ANSI SCTE 128-2-2018 pdf free download – AVC Video Constraints for Cable Television Part 2- Transport
6. MPEG-2 Multiplex And Transport Constraints For Avc
This section and its subsections describe MPEG-2 System details pertaining to AVC that extends thespecifications of SCTE 54 [1].
6.1. Services and Features
This section describes additional services and features details pertaining to AVC.
Note: As described in SCTE 54 [1] and other SCTE standards, the MPEG-2 Transport provides servicesand features enabled by information carried at the MPEG-2 Transport multiplex level and not at the videoelementary stream component level.Some of these services are System Information and Program Guide,Emergency Alerts, and Specification of Private Data Services.
Note:The bitrate value for the AVC Bitstream is application dependent and limited by the contiguousbandwidth of the transmission channel. In the application of AVC transmission over a 64-QAM channel,bitrate value in combination with other bitstreams in the MPEG-2 Transport multiplex, conforms to achannel bitrate of less than or equal to 27.0 Mbps; in transmissions over 256-QAM channels to less thanor equal to 38.8 Mbps.
6.2. MPEG-2 Systems Standard
6.2.1. Video T-STD
Video T-STD for AVC shall be based on Section 2.14.3.1 of ISO/IEC 13818-1 [4] and shall follow theconstraints for the profile and level encoded in the video elementary stream in Appendix A of AVC[5].
6.3. Assignment of identifiers
This section describes additional identifiers relevant to AVC video elementary stream components.
6.3.1.AvC Stream Type Codes
The AVC stream type value is Ox 1B.
6.3.2. Descriptors
6.3.2.1.Video descriptor
AVC video is signaled by the AVC_video_descriptor() when required by ISO/IEC 13818-1[4] or asotherwise appropriate. This descriptor, when carried, shall be placed in the descriptor loop for the videoprogram element of the PMT with a descriptor tag value of ox28.
Certain services may include video elementary streams that contain one or more AVC still pictures that conform to the still picture model of ISO/IEC 13818-1 [4]. Any elementary stream containing still pictures shall include a AVC_video_descriptor() with AVC_still_present_flag set to “1” in accordance with section 2.6.64 of 13818-1[4]. Constraints for transmitting AVC still pictures are defined in section 9.0 of this document. 6.3.2.2. Caption service descriptor When caption services are delivered within the AVC video elementary stream (as specified in Section 8.0 of SCTE 128 Part 1), the caption_service_descriptor(), as defined in Sec. 6.9.2 of ATSC A/65 [3], shall be present as described in SCTE 54 [1] section 5.8.3.6.
6.3.2.3. SCTE Adaptation field data descriptor When private data bytes of the adaptation field of the TS packets are in use, with tag, length, and data structures as defined in Section 6.4.3, the SCTE_adaptation_field_data_descriptor shall be placed in the descriptor loop for the video program element of the PMT. In the absence of such adaptation field private data, the descriptor shall not be included in the corresponding ES_info_loop of the PMT. The presence of the SCTE_adaptation_field_descriptor() shall mean that private_data_byte(s) carried in adaptation field data in this stream are in tag-length-data format, where the tag values are as defined in SCTE standards. The absence of this descriptor does not preclude private data in the adaptation header that could conform to MPEG or other standards. The SCTE adaptation field data descriptor shall be formatted per Table 2.ANSI SCTE 128-2 pdf download.