Technical Specifications for Standard Definition Programmes

Transcription

1 Technical Specifications for Standard Definition Programmes version 11.5 May 2012

2 Document history Title Subject Classification Specifications for purchasing Standard Definition Programmes Non classified Issuing body/structure Rai Radiotelevisione Italiana s.p.a. Contacts Review Date Notes /01/2012 review of the document structure /01/2012 review of the document structure /03/2012 General review, references to the legislation in force, tables of paragraph /04/2012 Paragraph 3 review /05/2012 Final editorial formatting 2/16

3 Table of contents 1 Preface Production Video recording formats Anti-PSE Safe area Conversions from other formats Content of the vertical blanking General characteristics of the audio signals Delivery formats Long programmes Accompanying paperwork and labelling Metadata Subtitles Package of recorded material Protection sequence Alignment sequence Identification sequence Start sequence Programme End sequence Timecode tracks assignment Alignment tones and identification of the audio channels Maximum audio level Programme Loudness Lip-sync Quality requirements Summary of technical regulations and recommendations Glossary /16

4 1 Preface This document describes the guidelines for the supply of Standard Definition content (known as SD Standard Definition). The technical aspects completing what has been indicated in the international regulations about standard (SD) video signals, are illustrated below. All technical parameters defined in the international regulations shall nevertheless be followed. Fore the sake of convenience, paragraph 6 includes references to the main regulations and recommendations. 2 Production RAI requires that the supplied video media contain programmes produced with an aspect ratio equal to 16:9 FHA (Full Height Anamorphic), and are recorded in compliance with the ITU-R BT standards. 2.1 Video recording formats RAI only accepts television programmes complying with the SMPTE D10, 50 Mbit/sec, 625 lines, 50 semi frame/s SMPTE 356M-2001, "Type D-10 Stream Specifications MPEG-2 ML for 525/60 and 625/50, recording format. Television programmes must be delivered either on a 120 mm Sony Professional Disc re-writable optical disc, or on a ½ Sony IMX magnetic medium. The content contained in the Sony Professional Disc optical disc must be recorded using the Sony MPEG IMX profile and with a bit rate equal to 50 Mbit/s. The delivery of programmes in different formats, if any, shall be subject to a specific prior agreement in relation thereto. Considering that a programme may be subject to additional works after the delivery thereof, it is hereby required that the programmes delivered to RAI are, at the maximum, second generation recordings in respect of the master. In the event that a programme deriving from a 525/60 (525 lines 60 Hz) is delivered, the conversion of the standard must be done using converters provided with motion compensation systems. 2.2 Anti-PSE Flashes, intermittent lights and a few types of repetitive visual schemes can cause problems to viewers suffering from photosensitive epilepsy PSE. For its own nature, television is an intermittent source of light, and thus it is not possible to completely eliminate the risk of causing convulsions in subjects suffering from such kind of epilepsy; however, a few cautionary measures can be taken to reduce this risk, above all, when it is gratuitous and unnecessary. For a few fundamental guidelines on this problem, please see the website of the English Independent Television Commission ( 4/16

5 2.3 Safe area The safe area must be the one described in EBU Recommendation R95, as represented in figure 1 herein below. Fig. 1 Area to be used for the action and for the captions The EBU Recommendation R95 provides that: The main action shall be included in the central area up to 93% of height and 93% of width of the image. Captions and graphics shall be included in the central area up to 90% of the height and 80% of the width of the image. The programmes produced will be broadcast in format 16:9 or 4:3 letterbox; therefore, any 16:9 protected shooting is not necessary. 5/16

6 2.4 Conversions from other formats In case of production made in cinematographic aspect ratios (1,66:1, 1.85:1, 2.35:1) the aspect ratio conversion will have to be made anyway, as it happens with the 4:3 aspect ratio, making sure the main elements of the native contents are kept, and without altering geometric proportions. The following example shows a conversion to 16:9, merely consisting of the addition of black bars without eliminating any parts of the original video image: 1,66:1 1,85:1 2,39:1 Fig. 2 Conversion of aspect ratios 2.5 Content of the vertical blanking The vertical blanking interval may be used for the insertion of data, such as Televideo. It is hereby specified that RAI shall make recourse to the utilization of the vertical blanking interval in view of the satisfaction of the above mentioned purposes, and does not accept, unless otherwise specifically agreed upon, that the vertical blanking interval of the video media delivered to it bears insertion signals such as, without limitation, Video Index, AFD (Active Format Descriptor) or WSS (wide screen signalling). A timecode, if any, inserted in the vertical blanking interval (VITC) must coincide with the longitudinal timecode (LTC), so that it may be cancelled without causing any problem. 2.6 General characteristics of the audio signals content must be produced in compliance with the audio/video industry standards, with worldwide shared regulations, and with best practices. source and the media must be produced with the necessary cautionary measures, making sure that noise, radio interference, interruptions or distortions are not present. levels shall be consistent throughout the programme. tracks must not show alterations in dynamic and/or bandwidth due to the action of noise (or rustle) reduction systems or of coding/decoding systems with an insufficient number of bits. 6/16

