incorrect channel/speakers mapping

[SDLBugzilla]

This bug report was migrated from our old Bugzilla tracker.

Reported in version: unspecified Reported for operating system, platform: Windows 7, x86_64

Comments on the original bug report:

On 2019-05-31 15:26:25 +0000, AltairPL wrote:

Some time ago I tried using Mix_SetPosition() to test the idea of using rudimentary audio positioning in my engine. Simply put, wrong channels were used. Tried using both mono and stereo audio files and Mix_SetPanning() with pretty much the same result. After that I decided to make a separate test to see how playback of 5.1 ogg is handled and I noticed the same thing. Same file was played correctly in various media players and other applications. Results look like this (with test app restarted between tests):

Speakers set to 2.0/2.1: src SDL should be FL FL FL FC FR FL/FR FR FL/FR FR BL ? FL BR FL FR LF LF LF

Speakers set to 4.0/4.1: src SDL should be FL FL FL FC FR FL/FR FR FL/FR FR BL ? BL BR BL BR LF LF LF

Speakers set to 5.1: src SDL OK FL FL FL FC FR FC FR FC FR BL ? BL BR BL BR LF LF LF

This test was performed using:

• SDL 2.0.8 (x86)
• pre-release SDL_mixer 2.0.3 (x86) "released" on discourse (https://discourse.libsdl.org/t/sdl-mixer-2-0-3-prerelease/23959)
• Windows 7 64-bit
• Auzentech X-Fi Prelude 7.1 sound card
• 5.1 speaker set
• 5.1 ogg file from https://people.xiph.org/~xiphmont/demo/surround/demo.html - for some reason SDL_mixer refused to play 5.1 wav file

Had no chance to test it in SDL_mixer 2.0.4, but I haven't seen any mention of it in changelog, so I assume it's still the case.

[slouken]

@icculus, possibly related to your other planned multi-channel work.