1、 Rec. ITU-R BR.1575 1 RECOMMENDATION ITU-R BR.1575 Guide to the selection of digital video tape recording formats for studio production in the standard definition television (SDTV) environment based on production requirements (Question ITU-R 239/11) (2002) The ITU Radiocommunication Assembly, consid
2、ering a) that digital video tape recording (VTR) formats for programme production are selected based on user requirements such as performance and operational requirements; b) that Recommendation ITU-R BR.657 Digital television tape recording, standards for the international exchange of television pr
3、ogrammes on magnetic tape, describes user requirements for digital television tape recorders, and is the basis for the standardization of D-1 format; c) that Recommendation ITU-R BR.1292 Engineering guidelines for video recording in SDTV production and post-production chains, recommends engineering
4、guidelines for television post-production; d) that Recommendation ITU-R BR.1356 User requirements for application of compression in television production, lists user requirements for application of compression in television production, for bit rates up to 50 Mbit/s in particular; e) that Recommendat
5、ion ITU-R BR.1376 Compression families for use in recording and networked SDTV production, recommends compression based on intra-frame coding at a data rate close to 50 Mbit/s for mainstream applications which require high margin of quality overhead for post-production; f) that Recommendation ITU-R
6、BR.1376 specifies the two compression families which meet the requirements in considering e) above: DV-based 50 Mbit/s 4:2:2 intra-frame; MPEG-2 4:2:2PML 50 Mbit/s intra-frame; g) that the two categories of programme production in standard definition television (SDTV) environment, the “high-end” and
7、 the “mainstream”, are identified based on the users requirements in Appendix 3 of Recommendation ITU-R BR.1376, 2 Rec. ITU-R BR.1575 recommends 1 that for digital VTRs for studio production and post-production for SDTV, one of the following families of recorders should preferably be used according
8、to required margin of quality overhead: uncompressed or loss-less compression recorders suitable for high-end production which requires highest margin of quality overhead for intensive post-production; slightly compressed recorders suitable for high-end production which requires higher margin of qua
9、lity headroom for post-production; recorders at around 50 Mbit/s employing intra-frame coding, such as DV-based 4:2:2 or MPEG-2 4:2:2PML suitable for mainstream production which requires modest margin of quality overhead for post-production. NOTE 1 Digital VTRs for SDTV program production that use c
10、ompression below 50 Mbit/s will be covered in a separate Recommendation. APPENDIX 1 Features and specifications of digital tape recording formats for SDTV production (Informative) Tables 1 (SDTV digital VTR for 525/59.94) and 2 (SDTV digital VTR for 625/50) provide the major features and specificati
11、ons of the commercially available tape-based storage devices for SDTV high-end and mainstream production. Rec. ITU-R BR.1575 3 TABLE 1 SDTV Digital VTR for 525/59.94 Category High-end Mainstream Manufacture specification D1 D5 Digital BETACAM DVCPRO 50 D-9 (Digital-S) D10 (MPEG IMX)Video (MHz) 13.5
12、13.5/18 13.5 Sampling frequency Audio (kHz) 48 Video (bits) 8 10/8 10 8 Quantization Audio (bits) 20 16 24/16 Number of AES 3 channels(1)2 2/4 Number of Y samples 720 720/960 720 Recorded lines 500 510 512 480 512 Raster structure Y/C sampling 4:2:2 Intra frame DCT Intra frameDCT Compression (video)
13、 Coding scheme Uncompressed Intra field DCT DV-based MPEG-2(2)4:2:2PML Video rate (Mbit/s) 173 235 90 50 Inner 64, 60 95, 87 178, 164 85, 77 162, 150 Outer 32, 30 128, 120 106, 96 149, 138 60, 46 ECC Video Redundancy (%) 14 16 20 19 41 Inner 64, 60 95, 87 178, 164 85, 77 117, 105 Outer 10, 7 16, 8 1
14、0, 5 14, 9 18, 8 ECC Audio Redundancy (%) 105 118 117 72 152 Channel coding S-NRZ 8-14 S-NRZI 24-25 I-NRZI S-NRZI Total rate (Mbit/s) 225.3 300.6 128 84 99 97 Number of recording RF channels 4 2 Drum diameter (mm) 75.0 76.0 81.4 21.7 62.0 81.4 Drum rotation (rps) 150 90 89.91 149.85 75 59.94 Number
