , 210 , 0 };
+                            break;
+  //case AV_CH_LAYOUT_8POINT1:
+  //                        pf_pos_temp = (float[8]){ 30 , 330 , 90 , 270 , 150 , 210 , 180 , 0 };
+  //                        break;
+    default:
+                            return -1;
+    }
+
+    memcpy(pf_speaker_pos, pf_pos_temp, i_n_conv * sizeof(float));
+
+    return 0;
+
+}
+
+static int MaxDelay ( struct NCSofa *sofa )
+{
+    int i_max = 0;
+    for ( int  i = 0; i < ( sofa->i_m_dim * 2 ) ; i++ )
+    {   /* search maximum delay in given SOFA file */
+        if ( *( sofa->pi_data_delay + i ) > i_max )
+            i_max = *( sofa->pi_data_delay + i) ;
+    }
+    return i_max;
+}
+
+static int find_m(SOFAlizerContext *s, int azim, int elev, float radius)
+{
+    /* get source positions and M of currently selected SOFA file */
+    float *pf_sp_a = s->sofa[s->i_sofa_id].pf_sp_a; /* azimuth angle */
+    float *pf_sp_e = s->sofa[s->i_sofa_id].pf_sp_e; /* elevation angle */
+    float *pf_sp_r = s->sofa[s->i_sofa_id].pf_sp_r; /* radius */
+    int i_m_dim = s->sofa[s->i_sofa_id].i_m_dim; /* no. measurements */
+
+    int i_best_id = 0; /* index m currently closest to desired source pos. */
+    float delta = 1000; /* offset between desired and currently best pos. */
+    float f_current;
+    for ( int i = 0; i < i_m_dim ; i++ )
+    {   /* search through all measurements in currently selected SOFA file */
+        /* distance of current to desired source position: */
+        f_current = fabs ( *(pf_sp_a++) - azim )
+                    + fabs( *(pf_sp_e++) - elev )
+                    + fabs( *(pf_sp_r++) - radius );
+        if ( f_current <= delta )
+        {   /* if current distance is smaller than smallest distance so far */
+            delta = f_current;
+            i_best_id = i; /* remember index */
+        }
+    }
+    return i_best_id;
+}
+
+static int compensate_volume(AVFilterContext *ctx)
+{
+    struct SOFAlizerContext *s = ctx->priv;
+    float f_energy = 0;
+    int i_m;
+    int i_sofa_id_backup = s->i_sofa_id;
+    float *pf_ir;
+    float f_compensate;
+    /* compensate volume for each SOFA file */
+    for ( int i = 0 ; i < N_SOFA ; i++ ) { /* go through all SOFA files */
+        if( s->sofa[i].i_ncid ) {
+            /* find IR at front center position in i-th SOFA file (IR closest to 0°,0°,1m) */
+            struct NCSofa *p_sofa = &s->sofa[i];
+            s->i_sofa_id = i;
+            i_m = find_m( s, 0, 0, 1 );
+            /* get energy of that IR and compensate volume */
+            pf_ir = p_sofa->pf_data_ir + 2 * i_m * p_sofa->i_n_samples;
+            for (int j = 0 ; j < p_sofa->i_n_samples ; j++) {
+                f_energy += *(pf_ir + j ) * *(pf_ir + j);
+            }
+            f_compensate = 256 / (p_sofa->i_n_samples * sqrt(f_energy));
+            av_log(ctx, AV_LOG_DEBUG, "Compensate-factor: %f\n", f_compensate);
+            pf_ir = p_sofa->pf_data_ir;
+            for (int j = 0; j < ( p_sofa->i_n_samples * p_sofa->i_m_dim * 2 ) ; j++) {
+                *( pf_ir + j ) *= f_compensate; /* apply volume compensation to IRs */
+            }
+        }
+    }
+
+    s->i_sofa_id = i_sofa_id_backup;
+
+    return 0;
+}
+
+static void sofalizer_convolute(SOFAlizerContext *s, AVFrame *in, AVFrame *out, int offset,
+                                int *write, int *delay, float *pf_ir, int *i_n_clippings,
+                                float *ringbuffer)
+{
+    int i_n_samples = s->sofa[s->i_sofa_id].i_n_samples; /* length of one IR */
