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authorMax Kellermann <max@duempel.org>2013-12-28 17:42:03 +0100
committerMax Kellermann <max@duempel.org>2013-12-28 18:30:27 +0100
commitda29298d4dbe8dddade7cf241dd1af267470f2a8 (patch)
tree4cbb96c50418ce5d1dad66db9a946b1ba0a259aa /src
parentafcf0795c44260f54e74ec854297de439e7562c3 (diff)
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pcm/PcmMix: improved dithering
Use the existing PcmDither library.
Diffstat (limited to 'src')
-rw-r--r--src/OutputInternal.hxx6
-rw-r--r--src/OutputThread.cxx2
-rw-r--r--src/pcm/PcmMix.cxx45
-rw-r--r--src/pcm/PcmMix.hxx4
4 files changed, 38 insertions, 19 deletions
diff --git a/src/OutputInternal.hxx b/src/OutputInternal.hxx
index f05073bd7..ab1c1242e 100644
--- a/src/OutputInternal.hxx
+++ b/src/OutputInternal.hxx
@@ -22,6 +22,7 @@
#include "AudioFormat.hxx"
#include "pcm/PcmBuffer.hxx"
+#include "pcm/PcmDither.hxx"
#include "thread/Mutex.hxx"
#include "thread/Cond.hxx"
#include "thread/Thread.hxx"
@@ -172,6 +173,11 @@ struct audio_output {
PcmBuffer cross_fade_buffer;
/**
+ * The dithering state for cross-fading two streams.
+ */
+ PcmDither cross_fade_dither;
+
+ /**
* The filter object of this audio output. This is an
* instance of chain_filter_plugin.
*/
diff --git a/src/OutputThread.cxx b/src/OutputThread.cxx
index 1a8c70196..62833e360 100644
--- a/src/OutputThread.cxx
+++ b/src/OutputThread.cxx
@@ -392,7 +392,7 @@ ao_filter_chunk(struct audio_output *ao, const struct music_chunk *chunk,
void *dest = ao->cross_fade_buffer.Get(other_length);
memcpy(dest, other_data, other_length);
- if (!pcm_mix(dest, data, length,
+ if (!pcm_mix(ao->cross_fade_dither, dest, data, length,
ao->in_audio_format.format,
1.0 - chunk->mix_ratio)) {
FormatError(output_domain,
diff --git a/src/pcm/PcmMix.cxx b/src/pcm/PcmMix.cxx
index caf7fe516..c1ffd8633 100644
--- a/src/pcm/PcmMix.cxx
+++ b/src/pcm/PcmMix.cxx
@@ -25,41 +25,47 @@
#include "Traits.hxx"
#include "util/Clamp.hxx"
+#include "PcmDither.cxx" // including the .cxx file to get inlined templates
+
#include <assert.h>
#include <math.h>
template<SampleFormat F, class Traits=SampleTraits<F>>
static typename Traits::value_type
-PcmAddVolume(typename Traits::value_type _a, typename Traits::value_type _b,
+PcmAddVolume(PcmDither &dither,
+ typename Traits::value_type _a, typename Traits::value_type _b,
int volume1, int volume2)
{
typename Traits::long_type a(_a), b(_b);
+ typename Traits::long_type c(a * volume1 + b * volume2);
- typename Traits::value_type c = ((a * volume1 + b * volume2) +
- pcm_volume_dither() + PCM_VOLUME_1S / 2)
- / PCM_VOLUME_1S;
-
- return PcmClamp<F, Traits>(c);
+ return dither.DitherShift<typename Traits::long_type,
+ Traits::BITS + PCM_VOLUME_BITS,
+ Traits::BITS>(c);
}
template<SampleFormat F, class Traits=SampleTraits<F>>
static void
-PcmAddVolume(typename Traits::pointer_type a,
+PcmAddVolume(PcmDither &dither,
+ typename Traits::pointer_type a,
typename Traits::const_pointer_type b,
