BS ISO 9642:2020 pdf download.Cinematography Time and control code for 24, 25 and 30 frames per second motionpicture film systems Specifications.
1 Scope
BS ISO 9642 specifies digital code for mats and modulation methods for motion-picture film to be used for timing, control, editing and synchronization purposes. BS ISO 9642 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.
Figure 2 — Type C code
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.
5.2.7 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 to data 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.BS-ISO-9642-2020