diff --git a/aegisub/src/audio_provider_ffmpegsource.cpp b/aegisub/src/audio_provider_ffmpegsource.cpp
index 930b9ad7b..b843e16af 100644
--- a/aegisub/src/audio_provider_ffmpegsource.cpp
+++ b/aegisub/src/audio_provider_ffmpegsource.cpp
@@ -173,6 +173,22 @@ void FFmpegSourceAudioProvider::LoadAudio(wxString filename) {
 		default:
 			throw agi::AudioProviderOpenError("unknown or unsupported sample format", 0);
 	}
+
+#if FFMS_VERSION >= ((2 << 24) | (17 << 16) | (4 << 8) | 0)
+	if (channels > 1 || bytes_per_sample != 2) {
+		std::unique_ptr<FFMS_ResampleOptions, decltype(&FFMS_DestroyResampleOptions)>
+			opt(FFMS_CreateResampleOptions(AudioSource), FFMS_DestroyResampleOptions);
+		opt->ChannelLayout = FFMS_CH_FRONT_CENTER;
+		opt->SampleFormat = FFMS_FMT_S16;
+
+		// Might fail if FFMS2 wasn't built with libavresample
+		if (!FFMS_SetOutputFormatA(AudioSource, opt.get(), nullptr)) {
+			channels = 1;
+			bytes_per_sample = 2;
+			float_samples = false;
+		}
+	}
+#endif
 }
 
 void FFmpegSourceAudioProvider::FillBuffer(void *Buf, int64_t Start, int64_t Count) const {