ANSI SCTE-67-2006 pdf download Digital Program Insertion Cueing Message for Cable – Interpretation for SCTE 35
4.1 Scope This document is an informational companion to SCTE 35 2004. It is not in itself a specification or a standard. The information within is intended as guideline information. Where this document contradicts SCTE 35 2004, SCTE 35 2004shall take precedence.
4.2 Purpose The purpose of this document is to aid splicing equipment designers, ad insertion equipment designers and purchasers and users of such equipment. Also expected to be interested are the networks that will originate DPI cue messages from their uplink sites and the manufacturers of the equipment to do this. This document is also expected to aid in the system integration of advertising related equipment, both at the message origination end and at the message reception end. There may be crucial information within this document for manufacturers of equipment that pass the DPI cue message as part of the MPEG stream. An example of such equipment is a rate altering re-multiplexer, which performs complex processing of the stream. When the stream is demultiplexed and processed and then re-multiplexed, it is very important to place the DPI Cue Message in the proper position relative to the video service and relative to nearby time base discontinuities. Such equipment may also be required to alter the message before retransmission.
5 Application Guidelines
5.1 Practical Boundaries for splice_time() in splice_insert() How far ahead of the splice must a splice_insert message be sent, relative to the picture it refers to, in order to be safely responded to by an ad insertion system? The “arm time” denotes the time a DPI cue message must precede that actual insertion. The arm time should be in the range of 5 – 8 seconds. This is in line with the pre-roll time for analog cue- tones. The arm time must not be so short that the avail passes by before the ad insertion system has time to respond. A minimum of 4 seconds is believed to be required for safe operation. More thought about the possible consequences is required if it is desirable to extend the arm time beyond the recommended eight seconds. To specify a maximum arm time therefore seems premature.