66 lines
2.0 KiB
Diff
66 lines
2.0 KiB
Diff
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From bdf80e58af79d4e989cd8d701d97f888c9e2dadc Mon Sep 17 00:00:00 2001
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From: Zerg Cannibal <cnb_zerg@yahoo.com>
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Date: Mon, 21 Dec 2009 22:19:14 +0100
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Subject: [PATCH 2/2] pcm: Fix the sound distortions for S24_3LE stream in pcm_softvol plugin
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This patch fixes sound distortions in alsa-lib "softvol"
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for S24_3LE sound stream, when softvol slider is not at 0.0dB
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position.
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Signed-off-by: CannibalZerg <cnb_zerg@yahoo.com>
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Signed-off-by: Jaroslav Kysela <perex@perex.cz>
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---
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src/pcm/pcm_softvol.c | 22 ++++++++++++++++++++--
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1 files changed, 20 insertions(+), 2 deletions(-)
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diff --git a/src/pcm/pcm_softvol.c b/src/pcm/pcm_softvol.c
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index 637e5cb..2c7c006 100644
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--- a/src/pcm/pcm_softvol.c
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+++ b/src/pcm/pcm_softvol.c
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@@ -107,7 +107,8 @@ static inline int MULTI_DIV_32x16(int a, unsigned short b)
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v.i = a;
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y.i = 0;
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#if __BYTE_ORDER == __LITTLE_ENDIAN
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- x.i = (unsigned int)v.s[0] * b;
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+ x.i = (unsigned short)v.s[0];
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+ x.i *= b;
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y.s[0] = x.s[1];
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y.i += (int)v.s[1] * b;
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#else
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@@ -135,6 +136,23 @@ static inline int MULTI_DIV_int(int a, unsigned int b, int swap)
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return swap ? (int)bswap_32(fraction) : fraction;
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}
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+/* always little endian */
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+static inline int MULTI_DIV_24(int a, unsigned int b)
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+{
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+ unsigned int gain = b >> VOL_SCALE_SHIFT;
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+ int fraction;
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+ fraction = MULTI_DIV_32x16(a, b & VOL_SCALE_MASK);
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+ if (gain) {
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+ long long amp = (long long)a * gain + fraction;
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+ if (amp > (int)0x7fffff)
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+ amp = (int)0x7fffff;
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+ else if (amp < (int)0x800000)
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+ amp = (int)0x800000;
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+ return (int)amp;
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+ }
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+ return fraction;
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+}
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+
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static inline short MULTI_DIV_short(short a, unsigned int b, int swap)
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{
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unsigned int gain = b >> VOL_SCALE_SHIFT;
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@@ -223,7 +241,7 @@ static inline short MULTI_DIV_short(short a, unsigned int b, int swap)
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tmp = src[0] | \
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(src[1] << 8) | \
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(((signed char *) src)[2] << 16); \
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- tmp = MULTI_DIV_int(tmp, vol_scale, 0); \
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+ tmp = MULTI_DIV_24(tmp, vol_scale); \
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dst[0] = tmp; \
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dst[1] = tmp >> 8; \
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dst[2] = tmp >> 16; \
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--
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1.6.5.7
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