Hack 96. Back Up Your Computer to a DV Tape

Digital videotape records digital information to create audio and video. But the data doesn't have to be audio and video.

When transferring video from a digital videotape to a computer, you should plan on using about 13GB of hard drive storage per hour of footage. Considering the footage is coming off a digital source, you might have wondered if you can write computer data to the tape. After all, a 60-minute MiniDV tape can be purchased for less than $10.

8.8.1. DV Backup Software

Around 2001, Tim Hewett decided to find out if he could accomplish what many of us wondered. He began to experiment with writing data from his computer to a digital videotape. The result of his experiment is the Mac OS X application DV Backup.

If you are using Windows or Linux, you might have some luck using dvbackup (http://dvbackup.sourceforge.net/; free, open source). You will, however, need to be familiar with using the command line. It also helps if you are familiar with ANCI C, a programming language.

DV Backup can write data to DV, DVCAM, DVCPRO, and Digital8 tapes using a FireWire connection. A typical, 60-minute MiniDV tape can store slightly more than 10GB of data. Because the application can write to DVCAM and DCVPRO, and these formats offer larger capacity tapes up to 184 minutes, it is possible to use DV Backup to store over 50GB of data.

There are two editions of DV Backup available: Standard and Lite. Both versions are full-featured with backup, verify, and restore functionality. The Standard version has additional features most notably, those that allow you to backup to a hard disk, span a large backup across multiple tapes, create sets, and create scheduled backups.

8.8.2. Backing Up Your Files

Using the application for the first time is easy, because many of the more powerful features are tucked out of the way. When you launch the program, it searches for a connected digital video camera or deck. Once it finds one, it performs a brief search to see if there is a Table of Contents on the tape.

If you are using a digital video camera, make sure your camera is in Player mode.

8.8.2.1. Formatting your tape.

If you are using a new tape, DV Backup will ask about the length of the tape, the name you would like to use for the tape, and whether you would like to use a Normal or Strict recording format. For the length of tape, you should input the length as reported by the manufacturer for SP mode, as shown in Figure 8-13.

The Strict format will reduce the amount of storage by about 15% and is recommended for use only if the Normal format fails to work properly.

8.8.2.2. Selecting your files.

Every good backup program should allow you to choose the files you would like to backup. DV Backup does just this. After you have formatted your tape, simply click the Backup… button and then click the Add… button in the resulting window, shown in Figure 8-14.

Figure 8-13. Formatting options

Figure 8-14. Selecting the files to back up

Note there is a set of options available to you in a drawer attached to the Select Files for Backup window. The options include:

Error Protection Level

From 1:1 to none; 1:1 is full duplication and the best level of protection

Backup Comments

Any comments you would like to note about the backup; these will appear in the Table of Contents

Compressed

Will apply gzip compression to your backup; takes time but allows you to save more data

Follow symbolic links

Will back up the objects/files referred to by symbolic links, instead of backing up the symbolic links themselves

SP/LP

A radio button used to indicate which mode the camera has been set

Auto-verify

Indicates whether DV Backup should verify the backup upon completion

After selecting your files and options, click on Backup button and the program will begin its process.

8.8.3. Restoring Your Files

Should you need to recover your files, the process is even easier than backing up:

1. Launch DV Backup.

2. Insert the tape that contains the files you would like to restore.

3. Select the backup you would like to restore.

4. Click the Restore… button.

5. Choose where you would like to restore the files. Optionally, select the specific files you would like to restore.

6. Click the Restore button.

Upon completion, your restored data can be found in a directory labeled with the date and time of recovery. If you already have a DV camera, using DV Backup can prove itself very useful and affordable. Additionally, you can use it to back up your project (excluding the raw footage), including any special media like sound effects and still photos.