RECOMMENDATIONS FOR ORIGINAL SOUND TRACK INFORMATION AND TRANSFER PROCEDURES (1993).

Contents:

1. Introduction

2. Analogue Recording

3. R-DAT Digital Audio Tape Recording

4. Time Code

5. Identification

6. Sound Sheets and Labels

1. INTRODUCTION

The increasing diversity of original recording formats and subsequent requirements for various editing procedures, combined with the largely freelance nature of film and television production in Great Britain, has resulted in a pressing need for a more unified procedure for identification and retrieval of original production recordings and transfers therefrom.

It is not the Association's intention to stifle innovation in a creative business, but rather to encourage clearer communication and avoid 'glitches in the system'. We would commend adoption of the following procedures by Members and non-Members alike, also their study by film school students and others. However, diversity also means that there are incompatibilities between certain items of equipment, post-production facilities and timecodes, so these recommendations cannot be taken as a substitute for thorough pre-production consultation between relevant departments.

2. ANALOGUE RECORDING

2-1: Identification of Analogue Tracks recorded on tape for subsequent transfer to 35mm or 16mm Multitrack Magnetic Film.

Multitrack mono recording may be defined as where different or alternative information is recorded on separate tracks of the same tape.

When using a multitrack recorder, the uppermost audio track should be called, for example, "Nagra Channel 1" , and the next below that "Nagra Channel 2", etc. This numbering excludes any dedicated control or timecode tracks. The identification should be suitable to the machine used, e.g. "Stellavox Channel 1", etc.

Report sheets must state what each channel contains and to which tracks of the magnetic film they should be transferred. Track 1 of 35mm triple-track film is in the standard mono replay position, and is thus the one heard at rushes and used by most editors for cutting purposes. Therefore transfer to 35mm triple track magnetic film should be standardised as follows: FROM 1/4" TAPE TO 35mm TRIPLE TRACK

FROM 1/4" TAPE TO 16mm

If the production sound mixer does not require a Channel 1 + 2 transfer, it must be clearly indicated on the report sheet whether Channel 1 or Channel 2 is to be in the Track 1 position on the 35mm triple track. It is still recommended that Tracks 2 and 3 on the 35mm transfer should be used in the normal way: for example, if Channel 2 is selected by the production mixer to go to Track 1, then it should also go to its normal position on Track 3. Doing this gives the recording mixer the option of using the sound from Track 3 should there be blemishes on Track 1 due to wear and tear in editing and projection.

2-2: Noise Reduction

Dolby encoding of Tracks 2 and 3 on the 35mm triple track (even if not of the original tapes) should be given serious consideration, if possible after consultation with the rerecording mixer and sound editor. The sound transfer report sheets must indicate the type of encoding system (e.g. Dolby A, SR etc.), and sound editors must subsequently carry this information through to the dubbing charts, track leaders and containers. On original tapes, in addition to normal line-up tone, Dolby tone of 30 seconds should be provided at the head of every roll. Subsequently, even if only the transfers are encoded, the transfer operator should supply a roll of Dolby tone to the sound editor which can be used as a reference during dubbing. Track 1 of the 35mm should not be encoded.

2-3: Stereophonic Recording

When recording stereo on tape for motion picture or television use, production sound mixers are recommended to use the terms screen left and screen right. Nagra Channel 1 (Upper track) to contain screen left information, and Nagra Channel 2 (Lower track) to contain screen right information.

Transfer to triple track magnetic film should be as follows: FROM 1/4" TAPE TO 35mm TRIPLE TRACK

FROM 1/4" TAPE TO 16mm

The comments under section 2-2 also apply to this section.

2-4: Middle and Side (M&S) Recording for Stereophonic use.

It is recommended that Nagra Channel 1 (Upper track) be used to record the MID (forward facing) information, and Nagra Ch 2 (Lower track) be used to record the S (Side facing) information. As the S signal contains only phase related information for creating spatial effect, it is unnecessary, in fact undesirable, to make a combined Nag Channel 1 + 2 transfer to magnetic film.

Transfer to 35mm triple track magnetic film should be as follows: FROM 1/4" TAPE TO 35mm TRIPLE TRACK

It is desirable that Nagra Channel 1 be transferred on to Track 2 for the same reason as stated in section 2-1. The comments under section 2-2, Noise Reduction, also apply to this section.

Or to multitrack magnetic film: FROM 1/4" TAPE TO 16mm

It is recommended that the terms 'MS' is reserved to describe a particular microphone technique producing left and right signals. But 2-track recordings made with, for example, a Nagra Channel 1 containing forward-facing information and Channel 2 containing side-facing signals for later combination to produce stereo, should be referred to as 'M and S' recordings.

