diff --git a/include/audio.h b/include/audio.h
index 23bc1d5..10d5d90 100644
--- a/include/audio.h
+++ b/include/audio.h
@@ -78,6 +78,8 @@ int wav_get_volume(int id);
 int bgm_get_volume(int id);
 int wav_get_time_length(int id);
 int bgm_get_time_length(int id);
+int wav_get_data_length(int no);
+int bgm_get_data_length(int no);
 int wav_get_group_num(int id);
 //int bgm_get_group_num(int id);
 int wav_prepare_from_file(int id, char *filename);
diff --git a/src/audio.c b/src/audio.c
index fee9b48..9f29b7e 100644
--- a/src/audio.c
+++ b/src/audio.c
@@ -361,6 +361,18 @@ static int audio_get_time_length(struct id_pool *pool, int id)
 int wav_get_time_length(int id) { return audio_get_time_length(&wav, id); }
 int bgm_get_time_length(int id) { return audio_get_time_length(&bgm, id); }
 
+static int audio_get_data_length(enum asset_type type, int no) {
+	struct channel *ch = channel_open(type, no);
+	if (!ch)
+		return 0;
+	int len = channel_get_time_length(ch);
+	channel_close(ch);
+	return len;
+}
+
+int wav_get_data_length(int no) { return audio_get_data_length(ASSET_SOUND, no); }
+int bgm_get_data_length(int no) { return audio_get_data_length(ASSET_BGM, no); }
+
 static int audio_get_data_no(struct id_pool *pool, int id)
 {
 	struct channel *ch = id_pool_get(pool, id);
diff --git a/src/hll/KiwiSoundEngine.c b/src/hll/KiwiSoundEngine.c
index ab9100a..c512f48 100644
--- a/src/hll/KiwiSoundEngine.c
+++ b/src/hll/KiwiSoundEngine.c
@@ -23,7 +23,6 @@ HLL_WARN_UNIMPLEMENTED( , void, KiwiSoundEngine, SetGlobalFocus, possibly_unused
 
 //int KiwiSoundEngine_Sound_GetGroupNum(int nCh);
 //static bool KiwiSoundEngine_Sound_PrepareFromFile(int ch, struct string *filename);
-//static int KiwiSoundEngine_Sound_GetDataLength(int data_number);
 
 static int KiwiSoundEngine_GetMasterGroup(void)
 {
@@ -93,7 +92,7 @@ HLL_LIBRARY(KiwiSoundEngine,
 	    HLL_TODO_EXPORT(Sound_GetGroupNum, KiwiSoundEngine_Sound_GetGroupNum),
 	    HLL_EXPORT(Sound_GetGroupNumFromDataNum, wav_get_group_num_from_data_num),
 	    HLL_TODO_EXPORT(Sound_PrepareFromFile, KiwiSoundEngine_Sound_PrepareFromFile),
-	    HLL_TODO_EXPORT(Sound_GetDataLength, KiwiSoundEngine_Sound_GetDataLength),
+	    HLL_EXPORT(Sound_GetDataLength, wav_get_data_length),
 	    HLL_EXPORT(GetMasterGroup, KiwiSoundEngine_GetMasterGroup),
 	    HLL_EXPORT(GetBGMGroup, KiwiSoundEngine_GetBGMGroup),
 	    HLL_EXPORT(GetSEGroup, KiwiSoundEngine_GetSEGroup),