I needto convert the Quicktime movies to MP4

I don't understand the differences but my blue ray player won't play the Quicktime movies but it will play mp4 I need to know how to convert them.

A QuickTime file is an MOV file container with any form of compatible data in it. This data can be anything from text or still images to Windows Media Video or MP3 music. On the other hand, MP4 is a file container specifically associated with MPEG-4 or H.264 compressed video and/or AAC compressed audio. If the source MOV file already contains MPEG-4/H.264/AAC data, then simply changing the file extension from MOV to MP4 may solve your problem and, if not, then you may simply need to copy the MPEG-4/H.264/AAC data from the MOV file container to an MP4 file container. In cases, where the source file does not already contain MPEG-4, H.264, and/or AAC compressed data, you would have to transcode/convert the original data to MPEG-4, H.264, and/or AAC compressed data and wrap it in the target MP4 file container. The QT 7 Pro player, MPEG Streamclip, VLC, HandBreak, and similar free or commercial utilities are commonly used to create MP4 files under Mac OS X v10.6 (Snow Leopard). Normally it is best to avoid transcoding data if possible since transcoding may degrade quality.

i can't figure out how to change the extension or or extract the data.

To change the file extension, select the ".mov" portion of the file name in the Finder and change it to ".mp4" (assuming the data in the MOV file container is MP4 compatible). To copy the data from an MOV file container to an MP4 file container use the "Save..." File menu option in a an app like the free MPEG Streamclip app and select the ".mp4" output option. (NOTE: Any data not compatible with the MP4 file container will be filtered from the final file.) In addition, if you have QT 7 Pro installed, you can use the "Movie to MPEG-4" export option in the "passthrough" mode to copy the original video and audio data directly to an MP4 container without modifying either track of data.

I can convert it but you are right I lose a lot of quality.

Without knowing the specifics of your workflow, it is impossible to know if this reduction in quality can be avoided or moderated.

I am using Video Converter for Mac, luckily the output files are in good quality. This is a useful tutorial on How to Convert QuickTime MOV to MP4, hope it can help you tackle the issue.