What Is A Broadcast Quality Recording? Part 6: Formats
By Jerry Flattum - 02/03/2005 - 06:13 AM EST
What Is A Broadcast Quality Recording?
Part 6: Formats
Turns out that “broadcast quality” is a misleading term since “mastering” has multiple definitions, depending on the medium and format you are mastering for.
An excellent source for further understanding formats and the multiple meanings of “master” is:
AES (Audio Engineering Society) Technical Document (pdf).
Review the entire site: Audio Engineering Society
Broadcast quality essentially refers to a recording--a CD or DVD--that is ready for radio airplay. But generally, any CD that is fully mastered (and replicated) is ready to be broadcasted across any medium (radio, TV, film). No further audio enhancements are required. It's the best sound you can get, regardless of how it's played back.
However, the term “mastering” takes on new meaning when radio stations further enhance the audio signal or THX and Dolby come into play in film soundtracks, video games and even car stereos.
Mastering engineers master for a wide array of formats: CD, SACD, DVD, AIFF (Mac), WAV, MP3, WMA, RealAudio, AU (Sun/Next), CD Audio (CDDA) and Quicktime. There are 10 different CD sub-formats: CD-Audio, CD-ROM, CD-ROM XA, CD-I, CD-G&CD-Text, CD-Extra, Photo-CD, Video-CD, CD-i Bridge, PC-Games/Data.
CDs are obviously played on CD players and not all CD players can play DVD's. Radio stations play CD's but sending a signal out through the airwaves involves broadcasting technologies not found in CD manufacturing. Feature films often record music directly for the film. But what is incorporated into a soundtrack and heard while a film is playing is mastered differently than songs extracted from the soundtrack and incorporated into a soundtrack CD. When a song is licensed for film, some copyright owners place restrictions on re-mastering.
DVD comes in two main types: DVD-Audio and DVD-Video. DVD-ROM is used for data storage (games, encyclopedias, computer backup, etc.).
DVD-Audio is a new music format that offers Advanced Resolution stereo (2 channels) and/or multi-channel (surround sound up to 6 channels) music. DVD-Audio provides dramatically higher quality stereo than CD with a sampling rate of up to 192kHz (compared to 44.1 kHz for CD). There are four different sizes of DVDs. A DVD-5 (appox. 4.7 gigabytes), DVD-9 (appox. 8.4 gigabytes), DVD-10 (appox. 9.4 gigabytes) and DVD-18 (appox. 16.8 gigabytes).
DVD-Audio digital sound can be delivered with up to 24 bits of data (compared to 16 bits for the CD standard). The playback is far more faithful to the master recording than ever before possible in home entertainment systems.
A DVD-Audio disk contains up to seven times the data capacity of a CD. DVD-Audio discs may also offer visual content accessed from on-screen menus (artist bio’s, playlists, lyrics, photos and video). DVD-Audio can link directly to an artist’s website (discography, tour dates, history, games, blogs, etc.). CD led the way in combining audio plus other content, but DVDs can hold up to twenty times the data of a CD.
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