From b1ef4dc406e8a0bd9acea40d880aa4e74412075b Mon Sep 17 00:00:00 2001
From: Michael Niedermayer <michaelni@gmx.at>
Date: Tue, 10 Apr 2012 21:10:14 +0200
Subject: [PATCH] swr: add triangular dither support
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
---
libswresample/dither.c | 5 +++++
libswresample/swresample.c | 1 +
libswresample/swresample.h | 1 +
3 files changed, 7 insertions(+)
diff --git a/libswresample/dither.c b/libswresample/dither.c
index 4e39cceb0d2..663e2007ba5 100644
--- a/libswresample/dither.c
+++ b/libswresample/dither.c
@@ -40,6 +40,11 @@ void swri_get_dither(void *dst, int len, unsigned seed, enum AVSampleFormat out_
switch(method){
case SWR_DITHER_RECTANGULAR: v= ((double)seed) / UINT_MAX - 0.5; break;
+ case SWR_DITHER_TRIANGULAR :
+ v = ((double)seed) / UINT_MAX;
+ seed = seed*1664525 + 1013904223;
+ v-= ((double)seed) / UINT_MAX;
+ break;
default: av_assert0(0);
}
diff --git a/libswresample/swresample.c b/libswresample/swresample.c
index 8b06061e7c4..58096b39277 100644
--- a/libswresample/swresample.c
+++ b/libswresample/swresample.c
@@ -55,6 +55,7 @@ static const AVOption options[]={
{"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"},
{"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"},
{0}
};
diff --git a/libswresample/swresample.h b/libswresample/swresample.h
index 1f87617d9df..9bd5b6769db 100644
--- a/libswresample/swresample.h
+++ b/libswresample/swresample.h
@@ -48,6 +48,7 @@
enum SwrDitherType {
SWR_DITHER_NONE = 0,
SWR_DITHER_RECTANGULAR,
+ SWR_DITHER_TRIANGULAR,
SWR_DITHER_NB, ///< not part of API/ABI
};
--
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