Hello all I have been dealing with an issue with Premiere Pro CS6 on Windows 7. We shot a concert on sony pj30 and the clips were broken up on one of the cameras the other was just one continous file. So to remedy this we used TSMuxer a freeware piece of software to combine files into one file stopping any audio issue when going from clip to clip. So we took the clips from mts(s) clips to one M2TS. So they were both on the same timeline M2TS on video one and MTS on video 2 and premiere would play the video until you had the two files over lapping in the timeline. Then it would only play the audio and lock up for an extended period of time. So after 2 days of frustration we tried to make the MTS file a M2TS file. Once we did that no more issue. The video tracks played great no lock up and the playback is perfect. Hope this is a help to anyone in the future.