Backing up AVCHD video onto DVDs and playing them on a Blu-ray player
Tapeless AVCHD camcorders are the latest trend in consumer video. Prosumer video is geared towards AVCHD as well, as indicated by a recent announcement of the Panasonic AG-HMC150 camera. Compared to tape-based HDV format, AVCHD promises the same or better quality at reduced data rate, random access media and higher than realtime data transfer from camera onto a computer. While these changes are welcome, getting away with tapes poses new problems, like how to watch AVCHD video on consumer video equipment and how to store video in the long term.
In this article I will share my approach to storing AVCHD video on standard DVD-recordable disks. My goal was to create full backup of a memory card, while being able to watch unaltered video on a regular Blu-ray player. This article might be useful for those who record onto 4GB and 8GB memory cards, as these capacities closely match capacities of single-layer and dual-layer DVDs.
What is AVCHD?
You may have heard that AVCHD is a new video format, developed jointly by Sony and Panasonic. This is not exactly true. In reality, AVCHD is a watered down Blu-ray standard with just one encoding algorithm -- AVC.
Shown below is directory structure created on a memory card by Panasonic HDC-SD1 and Canon HF100 AVCHD camcorders. Other models record data in the similar fashion. Note, that BACKUP directory is not present on the Panasonic camcorder; it is defined on the Canon camcorder but empty. MISC directory is not present on the Canon camcorder. DCIM directory holds still photos and is created when a first photo is taken.
Names of directories and files comply with stone-aged "8.3" DOS standard, that is, no more than 8 characters for filename, no more than 3 characters for file extension. Also, all names are uppercase. This naming convention is really strange, considering that miniDVD disks, SD/SDHC cards and MemoryStick cards support long filenames. Blu-ray standard uses long names for directories and files.
Bringing AVCHD to compliance with Blu-ray
If you have a newer Blu-ray player, then to make a playable backup of your video all you need to do is burn BDMV and AVCHDTN directories with all their content onto a DVD disk and pop the disk into your Blu-ray player. This approach may not work with some players like my Samsung BD-P1200, which accept disks that are created according to Blu-ray spec only.
Here is what I do to make a playable backup of my 4GB memory cards:
- Copy BDMV directory off the camcorder onto a computer
- Rename INDEX.BDM to index.bdmv
- Rename MOVIEOBJ.BDM to MovieObject.bdmv
- Change extensions of MPL files to mpls
- Change extensions of CPI files to clpi
- Change extensions of MTS files to m2ts
I was wary of renaming MTS clips into m2ts. I thought that playlist and info files referred to clip files, so if I rename clip files these links would have been broken. Nope. Clip information files and playlist files in fact refer to non-existing m2ts clips, not to MTS. You can verify this yourself if you have a binary viewer.
To fully bring AVCHD directory into compliance with Blu-ray, continue with the following:
- Create BDJO, JAR and AUXDATA directories in the BDMV directory; keep them empty
- Create BACKUP directory in the BDMV directory if it does not exist
- Copy index.bdmv, MovieObject.bdmv files and PLAYLIST, CLIPINF, BDJO directories into BACKUP directory
- Create CERTIFICATE directory in the same directory where you put BDMV directory
- Create BACKUP directory in the CERTIFICATE directory; keep these directories empty
See the scheme below, this is how your file structure should look like:
Burning the disk
Any tool to burn a disk will do, it must be able to burn a DVD using UDF 2.50 file system. Nero Burning ROM can do this starting from version 7. You can also use free tools like ImgBurn. I will explain how to burn the disk using ImgBurn.
- First, switch to "Build" mode by selecting Mode->Build from the main menu.
- For source, select a directory that contains BDMV and CERTIFICATE directories.
- For target specify any name and location of your liking, this is where disk image will be written to.
- Select Options page in the tabbed notebook on the right, specify UDF file system, revision 2.50.
- Keep "Recurse subdirectories" checked.
- Press big button on the bottom of the left panel; it may not look like a button, so you can get lost for a moment.
After this step is done, you will get an ISO disk image. The last step is burning image file onto a DVD disk.
- Insert a DVD-recordable disk into disk burner (both DVD-R and DVD+R work with my Blu-ray player).
- Switch to recording mode by choosing Mode->Write from the main menu.
- For source select an image you just created.
- For Destination select a burner if you have several.
- Select as slow write speed as possible for your disk and drive to ensure a good burn.
- Press the big button on the bottom of the left panel to burn disk.
Now you have Blu-ray compliant disk with raw, unaltered video straight from the camcorder. This is a full backup of a 4GB memory card including clip information files and playlists. If you have a 8GB card, then you can back it up onto a dual-layer DVD. Try playing this disk in a Blu-ray player. Most likely it will play, but some players will still reject your disk. This would be the time to hit support sites and discussion boards. As always your mileage may vary.
In conclusion, I shall reiterate what was the point of the above procedure:
- to make full backup of one 4GB or 8GB memory card on a DVD
- to make a DVD that is playable on all Blu-ray players, even on old ones that do not play AVCHD directly
If you have a Blu-ray player and are considering buying an AVCHD camcorder, you may want to play with sample videos first. Here are couple of links to original videos right from a camcorder, you need to patch them according to this tutorial before burning onto a DVD.