15、of tracks (/field) 10 12 6 20/Frame 10/Frame 8/Frame Tape speed (mm/s) 286.6 167.228 96.7 67.640 57.737 64.5 Track pitch (m) 45.0 20.0 21.7 18 20 21.7 Minimum wavelength (m) 0.9 0.64 0.69 0.49 0.587 0.56 Width of tape (mm) 19.01 12.65 6.35 12.65 Media substance Oxide Metal particle Tape Hc (kA/m) 68
16、 143 125 184 143 120 Cassette size (mm) S: 172 109 M: 254 150 L: 366 206 S: 161 98 M: 212 124L: 296 167 S: 156 96 L: 254 145 M: 97.5 64.5 L: 125 78 188 104 S: 156 96 L: 254 145 Recording time (min) 13/41/94 23/63/124 40/124 33/92 124 60/184 (1)An AES 3 channel may carry two linear pulse code modulat
17、ion audio channels or it may carry data as indicated by Status Channel bit 1. (2)See Appendix 2. 4 Rec. ITU-R BR.1575 TABLE 2 SDTV Digital VTR for 625/50 Category High-end Mainstream Manufacture specification D1 D5 Digital BETACAM DVCPRO 50 D-9 (Digital-S) D10 (MPEG IMX)Video (MHz) 13.5 13.5/18 13.5
18、 Sampling frequency Audio (kHz) 48 Video (bits) 8 10/8 10 8 Quantization Audio (bits) 20 16 24/16 Number of AES 3 channels 2 2/4 Number of Y samples 720 720/960 720 Recorded lines 600 608 608 576 608 Raster structure Y/C sampling 4:2:2 Intra frame DCT Intra frameDCT Compression (video) Coding scheme
19、 Uncompressed Intra field DCT DV-based MPEG-2(1)4:2:2PML Video rate (Mbit/s) 173 233 89 50 Inner 64, 60 86, 78 178, 164 85, 77 162, 150 Outer 32, 30 128, 120 126, 114 149, 138 64, 54 ECC Video Redundancy (%) 14 18 20 19 28 Inner 64, 60 86, 78 178, 164 85, 77 137, 125 Outer 10, 7 16, 8 18, 9 14, 9 18
20、, 8 ECC Audio Redundancy (%) 105 121 117 72 147 Channel coding S-NRZ 8-14 S-NRZI 24-25 I-NRZI S-NRZI Total rate (Mbit/s) 225.3 303 126 84 99 88 Number of recording RF channels 4 2 Drum diameter (mm) 75.0 76.0 81.4 21.7 62.0 81.4 Drum rotation (rps) 150 100 75 150 75 50 Number of tracks (/field) 12 1
21、6 6 24/Frame 12/Frame 8/Frame Tape speed (mm/s) 286.9 167.228 96.7 67.708 57.795 53.8 Track pitch (m) 45.0 18.0 26 18 20 21.7 Minimum wavelength (m) 0.9 0.70 0.59 0.49 0.587 0.56 Width of tape (mm) 19.01 12.65 6.35 12.65 Media substance Oxide Metal particle Tape Hc (kA/m) 68 143 125 184 143 120 Cass
22、ette size (mm) S: 172 109 M: 254 150 L: 366 206 S: 161 98 M: 212 124L: 296 167 S: 156 96 L: 254 145 M: 97.5 64.5 L: 125 78 188 104 S: 156 96 L: 254 145 Recording time (min) 11/34/94 23/63/124 40/124 33/92 124 72/224 (1)See Appendix 2. Rec. ITU-R BR.1575 5 APPENDIX 2 Compression specifications of D10
23、 MPEG IMX format (Informative) Introduction The IMX-MPEG VTR is based upon a compliant MPEG elementary stream as its source of compressed data. MPEG-2 4:2:2PML is a very flexible standard. This contrasts with the unique requirements of a VTR. In order to provide accurate editing, slow-motion and var
24、iable speed playback, and pictures in shuttle, a constrained bit stream is required. The following paragraphs define encoding parameters suitable for the Type D10-IMX recording format. The MPEG-2 4:2:2PML video elementary stream bit stream constrained to these parameters can be successfully decoded
25、by a compliant MPEG-2 4:2:2 ProfileMain level decoder. D-10 bit stream definition This Appendix specifies the compression constraints and bit stream characteristics of an MPEG-2 4:2:2PML video elementary stream operating at bit rates up to 50 Mbit/s. The video compression format is fully compliant w
26、ith the MPEG-2 video standard (ISO/IEC 13818-2: 2000) 4:2:2PML. The video elementary stream bit stream shall comply with the syntax of SMPTE 328M MPEG-2 video elementary stream editing information. In order to provide accurate editing and playback in slow-motion and variable speed replay including p
27、ictures in shuttle, this clause defines encoding parameter specifications suitable for the Type D10 recording format capable of recording MPEG-2 4:2:2PML video elementary streams at bit rates up to 50 Mbit/s. The MPEG-2 4:2:2PML video elementary stream bit stream constrained to these parameter speci
28、fications is fully compliant with the MPEG-2 4:2:2PML video elementary stream syntax and can be successfully decoded by a compliant MPEG-2 4:2:2 ProfileMain level decoder. General bit stream characteristics TABLE 3 Basic bit stream constraints Source format SDTV 525/60/1.001 and 625/50 Bit rate Up t
29、o 50 Mbit/s constrained bytes per GoP (CBG) Group of pictures (GoP) structure I-picture only Up to 208 541 bytes net (30/1.001 I-frames/s) Maximum coded frame size Up to 250 000 bytes net (25 I-frames/s) 6 Rec. ITU-R BR.1575 Table 4 indicates recommended operating points to simplify studio operation
