af_volume: implement replaygain pre-amplification

This adds a new "replaygain_preamp" option to the filter, and simply adds its
value to the replaygain gain value.

Signed-off-by: Anton Khirnov <anton@khirnov.net>

1 files changed, 1 insertions, 0 deletions

diff --git a/libavfilter/af_volume.h b/libavfilter/af_volume.h
index ec13e80ae3..d831ec4a3d 100644
--- a/libavfilter/af_volume.h
+++ b/libavfilter/af_volume.h
@@ -47,6 +47,7 @@ typedef struct VolumeContext {
     AVFloatDSPContext fdsp;
     enum PrecisionType precision;
     enum ReplayGainType replaygain;
+    double replaygain_preamp;
     double volume;
     int    volume_i;
     int    channels;