[FFmpeg-cvslog] avfilter/ebur128: add dualmono measurement option
Kyle Swanson
git at videolan.org
Sun Oct 4 13:17:56 CEST 2015
ffmpeg | branch: master | Kyle Swanson <k at ylo.ph> | Wed Sep 30 10:35:08 2015 -0500| [4f721bfd46120aa2a7c7cdcbdd7c8db3b767dd1d] | committer: Clément Bœsch
avfilter/ebur128: add dualmono measurement option
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=4f721bfd46120aa2a7c7cdcbdd7c8db3b767dd1d
---
doc/filters.texi | 9 +++++++++
libavfilter/f_ebur128.c | 22 ++++++++++++++++++++++
2 files changed, 31 insertions(+)
diff --git a/doc/filters.texi b/doc/filters.texi
index 04b2d22..71f1456 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -12685,6 +12685,15 @@ stream for better peak accuracy. It logs a message for true-peak.
This mode requires a build with @code{libswresample}.
@end table
+ at item dualmono
+Treat mono input files as "dual mono". If a mono file is intended for playback
+on a stereo system, its EBU R128 measurement will be perceptually incorrect.
+If set to @code{true}, this option will compensate for this effect.
+Multi-channel input files are not effected by this option.
+
+ at item panlaw
+Set a specific pan law to be used for the measurement of dual mono files.
+This parameter is optional, and has a default value of -3.01dB.
@end table
@subsection Examples
diff --git a/libavfilter/f_ebur128.c b/libavfilter/f_ebur128.c
index 1d5c8fd..c63356f 100644
--- a/libavfilter/f_ebur128.c
+++ b/libavfilter/f_ebur128.c
@@ -139,6 +139,8 @@ typedef struct {
/* misc */
int loglevel; ///< log level for frame logging
int metadata; ///< whether or not to inject loudness results in frames
+ int dual_mono; ///< whether or not to treat single channel input files as dual-mono
+ double pan_law; ///< pan law value used to calulate dual-mono measurements
} EBUR128Context;
enum {
@@ -163,6 +165,8 @@ static const AVOption ebur128_options[] = {
{ "none", "disable any peak mode", 0, AV_OPT_TYPE_CONST, {.i64 = PEAK_MODE_NONE}, INT_MIN, INT_MAX, A|F, "mode" },
{ "sample", "enable peak-sample mode", 0, AV_OPT_TYPE_CONST, {.i64 = PEAK_MODE_SAMPLES_PEAKS}, INT_MIN, INT_MAX, A|F, "mode" },
{ "true", "enable true-peak mode", 0, AV_OPT_TYPE_CONST, {.i64 = PEAK_MODE_TRUE_PEAKS}, INT_MIN, INT_MAX, A|F, "mode" },
+ { "dualmono", "treat mono input files as dual-mono", OFFSET(dual_mono), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, A|F },
+ { "panlaw", "set a specific pan law for dual-mono files", OFFSET(pan_law), AV_OPT_TYPE_DOUBLE, {.dbl = -3.01029995663978}, -10.0, 0.0, A|F },
{ NULL },
};
@@ -661,6 +665,10 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *insamples)
}
if (nb_integrated)
ebur128->integrated_loudness = LOUDNESS(integrated_sum / nb_integrated);
+ /* dual-mono correction */
+ if (nb_channels == 1 && ebur128->dual_mono) {
+ ebur128->integrated_loudness -= ebur128->pan_law;
+ }
}
/* LRA */
@@ -707,6 +715,12 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *insamples)
}
}
+ /* dual-mono correction */
+ if (nb_channels == 1 && ebur128->dual_mono) {
+ loudness_400 -= ebur128->pan_law;
+ loudness_3000 -= ebur128->pan_law;
+ }
+
#define LOG_FMT "M:%6.1f S:%6.1f I:%6.1f LUFS LRA:%6.1f LU"
/* push one video frame */
@@ -855,6 +869,14 @@ static av_cold void uninit(AVFilterContext *ctx)
int i;
EBUR128Context *ebur128 = ctx->priv;
+ /* dual-mono correction */
+ if (ebur128->nb_channels == 1 && ebur128->dual_mono) {
+ ebur128->i400.rel_threshold -= ebur128->pan_law;
+ ebur128->i3000.rel_threshold -= ebur128->pan_law;
+ ebur128->lra_low -= ebur128->pan_law;
+ ebur128->lra_high -= ebur128->pan_law;
+ }
+
av_log(ctx, AV_LOG_INFO, "Summary:\n\n"
" Integrated loudness:\n"
" I: %5.1f LUFS\n"
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