Georgia Hilton MPE CAS MPSE Prod/Dir/Editor

Film Services Professional ( Producing / Editing / Delivery )

Blog

HD Technical Requirements for High Definition Programming

Posted on February 28, 2010 at 12:51 AM

HD Technical Requirements for High Definition Programming

2. AUDIO SPECIFICATIONS

Audio program material shall be produced using current industrystandards and accepted norms. The audio portion of the master andsource audio and videotapes must be produced so that no noise, static,dropouts or extraneous distortion is recorded in the audio.

Program audio must reflect reference tone level. Audio levels must be consistent throughout the program.

2.1 Stereo (LPCM) Programs

2.1.1 Phasing

Stereo audio must be fully mono compatible, i.e. the audio channelsmust be in the proper phase. NOTE: Full Mono compatibility means thatwhen the left and right stereo channels are actively combined to monothere is no discernible change in audio level or fidelity.

Full mix and M & E audio tracks should be phase coherent(synchronized) and level matched to prevent difficulty editing betweenthese tracks, as necessary.

2.1.2 Sound to Video Synchronization (Lip-synchronization)

The relative timing of sound to video should not exhibit anyperceptible error. Sound should not lead or lag the vision by more than10ms. This synchronization must be achieved at the last point at whichthe program supplier, or their facility provider, has control of thesignal.

2.1.3 Headroom

Transmission limiters clip at +8 dB. For broadcast stereo tracks,transient audio peaks must not exceed +8 dB above reference tone whenmeasured on an audio meter using the "True-peak" ballistic set (0 msrise, 200 ms fall). For 5.1 surround mixes, audio peaks may rise ashigh as +17 dBm (-3 dBfs). When mastering to a digital format and/orusing an Absolute Scale or Peak meter, where "0" is at the top of thescale and reference tone is at -20 dBfs, broadcast stereo tracks shouldpeak at no more than -12 dBfs.

2.1.4 Audio compression:

Program audio should have good dynamic range, within the parameterslisted above, but not be overly dynamic. While some compression may beneeded to control the dynamic range of the program audio, excessiveaudio compression of the final mix should be avoided as this reducesthe perception of audio quality by the listener.

2.2 Surround Programs

2.2.1 Formats

5.1, 5.0 or LCRS mixes are permitted. Surround English Fullmix(regardless of configuration (5.1, 5.0, etc) shall be expressed asDolby 'E' on ch3/4 of HDCAM master.

2.2.2 Documentation

An Audio Program Data Sheet shall be delivered with the master tape. (See accompanying example)

2.2.3 20bit Dolby E (6 channel)

Valid metadata in the Dolby 'E' stream for all contribution/transmission parameters is mandatory.

Timecode shall be present in the bit stream, reflecting picture master.

The Dolby E stream shall be formatted such that the program is in syncfollowing Dolby 'E' decoding using a DP572 or equivalent.

Note: One frame of audio delay is incurred for both Dolby E encodingand decoding. Program audio that is advanced two frames relative topicture prior to Dolby E encoding will therefore be advanced one frameas it is recorded to the HDCAM master. Following normal playback, theDolby E decode cycle will delay one additional frame, bringing theprogram back into sync.

Maximum permissible audio peaks in a 5.1 or 5.0 soundtrack shall be -3dBFS (+17dBm)

Although the Max dynamic range (max. peaks) for 5.1 channel mixes isconsiderably higher than for Stereo-only LPCM mixes, it is understoodthat many 5.1 mixes will have a dynamics structure which more closelyresembles a -10dBFS stereo mix in order to facilitate the simplecreation of an Lt/Rt fold-down mix.

Regardless of the gain structure of a 5.x channel surround mix, it iscrucial that the supplied DIALNORM value accurately reflects the Leq(A) of program dialogue.

2.2.4 Stereo English Full-mix (LPCM, conventional stereo digital)

This shall be recorded on channels 1 and 2 of the HDCAM master tape andmay be used for screening and/or Standard Definition Transmission.

This mix shall be derived from the 5.x channel surround mix. i.e. "Fold-down" of the 5.1 or 5.0 mix to LCRS or Stereo (L/R).

This stereo mix should be expressed as Dolby Surround (Lt/Rt) wheneverpossible, or Lo/Ro if Dolby Surround encoding is not available. Tapelabeling and slate information shall reflect the nature of channels 1and 2 (either Lt/Rt or Lo/Ro). In either case (Dolby Stereo or not),the LPCM stereo Full-mix shall obey the conventional specifications foraudio delivery (e.g. Max peaks to 8dB over ref.).

