@ -24,7 +24,6 @@
* @ see http : //tech.ebu.ch/loudness
* @ see https : //www.youtube.com/watch?v=iuEtQqC-Sqo "EBU R128 Introduction - Florian Camerer"
* @ todo implement start / stop / reset through filter command injection
* @ todo support other frequencies to avoid resampling
*/
# include <math.h>
@ -45,20 +44,6 @@
# define MAX_CHANNELS 63
/* pre-filter coefficients */
# define PRE_B0 1.53512485958697
# define PRE_B1 -2.69169618940638
# define PRE_B2 1.19839281085285
# define PRE_A1 -1.69065929318241
# define PRE_A2 0.73248077421585
/* RLB-filter coefficients */
# define RLB_B0 1.0
# define RLB_B1 -2.0
# define RLB_B2 1.0
# define RLB_A1 -1.99004745483398
# define RLB_A2 0.99007225036621
# define ABS_THRES -70 ///< silence gate: we discard anything below this absolute (LUFS) threshold
# define ABS_UP_THRES 10 ///< upper loud limit to consider (ABS_THRES being the minimum)
# define HIST_GRAIN 100 ///< defines histogram precision
@ -80,6 +65,7 @@ struct hist_entry {
struct integrator {
double * cache [ MAX_CHANNELS ] ; ///< window of filtered samples (N ms)
int cache_pos ; ///< focus on the last added bin in the cache array
int cache_size ;
double sum [ MAX_CHANNELS ] ; ///< sum of the last N ms filtered samples (cache content)
int filled ; ///< 1 if the cache is completely filled, 0 otherwise
double rel_threshold ; ///< relative threshold
@ -128,9 +114,11 @@ typedef struct EBUR128Context {
double x [ MAX_CHANNELS * 3 ] ; ///< 3 input samples cache for each channel
double y [ MAX_CHANNELS * 3 ] ; ///< 3 pre-filter samples cache for each channel
double z [ MAX_CHANNELS * 3 ] ; ///< 3 RLB-filter samples cache for each channel
double pre_b [ 3 ] ; ///< pre-filter numerator coefficients
double pre_a [ 3 ] ; ///< pre-filter denominator coefficients
double rlb_b [ 3 ] ; ///< rlb-filter numerator coefficients
double rlb_a [ 3 ] ; ///< rlb-filter denominator coefficients
# define I400_BINS (48000 * 4 / 10)
# define I3000_BINS (48000 * 3)
struct integrator i400 ; ///< 400ms integrator, used for Momentary loudness (M), and Integrated loudness (I)
struct integrator i3000 ; ///< 3s integrator, used for Short term loudness (S), and Loudness Range (LRA)
@ -388,6 +376,35 @@ static int config_audio_input(AVFilterLink *inlink)
AVFilterContext * ctx = inlink - > dst ;
EBUR128Context * ebur128 = ctx - > priv ;
/* Unofficial reversed parametrization of PRE
* and RLB from 48 kHz */
double f0 = 1681.974450955533 ;
double G = 3.999843853973347 ;
double Q = 0.7071752369554196 ;
double K = tan ( M_PI * f0 / ( double ) inlink - > sample_rate ) ;
double Vh = pow ( 10.0 , G / 20.0 ) ;
double Vb = pow ( Vh , 0.4996667741545416 ) ;
double a0 = 1.0 + K / Q + K * K ;
ebur128 - > pre_b [ 0 ] = ( Vh + Vb * K / Q + K * K ) / a0 ;
ebur128 - > pre_b [ 1 ] = 2.0 * ( K * K - Vh ) / a0 ;
ebur128 - > pre_b [ 2 ] = ( Vh - Vb * K / Q + K * K ) / a0 ;
ebur128 - > pre_a [ 1 ] = 2.0 * ( K * K - 1.0 ) / a0 ;
ebur128 - > pre_a [ 2 ] = ( 1.0 - K / Q + K * K ) / a0 ;
f0 = 38.13547087602444 ;
Q = 0.5003270373238773 ;
K = tan ( M_PI * f0 / ( double ) inlink - > sample_rate ) ;
ebur128 - > rlb_b [ 0 ] = 1.0 ;
ebur128 - > rlb_b [ 1 ] = - 2.0 ;
ebur128 - > rlb_b [ 2 ] = 1.0 ;
ebur128 - > rlb_a [ 1 ] = 2.0 * ( K * K - 1.0 ) / ( 1.0 + K / Q + K * K ) ;
ebur128 - > rlb_a [ 2 ] = ( 1.0 - K / Q + K * K ) / ( 1.0 + K / Q + K * K ) ;
/* Force 100ms framing in case of metadata injection: the frames must have
* a granularity of the window overlap to be accurately exploited .
