Dolby Surround Sound isn't properly implemented

[richard42]

Originally reported on Google Code with ID 308

I have a 5.1 surround sound system hooked up to my computer. In Legend of
Zelda: Majora's Mask, when selecting surround sound as the output, I can
only hear the N64 sound coming from the front 2 speakers, yet the sound
quality is worse than if it were set to stereo. This is probably because
selecting surround spilts the audio into different channels, but only the
front channels seem to be working. I know my surround sound works fine
because I have tested it in other applications. The issue is specific to mupen.

Reported by ALIENDUDE5300 on 2009-12-24 06:53:03

[richard42]

The original N64 hardware had no hardware output put for 5.1-channel audio.  It only
had 2 audio output channels.  The 'surround sound' that these games used was the old
Dolby Pro Logic scheme:

http://www.avforums.com/forums/nintendo-wii-ds-gaming/409104-outputs-how-do-n64-gamecube-produce-surround-sound.html

http://techforums.nintendo.com/nins/board/message?board.id=other_older&thread.id=742

If you set you receiver to "Pro Logic" mode then you will be getting the best that
these games have to offer.

Reported by richard42g on 2010-01-14 05:34:25

• Status changed: Invalid

[Squall-Leonhart]

Closing this was premature, the Phase based sound matrix required for Dolby Pro Logic cannot be output via software audio mixing and requires using Plugin/software DSP based decoding into a PCM 4+ mix, it only appears to work for DPLII receivers because DPLII incorporates an approximated stereo to 5.1 expansion mixing capability.

A pure Pro Logic receiver (not II) will play the output as stereo only unless run on XP, with a hardware accelerated sound card that can bypass the kernel streaming engine.