Simplify code and clean up Valgrind warning

--HG--
extra : convert_revision : svn%3Ac70aab31-4412-0410-b14c-859654838e24/trunk%40809

src/audio/SDL_audio.c

@@ -461,16 +461,11 @@ int SDL_OpenAudio(SDL_AudioSpec *desired, SDL_AudioSpec *obtained)
 	}
 
 	/* See if we need to do any conversion */
-	if ( memcmp(desired, &audio->spec, sizeof(audio->spec)) == 0 ) {
-		/* Just copy over the desired audio specification */
 	if ( obtained != NULL ) {
 		memcpy(obtained, &audio->spec, sizeof(audio->spec));
-		}
-	} else {
-		/* Copy over the audio specification if possible */
-		if ( obtained != NULL ) {
-			memcpy(obtained, &audio->spec, sizeof(audio->spec));
-		} else {
+	} else if ( desired->freq != audio->spec.freq ||
+                    desired->format != audio->spec.format ||
+	            desired->channels != audio->spec.channels ) {
 		/* Build an audio conversion block */
 		if ( SDL_BuildAudioCVT(&audio->convert,
 			desired->format, desired->channels,
@@ -491,7 +486,6 @@ int SDL_OpenAudio(SDL_AudioSpec *desired, SDL_AudioSpec *obtained)
 			}
 		}
 	}
-	}
 
 #ifndef ENABLE_AHI
 	/* Start the audio thread if necessary */