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S4C

Contacts

Broadcast and Distribution Directorate

This directorate is responsible for all aspects associated with the operation and smooth running of the systems used to distribute and broadcast S4C content.

The directorate incorporates the function associated with Presentation, Media Content (library), Home Services (IT and building) and Transmission Services (MCR transmission).

We are available for help and advice concerning all aspects of Television and Broadcasting technology, both through the document Technical Specifications for Delivered Programmes and in person.

If you have any questions or need further information about the directorate, or have a technical or operational query then please contact:

  • Angharad Williams
  • 02920 741200
  • tec// hide from spam bots //hnegol-sc@s4c.co.uk

Frequently Asked Questions

Technical FAQs

What should we deliver to S4C?

Master Tape in Digital Betacam format. All tapes delivered for transmission must be accompanied by suitable documentation.

Unless otherwise agreed:

2 x VHS copies of master tape with Hi Fi sound one with burnt-in timecode which must match that on the master tape, and one without. These will be used by the commissioning unit to review the programme, and by the marketing unit to select promotions and trailers.

If the programme is to be subtitled with closed captions that are not already encoded on line 335, one S-VHS and script as per section on subtitles.

Safety copy of master tape to be retained by the Production Company. R.O.T. of live programmes (or those played out "as live") to be delivered to S4C.

What is suitable documentation?

A recording report must accompany each recording and give the following details:

  1. Name of Production Company and facility providing master tape.
  2. The programme title and episode/subsidiary title and production number.
  3. Video and colour standard used.
  4. Mono/Stereo, audio track usage, Dolby surround sound.
  5. Picture Format:
    • 4:3 Full Screen
    • 16:9 Full Height Anamorphic (shot and protected for 14:9)
  6. Duration and timecode value for the start of each part.
  7. Verification if subtitles present on line 335 or as open captions.
  8. Confirmation that the tape has been approved by the supplier for transmission.

The cassette shell itself must be marked with items 2 & 5.

Can we super a logo over the pictures?

All S4C's commissioned programmes are now transmitted on our digital services, since the S4C logo is used in the top left hand corner of the screen on these services, this area must be free of captions, logos or any other graphic images that might conflict with the S4C logo.

How many audio tracks are needed?

Programmes must be provided with stereo sound unless this is impractical.

Stereo signals should be recorded:

  • Track 1 - Left Channel.
  • Track 2 - Right Channel.
  • Tracks 1 and track 2 must be recorded in identical phase relationship throughout the programme including line up tone signals at the head.
  • Tracks 3 and 4 must be replicas of tracks 1 and 2 unless specified otherwise by S4C.

Mono signals should be recorded:

  • Track 1 - mono mix.
  • Track 2 - must be identical to Track1.
  • (Known as DUAL CHANNEL MONO).
  • Tracks 1 and track 2 must be recorded in identical phase relationship throughout the programme including line up tone signals at the head.
  • Tracks 3 and 4 must be replicas of tracks 1 and 2 unless specified otherwise by S4C.

Documentation must unequivocally state whether the programme is stereo or dual channel mono.

Programmes delivered by line, as opposed to videotape, must conform to the above channel configurations.

Dual Language:

Programmes delivered with Dual Language sound need to conform to the above specifications, with the addition that:

  • Welsh programme sound will be on Tracks 1 and 2.
  • English programme sound will be on Tracks 3 and 4.

Audio Description:

Programmes delivered with Audio Description must conform to the above specifications, with the addition that:

  • Welsh programme sound will be on Tracks 1 and 2.
  • Audio description will be on Track 3.
  • Normal speech level (peaking PPM 5)
  • Pan and Fade control signal will be on Track 4.
  • Minus 12db wrt line up (peaking PPM 1)

What are acceptable audio levels?

The sound source must be controlled to ensure that the peak audio level does not exceed line up level by more than 8dB, (PPM 6).

Acceptable Audio Levels
MaterialNormal PeaksFull Range
Speech:
Talks, News, Drama, Documentaries. Discussions, Panel Games, Quiz Shows, Announcements.51-6
Music:
Variety, Dance Music.4 ½ 2-6
Brass Bands, Military Bands.42-5
Orchestral Concerts.-1-6
Light Music.5 ½ 2-6
'Pop' Music.52-5
Programmes containing a high degree of compression.42-4

Volume compression, if used, should be restricted to 6dB of compression and the onset of compression should not occur below PPM 4.

What are the arrangements for live programmes?