+    const float *src = (const float *)in->data[0]; /* get pointer to audio input buffer */
+    float *pf_temp_ir;
+    float *dst = (float *)out->data[0]; /* get pointer to audio output buffer */
+    int i_read;
+    int i_input_nb = in->channels; /* number of input channels */
+    /* ring buffer length is: longest IR plus max. delay -> next power of 2 */
+    int i_buffer_length = s->i_buffer_length;
+    /* -1 for AND instead of MODULO (applied to powers of 2): */
+    uint32_t i_modulo = (uint32_t) i_buffer_length - 1;
+    float *pf_ringbuffer[i_input_nb]; /* holds ringbuffer for each input channel */
+
+    dst += offset;
+    for (int l = 0 ; l < i_input_nb ; l++ ) {
+        /* get starting address of ringbuffer for each input channel */
+        pf_ringbuffer[l] = ringbuffer + l * i_buffer_length ;
+    }
+    int i_write = *write;
+
+    for (int i = 0; i < in->nb_samples; i++)
+    {   /* i is not used as an index in the loop! */
+        *(dst) = 0;
+        for ( int l = 0 ; l < i_input_nb ; l++ )
+        {   /* write current input sample to ringbuffer (for each channel) */
+            *( pf_ringbuffer[l] + i_write ) = *src++;
+        }
+        pf_temp_ir = pf_ir; /* using same set of IRs for each sample */
+        /* loop goes through all channels to be convolved (excl. LFE): */
+        for ( int l = 0 ; l < s->i_n_conv ; l++ )
+        {
+            /* current read position in ringbuffer: input sample write position
+             * - delay for l-th ch. + diff. betw. IR length and buffer length
+             * (mod buffer length) */
+            i_read = (i_write - *(delay + l) -
+                     (i_n_samples - 1 ) + i_buffer_length ) & i_modulo;
+
+            for (int j = 0; j < i_n_samples; j++) { /* go through samples of IR */
+                /* multiply signal and IR, and add up the results */
+                *dst += *(pf_ringbuffer[l] + ((i_read++) & i_modulo)) * *(pf_temp_ir++);
+            }
+        }
+        if (s->lfe) { /* LFE */
+            /* apply gain to LFE signal and add to output buffer */
+            *dst += *( pf_ringbuffer[s->i_n_conv] + i_write ) * s->f_gain_lfe;
+        }
+        /* clippings counter */
+        if (fabs(*dst) >= 1)
+            *i_n_clippings += 1;
+
+        /* move output buffer pointer by +2 to get to next sample of processed channel: */
+        dst    += 2;
+        i_write = ( i_write + 1 ) & i_modulo; /* update ringbuffer write position */
+    }
+
+    *write = i_write; /* remember write position in ringbuffer for next call */
+
+    return;
+}
+
+static int filter_frame(AVFilterLink *inlink, AVFrame *in)
+{
+    AVFilterContext *ctx = inlink->dst;
+    SOFAlizerContext *s = ctx->priv;
+    AVFilterLink *outlink = ctx->outputs[0];
+    AVFrame *out;
+
+    out = ff_get_audio_buffer(outlink, in->nb_samples);
+    if (!out) {
+        av_frame_free(&in);
+        return AVERROR(ENOMEM);
+    }
+    av_frame_copy_props(out, in);
+
+    /* gain -3 dB per channel, -6 dB to get LFE on a similar level */
+    s->f_gain_lfe = expf((s->f_gain - 3 * inlink->channels - 6) / 20 * logf(10));
+
+    sofalizer_convolute(s, in, out, 0, &s->i_write_l,
+                        s->pi_delay_l, s->pf_data_ir_l,
+                        &s->i_n_clippings_l,
+                        s->pf_ringbuffer_l);
+    sofalizer_convolute(s, in, out, 1, &s->i_write_r,
+                        s->pi_delay_r, s->pf_data_ir_r,
+                        &s->i_n_clippings_r,
+                        s->pf_ringbuffer_r);
