1、BRITISH STANDARD BS EN 61834-2: 1999 IEC 6 1834-2:1998 Recording - Helical-scan digital video cassette recording system using 6,35 mm magnetic tape for consumer use (525-60, 625-50,1125-60 and 1250-50 systems) - Part 2: SD format for 525-60 and 625-50 systems The European standard EN 61834-2:1998 ha
2、s the status of a British Standard ICs 33.180.40 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAV BS EN 61834-2:1999 Amd. No. Date This British Standard, having been prepared under the direction of the Eiectrotechnicai Sector Commiaee,was pubiished under the authority of the St
3、andards Committee and comes into effect on 16 January 1999 Text affected Q BSI 01-1999 ISBN O 680 80869 8 National foreword This British Standard is the English language version of EN 61834-21998. It is identicai with IEC 61834-21998. The UK pdcipation in its prepasation was entrusted to Technid Com
4、mittee EPUl, Audio, video and multimedja systems and equipment, to Subcommittee Epylfi, Recording, which has the responsibility to: - aid enquirers to understand the text; - present to the responsible intemaionM3uropean committee any enquines on the interpretation, or proposals for change, and keep
5、the UK interests - monitor reiak in them in the UK. A iist of organizations represented on this subcommitke can be obtaine on request to its secretary. From 1 January 1997, ail IEC publications have the number 60000 aded to the old number. For instance, IEC 27-1 has been renumbered as EC 627-1. For
6、a period of time during the change over from one numbering system to the other, publications may contain ideners from both systems. Cross-references Attention is drawn to the fact that CEN and CENELEC stan- normally include an annex which lists nomiative references to intemational publications with
7、their corresponding European publications. The British Stan- which implement these intedonal or European publications may be found in the BSI Stan - Relative humidity: (50 i 2) %; - Barometric pressure: from 86 kPa to 106 kPa; - Tape conditioning: not less than 24 h. 1.5 Reference tape Blank tape to
8、 be used for calibration recordings may be purchased from the manufacturers given in annex C. 1.6 Calibration tape Manufacturers of video tape recorders designed for this format specification may sell Calibration tapes meeting the following requirements. 1.6.1 Record locations and dimensions Toleran
9、ces shown in table 3 in part 1, tables 1 and 2 in part 2 should be reduced by 50 YO. 1.6.2 Calibration signals Test signals should be recorded on the calibration tapes: Video: 1 O0 Yo colour bars; Audio: 1 kHz tone at -20 dB below full level. 1.6.3 Purchase The calibration tape may be purchased from
10、 the manufacturers given in annex C. 2 Helical recordings 2.1 Record location and dimensions Record location and dimensions for continuous recording shall be as specified in figure 1. Each value is described in table 3 of part 1. For recording, helical tracks shall be contained within the tolerance
11、specified in table 3 of part 1. 10 EN 618342:1998 Each sector location from the start of the SSA shall be as specified in figure 2 and table 1 (525-60 system) or table 2 (625-50 system). The physical tape pattern shall be specified by the centre line of each track. 2.1.1 The effective area upper edg
12、e The effective area upper edge (Ho) is specified by the intersection of the ending line of the subcode postamble and the centre line of the track. 2.1.2 Record and playback guarantee Every recorder or player shall record or play back the track data from the beginning of the IT1 preamble to the end
13、of the subcode sync blocks with interchangeability. 2.1.3 Overwrite margin (OM) When whole sectors (ITI, audio, video, subcode) are overwritten, the overwrite margin (OM) shall be recorded concatenations of run pattern A and run pattern B as described in 5.5 of part 1 in order to erase the old subco
14、de data. In an insert editing mode using the SSA, it is not necessary to record the overwrite margin. For the areas which are outside the guaranteed heights described in 3.2.3 of part 1, there is no need to record or play back the areas, as they have no effective data. 2.1.4 Switching margin for rec
15、ording amplifiers To avoid erasing the information in the optional tracks, the recording amplifier shall be switched to less than or equal to 0,245 mm along the track length before the IT1 preamble and 0,133 mm after the overwrite margin. In an insert editing, the recording amplifier shall be switch
16、ed to less than or equal to 0,102 mm along the track length before and after the recording sector. 2.1.5 Scanner example Scanner dimensions in table 3 are one possible configuration. Other mechanical configurations are permitted, if the same footprint of recorded information is produced on tape. 3 P
17、rogramme track data arrangement 3.1 Introduction Each television frame is recorded on 10 tracks for the 525-60 system and 12 tracks for the 625-50 system. The helical tracks are recorded with video, audio and system data. These data are arranged in four sectors such as ITI, audio, video and subcode