The programme supplier is responsible for arranging the necessary broadcast quality links to carry the signal from the outside broadcast venue to S4C, unless expressly agreed otherwise.

General arrangements should be made known (and confirmed in writing) to the Head of Tranmission Services at an early planning stage. These details should include the communication arrangements, the location and confirm the lines booking information.

For special live events the Producer and/or Technical Supervisor will be required to attend a technical production meeting at S4C to discuss details with the Transmission and Presentation units and any other relevant party.

You are required to confirm any amendments to the original details, the timetable for the rehearsal/test process and confirm the contact name(s) and telephone numbers to S4C's Librarian (telephone number 029 20 741209) at least 24 hours beforehand (or by 16:30 on the Friday afternoon if the programme is scheduled for transmission over the weekend). You will be asked to confirm an approximate running time for the programme. This information will be circulated to the Tranmission Services, the Presentation Team and MCR (PC's and Engineering).

The Producer is expected to contact S4C's Presentation team at the latest 3 hours prior to transmission, to establish a line of communication and to discuss any last minute changes (Presentation Department 029 20 741265 within office working hours or 029 20 741230 at other times). Similarly contact should be made between the on site programme director and S4C MCR (Engineering).

S4C will transmit a stand by programme if the Producer does not adhere to the above guidelines.

In accordance with the Commissioning Agreement, S4C expects delivery of a Digital Betacam copy of those programmes transmitted down the line, together with two VHS copies (one with and one without timecode) to S4C's library within a fortnight of transmission or as stated in the Agreement.

A contact card is available to remind Producers of S4C's contact telephone numbers.

Cards can be obtained from Mair on 029 20741479 or Elin on 029 20741265

Office working hours: 09:00---17:15

  • Librarian S4C:
  • 029 20 741209
  • Presentation:
  • 029 20 741265
  • Fax 029 20 741259

Outside office working hours:

  • MCR (P.C's):
  • 029 20 741230
  • MCR (Engineering):
  • 029 20 741240
  • Fax 029 20 741375

Line-up / Signal Stability:

The on-site facility must be able to originate audio and video line-up signals. These should consist of 100% colour bars (75% if the vision signal is to be linked by satellite) together with zero level reference tone. For stereo origination, the left-hand channel tone should be intermittent. Video pulse and bar, preferably as an insertion test signal, will also be required to equalise the circuit.

Line-up signals must be available at least 30 minutes before the start of the programme and an engineer designated to liase with S4C MCR.

The video signal must be stable and continuous throughout the broadcast.

What are the arrangements if my programme is of a topical nature and needs to be delivered on the day of transmission?

The Commissioning Agreement specifies an actual time at which tapes, delivered on the day of transmission, should take place.

Confirmation of the edit/facility location, a contact name (the producer or director) and number(s) should be made to the Librarian at S4C (telephone number 029 20 741209) at least 24 hours beforehand (or by 16:30 on the Friday afternoon if the delivery/transmission is over the weekend). This information will be circulated to the Head of Technical Operations, the Presentation Unit and MCR (PC's and Engineering).

After completing the editing work, the Producer should contact S4C's Presentation Unit to confirm the actual duration and content of the programme (029 20 741265 during S4C's office working hours or MCR Presentation Controllers (PC's) 029 20 741230 at other times).

If, on the day, the Producer is unable to meet the delivery terms, then he/she has a responsibility to contact S4C's Librarian during office hours telephone number 029 20 741209 (or MCR - PC's on 029 20 741230 at other times), to explain the circumstances. Where appropriate S4C will agree to amend the delivery time and arrangements.

S4C will transmit a stand by programme if communication has not been established and/or if the tape has not arrived at the time specified in the Commissioning Agreement.

In accordance with the Commissioning Agreement, S4C will expect delivery of two VHS copies of the programme (one with and one without timecode) to S4C's Library within two weeks of transmission or as noted in the Agreement.

Can you give me guidance on flashing images in my programme?

