AVCHD is quickly becoming a more common way to record footage in consumer and other mid to higher tier camcorders and cameras. It has many advantages, the primary being that it compresses high quality video into smaller files, thus allowing for more footage to fit in inexpensive flash storage. AVCHD has also been a source of extreme frustration for Mac users who wish to edit, organize, and archive their footage. In this post I’d like to provide some guidance based on my experience working with the Canon HF10 (similar to the HF100) camcorder.

The first thing that folks new to using AVCHD devices need to know is that although recordings from your camera are digital and are files in the storage card, they are stored within a structure such as this:

As you can see, the videos are not just at the root level of your card, but rather part of detailed structure made up of the videos themselves as well as other files that contain information “about the videos.” This brings us to our first challenge. Let’s say that you went to a party and recorded 45 video clips. In all likelihood there will be some clips that you might not want to keep. Well, if you go through each one in your camera and delete them there, then the other files in the AVCHD structure will be updated and you will be fine. However, if you copy the entire directory structure to your mac and later decide to delete a few of these videos, you are in trouble because the other files in the structure will not be updated to account for this deletion. Why does this other data matter? Final Cut Pro does not support editing AVCHD video files directly (as of FCP 7). The clips must be transcoded to an intermediate codec. Usually, ProRes (LT). FCP imports / transcodes AVCHD footage via the “Log and Transfer” dialog. The unfortunate thing is that FCP will not work with your video files if the AVCHD directory structure is not intact.

So how do we overcome this problem? The best solution is to find a way to transcode that does not require the entire directory structure. With such a tool, one would be able to selectively keep individual video files knowing that they could be converted to a FCP-friendly format without much trouble. There are several tools that can do this, the best two are VoltaicHD and Toast Titanium 10. After much trial and error, I found Toast to be the preferred choice for this for reasons that I will outline further on.

Before continuing with solutions, there are still a couple more things that need to be understood about working with AVCHD in general, and specifically with the Canon HF10 (or HF100) camera. Frame rates.

The HF10 and 100, both can record in 3 frame rates: 24p, 30p, and 60i. This is great, but there is a drawback. When recording in any of these frame rates, they all get stored in the same 60i wrapper. This means that when you record 24p, the file has some frames inserted to make it 60i compatible. You don’t want these frames and they must be removed before being able to edit the footage as 24p footage. The other major and annoying drawback with this is that you have a bunch of MTS files with mixed frame rates, it’s difficult to tell which is which since they all appear to be 60i.

With all this, I come to my workflow:

1. Set your frame rate as desired for a particular project and record all footage without changing it. Do not use the “Easy Button” if you want any frame rate other than 60i as it ignores your frame rate choice and always records at 60i.
2. Copy all the MTS files to a folder on your mac.
3. Use VLC to look at your footage and decide if you want to completely delete any recordings.
4. All files are named 0000.MTS, 0003.MTS, etc… You might have gaps in the file number sequence since you could have deleted some recordings. It’s time to rename these into something meaningful. I recommend the excellent and free program Name Mangler. Rename your files into something like this: 01_project_name_24p.mts, 02_project_name_24p.mts. This gives you meaningful file names as well as mark the frame rate you used.
5. Use Toast to transcode the MTS files. Select the Convert tab, and then choose video files. Add your files and transcode. I recommend ProRes LT, same size as your footage, and uncompressed audio. Set the destination to a new project folder on your scratch hard disk (any drive that is NOT your main boot drive).
6. If you recorded in 24p, you need to remove the extra frames your camera added to maintain 60i compatibility.  You can use Compressor for this. I’ll post the details on how to do this in another post. UPDATE: Check here for the details.
7. Start up Final Cut Pro and create a new project. Now, immediately save it with a proper name. This is important. If you start to work on a project without saving it first, your render files will NOT be neatly organized in your scratch disk! Save your project file on your main hard disk (I use a folder I made in the my accounts Documents folder). In this folder keep all assets EXCEPT video files. They should be in a different drive as mentioned on step 5.
8. Add your files to your project and edit them to the time line. If your footage is 30p, then you need to verify in the Sequence Menu->Settings that the Field Dominance is set to NONE. It usually is, but it’s good to check.
9. Complete your edit and output your final edit in whatever format you want (MPEG4, h.264, etc).
10. Your project is done, save your original (renamed) mts files and delete your ProRes files as well as any audio and video render files. If you do this and ever want to reedit your project, open your project and Final Cut will ask for the location of the ProRes files. You can just recreate them as in step 5 by going back to your saved original MTS files.

Hopefully this is useful to you, I will follow up later with how to convert your 24p footage that is wrapped in 60i as well as an effective back up strategy for your footage.

Leave a comment if you have any questions.

-Ed

Tags: AVCHD, FCP, Final Cut Pro, HF10