Sound for Film and Video

Last week I just finished a job for MCI requiring 16bit 48Khz WAV files.
Currently I'm mixing a short film in 16bit 48Khz AIFF files which needs to be sent out via internet as an MP3 file. Then Tomorrow it's a 44.1Khz afternoon of music and mayhem! What gives with all these formats? Why so many, why so many more on the way?

Well it all goes back to time long long ago on a planet far far. actually it's this planet. Remember the Beta VHS wars? I may be dating myself but there was a time when VHS didn't rule the home video recording world (Now loosing ground to recordable DVD's). Two competing companies were trying to become the de-facto format. This has many advantages, one large one being the ability to license your format to others and sit back, relax, and collect the checks!

Well in the audio world this holds a lot of the same credence. Simply put, the WAV format was developed for the PC computer, the AIFF format is for the Macintosh and MP3's are a compression scheme for crunching your audio into a form for email transport. Now there are new formats like AAC, and a golden oldy called SDII.

What's most important in this world of many formats is knowing which format is High resolution and which is a compression format. MP3 is a lossy format, meaning audio is thrown in the dumpster to allow for a smaller file.
You can't hear the difference you say? Well trust me, your speakers are either to lo-fi to deliver the sonic clarity or you have to much wax in your ears. WAV and AIFF is a full res format. They retain what was recorded from when it was first recorded.

A good rule for sizing audio files is this. Every stereo minute of a 44.1 Khz 16bit AIFF or WAV runs approx 10 megabytes. This little info comes in extremely handy when working with others who are sending you data.

Think about it for a moment. Your short film runs 20 minutes and you prep an OMF file for your mixing guru who lives down the street. When you are done prepping, the OMF file is 800 kilobytes. Now do the extremely simple math. 20 minutes times 10 megabytes is, yes 200 megabytes. So now you know you've done something wrong with your OMF because your file has to be at least 200 megs! Of course if you have more than two tracks which you must if someone is speaking and there is some music in the background. Your file will exceed this 200 meg number. Would love to address the audio in the new 24p HD cameras but alas this will have to wait for another article. Good luck and great recording!