The ITC rules are as follows:

  1. Flashing lights and certain types of regular visual patterns can cause problems for some viewers who have photosensitive epilepsy. People below the age of 20 Years are the most susceptible group and many are unaware of their susceptibility. Care must be taken to minimise these risks in all programmes, but especially where young people are likely to be watching in significant numbers. This might mean cutting or amending certain scenes or sequences or rejecting entirely some material. At times difficulties in minimising the effects may be encountered, for example with some types of live coverage, such as a news report. Where there is likely to be significant risk, viewers should be given an appropriate warning at the start of the programme item.
  2. Television is by nature a flickering medium (because of the 50Hz refresh rate of typical TV receivers and the 25Hz effects of interlaced scanning) and it is therefore not possible to completely eliminate the risk of television causing convulsions in those viewers with photosensitive epilepsy. There are certain types of visual stimuli that are most likely to cause these problems, however, and these should, therefore, be avoided in television programmes or advertisements where possible.
  3. Flashing and flickering images in colour or black and white, which result in visible screen brightness changes of more than 10% screen area at a rate exceeding 3 flashes per second, should be avoided.
    1. Moderate repetitive changes in screen brightness exceeding 10% screen area are acceptable, provided the difference in brightness over any two consecutive frames in a sequence does not exceed 10%. This is measured as the difference in brightness between the lighter and corresponding darker image area expressed as a percentage of the brighter image. Brightness changes greater than 10% will produce a visible flash and this therefore represents a risk. In this case only one flash will be allowed in any nine-frame period.
    2. Brightness level changes exceeding 10% are also acceptable in small areas. Up to 10% of the screen, either a single area or a sum of smaller parts, may change at any rate or brightness level.
    3. Flashes involving highly saturated red are particularly dangerous and should be avoided.
  4. Rapidly changing image sequences are provocative when they result in a visible brightness change over more than 10% of the screen area, at a greater rate than 3 changes per second. An image, which changes every 9 frames or more, irrespective of its brightness or screen area, will comply with this guideline.
  5. Regular patterns, which cover more than 10% of the screen area, should be avoided. A single pattern cycle may consist of distinct vertical, horizontal, diagonal, circular, radial line or bar segments followed by a segment of different brightness. Pattern cycles, which are repeated, can form grid patterns.
  6. A pattern is considered provocative if it produces the equivalent of 10 to 40 cycles across the screen and the difference in screen brightness between any two adjacent segments exceeds 10%.
  7. Moving patterns, which flow smoothly across, into or out of the screen in one direction, are not considered hazardous. However, a moving pattern, which changes direction, oscillates, flashes or reverses in contrast is particularly hazardous. Pattern contrast reversals using fully saturated red are not allowed.
  8. Computer generated images which are highly detailed can cause a high degree of inter-line flicker in the picture at a rate of 25 times per second and should be avoided.

Screen brightness refers to luminance intensity. This can be measured directly on a monitor screen using a spot photometer suitable for T.V display measurements. Video waveform luminance is not a direct measure of display screen brightness.

How does S4C handle widescreen programmes?

S4C has two transmission environments, Analogue and Digital.

For our Digital services widescreen programmes are transmitted as widescreen, viewers with widescreen sets will see the full picture; those with normal 4:3 sets will see a centre cut out of the widescreen picture. This is an effect delivered by the set top box that the viewer is using to receive their digital signals.

Therefore when shooting and captioning widescreen programmes for Digital transmission, it must be borne in mind that some viewers will only see the centre portion of the picture.

On our analogue service we transmit widescreen programmes in the form of 14:9 letterbox. This results in very thin black bands at top and bottom of picture and also the loss of a small amount of the edges of the frame, approx. 6%. Again when shooting and captioning widescreen programmes this must be taken into account. This should make clear the reason for the requirement when asked for 'shoot and protect 14:9' on 16:9 commissions.

Finally it should be remembered that widescreen programmes should be delivered to S4C in their 'Full Height Anamorphic' form and that programmes delivered in any form of Letterbox format are not acceptable to S4C.

When producing computer animations, what aspect ratio and pixel shape should I use?

The Canvas pixel ratio chosen in the menu of the programme (e.g. PhotoShop ) should be such that the horizontal to vertical ratio is 16x9 for Widescreen and 4x3 for standard. There is a slight complication in that computer pixels are square and TV pixels are slightly oblong or 1.0667 times as wide to be precise.

This means that although a TV picture is 720 wide by 576 high, if this ratio is chosen in the computer package for the canvas, then a true circle drawn in the computer will, when viewed on the TV look slightly horizontally stretched (egg shaped) horizontally. This slight distortion is easily addressed if the following ratios are selected:

  1. For material to be shown on TV in 16x9 Widescreen format 1024 horizontally x 576 Vertically.
  2. For material to be shown on TV in 4x3 format 768 horizontally x 576 Vertically.

These ratios are generally on of the standard options seen in the menus of most of the popular computer graphics packages. If there are any doubts then as always a short test piece should be created and submitted to S4C Broadcast + Distribution for verification before the main project is started.

© 2008 S4C
O Gymru / Made in Wales