I want to clearly state: An ".MTS" file is not a complete video, it is just a very raw stream! Tons of information is missing. You could compare it to a bunch of wood from IKEA without any screws or instructions how to assemble it. Sure you can write clever programs that try to guess how it works, but this is not the purpose. Anyone who gets their eyes on such a file has been digging withing the AVCHD folder structure, which you just shouldn't do and which is much harder to do since Mountain Lion.
I just tried dragging an MTS file into iMovie and, as expected, it doesn't work at all and shouldn't. Whatever files you had must have been strange and very specific.
Everyone who reads this: .MTS files are not video files! They are raw stream data! AVCHD is complicated! Watch the video I posted above!
So any software that allows to just drag and drop such an .MTS file onto the timeline is cheating you into thinking that this is the way it is supposed to work. No professional software will do this. The hope is that the mess that is AVCHD will go away in the near future, when the upcoming high bitrates and resolutions will not fit into the container specifications anymore. Then all camcorders will record into an easier container. But until then: Just use AVCHD the way it is supposed to be used: Import from the card/backup into your editing software! It's actually quite simple if you don't think "file based" but "clip based".
Just for your entertainment, I thought I would record my experiences here. I have about 24 hours of 1080p home video recorded on a Sony video camera. Before I was aware of any of this, I copied and pasted all of my .MTS files (without the appropriate attached file structure) into folders on my hard drive. Thus, my nightmare began.
Over the last several years, I attempted on several occasions to convert the files, without any success. On 12/7/13, I decided to record my efforts in a journal:
1) direct import to FCPX impossible due to file structure not being built
2) 'MTS wrapper' bought for $3.99, converts file to .mov, but the file had all sorts of color and interlacing disruption
3) tried Handbrake, which works reasonably well, but loses a moderate amount of image quality
4) in the past, used Quicktime (worked great), but this function is now disabled????
5) tried Brorsoft - seemed to retain quality
Will burn Bluray with 3 types for comparison (original, handbrake, Brorsoft, each with 2" video)
Burned it to BluRay. Won't load to DVD Player (program). Downloaded VLC, which views the BluRay well.
Both handbrake and Brorsoft work well for the conversion. I guess I can go to work on converting the family videos.
Plan:
1) edit video to 1-hr segments
2) make BluRay disks *6
3) make MP4 backups to a hard drive
Workflow:
a) gather 1 hr of MTS files
b) convert using handbrake -> scratch disk
c) import to FCPX and output to BluRay, then 3 TB HDD
d) catalog by dates
12/8/13 - I started the project today, but noticed that Handbrake can only bring in one MTS files at a time to transcode. Since I have hundreds to do, I may use Brorsoft if it works better.
I also noticed that I am maxing out the RAM all the time. Will need to upgrade from 12 GB, sadly. ** note that I did not realize that OSX
always maxes out the RAM. I bumped my RAM to 48 GB, then realized my mistake **
Brorsoft makes batch conversions easier. Plan is to convert files and place on a temp HD attached through Voyager Q.
Just ordered 48 GB ram (6*8 GB) Hynix 1333 GHz from MacRamDirect (actually, it wasn't Hynix after-all, but some other brand).
I notice that while importing and transcoding video, the hard disk speed is definitely a bottleneck.
I bought a Brorsoft video converter for $40. When converting from .MTS to Prores 422 HD, by far the limiting factor was the RAM (
I may have been wrong here). When importing the media from an external 7,200 drive on FW800, both memory and data transfer (read) seems to be maxed out, while the CPU does almost nothing (12-core MP).
Uh oh. I have had FCPX stop in the middle of transcoding the video to BluRay, each time with some sub-program (seen in activity monitor) not responding. I guess I'll wait to see whether the RAM fixes this problem.
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12/14/13 - I installed Micron RAM today, but FCPX still crashed while transcoding. An online search suggested I turn off 'App Nap', which at least allowed me to burn a DVD. I am in the middle of burning a BluRay. We'll see how that works.
Epilogue: In the end, once I turned off 'App nap', the above workflow worked well, with very little degradation in video quality.
What a royal hassle!
I hope this post was humorous if not helpful