audioclip length half

Audio & Video
1

now i have a mp3 audio load by WWW class, but the length is just half of the real length, test code can be very simple, and it happened on Android, i think this is a Bug

AudioClip audio = www.audioClip;
                    Debug.Log("audio.channels:" + audio.channels);
                    Debug.Log("audio.length:" + audio.length);

and it can just play half of the audio

2 
                    AudioClip audio = www.GetAudioClip(false, true);
                    Debug.Log("audio.length:" + audio.length);

if i use this code, the out put length is half too, but the audio can play full…

anyone has some ideas?