18、sectors per track. An edit gap between sectors, accommodates timing errors during editing. The IT1 sector is already explained in clause 6 of part 1. Figure 3 shows the arrangement of a track for the 525-60 system and figure 4 shows the arrangement of a track for the 625-50 system. Each track is num
19、bered from the beginning track of the television frame in order. A track which has track number i (i = O to 9 for the 525-60 system or i = O to 11 for the 625-50 system) is referred to as track i. Placement of FO, F1 and F2 tracks is shown in figure 5 for the 525-60 system, and figure 6 for the 625-
20、50 system. In the 525-60 system, there are two types of track 1, which are track F1 or track F2, and two types of pilot frame which are defined as follows: 11 EN 61834-21998 Pilot frame O: track 1 is track F1. Pilot frame 1: track 1 is track F2. In the 525-60 system, pilot frame O and pilot frame 1
21、alternate with each other. In the 625-50 system, pilot frame O repeats. 3.2 Labelling convention The most significant bit is written on the left and is the first recorded on the tape. The lowest numbered byte is shown on the top left and is the first encountered in the input data stream. Byte values
22、 are expressed in binary coded decimal notation unless otherwise noted. An “h“ indicates a hexadecimal value. A “b“ indicates a binary value. 3.3 Audio sector 3.3.1 Structure The audio sector consists of an audio preamble, 14 data-sync blocks and audio postamble. Audio preamble begins with run-up of
23、 modulated 400 bits and ends with two pre-sync blocks. Audio postamble begins with a post-sync block and ends with a guard area of modulated 500 bits. Details on run-up and guard area are described in 5.5 of part 1. The structure of sync blocks in the audio sector is shown in figure 7. 3.3.2 Sync pa
24、tterns Sync patterns of two bytes are already modulated to 17 bits patterns as described in 5.2.1 of part 1. Sync pattern F and sync pattern G are used. 3.3.3 ID part The ID part consists of ID data (IDO, ID1) of 2 bytes and ID parity (IDP) of one byte. Figure 8 shows the ID data in the audio sector
25、. ID data consists of application ID of area 1 (APl, AP1 1, APl, see table 4), sequence number (Seq3, Seq2, Seq, Seqo, see table 5 and table 6), track pair number (Trp3, Trp2, Trp, Trpol see table 7 and table 8) and sync block number (Syb, SYb, SYb, Syb, Syb, Syb, Sybl, Sybo). Sync block numbering g
26、oes from O to 16, and is stored in ID1 in binary notation. Sync block number = FFh means no information. The sequence number shall keep the same value during one video frame and is numbered from O to 11 sequentially. When a video signal is given from a colour decoder which decodes a composite video
27、signal to the component video signals and the field number can be recognized, the colour phase information should coincide with a sequence number. Definitions of colour frame A and B (525-60 system) and field 1 to field 8 (625-50) are shown in ITU-R Report 624-4. ID parity is defined as (12, 8, 3) B
28、CH code of which a generator polynomial is X4 + X+ 1. The ID code is divided into two ID code-words (ID-CWO, ID-CWl). The bit assignment of ID code- words is shown in figure 9. ID-CWO: C14, C12, C10, C8, C6, C4, C2, CO, P6, P4, P2, PO ID-CW1: C15, C13, C11, C9, C7, C5, C3, C1, P7, P5, P3, P1 12 STD-
29、BSI ES EN bL834-2-ENGL 1117 81 Zb2Libb9 C175b14U 786 I EN 61834-21998 Parity bits PO to P7 are given by the following equations. P6 = C14 + C10 + C6 + C4 P4 = CI4 + C12 + C8 + C4 + C2 P2=C14+C12+ClO+C6+C2+CO PO = C12 + C8 + C6 + CO P7=C15+C11+C7+C5 P5 = cl5 + cl3 + c9 + c5 + c3 P3 = CI5 + CI3 + CI1
30、+ c7 + c3 + CI P1 = cl3 + c9 + c7 + c1 where + is the symbol for “exclusive or“. 3.3.4 Pre-sync block The pre-sync block consists of 6 bytes as shown in figure 7. Byte position number 5 indicates track pitches. Byte position number 5 = FFh: track pitch O for SP mode Byte position number 5 = OOh: tra
31、ck pitch 1 Byte position number 5 = FOh: track pitch 2 Byte position number 5 = OFh: track pitch 3 Track pitch O for SP mode shall be 10 pm. Other track pitches shall be different from 10 pm and these values are reserved. 3.3.5 Post-sync block The post-sync block consists of 6 bytes as shown in figu
32、re 7. Byte position number 5 is FFh. 3.3.6 Data-sync block The data-sync block consists of 90 bytes. Byte position numbers 5 to 9 of sync block numbers 2 to 10 are audio auxiliary data (AAUX, see 6.5). Byte position numbers 10 to 81 of sync block numbers 2 to 10 are audio data (see clause 6). Byte p
33、osition numbers 82 to 89 of sync block numbers 2 to 15 are inner parities (see 6.2). Byte position numbers 5 to 81 of sync block numbers 11 to 15 are outer parities (see 6.2). 3.4 Video sector 3.4.1 Structure The video sector consists of a video preamble, 149 data-sync blocks and a video postamble.