+
+    /* display error message if clipping occured */
+    if (s->i_n_clippings_l + s->i_n_clippings_r > 0 ) {
+        av_log(ctx, AV_LOG_WARNING, "%d of %d samples clipped. Please reduce gain.",
+               s->i_n_clippings_l + s->i_n_clippings_r, out->nb_samples * 2);
+    }
+
+    av_frame_free(&in);
+    return ff_filter_frame(outlink, out);
+}
+
+static int query_formats(AVFilterContext *ctx)
+{
+    AVFilterFormats *formats = NULL;
+    AVFilterChannelLayouts *layouts = NULL;
+    static int sample_rates[] = { 48000, -1 };
+    int ret;
+
+    ret = ff_add_format(&formats, AV_SAMPLE_FMT_FLT);
+    if (ret)
+        return ret;
+    ret = ff_set_common_formats(ctx, formats);
+    if (ret)
+        return ret;
+
+    ret = ff_add_channel_layout(&layouts, AV_CH_LAYOUT_5POINT0);
+    if (ret)
+        return ret;
+    ret = ff_add_channel_layout(&layouts, AV_CH_LAYOUT_5POINT1);
+    if (ret)
+        return ret;
+
+    ret = ff_channel_layouts_ref(layouts, &ctx->inputs[0]->out_channel_layouts);
+    if (ret)
+        return ret;
+
+    layouts = NULL;
+    ret = ff_add_channel_layout(&layouts, AV_CH_LAYOUT_STEREO);
+    if (ret)
+        return ret;
+
+    ret = ff_channel_layouts_ref(layouts, &ctx->outputs[0]->in_channel_layouts);
+    if (ret)
+        return ret;
+
+    formats = ff_make_format_list(sample_rates);
+    if (!formats)
+        return AVERROR(ENOMEM);
+    return ff_set_common_samplerates(ctx, formats);
+}
+
+static int load_data(AVFilterContext *ctx, int i_azim, int i_elev, float f_radius)
+{
+    struct SOFAlizerContext *s = ctx->priv;
+    if (!s->sofa[s->i_sofa_id].i_ncid) { /* if an invalid SOFA file has been selected */
+        av_log(ctx, AV_LOG_ERROR, "Selected SOFA file is invalid. Please select valid SOFA file." );
+        return -1;
+    }
+    const int i_n_samples = s->sofa[s->i_sofa_id].i_n_samples;
+    int i_n_conv = s->i_n_conv; /* no. channels to convolve (excl. LFE) */
+    int pi_delay_l[i_n_conv]; /* broadband delay for each IR */
+    int pi_delay_r[i_n_conv];
+    int i_input_nb = ctx->inputs[0]->channels; /* no. input channels */
+    float f_gain_lin = expf( (s->f_gain - 3 * i_input_nb) / 20 * logf(10) ); /* gain - 3dB/channel */
+
+    float *pf_data_ir_l = NULL;
+    float *pf_data_ir_r = NULL;
+
+        /* get temporary IR for L and R channel */
+    pf_data_ir_l = av_malloc(sizeof(float) * i_n_conv * i_n_samples);
+    pf_data_ir_r = av_malloc(sizeof(float) * i_n_conv * i_n_samples);
+    if (!pf_data_ir_r || !pf_data_ir_l)
+        return AVERROR(ENOMEM);
+
+    int i_offset = 0; /* used for faster pointer arithmetics in for-loop */
+
+    int i_m[s->i_n_conv]; /* measurement index m of IR closest to required source positions */
+    if (s->i_switch) { /* if switch not 0, use pre-defined virtual source positions */
+        i_azim = s->pi_azimuth_array[s->i_switch - 1];
+        i_elev = s->pi_elevation_array[s->i_switch -1];
+    }
+    int i_azim_orig = i_azim;
+
+    for ( int i = 0; i < s->i_n_conv; i++ ) {
+        /* load and store IRs and corresponding delays */
+        i_azim = (int)( s->pf_speaker_pos[i] + i_azim_orig ) % 360;
+        /* get id of IR closest to desired position */
+        i_m[i] = find_m( s, i_azim, i_elev, f_radius );
+
+        /* load the delays associated with the current IRs */
+        pi_delay_l[i] = *( s->sofa[s->i_sofa_id].pi_data_delay + 2 * i_m[i] );
+        pi_delay_r[i] = *( s->sofa[s->i_sofa_id].pi_data_delay + 2 * i_m[i] + 1);
+
