Last updated 12 April 2008
How to destroy your recordings!
Look I know we don’t like reading instruction manuals, but you MUST read the bit about when it’s safe to fit and remove a Compact Flash or Secure Digital card and when it isn’t! Otherwise you’re going to lose files and waste a lot of time recovering them (if at all). The same applies to USB cables – DON’T just pull them out of your computer without a moment’s thought. There’s a proper, safe, way to do it. READ THE MANUAL!
Repairing Compact Flash and Secure Digital cards
Fortunately the wide use of CF and SD cards in digital photography means that there’s already a wealth of information out there on recovering lost audio files.
Step 1: don’t panic! In almost every case your interview is still there, it’s the infamous “Table of Contents” that’s been corrupted (yes, shades of mini-discs). Never continue recording on the same card -- you could record over the hidden file, then you'll never recover it.
Step 2: You need a program like "File-Rescue Plus" or "PhotoRescue" to save it. Follow the instructions and cross your fingers. It’s a lot easier than repairing a corrupted mini-disc. I did some experiments with PhotoRescue and found it would recover files even after blanking a card by formatting it.
Step 3: re-read the manual -- was it really just bad luck the card got corrupted?
Choosing a File Format:
what’s all these WAV files? And “compression”? What’s wrong with MP3? You need to know a little of this – sorry! I’ll stick to a few basics. Techies know this already, or where to find it.
A WAV file is a simple standard audio file. You’ve probably seen them in your PC, they’re the ones ending “.wav”. WAV files tend to be big – 5 megabytes (MB) per minute of mono sound, or 10 MB per minute of stereo sound. If you are presented with a range of choices of "sampling rate" and "bit size" just choose "44.1 KHz" and "16 bits" - that's the same as CDs use. Nice and easy. A standard compact disc, which holds 650 MB of data, will hold 65 minutes of stereo audio in the form of WAV files. WAV files are also known as BWF files, just to confuse you.
There is a different standard on Apple Macintosh computers, known as AIFF – also uncompressed, so same size files. But recent model Macs cope just as well with WAV files.
Compression is a way of reducing file sizes. A lot of compression, such as the ones used in mini-discs, removes some of the audio data, and that’s what can upset the new BBC digital playout system. An approved compression program, such as FLAC, only reduces the file size, so a WAV file can be compressed in FLAC, winged over the internet, and then restored to original WAV perfection at the other end.
MP3 is another form of compression, and it also removes some audio data. You can basically forget MP3 for broadcasting.
In the studio
Digital recorders have changed the way we work. At the very least you’ll need to get used to copying your interviews from the Compact Flash card onto the computer before editing them. CF cards are more expensive than mini-discs so you will want to erase and re-use them. To dub sound-files across, either plug your recorder into your computer using a USB cable, or remove the CF card and plug it into a card-reader.
Card-readers come in a variety of types – built-in to desktops, plugged in to a USB port (desktop or laptop), plugged into a PCMCIA slot (laptop, with adaptor) and so on. Audio files transfer VERY quickly this way – depending on your system a 1 hour recording can be dubbed onto your computer and into the digital editor in a minute or two.
TIP: remember your audio files can vanish inside your computer!
So back them up onto CD or DVD for safety before you start editing. Then you can erase your CF card to use it again.
Workflow:
(1) news reporters can mark up clips on recorders like the Marantz on their way back from an interview, and then just dub the clips in studio/workshop ready for fine editing
(2) feature makers don’t need to laboriously dub lots of little bits from mini-disc, having first listened to the lot first. Provided the computer’s reasonably up to date, just dub all the material into the computer (backing it up onto CD/DVD) then log and choose clips within the digital editor. Works best if everyone’s got their own desktop editor rather than competing for workshops or studios.
TIP: rename your files with meaningful labels. If you’re making a complex feature from dozens of interviews all called something like “audio012” it will get confusing.
And now you've got nicely-edited digital files, why drive miles to a studio? ... go to the "digital filing" page.