Re: Playing 5.1 sound on a stereo device with OpenAL Soft
Martin Lambers <[email protected]>
| Newsgroups | gmane.comp.lib.openal |
|---|---|
| Message-ID | <[email protected]> |
On 05/11/10 07:21, Chris Robinson wrote: > On Thursday, November 04, 2010 9:59:15 pm Martin Lambers wrote: >> How do I play multichannel sound on a stereo device using OpenAL (Soft)? >> >> >From the example alffmpeg.c, I had the impression that OpenAL would >> automatically perform downmixing of a 5.1 file if the output device was >> stereo, but that does not seem to be the case. For example, with this >> test file >> <http://www.lynnepublishing.com/surround/www_lynnemusic_com_surround_test.a >> c3>, alffmpeg only plays static noise on my system. Other ffmpeg-based >> players can play it fine, so I don't think it's a decoding problem. > > What version of OpenAL Soft are you using? The downmixing is automatic, and it > seems to work fine for me. If possible, try recompiling alffmpeg... ffmpeg > updates sometimes break compatibility in odd ways. You're right, it is indeed an ffmpeg problem. Some audio streams are apparently *not* decoded to signed 16 bit sample formats. The ffplay player contains code to convert sample formats in this case, but uses an internal ffmpeg API for this purpose that is not part of the installed header files. So, no luck for alffmpeg and my project... Test case: http://www.lynnepublishing.com/surround/www_lynnemusic_com_surround_test.wma (WMA version of the above file; the AC3 version decodes to s16 samples and plays fine). I'll report this to the ffmpeg bug tracker. Martin _______________________________________________ Openal mailing list [email protected] http://opensource.creative.com/mailman/listinfo/openal