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pcm dmix plugin: fix generic direct remixing

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In the case of the sum buffer being uninitialized, the source sample
must be negated not only when writing to the sum but also when writing
to the destination.
This commit is contained in:
Clemens Ladisch 2008-01-14 08:52:16 +01:00
parent 0e8a259914
commit fb3a4e8b70
1 changed files with 8 additions and 6 deletions
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14
src/pcm/pcm_dmix_generic.c
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@ -173,7 +173,7 @@ static void generic_remix_areas_16_native(unsigned int size,
sample = *src;
if (! *dst) {
*sum = -sample;
*dst = *src;
*dst = -sample;
} else {
*sum = sample = *sum - sample;
if (sample > 0x7fff)
@ -238,7 +238,7 @@ static void generic_remix_areas_32_native(unsigned int size,
sample = *src >> 8;
if (! *dst) {
*sum = -sample;
*dst = *src;
*dst = -*src;
} else {
*sum = sample = *sum - sample;
if (sample > 0x7fffff)
@ -303,7 +303,7 @@ static void generic_remix_areas_16_swap(unsigned int size,
sample = (signed short) bswap_16(*src);
if (! *dst) {
*sum = -sample;
*dst = *src;
*dst = (signed short) bswap_16((signed short) -sample);
} else {
*sum = sample = *sum - sample;
if (sample > 0x7fff)
@ -368,7 +368,7 @@ static void generic_remix_areas_32_swap(unsigned int size,
sample = bswap_32(*src) >> 8;
if (! *dst) {
*sum = -sample;
*dst = *src;
*dst = bswap_32(-sample);
} else {
*sum = sample = *sum - sample;
if (sample > 0x7fffff)
@ -434,7 +434,8 @@ static void generic_remix_areas_24(unsigned int size,
for (;;) {
sample = src[0] | (src[1] << 8) | (((signed char *)src)[2] << 16);
if (!(dst[0] | dst[1] | dst[2])) {
*sum = -sample;
sample = -sample;
*sum = sample;
} else {
*sum = sample = *sum - sample;
if (sample > 0x7fffff)
@ -493,7 +494,8 @@ static void generic_remix_areas_u8(unsigned int size,
for (;;) {
register int sample = *src - 0x80;
if (*dst == 0x80) {
*sum = -sample;
sample = -sample;
*sum = sample;
} else {
*sum = sample = *sum - sample;
if (sample > 0x7f)