Asked to deliver 8 tracks of audio on HDCAM tape? Tough luck, but there may be a way.

Video tape recorders (VTRs) support different numbers of audio channels based on the format.

HDCAM 4 tracks

HDCAM SR 12 tracks

D5 8 tracks (older ones up to 4 tracks)

DVCPRO HD 8 tracks

VTR formats not listed here are not likely to be requested as delivery formats. Most common mastering format at this time is D5 and 8 channels is adequate although not perfect.

HDCAM’s 4 channels may not be enough in some situations. If you need to deliver 5.1 mix on an HDCAM tape how do you record 6 channels on a 4 channel tape? Dolby E process allows you to squeeze 6 digital audio channels into 2 channels.

Once encoded you can not play such audio back without a Dolby E decoder. The master can not be easily downconverted or run through standards converter while maintaining the integrity of the Dolby E tracks.

Standard for NTSC DVDs and beyond.

AC-3 (AC3) is a Dolby file format engineered to provide high quality 6 discreet channels of audio. The encoding is compressed in order to maximize limited bandwidth of the delivery media. AC-3 also supports stereo left & right configuration as well as mono configuration.

The system is in widespread use in movie theaters, NTSC DVDs and Digital TV broadcasting.

Commonly used in theaters and at home.

5.1 surround sound specifies three front channels, two rear surround channels and a low frequency channel totaling 6 discreet channels. It is commonly provided on DVDs and is used in Digital Theater System (DTS).

The track layout:

L (Left)

C (Center)

R (Right)

LFE (Low Frequency Effects)

Ls (Left Surround)

Rs (Right Surround)

HD deliveries often require 5.1 audio mix in addition to Stereo Left & Right Composite Mix. In case M&E is required another set of 5.1 M&E tracks will be needed totaling the number of tracks to 16. Additional audio can be folded into a smaller number of tracks using Dolby E process or the tracks can be delivered on an audio tape such as DA88.