size_t n, int volume1, int volume2)
{
for (size_t i = 0; i != n; ++i)
- a[i] = PcmAddVolume<F, Traits>(a[i], b[i], volume1, volume2);
+ a[i] = PcmAddVolume<F, Traits>(dither, a[i], b[i],
+ volume1, volume2);
}
template<SampleFormat F, class Traits=SampleTraits<F>>
static void
-PcmAddVolumeVoid(void *a, const void *b, size_t size, int volume1, int volume2)
+PcmAddVolumeVoid(PcmDither &dither,
+ void *a, const void *b, size_t size, int volume1, int volume2)
{
constexpr size_t sample_size = Traits::SAMPLE_SIZE;
assert(size % sample_size == 0);
- PcmAddVolume<F, Traits>(typename Traits::pointer_type(a),
+ PcmAddVolume<F, Traits>(dither,
+ typename Traits::pointer_type(a),
typename Traits::const_pointer_type(b),
size / sample_size,
volume1, volume2);
@@ -80,7 +86,7 @@ pcm_add_vol_float(float *buffer1, const float *buffer2,
}
static bool
-pcm_add_vol(void *buffer1, const void *buffer2, size_t size,
+pcm_add_vol(PcmDither &dither, void *buffer1, const void *buffer2, size_t size,
int vol1, int vol2,
SampleFormat format)
{
@@ -91,22 +97,26 @@ pcm_add_vol(void *buffer1, const void *buffer2, size_t size,
return false;
case SampleFormat::S8:
- PcmAddVolumeVoid<SampleFormat::S8>(buffer1, buffer2, size,
+ PcmAddVolumeVoid<SampleFormat::S8>(dither,
+ buffer1, buffer2, size,
vol1, vol2);
return true;
case SampleFormat::S16:
- PcmAddVolumeVoid<SampleFormat::S16>(buffer1, buffer2, size,
+ PcmAddVolumeVoid<SampleFormat::S16>(dither,
+ buffer1, buffer2, size,
vol1, vol2);
return true;
case SampleFormat::S24_P32:
- PcmAddVolumeVoid<SampleFormat::S24_P32>(buffer1, buffer2, size,
+ PcmAddVolumeVoid<SampleFormat::S24_P32>(dither,
+ buffer1, buffer2, size,
vol1, vol2);
return true;
case SampleFormat::S32:
- PcmAddVolumeVoid<SampleFormat::S32>(buffer1, buffer2, size,
+ PcmAddVolumeVoid<SampleFormat::S32>(dither,
+ buffer1, buffer2, size,
vol1, vol2);
return true;
@@ -201,7 +211,7 @@ pcm_add(void *buffer1, const void *buffer2, size_t size,
}
bool
-pcm_mix(void *buffer1, const void *buffer2, size_t size,
+pcm_mix(PcmDither &dither, void *buffer1, const void *buffer2, size_t size,
SampleFormat format, float portion1)
{
float s;
@@ -217,5 +227,6 @@ pcm_mix(void *buffer1, const void *buffer2, size_t size,
int vol1 = s * PCM_VOLUME_1S + 0.5;
vol1 = Clamp<int>(vol1, 0, PCM_VOLUME_1S);
- return pcm_add_vol(buffer1, buffer2, size, vol1, PCM_VOLUME_1S - vol1, format);
+ return pcm_add_vol(dither, buffer1, buffer2, size,
+ vol1, PCM_VOLUME_1S - vol1, format);
}
diff --git a/src/pcm/PcmMix.hxx b/src/pcm/PcmMix.hxx
index 637c88f8a..a6657a979 100644
--- a/src/pcm/PcmMix.hxx
+++ b/src/pcm/PcmMix.hxx
@@ -25,6 +25,8 @@
#include <stddef.h>
+class PcmDither;
+
/*
* Linearly mixes two PCM buffers. Both must have the same length and
* the same audio format. The formula is:
@@ -44,7 +46,7 @@
*/
gcc_warn_unused_result
bool
-pcm_mix(void *buffer1, const void *buffer2, size_t size,
+pcm_mix(PcmDither &dither, void *buffer1, const void *buffer2, size_t size,
SampleFormat format, float portion1);
#endif