Among those plenty of MPG to MP4 converters, Pavtube Video Converter for Windows/Mac are recommended strongly here to convert MPG to MP4 easily.
Official Guide(More details here): http://www.pavtube.com/mpg-to-mp4-converter.html
Pavtube Video Converter: http://www.pavtube.com/video_converter/
Pavtube Video Converter for Mac: http://www.pavtube.com/video-converter-mac/
Still wanna to know more tips about video/audio playback or editing? Please feel free to Email Us: support@pavtube.com