C.W. Betts 2012-10-28 19:42:01 PDT
I noticed when looking through the CoreAudio code of SDL 2.0 that there was a
fix me wondering how iOS closed the audio system. While working on my own audio
code on PlayerPRO, I discovered that Carbon's component code was replaced in
the audio subsystem with Audio Component Services.
It's a long-dead platform, and we don't have any way to build for, test, or
maintain it, so there's no sense in doing acrobatics to support it.
If you need Windows CE support, use SDL 1.2. If you need Windows Phone support,
send SDL 2.0 patches for the newer Windows Mobile platform.
Markovtsev Vadim 2011-01-18 22:00:16 PST
SDL_audiocvt.c:
static void SDLCALL
SDL_ConvertStereo(SDL_AudioCVT * cvt, SDL_AudioFormat format):
#define dup_chans_1_to_2(type) \
{ \
const type *src = (const type *) (cvt->buf + cvt->len_cvt); \
type *dst = (type *) (cvt->buf + cvt->len_cvt * 2); \
for (i = cvt->len_cvt / 2; i; --i, --src) { \
const type val = *src; \
dst -= 2; \
dst[0] = dst[1] = val; \
} \
}
Pay attention to cvt->len_cvt / 2. 2 is the sizeof(Uint16), hovewer, below we
see that the conversion function supports Uint8 and Uint32:
switch (SDL_AUDIO_BITSIZE(format)) {
case 8:
dup_chans_1_to_2(Uint8);
break;
case 16:
dup_chans_1_to_2(Uint16);
break;
case 32:
dup_chans_1_to_2(Uint32);
break;
}
If type is Uint32, src will be decreased twice as it should be, memory being
written before the cvt->buf. If type is Uint8, the conversion will not be
complete. I suggest to change that define to
#define dup_chans_1_to_2(type) \
{ \
const type *src = (const type *) (cvt->buf + cvt->len_cvt); \
type *dst = (type *) (cvt->buf + cvt->len_cvt * 2); \
for (i = cvt->len_cvt / sizeof(type); i; --i, --src) { \
const type val = *src; \
dst -= 2; \
dst[0] = dst[1] = val; \
} \
}
I tested that and now it's working fine. I did not consider the similar defines
in functions nearby.
The patch Mark attached looks good and valgrind gives it a clean bill of health:
Mark.Howson@ntu.ac.uk 2010-12-15 07:45:25 PST
Reproducible here under Windows and Linux. Looking at the code for
SDL_Upsample_S16LSB_2c:
const int dstsize = (int) (((double)cvt->len_cvt) * cvt->rate_incr);
Sint16 *dst = ((Sint16 *) (cvt->buf + dstsize)) - 2;
const Sint16 *target = ((const Sint16 *) cvt->buf) - 2;
while (dst > target) {
dst[1] = ((Sint16) SDL_SwapLE16(sample1));
dst[0] = ((Sint16) SDL_SwapLE16(sample0));
dst -= 2;
...
if dstsize is odd (and therefore dst), it'll write to target[1] which is one
byte before the allocated buf.
The attached patch to sdlgenaudiocvt.pl changes dst > target to dst >= target,
and removes the - $channels for the upsample case. The patch is not fully
tested, but seems to work here.
Pallav Nawani 2012-01-04 00:48:29 PST
Issue:
Attempted to compile SDL as a static library.
DirectX SDK: Feb 2007
OS: Win 7
Visual C++ Express 2008
Compliation Mode: Static (Changed project settings from dll to lib)
Error:
C1021: invalid preprocessor command 'warning'
It seems that the #warning directive does not exist in Vc++ Express 2008.
