Crackle in audio

SDL Development
1

Hi, I’ve come across de bug described in
http://bugzilla.libsdl.org/show_bug.cgi?id=649 and fixed it in the without
disabling mmx, the problem is that the mmx code only mixes buffers up to a
multiple of 16 samples. I’ve seen that the 1.14 version was already released
and that the bug was already closed so I don’t know if a patch would be
accepted in this case. Shall I prepare one for revision?

2

Hey, great find! Is this due to a limitation in MMX that it can only
perform an operation in multiples of 16?On Sat, Dec 5, 2009 at 8:45 PM, Felipe <felipe.otamendi at gmail.com> wrote:

Hi, I’ve come across de bug described in
http://bugzilla.libsdl.org/show_bug.cgi?id=649 and fixed it in the without
disabling mmx, the problem is that the mmx code only mixes buffers up to a
multiple of 16 samples. I’ve seen that the 1.14 version was already released
and that the bug was already closed so I don’t know if a patch would be
accepted in this case. Shall I prepare one for revision?

SDL mailing list
SDL at lists.libsdl.org
http://lists.libsdl.org/listinfo.cgi/sdl-libsdl.org

–
http://codebad.com/

3

Hey, great find! Is this due to a limitation in MMX that it can only
perform an operation in multiples of 16?

SIMD instructions like MMX apply the same operation to several pieces
of data at once (e. g. a vector addition of 4 16-bit words). So if you
have buffer sizes not divisible by the size of one vector, you have to
process the remaining data separately.

I’m having the crackling problem too, so I’m glad this was found :)On Mon, 7 Dec 2009 10:28:07 -0500 Donny Viszneki <donny.viszneki at gmail.com> wrote:

4

Sure, that would be great!

Thanks,On Sat, Dec 5, 2009 at 5:45 PM, Felipe <felipe.otamendi at gmail.com> wrote:

Hi, I’ve come across de bug described in
http://bugzilla.libsdl.org/show_bug.cgi?id=649 and fixed it in the without
disabling mmx, the problem is that the mmx code only mixes buffers up to a
multiple of 16 samples. I’ve seen that the 1.14 version was already released
and that the bug was already closed so I don’t know if a patch would be
accepted in this case. Shall I prepare one for revision?

SDL mailing list
SDL at lists.libsdl.org
http://lists.libsdl.org/listinfo.cgi/sdl-libsdl.org

–
-Sam Lantinga, Founder and President, Galaxy Gameworks LLC