3. R-DAT DIGITAL AUDIO TAPE RECORDING

In most respects R-DAT recording practice is similar to that of analogue recording. Therefore all the procedures listed under Section 2 above can be used provided that the following points are noted.

3-1: Analogue Input Channel Identification

R-DAT was originally conceived as a consumer medium; it involved a number of manufacturers among whom no industry 'standard' of labelling has yet been established. Thus in this document: EQUIVALENT TERMS

3-2: Digital Channel Identification

Once the analogue signals have been converted to digital they become a single data stream and the tracks cannot, at present, be easily re-assigned so care must be taken to get the routing correct.

3-3: Digital Recording Sampling Frequencies

Most R-DAT recordings are currently made at one of two sampling rates, either 44.1 or 48KHz, so the chosen rate must be stated on the report sheet. Many consumer portable R-DAT recorders now used in the field will only record at 48KHz, but many post-production editing systems operate only at 44.1KHz. So if digital-to-digital transfers are to be made, for example, to such a system it is desirable to check with the post-production department so that both the original recorder and the editing system operate at the same sampling rate.

However, 'Black Box' conversions is possible if unavoidable. It is advisable to avoid machines which impose a copy protect code.

3-4: Indexing

Indexing is a very useful feature of R-DAT. It enables the operator to number each recording individually, either at the time or at a later stage. The numbering ascends from 0 to 99 or higher, and is an ideal way of logging slates and takes. At present logging is not completely compatible from model to model or make to make of recorder, so this facility should be carefully checked.

3-5: Absolute Time Recording ('A' Time)

This facility is not to be confused with timecode. It provides a useful additional logging tool to indexing, recording (with the audio) hours, minutes and seconds consumed as each tape is used. This 'A' time will thus remain tied to the recording on replay.

3-6: PRO-R (I.E.C.) Timecode Recording

The original Fostex timecode format should not be used because it has been superseded by PRO-R timecode which is supported by all current manufacturers.

3-7: Cassette Labelling and Reports

Due to the diminutive tape box, retaining report sheets safely with the relevant cassette is a problem, since they do not fit into the box even when folded. Proprietary boxes are commercially available, but twisted elastic bands holding the sheets to the box are a method of last resort. Production sound mixers should label each cassette itself and record a head announcement.

4. TIME CODE

4-1: Run up

When time code is employed, the production sound mixer should ensure that there is adequate runup before slating or action to suit the synchronisation system to be used at a later stage. Minimum times currently range from 4 to 10 seconds. This is not necessary where 'record-run' timecode is used on DAT, because it jams to the previous take and becomes continuous. Where end slates are used, ensure that the camera is running for the duration of the slate information or this will be lost during telecine transfer.

4-2: Time and User Bits

Time code consists of two sections of information, each having 8 characters. The first section is TIME, which on video productions may be slaved to a VTR with its own internal time code, but on film production would normally be set to the 'real' time of day, made up of 'Hours', 'Minutes', 'Seconds' and 'Frames'. Recording with the time code running through midnight must be avoided (if it seems likely, then advance all time code generators past midnight before turning over). The second section is USER BITS, where the recorder can be set to define additional information. For film and TV production they would usually be set as follows, but it is advisable to check the requirements of the post-production department, because, for example, some systems require the roll number to be set in the first two digits. TIME CODE USER BITS

This unique identification of every frame of original sound recorded is the key to the economic benefits of digital post production.

4-3: Timecode Frame Rate - Film Production

The frame rate is decided by the video rate of the country of origin. For example:- TIMECODE FOR FILM PRODUCTION

4-4: Timecode Frame Rate - Video Production

TIMECODE FOR VIDEO PRODUCTION

Both the camera and sound should be regularly jammed** to the reference generator. This may be a special unit, camera or recorder. It should be noted that video cameras in general do not have stable crystal SPGs built in. An accuracy of better than 1 part per million is needed to guarantee sync to 1 frame in 12 hours.

* NOTE: Currently (May 1993), Arriflex and Aaton cameras when running at 24 fps record 24 fps code on the edge of the film.

**NOTE: JAM - Unlike pulse which conveys only speed information and requires the use of a clapper board, timecode conveys both speed and position. Acceptable short term speed errors become unacceptable positional errors as time passes. Unless all the timecode generators are linked to a single speed reference it is necessary periodically to synchronise them and this process is called jamming. To do this a single generator is used as the master time reference, this generator is connected to each reader/generator on the set in turn and the current time and user information is transferred. This should be carried out at the beginning of the shoot and then as often as possible. An uncorrected crystal accuracy of 100 parts per million will result in an error of 10 frames per hour. A good temperature compensated crystal with an accuracy of 5ppm will result in an error of 0.5 frames per hour.