+        i_offset = i * i_n_samples; /* no. samples already written */
+        for (int j = 0; j < i_n_samples; j++) {
+            /* load reversed IRs of the specified source position
+             * sample-by-sample for left and right ear; and apply gain */
+            *( pf_data_ir_l + i_offset + j ) = /* left channel */
+            *( s->sofa[s->i_sofa_id].pf_data_ir +
+            2 * i_m[i] * i_n_samples + i_n_samples - 1 - j ) * f_gain_lin;
+            *( pf_data_ir_r + i_offset + j ) = /* right channel */
+            *( s->sofa[s->i_sofa_id].pf_data_ir +
+            2 * i_m[i] * i_n_samples + i_n_samples - 1 - j  + i_n_samples ) * f_gain_lin;
+        }
+
+        av_log(ctx, AV_LOG_DEBUG, "Index: %d, Azimuth: %f, Elevation: %f, Radius: %f of SOFA file.\n",
+               i_m[i], *(s->sofa[s->i_sofa_id].pf_sp_a + i_m[i]),
+               *(s->sofa[s->i_sofa_id].pf_sp_e + i_m[i]),
+               *(s->sofa[s->i_sofa_id].pf_sp_r + i_m[i]) );
+    }
+
+    /* copy IRs and delays to allocated memory in the SOFAlizerContext struct: */
+    memcpy(s->pf_data_ir_l, pf_data_ir_l,
+        sizeof(float) * i_n_conv * i_n_samples);
+    memcpy(s->pf_data_ir_r, pf_data_ir_r,
+        sizeof(float) * i_n_conv * i_n_samples);
+
+    av_free(pf_data_ir_l); /* free temporary IR memory */
+    av_free(pf_data_ir_r);
+
+    memcpy(s->pi_delay_l, &pi_delay_l[0], sizeof(int) * s->i_n_conv);
+    memcpy(s->pi_delay_r, &pi_delay_r[0], sizeof(int) * s->i_n_conv);
+
+    return 0;
+}
+
+static inline unsigned clz(unsigned x)
+{
+    unsigned i = sizeof(x) * 8;
+    
+    while (x) {
+        x >>= 1;
+        i--;
+    }
+
+    return i;
+}
+
+static int config_input(AVFilterLink *inlink)
+{
+    AVFilterContext *ctx = inlink->dst;
+    SOFAlizerContext *s = ctx->priv;
+    int i_samplingrate = 0; /* get sampling rate of audio file/stream: */
+    int i_status = 0; /* zero, if no file could be loaded */
+
+    /* load SOFA files, resample if sampling rate different from audio file */
+    for (int i = 0; i < N_SOFA; i++) {
+        /* initialize file IDs to 0 before attempting to load SOFA files,
+         * this assures that in case of error, only the memory of already
+         * loaded files is free'd ( e.g. in FreeAllSofa() ) */
+        s->sofa[i].i_ncid = 0;
+    }
+    for (int i = 0;  i < N_SOFA; i++ ) {
+        if ( load_sofa( ctx, s->filename[i], i , &i_samplingrate) != 0 )
+        {   /* file loading error */
+            av_log(ctx, AV_LOG_ERROR, "Error while loading SOFA file %d: '%s'\n", i + 1, s->filename[i] );
+        } else { /* no file loading error, resampling not required */
+            av_log(ctx, AV_LOG_DEBUG, "File %d: '%s' loaded.\n", i + 1 , s->filename[i] );
+            i_status++; /* increase status after successful file loading */
+        }
+    }
+    if (!i_status) {
+        av_log(ctx, AV_LOG_ERROR, "No valid SOFA file could be loaded. Please specify at least one valid SOFA file.\n" );
+        return -1;
+    }
+
+    int i_input_nb = inlink->channels; /* no. input channels */
+    if (inlink->channel_layout & AV_CH_LOW_FREQUENCY) { /* if LFE is used */
+        s->lfe = 1;
+        s->i_n_conv = i_input_nb - 1 ; /* LFE is an input channel but requires no convolution */
+    } else /* if LFE is not used */ {
+        s->lfe = 0;
+        s->i_n_conv = i_input_nb ;
+    }
+
+    /* get size of ringbuffer (longest IR plus max. delay) */
+    /* then choose next power of 2 for performance optimization */
+    int i_n_max = 0;
+    int i_n_current;