7 3 Delivery formats Any and all materials must be delivered to Rai either on a 120 mm Sony Professional Disc XDCAM re-writable optical disc, or, alternatively, on a ½ Sony IMX magnetic medium. The delivered product shall be originated from the master with the best possible quality, minimising the number of multi-generations, if any (see paragraph 2.1). As an alternative to the optical medium, Rai may require, on an extraordinary basis, a MFX format file. Supplier s procedure to deliver the MXF file shall be agreed with RAI. 3.1 Long programmes In case a programme lasts more than the maximum recording capacity of the medium, the programme will be recorded in two or more media. In the latter case, the programme images at the end of a medium must connect with the ones at the beginning of the following medium with no superimposition. Media are numbered in sequence starting from 1. The programme timecode must be progressive among several media, in such a way that there is no discontinuity between the last useful frame of the portion of programme recorded in a medium and the first frame of the programme portion in the following medium (paragraph 4.7). The recording structure in each medium shall nevertheless respect provisions in paragraph 4. Each medium shall not include more than one programme, apart from the case of compilation of homogeneous and very short programmes. 3.2 Accompanying paperwork and labelling Each medium shall be accompanied with all the information necessary for its identification. In particular, each medium shall be provided with a label (placed in the proper spaces) necessarily including: Production Company and contact data Rai agreement number Programme full title Secondary title and/or number of the series Medium number (written in format 1/N, 2/N, etc., where N is the total number of media making up the programme); in case the programme is written in just one medium, please use the writing 1/1 signal format (stereo, double audio, multichannel) Program Loudness Level (ref. EBU R128) Loudness Range (ref. EBU R128) Maximum True Peak Level (ref. EBU R128) Video image format Original image format The same information shall be present in the label on the medium s case (container). Moreover, a technical sheet on paper support shall be attached, including the aforesaid information, as well as: 7/16

8 Overall programme time Medium programme time (in case of several media) Timecode of the first useful frame of the programme Presence of up-converted content or content with lower quality for definite editorial needs Loudness value (see paragraph 4.11). Special notes, relevant for correct broadcasting 3.3 Metadata RAI reserves the right to prepare a list of metadata to be processed in IT format (e.g. Excel spread sheet) to be supplied together with the Master. In that case, delivery procedure, formats and structure of metadata required will also be specified. 3.4 Subtitles In presence of Italian and/or English subtitles, they must be supplied in a file whose format shall comply with EBU Recommendations Tech N19 and Tech 3264-E. The file shall be delivered to the requiring department on CD, or by . In addition, it can be stored in the user data space of the XDCAM disk. 8/16

9 4 Package of recorded material The structure of the recording is summarised in the table herein below Table 1 Structure of the recorded material Tape section Time (sec.) Video Protection 10" Not recorded Not recorded sequence (minimum) Alignment sequence 60" (minimum) 75% SMPTE colour bars 1 khz on reference level Identification sequence 15" (maximum) Programme visual identification Silence or sound identification Start sequence 10" Countdown Silence Programme Programme duration Programme video Programme audio End sequence 30" (minimum) Black Silence 4.1 Protection sequence Just for the Sony IMX medium, a protection sequence of at least 10 seconds unrecorded tape portion shall be at the opening of the recording. 4.2 Alignment sequence The reference signals are to be recorded immediately after the protection sequence (present just for the IMX medium). The timecode track begins at the same time with the beginning of the alignment sequence. The alignment signals are: Video: SMPTE colour bars with 75% saturation : continuous 1 KHz tone, on alignment level. In case of stereophonic signal, the left channel (channel 1) is identified with the interruption of the 1 KHz tone for 250 ms every 3 seconds (see: EBU Tech ). 4.3 Identification sequence The programme must be identified by a recorded static image lasting 15 seconds at most; the image must show the essential information of the programme (consistent with the accompanying paperwork and the disk label). Essential information are: Production house Title Subtitle and/or series number Medium number (written in format 1/N, 2/N, etc., where N is the total number of tapes making up the programme); in case the programme is written in just one tape, please use the writing 1/1 Format of the audio signal Formal of the video signal Original video format Duration 9/16

