Eardamaging audio bug

[davidarbor]

This isn't a bug. Renaming the extension of a video only changes how Premiere things it should interpret the file, you didn't actually change anything about the video. If your machine is choking on playback then you need to convert it to an intermediate format that's less compressed, but easier to playback. This is what ProRes 422, Cineform, or DNxHR are for. Throw your video in Media Encoder, use the QuickTime > ProRes 422 preset, convert, and bring it back in and you should have better luck playing the file back than if you started with a highly compressed MP4.

You didn't mention anything about your system specs, the type of drive your footage is playing back from, or even what the source format of the footage was, but in general, what I mentioned above is the proper steps to take when your machine can't playback footage smoothly.