34、The video preamble begins with a run-up of modulated 400 bits and ends with two pre-sync blocks. The video postamble starts with a post-sync block and ends with a guard area of modulated 925 bits. Details on run-up and guard area are described in 5.5 of part 1. The structure of data-sync blocks in t
35、he video sector is shown in figure 10. 3.4.2 Sync patterns Same as audio sector. 13 I I EN 61834-21998 3.4.3 ID part Same as audio sector except for application ID of area 2 (AP2, AP2, AP2, see figure 11 and table 9) and sync block number which is numbered from 17 to 168. 3.4.4 Pre-sync block Same a
36、s audio sector. 3.4.5 Post-sync block Same as audio sector. 3.4.6 Data-sync block The data sync block consists of 90 bytes. Byte position numbers 5 to 81 of sync block numbers 19, 20 and 156 are video auxiliary data (VAUX, see 7.5). Byte position numbers 5 to 81 of sync block numbers 21 to 155 are v
37、ideo data (see clause 7). Byte position numbers 82 to 89 of sync block numbers 19 to 167 are inner parities and byte position numbers 5 to 81 of sync block numbers 157 to 167 are outer parities (see 7.2). 3.5 Subcode sector 3.5.1 Structure The subcode sector consists of a subcode preamble, 12 data-s
38、ync blocks and a subcode postamble. The subcode preamble has a run-up of modulated 1 200 bits. Subcode postamble begins with a run-up of modulated 1 325 bits (525-60 system) or modulated 1 200 bits (625-50 system) and ends with overwrite margin of modulated 1 250 bits. The subcode sector has the rol
39、e of an APT saving area. The structure of sync blocks in subcode sector is shown in figure 12. 3.5.2 Sync patterns Sync patterns of two bytes are already modulated to 17 bit patterns as described in 5.2.1 of part 1. Sync pattern D and sync pattern E are used. 3.5.3 ID part The ID part consists of ID
40、 data (IDO, ID1) of two bytes and ID parity (IDP) of one byte. ID parity is the same as audio sector and video sector. Figure 13 shows the ID data in subcode sector. ID data consists of application ID of area 3 (AP3, AP3,. AP3, see table lo), application ID of a track (APT, APT, APT, see table 16 of
41、 part i), FR ID, Index ID, Skip ID, PP ID, absolute track number (ABST) and sync block number (Syb, Syb, Syb, Syb,). Sync block numbering goes from O to 11, and is stored in ID1 in binary notation. Sync block number = Fh means no information. More details are described in clause 8. 3.5.4 Pre-sync bl
42、ock There is no pre-sync block. 3.5.5 Post-sync block There is no post-sync block. 14 STD-BSI BS EN bL03LI-Z-ENGL 1777 S 1124bS9 075hL42 757 EN 618342:1998 3.5.6 Data-sync block The data-sync block consists of 12 bytes. Byte position numbers 5 to 9 of each sync block are subcode data (see 8.5). Byte
43、 position numbers 10 to 11 of each sync block are parities (see 8.2). 4 Audio interface The principal mode of interface is analogue. The analogue audio signal shall be converted according to 6.4.1. The audio signal may also be input and output digitally in a bit-serial form. The bit-serial interface
44、 for audio data only, if present, shall conform to IEC 60958. When the bit-serial interface for this standard is prepared, the data structure for transmission shall conform to 11. With regard to the interface standard, IEC 61883-1 and IEC 61883-2 should be referred to. 5 Video interface The principa
45、l mode of interface is analogue. The analogue video signal shall be converted according to 7.4.1. The video signal may also be input and output digitally in a bit-serial form. When the bit-serial interface for this standard is prepared, the data structure for transmission shall conform to clause 11.
46、 With regard to the interface standard, IEC 61883-1 and IEC 61883-2 should be referred to. 6 Audio signal processing 6.1 Introduction The audio signal is recorded on two audi blocks. Each audio block is processed independently and identically. The audio block is composed of five audio sectors in fiv
47、e consecutive tracks (525-60 system) and six audio sectors in six consecutive tracks (625-50 system). Each audio sector is processed in a product block of 77 columns by 9 rows and audio auxiliary data (AAUX) are multiplexed with the audio data in the product block as shown in figure 7. For recording
48、, the audio samples are shuffled in the audio block before the addition of error correction data to the product block. 6.2 Error correction code Audio data are protected by inner error correction code and outer error correction code. 6.2.1 Inner error correction code The inner parity as shown in fig
49、ure 7 is defined as a code-word of an inner error correction code. The inner error correction code is a (85, 77) Reed-Solomon code in GF(256) of which the field generator polynomial is shown as: 8 + x4 + 3 + 2 + 1 where Xi are place-keeping variables in GF(2), the binary field. 15 The generator polynomial of the code in GF(256) is: gin(X) = (X+ l)(X+ a)(X+ $)(X+ $)(X+ ! + 1 where Xi are place-keeping variables in GF(2), the binary field. The generator polynomial of the code in GF(256) is: where a is given by 2h in GF(256). Parities, K4, K3, K2, Ki, KO as s