10 4.4 Start sequence It must last 10 seconds and include countdown with round clock. The counting is interrupted 2 seconds before the programme starts. The aspect ratio should be 1,77 (16:9). The audio track should include silence for the whole length of the sequence. A timecode track consistent with previous parts should nevertheless be present. 4.5 Programme The timecode track must be consistent with the previous recording portions without gaps or interruptions for the whole programme. 4.6 End sequence At the programme end at least 30 seconds of black video and silence must be present; the timecode track is nevertheless present and consistent with the programme. 4.7 Timecode All media (including file) should be supplied with timecode. The timecode signal must comply with SMPTE 12M or EBU N regulations. The timecode corresponding to the first frame of the programme must be 01:00:00:00 or 10:00:00:00. The following table includes an example of timecode values in case of first frame of the programme with timecode 01:00:00:00. Reference is made to the structure of the recording described in this chapter. Table 2. Example of timecode for a programme lasting 90 minutes Timecode Start Tape section Time Medium 1 No timecode Protection sequence 10" 00:58:35:00 Alignment sequence 60" 00:59:35:00 Identification sequence 15" 00:59:50:00 Start sequence 10" 01:00:00:00 Programme 90 02:30:00:00 End sequence 30" Different timecode values may be accepted through prior agreement with Rai. In any case, the timecode signal throughout the entire programme within the single medium must be continuous, consistent and with no errors, and shall not go through zero in any point of the whole recording (including start and end sequences). 10/16

11 4.8 tracks assignment tracks are assigned to the different components of the audio of the programme in accordance with EBU Recommendation R48, as specified in tables 2a and 2b herein below. ID 1 Ref EBU R48 1b 2 1c * - Table 2a Supply of Italian language programmes Type of Programme Mono Prog. in the Italian language Mono Prog. in the Italian language Stereo Prog. in the Italian language Stereo Prog. in the Italian language Italian complete stereo Prog. and Double Tracks Number of the Track ,6,7,8 Left Channel Left Channel Left Channel Italian Mix Silence Silence Silence - Silence Silence Silence Silence Right Channel Right Channel Right Channel Right Mix Silence Silence - Silence Silence Silence Left Channel Mix Second Right Channel Second Italian Right Channel Left Channel complete Left Channel stereo Prog. 8 Right Mix Mix Second and Double Italian Mix * The hypothesis under 5 and 6 are only accepted subject to specific previous agreements. 6* 3b Right Channel Second - Silence Table 2b Supply of foreign language programmes ID Ref EBU R48 Type of Programme Tracks Number of the Track ,6,7,8 7 1b Mono Prog. in foreign edition 4 Original audio Silence Intl. Silence - 8 1c Mono Prog. in foreign edition 8 Original audio Silence Intl.. Silence Silence 9 2b Stereo Prog. in foreign edition 4 Original Left Channel Original Right Channel Intl. Left Intl. Right c Stereo Prog. in foreign edition 8 Original Left Channel Original Right Channel Intl. Left Intl. Right Silence 11/16

12 In case of multichannel audio, audio tracks 1 and 2 of the medium shall include the stereo down mix (possibly encoded in Dolby Surround) of the multichannel audio, in compliance with EBU R48 regulation. The multichannel audio will be allocated on tracks 3-8 pursuant to the following scheme (ref R48 scheme 11b): Table 3 Track Channel 1 Lt Left mix (total) Left down mix Italian language 2 Rt Right mix (total) Right down mix Italian language 3 L Left 4 R Right 5 C Centre 5.1 audio 6 LFE Low Frequency E. Italian language 7 LS Left Surround 8 RS Right Surround Since the accepted media are limited to 8 audio tracks, in case of programmes with a second language, a separate medium for the second language should be prepared, with the same audio track allocation. In case of programmes with a second language but with stereophonic audio, the second language should be allocated on tracks 3 and 4. A later version of the document will deal with the possibility to receive media with encoded multichannel audio in Dolby E. In case of programmes provided with the audio description (so-called Teleaudio), a new medium with audio tracks arranged as per Table 4, must be produced. Table 4 Track Channel 1 Lt Left mix (total) Left down mix Italian language 2 Rt Right mix (total) Right down mix Italian language 3-6 DE Silence Not used 7-8 Mono Single track or dual mono Teleaudio: audio description for blind/visually impaired In case of programmes with just stereophonic audio, the teleaudio track can be allocated in the same medium. 12/16

