diff --git a/libao2/ao_sdl.c b/libao2/ao_sdl.c
index e3bdadf5a3..cac6a71bb0 100644
--- a/libao2/ao_sdl.c
+++ b/libao2/ao_sdl.c
@@ -160,6 +160,10 @@ static int init(int rate,int channels,int format,int flags){
 		printf("SDL: using %s audio driver\n", ao_subdevice);
 	}
 
+	ao_data.channels=channels;
+	ao_data.samplerate=rate;
+	ao_data.format=format;
+
 	ao_data.bps=channels*rate;
 	if(format != AFMT_U8 && format != AFMT_S8)
 	  ao_data.bps*=2;