All of a sudden I am having problems with mp4s. I load the videos I want to edit and, after about a minute, the video goes black and Im unable to see it. It will also render black....on others, the audio disappears, I hear a quick blip of audio at the beginning then nothing. On the waveform bar of the track, the audio slider is no longer present. this is really becoming annoying....Yes I paid the 4.99 to update the CODEC