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PODoes OpenAL support 5.1 output on Mac OS X?
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copied!<p>I'm in the process of porting an application from Windows to Mac OS X. It is using OpenAL for handling the sound, but I'm getting a strange behavior in the initialization of the sound engine on Mac OS X (the code is running on a MacBook Pro).</p> <p>Here is the code:</p> <pre><code>int InitSoundEngine(void* data[NB_BUFFERS], size_t data_size[NB_BUFFERS]) { ALCdevice *device; ALCcontext *context; ALenum format; ALuint buffers[NB_BUFFERS]; device = alcOpenDevice(NULL); if (device == NULL) goto failed; context = alcCreateContext(device, NULL); if (context == NULL) goto failed; alcMakeContextCurrent(context); format = alGetEnumValue("AL_FORMAT_51CHN16"); if (format == 0) goto failed; alGenBuffers(NB_BUFFERS, buffers); if (alGetError() != AL_NO_ERROR) goto failed; for (int i = 0; i < NB_BUFFERS; ++ i) { alBufferData(buffers[i], format, data[i], data_size[i], 48000); if (alGetError() != AL_NO_ERROR) goto failed; } return NO_ERROR; failed: /* Cleanup omitted for brievety */ return INITIALIZATION_FAILED; } </code></pre> <p>This fails when during the call to <code>alBufferData</code>, with an error of <code>AL_INVALID_VALUE</code>. While tracing the code, we discovered that <code>alGetEnumValue("AL_FORMAT_51CHN16")</code> is returning <code>0xfffffffful</code>, and we suspect this is the root of the issue.</p> <p>The <code>alGetEnumValue</code> says:</p> <blockquote> <p><code>ALuint alGetEnumValue(const ALchar *enumName);</code></p> <p>Returns <code>0</code> if the enumeration can not be found, and sets an <code>AL_INVALID_VALUE</code> error condition. The presence of an enum value does not guarantee the applicability of an extension to the current context. A non-zero return indicates merely that the implementation is aware of the existence of this extension.</p> </blockquote> <p>I think I use the function correctly. Is there a bug in the Mac OS X implementation of OpenAL ? Is 5.1 output supported via OpenAL on Mac OS X ? Is it supported via Core Audio (porting to Core Audio could be an option if this is true) ? Should I convert my audio from 5.1 to another format (3.1, stereo, ...) ?</p>

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