AVCHD on a Mac

August 20, 2008 in Computing, Mac, Photography

I have recently replaced a totally knackered 10 year old Canon MiniDV camcorder with a Panasonic HDC-SD9. It’s a great little camera and I’m happy at the idea of waving bye-bye to tape. I loath tape. Having to wind through it and always having the possibility of a tape chewing incident. The HDC-SD9 records high definition video to an SD card (as the name suggests).

Where tape did have an advantage was ease of archiving. If you wanted to keep the original footage then you just kept the MiniDV tape you shot it onto. Simple.

The SD card is great, but until 8GB SD cards are as cheap as MiniDV tapes are now then it’s not viable to keep the original footage on the SD card.

I’ve only shot a few test sequences with the HDC-SD9 so far, getting used to the camera and getting a work flow sorted out to deal with importing, editing and archiving the high definition video. I’m more of a still photographer, video is fun of course, but the main reason I want a video camera is for footage of my 5 year old daughter. I would have been happy to get a standard definition camcorder, but it seemed a retrograde step to me. In years to come I would have been kicking myself at the low quality of the standard definition footage. The HDC-SD9 was way cheaper than the old Canon standard definition camera was when I bought it ten years ago.

I did do some reading up before purchase and discovered that to stand any chance of dealing with the AVCHD encoded footage on a Mac I needed to have and Intel Mac with iLife 08 installed or a tool called VoltaicHD which would convert the AVCHD files to .MOV files (albeit pretty slowly).

I had an Intel Mac with iLife 08, so I was away, right?

Well, sort of…

Yes, I could plug in the HDC-SD9 and iMovie 08 saw the camera and offered to import the video clips. Hurrah! It was all working as planned. I was able to edit together some very short and simple test movies and export them in various formats – excellent!

Until…

With my still photography I like to keep all my RAW files archived, I have them on a big external HDD and also on DVDs. If I ever want to work with the original data at some time in the future then I have my digital “negatives” and I can re-process as I want to. I can fit quite a lot of RAW images onto a DVD – it’s manageable.

With my old MiniDV camcorder then I could keep the tapes, as mentioned above. Simple.

So, let me see where iMovie has imported my video to and then I can just bung that out to a recordable DVD for archiving. Sounds nice and easy…

Erm. This 8 minute clip I was playing with seems to have produced 6 gigabytes worth of data? Okay, I knew that hi-def would generate some large files, but my SD card is only 8GB and will hold about an hour recorded at the highest quality settings.

What’s going on?

Well, iMovie is reading the original AVCHD files from the camera and then transcoding the video to a .MOV file. The original AVCHD file is around 1 gigabyte for this 8 minute clip, so it has expanded by a factor of around 6 times in the process of importing it into iMovie, admittedly at the highest size and quality settings.

This is all fine for producing a finished movie, but for archiving? A full hour of footage is going to be many tens of gigabytes and how am I going to archive that realistically?

First thought – find the original AVCHD files on the SD card and copy them off to DVD. Much smaller files, much more workable. Well, yes, but… iMovie 08 will not then open the original AVCHD files on their own, it insists on only importing them from the camera.

I finally twigged a solution at this point. If iMovie wouldn’t work with the AVCHD file (stored with a .MTS file extension) alone then there had to be something else it needed on the SD card.

So, my solution :-

1) Connect the camera.

2) Camera appears on desktop as a disk called “no name”.

3) Make a disk image (using Disk Utility) of the complete file structure of the SD card.

4) Remove the camera.

5) Open the disk image.

OS X complains at me that it might be a damaged disk image (not quite sure what that is about, further investigation required) and gives me dire warnings of potential damage and loss of life etc… However once that disk image is open I can fire up iMovie 08 and it sees the disk image as if I had plugged in the camera. It needs the whole file structure in order to work.

Now I can save the disk image file to a DVD and keep my archive of original footage. Of course when I want to use that footage again I have to accept that iMovie will inflate the files to something like 6 times their original size, but that imported video can then be deleted once I’m done working with it.

It feels a bit strange to find myself in a situation where OS X has some catching up to do when working with video files. Macs are supposed to be the multimedia platform of choice, right?

AVCHD was developed by Sony and Panasonic who traditionally have tailored their products for the Windows platform, virtually ignoring OS X. I’m just glad to have found a solution that will leave me with my original footage in a usable format without the outlay of more money, well no more than the price of blank DVD media of course.

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