GUI: Remove mostly-broken audio output sample rate control

Removing this GUI control was suggested as far back as 2011 at
<http://lists.scummvm.org/pipermail/scummvm-devel/2011-November/010416.html>.
There were no objections, but it was never removed. When working
on audio latency bugs, I independently rediscovered that the GUI
option was broken: the per-game options would *never* work, and the
option would not take effect until ScummVM was restarted because
there is no API for interacting with the backend audio mixer. So
now, it is finally gone.

Primarily for the sake of future troubleshooting, configurability
of the audio sample frequency within SdlMixerManager is maintained
for the moment, but now users will need to edit their ScummVM
configuration file manually to change it.

1 files changed, 12 insertions, 8 deletions

diff --git a/backends/mixer/sdl/sdl-mixer.cpp b/backends/mixer/sdl/sdl-mixer.cpp
index 3e65fbae97..5a31feb4dc 100644
--- a/backends/mixer/sdl/sdl-mixer.cpp
+++ b/backends/mixer/sdl/sdl-mixer.cpp
@@ -128,23 +128,27 @@ void SdlMixerManager::init() {
 SDL_AudioSpec SdlMixerManager::getAudioSpec(uint32 outputRate) {
 	SDL_AudioSpec desired;
 
-	// Determine the desired output sampling frequency.
-	uint32 samplesPerSec = 0;
-	if (ConfMan.hasKey("output_rate"))
-		samplesPerSec = ConfMan.getInt("output_rate");
-	if (samplesPerSec <= 0)
-		samplesPerSec = outputRate;
+	const char *const appDomain = Common::ConfigManager::kApplicationDomain;
+
+	// There was once a GUI option for this, but it was never used;
+	// configurability is retained for advanced users only who wish to modify
+	// their ScummVM config file directly
+	uint32 freq = 0;
+	if (ConfMan.hasKey("output_rate", appDomain))
+		freq = ConfMan.getInt("output_rate", appDomain);
+	if (freq <= 0)
+		freq = outputRate;
 
 	// Determine the sample buffer size. We want it to store enough data for
 	// at least 1/16th of a second (though at most 8192 samples). Note
 	// that it must be a power of two. So e.g. at 22050 Hz, we request a
 	// sample buffer size of 2048.
 	uint32 samples = 8192;
-	while (samples * 16 > samplesPerSec * 2)
+	while (samples * 16 > freq * 2)
 		samples >>= 1;
 
 	memset(&desired, 0, sizeof(desired));
-	desired.freq = samplesPerSec;
+	desired.freq = freq;
 	desired.format = AUDIO_S16SYS;
 	desired.channels = 2;
 	desired.samples = (uint16)samples;