Major errors sometimes occur as follows:
 

4-5: Transfer

If post-production sound editing is to be done using digital techniques, the time code recorded on the original should be used to jam the generator which records timecode on the film transfer. At this time, the roll information in the user bits should be checked, corrected or added. New developments allow Scene and Take numbers to be added to the user bit information at this point for use in the post-production stage when the slate information will have been edited out.

The timecode sould be recorded on to Track 3 of 35mm triple track or, for 16mm, it should be ascertained whether the code is needed on the edge track or the cue track.

As the copy at this time is for rushes and picture editing, it is only necessary to transfer a mono reduction of a stereo recording or the M track of an M and S recording.

The type of Time Code recorded must be indicated on production and transfer report sheets, and on master recording box labels.

Transfer to magnetic film should be as follows:

1/4" MULTITRACK MONO TO 35mm TO 16mm

1/4" STEREOPHONIC TO 35mm TO 16mm

1/4" M & S TO 35mm TO 16mm

5. IDENTIFICATION OF NON-SYNCHRONOUS RECORDINGS

5-1: Wild Tracks

The term `Wild Track' should only be used to identify recordings made to cover lines or sounds occurring during sync takes where, for some reason, the recording was not satisfactory. These recordings should be identified as "Wild Track" followed by the sync slate number with an X added, then the wild track take number, e.g. "Wild Track 17X Take 1" (written W/T 17X t1). Wild tracks should be made after the last camera take whilst the artistes remember their lines and timing. Recordings of other material such as effects, music or voices other than sync should not be called wild tracks.

5-2: Sound Effects

Sound effects should be prefixed "FX" followed by a number, a brief description, then a take number, e.g. "FX 22 Volvo 360 car past, take 1", written on the report sheet as FX 22 t1 with short details in the remarks column. Numbers would normally start at 1 for each production, however on TV series it could be desirable to devise a numbering system to suit each episode; e.g. "FX 1/1 for Episode 1", "FX 1/2 for Episode 2", "FX 1/3 for Episode 3", etc. Short numbers are preferable not only because they fit the column spaces on report sheets but also because cutting room numbering machines only provide 3 digits before the take number.

5-3: Voice Over

Voice recordings for `Voice Over' or uses other than lip sync should be identified by the prefix "V/O" followed by a number then a take number. If there is a special place for the lines then the script scene number should be used, e.g. "Voice over Scene 271, take 1" (written V/O 271 t1). The name of the character in the script should also be noted on the report.

5-4: Music

Music recorded during production should be given "M" numbers, and titles of compositions announced along with take numbers, e.g. "Music 1, take 1, Sweet Lass of Richmond Hill". In addition to this appearing on the report sheet, it is most important that the names of the composer, music publisher and performers are also noted.

5-5: Announcements

Each take of wild, effects, music or voice over track must have the full announcement on it. If only the first take has the full identification, subsequent takes being slated only as "Take 2, Take 3" and so on, when the chosen transfer is broken down the editor picking up the roll may have no idea from which slate the take has come. All tracks should, wherever possible, be announced at the start to avoid later confusion. If this is not possible, the announcement should state "End announcement" or "End number", e.g. "End number FX 22 take 1". Report sheets must also state this, using the abbreviation "N.O.E." (number on end).

6. SOUND SHEETS AND LABELS

6-1: Essential Data

Production recording services are often supplied by individuals or companies unconnected with a studio or post-production service, and sound report sheets may be provided with the equipment or by the production sound mixer. This has resulted in a multiplicity of styles, some of which do not allow sufficient space for the extra details and instructions necessary for efficient communication. The following information should always be included on report sheets and, if possible, on tape or cassette box labels:

Tape number; recording date; production title; production company name; recorder; type of recording; tape speed; synchronising system; timecode frame rate; sampling rate; user bits; camera speed; line-up tone level; type of noise reduction; gauge of film for transfer.

6-2: Design

On report sheets, in addition to slate and take details, there should be adequate space for transfer instructions and mixer's comments. It is therefore recommended that the minimum size of paper should be A4, despite it not fitting easily into most tape boxes. It is normal to use self-carboning sets of up to 5 copies of each sheet, in different pale colours to distinguish which copy goes to each department.

Ideally, sheets and box labels would be purpose-designed for different types of work, but as this may be too expensive for many situations, a basic design for each is appended which the Association recommends for general use. Readers are invited to copy them freely.

7. DOWNLOADS

The Sound Report Sheets and 5" Box Labels are available in Microsoft Word For Windows 6.0 Format and have been compressed using WinZip.  They are also available in Adobe Acrobat PDF format. Please note that dimensional stability cannot be guaranteed due to software variations. If you have any problems with the download, please contact info@amps.net for advice.