This adds a new "replaygain-noclip" option to the filter, and, if enabled,
limits the gain applied for tracks where clipping would occur.
---
Made clipping prevention optional with new "replaygain-noclip" option (not sure
about the name though).
Note that this patch depends on the 1/5 one in this set, whch unbreaks the peak
decoding (necessary for clipping prevention).
doc/filters.texi | 5 +++++
libavfilter/af_volume.c | 32 ++++++++++++++++++++++----------
libavfilter/af_volume.h | 1 +
3 files changed, 28 insertions(+), 10 deletions(-)
diff --git a/doc/filters.texi b/doc/filters.texi
index 4a737ef..89d18c2 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -639,6 +639,11 @@ Pre-amplification gain in dB to apply to the selected
replaygain gain.
Default value for @var{replaygain-preamp} is 0.0.
+@item replaygain-noclip
+Prevent clipping by limiting the gain applied.
+
+Default value for @var{replaygain-noclip} is 1.
+
@end table
@subsection Examples
diff --git a/libavfilter/af_volume.c b/libavfilter/af_volume.c
index 393c4e7..0ebb105 100644
--- a/libavfilter/af_volume.c
+++ b/libavfilter/af_volume.c
@@ -61,6 +61,8 @@ static const AVOption options[] = {
{ "album", "album gain is preferred", 0, AV_OPT_TYPE_CONST, {
.i64 = REPLAYGAIN_ALBUM }, 0, 0, A, "replaygain" },
{ "replaygain-preamp", "Apply replaygain pre-amplification",
OFFSET(replaygain_preamp), AV_OPT_TYPE_DOUBLE, { .dbl = 0.0 },
-15.0, 15.0, A },
+ { "replaygain-noclip", "Apply replaygain clipping prevention",
+ OFFSET(replaygain_noclip), AV_OPT_TYPE_INT, { .i64 = 1 }, 0, 1, A
},
{ NULL },
};
@@ -246,25 +248,35 @@ static int filter_frame(AVFilterLink *inlink, AVFrame
*buf)
if (sd && vol->replaygain != REPLAYGAIN_IGNORE) {
if (vol->replaygain != REPLAYGAIN_DROP) {
AVReplayGain *replaygain = (AVReplayGain*)sd->data;
- int32_t gain;
- float g;
-
- if (vol->replaygain == REPLAYGAIN_TRACK &&
- replaygain->track_gain != INT32_MIN)
- gain = replaygain->track_gain;
- else if (replaygain->album_gain != INT32_MIN)
- gain = replaygain->album_gain;
- else {
+ int32_t gain = 100000;
+ uint32_t peak = 100000;
+ float g, p;
+
+ if (vol->replaygain == REPLAYGAIN_TRACK) {
+ if (replaygain->track_gain != INT32_MIN)
+ gain = replaygain->track_gain;
+
+ if (replaygain->track_peak != 0)
+ peak = replaygain->track_peak;
+ } else if (vol->replaygain == REPLAYGAIN_ALBUM) {
+ if (replaygain->album_gain != INT32_MIN)
+ gain = replaygain->album_gain;
+
+ if (replaygain->album_peak != 0)
+ peak = replaygain->album_peak;
+ } else {
av_log(inlink->dst, AV_LOG_WARNING, "Both ReplayGain gain "
"values are unknown.\n");
- gain = 100000;
}
g = gain / 100000.0f;
+ p = peak / 100000.0f;
av_log(inlink->dst, AV_LOG_VERBOSE,
"Using gain %f dB from replaygain side data.\n", g);
vol->volume = pow(10, (g + vol->replaygain_preamp) / 20);
+ if (vol->replaygain_noclip)
+ vol->volume = FFMIN(vol->volume, 1.0 / p);
vol->volume_i = (int)(vol->volume * 256 + 0.5);
volume_init(vol);
diff --git a/libavfilter/af_volume.h b/libavfilter/af_volume.h
index d831ec4..6bd89ac 100644
--- a/libavfilter/af_volume.h
+++ b/libavfilter/af_volume.h
@@ -48,6 +48,7 @@ typedef struct VolumeContext {
enum PrecisionType precision;
enum ReplayGainType replaygain;
double replaygain_preamp;
+ int replaygain_noclip;
double volume;
int volume_i;
int channels;
--
1.9.1
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