+    int i_n_max_ir = 0;
+    for ( int i = 0 ; i < N_SOFA ; i++ )
+    {   /* go through all SOFA files and determine the longest IR */
+        if ( s->sofa[i].i_ncid != 0 )
+        {
+            i_n_current = s->sofa[i].i_n_samples + MaxDelay ( &s->sofa[i] );
+            if ( i_n_current > i_n_max )
+            {
+                /* length of longest IR plus max. delay (in all SOFA files) */
+                i_n_max = i_n_current;
+                /* length of longest IR (without delay, in all SOFA files) */
+                i_n_max_ir = s->sofa[i].i_n_samples;
+            }
+        }
+    }
+    s->i_n_longest_filter = i_n_max; /* longest IR plus max. delay */
+    /* buffer length is longest IR plus max. delay -> next power of 2
+       (32 - count leading zeros gives required exponent)  */
+    s->i_buffer_length = exp2(32 - clz((uint32_t)i_n_max));
+
+    s->i_output_buffer_length = 0; /* initialization */
+
+    /* Allocate memory for the impulse responses, delays and the ringbuffers */
+    /* size: (longest IR) * (number of channels to convolute), without LFE */
+    s->pf_data_ir_l = malloc( sizeof(float) * i_n_max_ir * s->i_n_conv );
+    s->pf_data_ir_r = malloc( sizeof(float) * i_n_max_ir * s->i_n_conv );
+    /* length:  number of channels to convolute */
+    s->pi_delay_l = malloc ( sizeof( int ) * s->i_n_conv );
+    s->pi_delay_r = malloc ( sizeof( int ) * s->i_n_conv );
+    /* length: (buffer length) * (number of input channels),
+     * OR: buffer length (if frequency domain processing)
+     * calloc zero-initializes the buffer */
+    s->pf_ringbuffer_l = av_calloc(s->i_buffer_length * i_input_nb, sizeof(float));
+    s->pf_ringbuffer_r = av_calloc(s->i_buffer_length * i_input_nb, sizeof(float));
+    /* length: number of channels to convolute */
+    s->pf_speaker_pos = malloc( sizeof( float) * s->i_n_conv );
+
+    /* memory allocation failed: */
+    if ( !s->pf_data_ir_l || !s->pf_data_ir_r || !s->pi_delay_l ||
+         !s->pi_delay_r || !s->pf_ringbuffer_l || !s->pf_ringbuffer_r ||
+         !s->pf_speaker_pos )
+        return AVERROR(ENOMEM);
+
+    compensate_volume(ctx);
+
+    /* get speaker positions */
+    if (get_speaker_pos(ctx, s->pf_speaker_pos)) {
+        av_log(ctx, AV_LOG_ERROR, "Couldn't get speaker positions. Input channel configuration not supported.\n");
+        return -1;
+    }
+    /* load IRs to pf_data_ir_l and pf_data_ir_r for required directions */
+    /* only load IRs if time-domain convolution is used,
+     * otherwise, data is loaded on FFT size change */
+    if (load_data(ctx, s->f_rotation, s->f_elevation, s->f_radius)) {
+        return AVERROR(ENOMEM);
+    }
+
+    av_log(ctx, AV_LOG_DEBUG, "Samplerate: %d Channels to convolute: %d, Length of ringbuffer: %d x %d\n",
+        inlink->sample_rate, s->i_n_conv, i_input_nb, (int)s->i_buffer_length );
+
+    return 0;
+}
+
+static av_cold void uninit(AVFilterContext *ctx)
+{
+    SOFAlizerContext *s = ctx->priv;
+
+    /* go through all SOFA files and free associated memory: */
+    for ( int i = 0 ; i < N_SOFA ; i++) {
+        if (s->sofa[i].i_ncid) {
+            av_freep(&s->sofa[i].pf_sp_a );
+            av_freep(&s->sofa[i].pf_sp_e );
+            av_freep(&s->sofa[i].pf_sp_r );
+            av_freep(&s->sofa[i].pi_data_delay );
+            av_freep(&s->sofa[i].pf_data_ir );
+        }
+    }
+    av_freep(&s->pi_delay_l );
+    av_freep(&s->pi_delay_r );
+    av_freep(&s->pf_data_ir_l );
+    av_freep(&s->pf_data_ir_r );