* As for the true peaks mode , it just simplifies the resampling buffer
@ -418,6 +435,9 @@ static int config_audio_output(AVFilterLink *outlink)
if ( ! ebur128 - > ch_weighting )
return AVERROR ( ENOMEM ) ;
# define I400_BINS (outlink->sample_rate * 4 / 10)
# define I3000_BINS (outlink->sample_rate * 3)
for ( i = 0 ; i < nb_channels ; i + + ) {
/* channel weighting */
const uint64_t chl = av_channel_layout_extract_channel ( outlink - > channel_layout , i ) ;
@ -433,8 +453,10 @@ static int config_audio_output(AVFilterLink *outlink)
continue ;
/* bins buffer for the two integration window (400ms and 3s) */
ebur128 - > i400 . cache [ i ] = av_calloc ( I400_BINS , sizeof ( * ebur128 - > i400 . cache [ 0 ] ) ) ;
ebur128 - > i3000 . cache [ i ] = av_calloc ( I3000_BINS , sizeof ( * ebur128 - > i3000 . cache [ 0 ] ) ) ;
ebur128 - > i400 . cache_size = I400_BINS ;
ebur128 - > i3000 . cache_size = I3000_BINS ;
ebur128 - > i400 . cache [ i ] = av_calloc ( ebur128 - > i400 . cache_size , sizeof ( * ebur128 - > i400 . cache [ 0 ] ) ) ;
ebur128 - > i3000 . cache [ i ] = av_calloc ( ebur128 - > i3000 . cache_size , sizeof ( * ebur128 - > i3000 . cache [ 0 ] ) ) ;
if ( ! ebur128 - > i400 . cache [ i ] | | ! ebur128 - > i3000 . cache [ i ] )
return AVERROR ( ENOMEM ) ;
}
@ -613,7 +635,8 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *insamples)
# define MOVE_TO_NEXT_CACHED_ENTRY(time) do { \
ebur128 - > i # # time . cache_pos + + ; \
if ( ebur128 - > i # # time . cache_pos = = I # # time # # _BINS ) { \
if ( ebur128 - > i # # time . cache_pos = = \
ebur128 - > i # # time . cache_size ) { \
ebur128 - > i # # time . filled = 1 ; \
ebur128 - > i # # time . cache_pos = 0 ; \
} \
@ -634,20 +657,20 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *insamples)
continue ;
/* Y[i] = X[i]*b0 + X[i-1]*b1 + X[i-2]*b2 - Y[i-1]*a1 - Y[i-2]*a2 */
# define FILTER(Y, X, name) do { \
# define FILTER(Y, X, NUM, DEN) do { \
double * dst = ebur128 - > Y + ch * 3 ; \
double * src = ebur128 - > X + ch * 3 ; \
dst [ 2 ] = dst [ 1 ] ; \
dst [ 1 ] = dst [ 0 ] ; \
dst [ 0 ] = src [ 0 ] * name # # _B0 + src [ 1 ] * name # # _B1 + src [ 2 ] * name # # _B2
- dst [ 1 ] * name # # _A1 - dst [ 2 ] * name # # _A2 ;
dst [ 0 ] = src [ 0 ] * NUM [ 0 ] + src [ 1 ] * NUM [ 1 ] + src [ 2 ] * NUM [ 2 ]
- dst [ 1 ] * DEN [ 1 ] - dst [ 2 ] * DEN [ 2 ] ;
} while ( 0 )
// TODO: merge both filters in one?
FILTER ( y , x , PRE ) ; // apply pre-filter
FILTER ( y , x , ebur128 - > pre_b , ebur128 - > pre_a ) ; // apply pre-filter
ebur128 - > x [ ch * 3 + 2 ] = ebur128 - > x [ ch * 3 + 1 ] ;
ebur128 - > x [ ch * 3 + 1 ] = ebur128 - > x [ ch * 3 ] ;
FILTER ( z , y , RLB ) ; // apply RLB-filter
FILTER ( z , y , ebur128 - > rlb_b , ebur128 - > rlb_a ) ; // apply RLB-filter
bin = ebur128 - > z [ ch * 3 ] * ebur128 - > z [ ch * 3 ] ;
@ -896,7 +919,6 @@ static int query_formats(AVFilterContext *ctx)
int ret ;
static const enum AVSampleFormat sample_fmts [ ] = { AV_SAMPLE_FMT_DBL , AV_SAMPLE_FMT_NONE } ;
static const int input_srate [ ] = { 48000 , - 1 } ; // ITU-R BS.1770 provides coeff only for 48kHz
static const enum AVPixelFormat pix_fmts [ ] = { AV_PIX_FMT_RGB24 , AV_PIX_FMT_NONE } ;
/* set optional output video format */
@ -920,7 +942,7 @@ static int query_formats(AVFilterContext *ctx)
( ret = ff_channel_layouts_ref ( layouts , & outlink - > incfg . channel_layouts ) ) < 0 )
return ret ;
formats = ff_make_format_list ( input_srate ) ;
formats = ff_all_samplerates ( ) ;
if ( ( ret = ff_formats_ref ( formats , & inlink - > outcfg . samplerates ) ) < 0 | |
( ret = ff_formats_ref ( formats , & outlink - > incfg . samplerates ) ) < 0 )
return ret ;
Paul B Mahol
4 years ago