30、s and to provide users with a tool to be used in designing systems. TABLE 4 Optional operating points (bit rates) MPEG compression parameter constraints The following defined constraints shall apply. The bit_rate_value in sequence_header shall be set with a value up to 50 Mbit/s. The sequence_extens
31、ion parameter shall be set with the following value: - sequence_extension: bit_rate_extension = 0h Video buffering verifier (VBV) delay constraint The VBV delay parameter shall be constrained to a 1-frame delay for each GoP by defining the following values: 525/60 systems - picture_header: vbv_delay
32、 = 0BBBh 625/50 systems - picture_header: vbv_delay = 0E10h MPEG-2 4:2:2 ProfileMain Level The sequence_extension parameters shall be constrained to the following values: - sequence_extension: profile_and_level_indication = 85h (MPEG-2 4:2:2PML) - sequence_extension: chroma_format = 2h (MPEG-2 4:2:2
33、PML) All I-picture encoding The picture_header parameter shall be constrained to the following values: - picture_header: temporal_reference = 0h (1 picture in a GoP) - picture_header: picture_coding_type = 1h (I-picture only) D-10 profile Bit rate (Mbit/s) Sequence header bit rate value Comments Ope
34、rating Point E 50 1E848h To be used when compliant with EBU statement D84/85 1999 Operating point F 40 186A0h May be used for interfaces to T3 telco circuits and other content production Operating point G 30 124F8h May be used for E3 telco interfaces, and non critical content material Rec. ITU-R BR.
35、1575 7 Picture structure is frame picture only The picture_coding_extension parameter shall be set to constrain the picture coding to frame pictures only by constraining to the following value: - picture_coding_extension: picture_structure = 3h (frame picture) Frame frequency The sequence_header par
36、ameters shall be constrained to the following values: # 525/60 systems - sequence_header: frame_rate_code = 4h (30/1.001 Hz) # 625/50 systems - sequence_header: frame_rate_code = 3h (25 Hz) Picture coding parameter constraints The picture coding constraints shall be defined as follows: - picture_cod
37、ing_extension(): intra_dc_precision = 2h (10 bit DC) - picture_coding_extension(): frame_pred_frame_dct = 0h (field/frame adaptive) - picture_coding_extension(): q_scale_type = 1h (non-linear quantizer) - picture_coding_extension(): intra_vlc_format = 1h (use intra-VLC table) - picture_coding_extens
38、ion(): alternate_scan = 0h (zig-zag scan) - picture_coding_extension(): top_field_first = 1h (top field first only) - picture_coding_extension(): repeat_first_field = 0h (no repeat first field) - picture_coding_extension(): progressive_frame = 0h (interlace frames only) - sequence_extension(): progr
39、essive_sequence = 0h (interlace frames only) Slice structure All slices shall contain only one macroblock. Each macroblock shall have a slice header as a sync-code. In case of any errors occurring during transmission/recording the error propagation will be less than one macroblock. The slice structu
40、re syntax shall be as follows: slice() No.of bits Mnemonic slice_start_code 32 bslbf if (vertical_size 2800) slice_vertical_position_extension 3 uimsbf if () if (scalable_mode = “data partitioning“) priority_breakpoint 7 uimsbf 8 Rec. ITU-R BR.1575 quantiser_scale_code 5 uimsbf if (nextbits() = 1) i
41、ntra_slice_flag 1 bslbf intra_slice 1 uimsbf reserved_bits 7 uimsbf while (nextbits() = 1) extra_bit_slice ( with the value 1 ) 1 uimsbf extra_information_slice 8 uimsbf extra_bit_slice ( with the value 0 ) 1 uimsbf macroblock() next_start_code() Sequence_header and sequence_extension The sequence_h
42、eader and sequence_extension shall be present for every picture as per SMPTE 328M, specified as follows. video_sequence() No.of bits Mnemonic next_start_code() sequence_header() if (nextbits() = extension_start_code) sequence_extension() do extension_and_user_data(0) if (nextbits() = group_start_cod
43、e) group_of_picture_header() extension_and_user_data(1) picture_header() picture_coding_extension() extension_and_data(2) picture_data() if (nextbits() != sequence_end_code) sequence_header() sequence_extension() while (nextbits() != sequence_end_code) else ( ISO/IEC 11172-2 ) sequence_end_code 32 bslbf
