ANSI SCTE 172-2017 pdf free download – Constraints On AVC and HEVC Structured Video Coding for Digital Program Insertion
6. Digital Program Insertion System Overview (Informative)
Digital Program Insertion assumes a linear program delivery with periodic insertion opportunities
signaled by ANSISCTE 35[ 1]splice_info_section( ) messages carried in TS packets of a particular PIDor PIDs within the program’s TS. Insertion opportunities signal first a splice from network PTS value(usually to an advertisement) and optionally followed some time later by the signaling of a splice backinto a different (usually later) network PTS value. An alternative signaling method signals only the firstPTS but supplies a duration and signals “auto return to network.”Signaling may also, in the case ofcontent which may be delivered in a non-time-linear method (e.g.VoD), specify that the return tonetwork PTS value be the same as the initial PTS value.
Insertion durations are seconds in length normally, although they are sometimes hours in length.Fortypical commercials durations run 30,60, or 120 seconds.
Different delivery mechanisms may use different technologies to perform the insertions.For example,insertions in linear program delivery are typically done by a splicer/content server pair. In a VODenvironment a VOD server may assemple a playlist of entertainment content and the inserted ads.ForDASH delivery ad content segments may be inserted into or replaced in the manifest.The codingconstraints defined in the specification are applicable to all delivery mechanisms. The transportconstraints are applicable to delivery mechanisms that are based on MPEG transport [6]
6.1. Collective Terminology for NAL Based Video Streams (Informative)Text in this specification related to NAL based video streams use the following structures and syntax tosupport use of common collective terminology across codecs for describing spliced based expectationsand constraints in this specification.The“context”when referring to NAL based terminology is
determined by expectations of which coding format (e.g.AVC or HEVC) is being used. There is nointention of mixing of different coding format NAL structures so collective terminology is not to beinterpreted as such. If there are splicing conditions that are specific to particular codec formats then thiswill be explicitly documented in the specification without the use of collective NAL terminology.
When NAL ISO/IEC Video Coding Standard is used this cithers refers to ISO/IEC 14496-10 (ITU-TH.264), International Standard,Advanced video coding for generic audiovisual services [7] or ISO/IEC23008-2 (ITU-T Rec.H.265), International Standard (2015)-MPEG H Information technology -Highefficiency coding and media delivery in heterogeneous environments Part 2:High efficiency video coding[9].
The following list is the set of NAL collective terminologies used in this specification.The specific codeccontext needs to be selected to understand details relevant to that specific format.
NAL Video Coding Standard
14496-10 context: AVC ISO/IEC 14496-10 Coding Specification[7].23008-2 context: HEVC ISO/IEC 23008-2 Coding Specification [9].
. NAL SCTE In-Point
14496-10 context: refers to an IDR picture that meets the requirements of an SRAP as definedin Section 6.4.1 of ANSISCTE 128-12013[2].
23008-2 context: refers to an IDR, BLA, or CRA picture or a TRAIL_R field picture thatmeets the requirements of an SHRAP as defined in Section 7.1.2.1 of ANSI/SCTE 215-12015 [4].BLA or CRA pictures can have associated RADL pictures but no associated RASLpictures.
Note: To condition a NAL SCTE In-Point that is also aligned as a start of an adaptive streaming segment, NAL SCTE In-Points also needs to meet the requirements of SAP type 1 or 2 [11].ANSI SCTE 172 pdf download.