BS ISO 9642-2020 pdf free download.Cinematography — Time and control code for 24, 25 and 30 frames per second motion- picture film systems — Specifications
This document specifies digital code for mats and modulation methods for motion-picture film to be used for timing, control, editing and synchronization purposes. This document also specifies the relationship of the codes to the motion picture frame.
Two types of code are described in this document. The first type, Type C, is a continuous code which is very similar to the continuous code specified in IEC 60461. This type of code can be used in situations where the film is moving continuously at the time of both recording and reproduction.
The second type of code, Type 8, is a non-continuous, block-type code, composed of blocks of data, each complete in itself, with gaps between the blocks. It is designed so that the code can be recorded and played back on equipment with intermittent film motion but still be decoded with the same type of electronic equipment used to read the Type C or continuous time code.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO/IEC 2022, Information technology — Character code structure and extension techniques
ISO 4241, Cinematography — Projection film leader (time-based), trailer and cue marks — Specifications
ISO 8758, Cinematography — Photographic control and data records on 16 mm and 35 mm motion-picture film and prints — Dimensions and location
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https://www.iso.org/obp
— IEC Electropedia: available at http://www.electropedia.org/
3.1 real time
<NTSC colour recording> time elapsed during the scanning of 60 fields (or any multiple thereof) in an ideal television system at a vertical field rate of exactly 60 fields per second
3.2 colour time
<NTSC colour recording> time elapsed during the scanning of 60 fields (or any multiple thereof) in a colour television system at a vertical field rate of approximately 59,94 fields per second
5.2 Type 8 code format
5.2.1 Each motion-picture frame shall be identified by a unique and complete address.
5.2.2 The frames shall be numbered successively 0 to 23, 24 or 29 inclusive, corresponding to the frame rate being used.
5.2.3 Each address shall consist of 112 bits numbered 0 to 111 inclusive.
5.2.4 The bits shall be assigned as shown in the appropriate columns of Figure 1 and in Table 1.
5.2.5 The block of data for a single frame may be recorded anywhere within that frame except that no part of the block may occupy the region extending from the frameline to 5 % of a frame length on either side of it. This region is thus a gap in the data which has a minimum length of 10 % of a frame length.
See Figure 3.
5.2.6 The length of any one bit shall not differ by more than 5 % from the length of either adjacent bit. In addition, the length of no bit shall be so short as to make the recording and reproduction of that data, using practical equipment, unreliable. The length of no series of bits shall cause the total length of 112 bits to exceed 90 % of frame length.
5.2.7 In order to reduce the d.c. content of the signal, a repetitive pattern of zeros and ones shall be recorded in as much of the gap area (the frameline region defined in 5.2.5) as is practical. This region shall not contain a sync word of the previous frame or the first sync word of the following frame and shall not be decodable as a valid time code word. The bit length tolerance in 5.2.6 does not apply todata in the gap.
5.3 Use of binary groups
5.3.1 The binary groups are intended for storage of data by the users and the 32 bits within the 8 groups may be assigned in any fashion without restrictions if the character set used for the data insertion is not specified and the binary group flag bits, Nos. 43 and 59, are both zero.
5.3.2 Encoding of frame identification by definition provides considerable redundancy that aids in minimizing decoding errors. In the design for storage of additional data for optional user applications,consideration shall be given to encoding of appropriate redundancies. In addition, data is specifically permitted to be spread across frame lines.
The binary group flag bits 43 and 59 (67 and 83 for Type 8 code) shall be set according to Table 2.BS ISO 9642 pdf download.