M src/gba/gba-audio.c → src/gba/gba-audio.c

@@ -4,6 +4,7 @@ #include "gba.h"
 #include "gba-io.h"
 #include "gba-serialize.h"
 #include "gba-thread.h"
+#include "gba-video.h"
 
 const unsigned GBA_AUDIO_SAMPLES = 512;
 const unsigned GBA_AUDIO_FIFO_SIZE = 8 * sizeof(int32_t);
@@ -751,3 +752,7 @@ audio->nextEvent = state->audio.nextEvent;
 	audio->eventDiff = state->audio.eventDiff;
 	audio->nextSample = state->audio.nextSample;
 }
+
+float GBAAudioCalculateRatio(struct GBAAudio* audio, float desiredFPS, float desiredSampleRate) {
+	return desiredSampleRate * GBA_ARM7TDMI_FREQUENCY / (VIDEO_TOTAL_LENGTH * desiredFPS * audio->sampleRate);
+}

M src/gba/gba-audio.h → src/gba/gba-audio.h

@@ -251,4 +251,6 @@ struct GBASerializedState;
 void GBAAudioSerialize(const struct GBAAudio* audio, struct GBASerializedState* state);
 void GBAAudioDeserialize(struct GBAAudio* audio, const struct GBASerializedState* state);
 
+float GBAAudioCalculateRatio(struct GBAAudio* audio, float desiredFPS, float desiredSampleRatio);
+
 #endif

M src/platform/sdl/sdl-audio.c → src/platform/sdl/sdl-audio.c

@@ -43,8 +43,7 @@ if (!context || !audioContext->audio) {
 		memset(data, 0, len);
 		return;
 	}
-	float ratio = 280896.0f * FPS_TARGET / GBA_ARM7TDMI_FREQUENCY;
-	audioContext->ratio = audioContext->obtainedSpec.freq / ratio / (float) audioContext->audio->sampleRate;
+	audioContext->ratio = GBAAudioCalculateRatio(audioContext->audio, FPS_TARGET, audioContext->obtainedSpec.freq);
 	struct GBAStereoSample* ssamples = (struct GBAStereoSample*) data;
 	len /= 2 * audioContext->obtainedSpec.channels;
 	if (audioContext->obtainedSpec.channels == 2) {