2.3 Channel Allocations

All HDCAM masters should have the following audio channel allocations:

(A) SURROUND PROGRAM

Channel 1 - Program left (Lt or Lo)

Channel 2 - Program right (Rt or Ro)

Channel 3 - Dolby E

Channel 4 - Dolby E

Address Track - SMPTE drop frame time code

(B) STEREO PROGRAM

Channel 1 - Program left (Lt or Lo)

Channel 2 - Program right (Rt or Ro)

Channel 3 - M&E left

Channel 4 - M&E right

*If the stereo program is Dolby Surround encoded (Lt/Rt), then any stereo M&E mix

(where applicable) shall also be expressed as Lt/Rt.

Address Track - SMPTE drop frame time code

Dolby E Mastering Information

Date Program Start Time

Program Title Episode# or Sub Title

Producer Director

Post Sound Facility Mix Engineer

Dolby E Formatting

Sampling Frequency ? 48 kHz (mandatory)

Bit Resolution ? 16-bit ? 20-bit ? 24-bit

Time Code Format ? 23.976 ? 25/50 ? 29.97/59.94 DF

Tape Format ? HDCAM

Program Configuration ? 5.1 + 2 ? 5.1 ? 4

Sync (frame offset) ? -1 ? 0 ? +1

Audio Service Configuration Bitstream Information

Audio Coding Mode ? 3/2 ? 3/1 Audio Production Information ? YES ? NO

Bitstream Mode ? Complete Main ? Main M&E Original Bitstream ? YES ? NO

LFE Filter ? Enabled ? Disabled Copyright ? YES ? NO

Mix Room Type ? Large ? Small

Mix Level

Processing Extended Bitstream Information

Dialog Normalization Preferred Stereo Downmix Mode ? Not Indicated

RF Overmod Protection ? Enabled ? Disabled ? Lt/Rt Preferred

Digital De-emphasis ? Enabled ? Disabled ? Lo/Ro Preferred

DC Filter ? Enabled ? Disabled Lt/Rt Center Downmix Level

Bandwidth Lowpass ? Enabled ? Disabled Lt/Rt Surround Downmix Level

LFE Lowpass Filter ? Enabled ? Disabled Lo/Ro Center Downmix Level

Digital De-emphasis ? Enabled ? Disabled Lo/Ro Surround Downmix Level

Dynamic Range Control

Line Mode ? None ? Speech ? Film Std. ? Film Light ? Music Std. ? Music Light

RF Mode ? None ? Speech ? Film Std. ? Film Light ? Music Std. ? Music Light

Downmix Processing

Dolby Surround Mode ? Not Indicated ? Dolby Surround ? Not Dolby Surround

Center Downmix Level ? -3 dB ? -4.5 dB ? -6 dB

Surround Downmix Level ? -3 dB ? -6 dB ? -999 dB

Surround 3 dB Attenuation ? Enabled ? Disabled

90-Degree Phase-Shift ? Enabled ? Disabled

Track Format Notes

Channel 1 Front Left

Channel 2 Front Right

Channel 3 Center

Channel 4 LFE (where applicable)

Channel 5 Surround Left

Channel 6 Surround Right

Channel 7

Channel 8

MUSIC AND EFFECTS TRACKS

TECHNICAL FORMAT

2.4 Accompanying Audio Multi-track Format (if required)

Accepted format is DA-88.

2.4.1 TRACK ALLOCATION

8 Track Digital Audio (DA-98 or DA-88)

Track 1 - English Fullmix Left (Lt if available)

Track 2 - English Fullmix Right (Rt if available)

Track 3 - undipped BG/FX Left (Lt if available)

Track 4 - undipped BG/FX Right (Rt if available)

Track 5 - undipped Music Left (Lt if available)

Track 6 - undipped Music Right (Rt if available)

Track 7 - Narration/VO dialogue

Track 8 - On-camera/Actuality dialogue

29.97 SMPTE Time Code on the Time Code Track to be synchronous with picture master(s).

2.4.2 Mix reference

Reference on all Masters shall be -20dbFS (or equivalent) and peakprogram level shall be restricted to 8db above reference (or -12dbFS)

2.4.3 Timecode

On DA-88 Master, timecode shall match picture Masters (i.e. 01:00:00:00 program start, drop-frame)

2.4.4 Sample Rates

On DA-88 Master, sampling rate shall be 48kHz (16bit) and noise shaping(where applicable) shall not be used on Mix Stems (tracks 3 through 8).If noise shaping is employed on stereo full mix, this shall be noted ontape labels.

2.4.5 Audio Compression and Limiting

Mix Stems shall NOT be dynamically buss-limited (i.e. stems are notrestricted to the 12db over ref. peak limit). Stems summed at unitygain shall result in an unlimited version of the stereo full mix.

2.4.6 Reference Signals

Test tones for all Multi-track Masters shall be 1kHz tone @ -20dbFS.

cheers

geo __________________

ms georgia hilton mpse cas


Categories: None