+    av_freep(&s->pf_ringbuffer_l );
+    av_freep(&s->pf_ringbuffer_r );
+    av_freep(&s->pf_speaker_pos );
+}
+
+#define OFFSET(x) offsetof(SOFAlizerContext, x)
+#define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
+
+static const AVOption sofalizer_options[] = {
+    { "sofa",      "sofa filename",        OFFSET(filename[0]),           AV_OPT_TYPE_STRING, {.str=NULL},            .flags = FLAGS },
+    { "gain",      "set gain in dB",       OFFSET(f_gain),                AV_OPT_TYPE_FLOAT,  {.dbl=0},     -20,  40, .flags = FLAGS },
+    { "rotation",  "set rotation"  ,       OFFSET(f_rotation),            AV_OPT_TYPE_FLOAT,  {.dbl=0},    -360, 360, .flags = FLAGS },
+    { "elevation", "set elevation",        OFFSET(f_elevation),           AV_OPT_TYPE_FLOAT,  {.dbl=0},     -90,  90, .flags = FLAGS },
+    { "radius",    "set radius",           OFFSET(f_radius),              AV_OPT_TYPE_FLOAT,  {.dbl=1},       0, 2.1, .flags = FLAGS },
+    { "azi1",      "set pos 1. azimuth",   OFFSET(pi_azimuth_array[0]),   AV_OPT_TYPE_INT,    {.i64=90},   -180, 180, .flags = FLAGS },
+    { "ele1",      "set pos 1. elevation", OFFSET(pi_elevation_array[0]), AV_OPT_TYPE_INT,    {.i64=0},     -90,  90, .flags = FLAGS },
+    { "azi2",      "set pos 2. azimuth",   OFFSET(pi_azimuth_array[1]),   AV_OPT_TYPE_INT,    {.i64=180},  -180, 180, .flags = FLAGS },
+    { "ele2",      "set pos 2. elevation", OFFSET(pi_elevation_array[1]), AV_OPT_TYPE_INT,    {.i64=0},     -90,  90, .flags = FLAGS },
+    { "azi3",      "set pos 3. azimuth",   OFFSET(pi_azimuth_array[2]),   AV_OPT_TYPE_INT,    {.i64=-90},  -180, 180, .flags = FLAGS },
+    { "ele3",      "set pos 3. elevation", OFFSET(pi_elevation_array[2]), AV_OPT_TYPE_INT,    {.i64=0},     -90,  90, .flags = FLAGS },
+    { "azi4",      "set pos 4. azimuth",   OFFSET(pi_azimuth_array[3]),   AV_OPT_TYPE_INT,    {.i64=0},    -180, 180, .flags = FLAGS },
+    { "ele4",      "set pos 4. elevation", OFFSET(pi_elevation_array[3]), AV_OPT_TYPE_INT,    {.i64=90},    -90,  90, .flags = FLAGS },
+    { NULL }
+};
+
+AVFILTER_DEFINE_CLASS(sofalizer);
+
+static const AVFilterPad inputs[] = {
+    {
+        .name         = "default",
+        .type         = AVMEDIA_TYPE_AUDIO,
+        .config_props = config_input,
+        .filter_frame = filter_frame,
+    },
+    { NULL }
+};
+
+static const AVFilterPad outputs[] = {
+    {
+        .name = "default",
+        .type = AVMEDIA_TYPE_AUDIO,
+    },
+    { NULL }
+};
+
+AVFilter ff_af_sofalizer = {
+    .name          = "sofalizer",
+    .description   = NULL_IF_CONFIG_SMALL("SOFAlizer (Spatially Oriented Format for Acoustics)."),
+    .priv_size     = sizeof(SOFAlizerContext),
+    .priv_class    = &sofalizer_class,
+    .uninit        = uninit,
+    .query_formats = query_formats,
+    .inputs        = inputs,
+    .outputs       = outputs,
+};
diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
index 0eeef53..131e067 100644
--- a/libavfilter/allfilters.c
+++ b/libavfilter/allfilters.c
@@ -109,6 +109,7 @@ void avfilter_register_all(void)
     REGISTER_FILTER(SIDECHAINGATE,  sidechaingate,  af);
     REGISTER_FILTER(SILENCEDETECT,  silencedetect,  af);
     REGISTER_FILTER(SILENCEREMOVE,  silenceremove,  af);
+    REGISTER_FILTER(SOFALIZER,      sofalizer,      af);
     REGISTER_FILTER(STEREOTOOLS,    stereotools,    af);
     REGISTER_FILTER(STEREOWIDEN,    stereowiden,    af);
     REGISTER_FILTER(TREBLE,         treble,         af);
-- 
1.9.1



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