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We just purchased an iMac yesterday to view our travel videos. The thing is, all the videos we have stored on our external Hard Drive are in the .MTS file format (AVCHD). The thing is, the Mac or QuickTime won't recognize them. Are there any good / free file converters so we can convert the video files to .MOV as that seems to be the common file format for Macs.

I read on-line that you can fool your computer into thinking that it is reading the video file straight from the Camcorder instead of from an external Hard Drive but you have to reorganize the storage or hierarchy of the videos. Apparently this can take up a lot of memory though - maybe up to 10 times the size of the original video file size? Is it a viable solution?

What's the best / most straight-forward / preferably free way to get the videos into a usable format?

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First of all, players such as VLC should be able to play the files just fine. Usually there's no need to convert. Just install VLC and use that instead of QuickTime.

Chances are the MTS files (MPEG Transport Stream) contain video and audio data that can be natively wrapped in a more widely supported container such as MP4, MOV, or MKV.

The free, cross-platform FFmpeg can change the container on the fly, without re-encoding your video. This means your quality will stay the same, and the conversion process will take a few seconds.

Download a static build of FFmpeg for OS X from their download page. Extract the archive and locate the FFmpeg binary, e.g. ~/Downloads/ffmpeg. Now, open up your from /Applications/Utilities, and you can use the FFmpeg tool to convert video.

~/Downloads/ffmpeg -i input.mts -c copy output.mp4

Here, substitute the path to the input and output files to wherever your files are / should be.

This will copy both video and audio streams (-c copy) and write them to output.mp4. This file should be playable in QuickTime, and if it's not, you might need to install Perian, which is a codec library for OS X (VLC comes with its own codecs).

Finally, if you want to reduce the size of the MTS files, you could re-encode them, e.g. like this:

ffmpeg -i input.mts -c:v libx264 -preset:v slow -profile:v high -crf 23 \
-c:a aac -strict experimental -b:a 192K output.mp4

Here, the CRF value sets the quality. Lower means better, and sane values are from 18 to 28, depending on what you want. You can stop the processing with Q and take a look at the result file to inspect the quality. See the x264 Encoding Guide for more info and our FFmpeg blog entry for a general overview.

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FFmpeg works great but does not have the easiest interface to do this. There is a way to do it if you want simple "drag and drop GUI".

Get the freeware tool for Mac called Media Converter. It can do various conversion but also has a downloadable preset to do "rewrapping", that is putting the contents of the MTS into a MOV container.

Download Media Converter, then go to the preset page here and download the "Re-wrap AVCHD for Quicktime - uncompressed Audio" preset. Launch it and it will install into Media Converter. (you can also rewrap without sound, which is useful if you intend to scrap the sound anyway in editing).

(For a complete article on this, read EOSHD)

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protected by Journeyman Geek Oct 23 '13 at 3:00

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