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Commit 5b5e46f5 authored by Max Kellermann's avatar Max Kellermann
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pcm_utils: added inline function pcm_dither()

Merge some code into an inline function, so we can optimize it later only once.
parent 75cba934
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Showing with 10 additions and 8 deletions
src/pcm_utils.c
View file @ 5b5e46f5
...@@ -25,6 +25,12 @@ ...@@ -25,6 +25,12 @@
#include "audio_format.h" #include "audio_format.h"
#include "os_compat.h" #include "os_compat.h"
static inline int
pcm_dither(void)
{
return (rand() & 511) - (rand() & 511);
}
void pcm_volumeChange(char *buffer, int bufferSize, void pcm_volumeChange(char *buffer, int bufferSize,
const struct audio_format *format, const struct audio_format *format,
int volume) int volume)
...@@ -46,8 +52,7 @@ void pcm_volumeChange(char *buffer, int bufferSize, ...@@ -46,8 +52,7 @@ void pcm_volumeChange(char *buffer, int bufferSize,
while (bufferSize > 0) { while (bufferSize > 0) {
temp32 = *buffer16; temp32 = *buffer16;
temp32 *= volume; temp32 *= volume;
temp32 += rand() & 511; temp32 += pcm_dither();
temp32 -= rand() & 511;
temp32 += 500; temp32 += 500;
temp32 /= 1000; temp32 /= 1000;
*buffer16 = temp32 > 32767 ? 32767 : *buffer16 = temp32 > 32767 ? 32767 :
...@@ -60,8 +65,7 @@ void pcm_volumeChange(char *buffer, int bufferSize, ...@@ -60,8 +65,7 @@ void pcm_volumeChange(char *buffer, int bufferSize,
while (bufferSize > 0) { while (bufferSize > 0) {
temp32 = *buffer8; temp32 = *buffer8;
temp32 *= volume; temp32 *= volume;
temp32 += rand() & 511; temp32 += pcm_dither();
temp32 -= rand() & 511;
temp32 += 500; temp32 += 500;
temp32 /= 1000; temp32 /= 1000;
*buffer8 = temp32 > 127 ? 127 : *buffer8 = temp32 > 127 ? 127 :
...@@ -92,8 +96,7 @@ static void pcm_add(char *buffer1, const char *buffer2, size_t bufferSize1, ...@@ -92,8 +96,7 @@ static void pcm_add(char *buffer1, const char *buffer2, size_t bufferSize1,
temp32 = temp32 =
(vol1 * (*buffer16_1) + (vol1 * (*buffer16_1) +
vol2 * (*buffer16_2)); vol2 * (*buffer16_2));
temp32 += rand() & 511; temp32 += pcm_dither();
temp32 -= rand() & 511;
temp32 += 500; temp32 += 500;
temp32 /= 1000; temp32 /= 1000;
*buffer16_1 = *buffer16_1 =
...@@ -111,8 +114,7 @@ static void pcm_add(char *buffer1, const char *buffer2, size_t bufferSize1, ...@@ -111,8 +114,7 @@ static void pcm_add(char *buffer1, const char *buffer2, size_t bufferSize1,
while (bufferSize1 > 0 && bufferSize2 > 0) { while (bufferSize1 > 0 && bufferSize2 > 0) {
temp32 = temp32 =
(vol1 * (*buffer8_1) + vol2 * (*buffer8_2)); (vol1 * (*buffer8_1) + vol2 * (*buffer8_2));
temp32 += rand() & 511; temp32 += pcm_dither();
temp32 -= rand() & 511;
temp32 += 500; temp32 += 500;
temp32 /= 1000; temp32 /= 1000;
*buffer8_1 = *buffer8_1 =
......
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