From c1d404b9e400d15b1b29fb05303278be0859eb7a Mon Sep 17 00:00:00 2001
From: Michael Niedermayer <michaelni@gmx.at>
Date: Wed, 11 Apr 2012 13:44:48 +0200
Subject: [PATCH] swr: add a dither_scale parameter to tune the amplitude of
the dither.
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
---
libswresample/dither.c | 2 ++
libswresample/swresample.c | 3 ++-
libswresample/swresample_internal.h | 1 +
3 files changed, 5 insertions(+), 1 deletion(-)
diff --git a/libswresample/dither.c b/libswresample/dither.c
index 8d5d0bcca9d..a340733610d 100644
--- a/libswresample/dither.c
+++ b/libswresample/dither.c
@@ -36,6 +36,8 @@ void swri_get_dither(SwrContext *s, void *dst, int len, unsigned seed, enum AVSa
if(in_fmt == AV_SAMPLE_FMT_S32 && out_fmt == AV_SAMPLE_FMT_U8 ) scale = 1L<<24;
if(in_fmt == AV_SAMPLE_FMT_S16 && out_fmt == AV_SAMPLE_FMT_U8 ) scale = 1L<<8;
+ scale *= s->dither_scale;
+
for(i=0; i<len + TMP_EXTRA; i++){
double v;
seed = seed* 1664525 + 1013904223;
diff --git a/libswresample/swresample.c b/libswresample/swresample.c
index 3078e87c65e..089d3e83d1c 100644
--- a/libswresample/swresample.c
+++ b/libswresample/swresample.c
@@ -53,7 +53,8 @@ static const AVOption options[]={
{"rmvol", "rematrix volume" , OFFSET(rematrix_volume), AV_OPT_TYPE_FLOAT, {.dbl=1.0}, -1000, 1000, 0},
{"flags", NULL , OFFSET(flags) , AV_OPT_TYPE_FLAGS, {.dbl=0}, 0, UINT_MAX, 0, "flags"},
{"res", "force resampling", 0, AV_OPT_TYPE_CONST, {.dbl=SWR_FLAG_RESAMPLE}, INT_MIN, INT_MAX, 0, "flags"},
-{"dither", "dither method" , OFFSET(dither_method), AV_OPT_TYPE_INT, {.dbl=0}, 0, SWR_DITHER_NB-1, 0, "dither_method"},
+{"dither_scale" , "dither scale" , OFFSET(dither_scale ), AV_OPT_TYPE_FLOAT, {.dbl=1}, 0, INT_MAX, 0},
+{"dither_method", "dither method" , OFFSET(dither_method), AV_OPT_TYPE_INT , {.dbl=0}, 0, SWR_DITHER_NB-1, 0, "dither_method"},
{"rectangular", "rectangular dither", 0, AV_OPT_TYPE_CONST, {.dbl=SWR_DITHER_RECTANGULAR}, INT_MIN, INT_MAX, 0, "dither_method"},
{"triangular" , "triangular dither" , 0, AV_OPT_TYPE_CONST, {.dbl=SWR_DITHER_TRIANGULAR }, INT_MIN, INT_MAX, 0, "dither_method"},
{"triangular_hp" , "triangular dither with high pass" , 0, AV_OPT_TYPE_CONST, {.dbl=SWR_DITHER_TRIANGULAR_HIGHPASS }, INT_MIN, INT_MAX, 0, "dither_method"},
diff --git a/libswresample/swresample_internal.h b/libswresample/swresample_internal.h
index d2cb85b375c..0575cece29e 100644
--- a/libswresample/swresample_internal.h
+++ b/libswresample/swresample_internal.h
@@ -51,6 +51,7 @@ struct SwrContext {
int used_ch_count; ///< number of used input channels (mapped channel count if channel_map, otherwise in.ch_count)
enum SwrDitherType dither_method;
int dither_pos;
+ float dither_scale;
int int_bps; ///< internal bytes per sample
int resample_first; ///< 1 if resampling must come first, 0 if rematrixing
--
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