When shooting HD in AVCHD format, the camcorder spits out 2GB MTS files that needs to be binary concatenated into one large MTS file.

Attempting to use these mts files individually would results in losing a few frames at the file boundary.

Is there a utility that can convert each MTS file fragment into a complete MTS file so that each MTS file can be used individually without losing a few frames? I'm guessing all that needs to be done is to fix something in the file header or maybe create a new header.

Sony Play Memories Home I believe will concatenate files that have been segmented in camera provided they have a contiguous timecode.

As long as you keep the directory structure intact, certain programs can do it. I use the Device Explorer window in Vegas Pro 18 to import AVCHD files. That yields continuous video files. I suspect other NLEs do something similar.

Mac computers seem to recognize all the 2 GB pieces as one continuous video natively.

You could always use a join utility as found on the following link below. There are a number of free apps out there that overcome the problem of joining .MTS files without the audio and frame jump problems. Hunt and you will find a few out there in Google land.

Chris Young

https://software-download.name/merge-mts-software/

I think you can also do it with a simple command line operation.

Yes, you definitely can by using the Command prompt. Just very time consuming if you have dozens of spanned clips as you have to add them individually.

Chris Young

https://photography.tutsplus.com/tutorials/3-free-ways-to-join-spanned-avchd-video-files-into-continuous-clips-on-windows--cms-25830

I've been routinely using the Mts files on the timeline for ages in Premiere and never noticed any sync problems cause by dropped frames? This is Premiere on PCs and Macs. I just open the folder and drag them in and start editing?

It is best to use a utility for the camera used. The audio can be off by up to 1 and 1/2 frames depending on camera and the utility will correct this. Just simplistically joining on the timeline can lead to problems. PlayMemories works fine for Sony. There was also a pro version for the Sony Pro cameras that I used when I was shooting AVCHD too. Not sure if Sony Catalyst will join files too. Don't have any files to try now.

I've been routinely using the Mts files on the timeline for ages in Premiere and never noticed any sync problems cause by dropped frames? This is Premiere on PCs and Macs. I just open the folder and drag them in and start editing?

Premiere, Vegas and Edius don't seem to have any issues when "IMPORTING" from the cards. The problem for a lot of people is when they drag the MTS files straight into an NLE when there is no supporting metadata from the card. This metadata supports the stitching together of the long duration files that go past the 2/4GB file size boundaries of many cameras using FAT32 file formats on the SD cards. On some NLEs the video files when dragged it will join correctly but in most cases, there will be an audio break of around 12 frames at the clip boundaries.

This is how Adobe suggest it should be done. Adobe doesn’t make it clear (unless you’ve read the Premiere User Manual). And really this applies to all NLEs when working with MTS files.

There are at least three ways to ‘bring’ media into Premiere.

1. Dragging it into the project bin
2. File > Import
3. Media Browser

The first of these 3 methods work okay 90% of the time. Bringing media in via the Media Browser works 100% of the time and is the correct method to import media. As a rule, it is best that you only ever import media into Premiere via the Media Browser.

When importing AVCHD type media, right-click and select import at the top level of the folder ie on the ‘private’ folder, rather than digging down. This is so that all relevant metadata comes in too. Premiere does need those extra files because they contain the metadata that tells Premiere what to do with the clips where a single take has been split into two (or more) MTS files depending on the file size limit characteristic of the camera creating the files.

Hope that helps the confusion surrounding MTS file imports. This hairy question has been around since the invention of the MTS format.

If you are using Sony MTS files you could do far worse than using Sony's Catalyst Browse to import the files correctly for NLE use. Take note of the paragraph that states:

"To transcode spanned AVCHD clips, first copy them to a new folder. After the copy is complete, the indicator is removed, and the clips are combined in a new clip that you can transcode. For more information, see "Transcoding clips."

This will combine any spanned clips so that any broken boundaries are now contiguous and the time code is correctly maintained/continued and that there are no video or audio disturbances at the clip boundaries. You can then use them as is or transcode them if you wish to a new format.

Chris Young

https://www.sonycreativesoftware.com/webhelp/catalystbrowse/enu/Content/Transcoding_clips.htm#Copying

You can get Sony's Catalyst Browse here. It's free:

https://www.sonycreativesoftware.com/download/catalystbrowse

Chris Young