13 4.9 Alignment tones and identification of the audio channels Alignment tones must be at Alignment Level (AL) equalling 18 dbfs (PPM4 on an instrument PPM BBC IEC type IIa), with width tolerance not over +/- 0,1 db. The frequency of the alignment tones should be 1 khz +/- 100 Hz for main channels L, C, R and for surround channels LS and RS, and 80 Hz +/- 5 Hz for LFE channel. Channel identification shall comply with EBU Tech 3304; for all the channels, 3 seconds of 1 khz tone are followed by 0.5 seconds of silence, then channels are identified clockwise, starting from the L channel. The identification signal is a 1 khz tone 0.5 seconds long, followed by 0.5 seconds silence before the tone in the following channel; after a final pause of 0.5 seconds, the sequence is repeated starting from the 3 seconds of continuous and consistent tone for all the channels. The time necessary for each identification sequence depends on the number of channels of the chosen format (for example, 6.0 seconds for 5.1 or 5.0 audio), and thus it indirectly reveals the multichannel format chosen. The whole identification sequence should be repeated at least 4 times; in the interval between the end of the last sequence and the end of colour bars, the 1 khz tone shall be kept active for all the main channels. The 80 Hz tone for the LFE channel is continuous for the whole length of the sequence. Although the tone is recorded at alignment level, the LFE channel is conventionally reproduced at a 10 db higher level with respect to the main channels; as a consequence, a certain degree of balancing in the perceived sound intensity is respected Maximum audio level The maximum audio level is connected to the concept of True-Peak Level described in the recommendation ITU-R BS.1770 The Maximum True Peak Level of the programme shall respect the provisions contained in EBU recommendation R128 The Maximum True Peak Level shall be measured through an instrument complying with the procedures described in Recommendation ITU-R BS Program Loudness Program Loudness average value of programme loudness is defined EBU Recommendation R128 and shall be measured by means of instruments in compliance with the procedure described in Recommendation ITU-R BS The measurement of the Program Loudness shall refer to the whole length of the programme, starting from the first picture, and excluding technical signals in the beginning and in the end. The Program Loudness Level measures shall comply with the Target Level defined in EBU Recommendation R128. The same Program Loudness Level shall be guaranteed for the different soundtracks associated with the video (e.g. stereo and multichannel). 13/16

14 4.12 Lip-sync The audio signal and the video image must be synchronised in accordance with the EBU recommendation R37: the audio signal shall neither precede the video image by more thansignal must not anticipate by 5 milliseconds, or defer the video image by nor follow it by more than 15 millisecondss. 5 Quality requirements RAI requires quality for sound and image equal to degree 5 "excellent" in the evaluation scale of Recommendation ITU-BT 500. The medium shall be intact (with no abrasions, breaks or mechanical defects). The medium must not have any imperfection causing incorrect reproduction of the audio/video content. As for the audio/video content: The image shall be framed with respect to the TV frame, in compliance with paragraph 2.3; The image shall have no defects such as loss of resolution and scrambling noise; the audio shall have no distortions. 14/16

15 6 Summary of technical regulations and recommendations Identification EBU R37 EBU R48 EBU R95 EBU R128 EBU Tech N12 EBU Tech N19 EBU Tech 3264-E EBU Tech 3304 EBU Tech 3341 EBU Tech 3342 ITU-R BT.500 Title Relative timing of the sound and vision components of a television signal Allocation of audio tracks on digital television recorders Safe areas for 16:9 television production Loudness normalisation and permitted maximum level of audio signals Time-and-control codes for television recording Subtitling data exchange format Specification of the EBU Subtitling data exchange format Multichannel Line-up Tones Loudness Metering: EBU Mode metering to supplement loudness normalisation in accordance with EBU R 128 Loudness Range: A measure to supplement loudness normalisation in accordance with EBU R 128 Methodology for the subjective assessment of the quality of television pictures ITU-R BT Studio encoding parameters of digital television for standard 4:3 ITU-R BT.1702 ITU-R BS.1770 ITU-R BS.1771 SMPTE 356M SMPTE ST-377M SMPTE RP 218 SMPTE 12M and wide-screen 16:9 aspect ratios Guidance for the reduction of photosensitive epileptic seizures caused by television Algorithms to measure audio programme loudness and true-peak audio level Requirements for loudness and true-peak indicating meters Type D-10 Stream Specifications MPEG-2 ML for 525/60 and 625/50 Material Exchange Format (MXF) File Format Specification Specifications for Safe Action and Safe Title Areas for Television Systems Transmission of Time Code in the Ancillary Data Space 15/16

16 7 Glossary EBU European Broadcasting Union ITU - International Telecommunication Union SMPTE - Society of Motion Picture and Television Engineers SD Standard Definition VBI - Vertical Blanking Interval XDCAM : Sony apparatus able to record video formats in the format MPEG-2 4:2:2P@ML at 50 Mbit/s IMX : Sony apparatus able to record in the format MPEG-2 4:2:2P@ML a 50 Mbit/s Dolby E: proprietary format of audio encoding with transport onto digital interface AES/EBU PML: Permitted Maximum Level: maximum audio level permitted within a TV programme dbfs: decibels relative to full scale LKFS - Loudness, K-weighted Full Scale it is the loudness unit of measurement in Recommendation ITU R BS 1770 (equivalent to LUFS) LUFS - Loudness Unit Full Scale - it is the loudness unit of measurement in Recommendation EBU R128 (equivalent to LKFS) 16/16