decoder: rewind input stream after try_decode()

src/decoder/_ogg_common.c

@@ -30,13 +30,7 @@ ogg_stream_type ogg_stream_type_detect(struct input_stream *inStream)
 	unsigned char buf[41];
 	size_t r;
 
-	input_stream_seek(inStream, 0, SEEK_SET);
-
 	r = decoder_read(NULL, inStream, buf, sizeof(buf));
-
-	if (r > 0)
-		input_stream_seek(inStream, 0, SEEK_SET);
-
 	if (r >= 32 && memcmp(buf, "OggS", 4) == 0 && (
 				(memcmp(buf+29, "FLAC", 4) == 0
 					&& memcmp(buf+37, "fLaC", 4) == 0)

src/decoder/wavpack_plugin.c

@@ -424,8 +424,6 @@ static bool wavpack_trydecode(struct input_stream *is)
 		return false;
 
 	WavpackCloseFile(wpc);
-	/* Seek it back in order to play from the first byte. */
-	input_stream_seek(is, 0, SEEK_SET);
 
 	return true;
 }

src/decoder_thread.c

@@ -32,10 +32,17 @@ static bool
 decoder_try_decode(const struct decoder_plugin *plugin,
 		   struct input_stream *input_stream)
 {
+	bool ret;
+
 	if (plugin->try_decode == NULL)
 		return true;
 
-	return plugin->try_decode(input_stream);
+	ret = plugin->try_decode(input_stream);
+
+	/* rewind the stream, so the next reader gets a fresh start */
+	input_stream_seek(input_stream, 0, SEEK_SET);
+
+	return ret;
 }
 
 static void decodeStart(void)