scte35-splice

Formerly dvb-scte35. This crate was renamed from dvb-scte35 (last released as 7.9.0 in the DVB lockstep) to scte35-splice (v1.0.0) and is now independently versioned. The deprecated dvb-scte35 crate re-exports this one.

Install

[dependencies]
scte35-splice = "1.0"

Spec-cited ANSI/SCTE 35 2023r1 splice information (Digital Program Insertion cueing) parser and builder in Rust, with the rust-dvb family's symmetric Parse/Serialize round-trip discipline — every wire type round-trips byte-for-byte.

Edition note. This crate implements ANSI/SCTE 35 2023r1, the single-document edition of the standard. SCTE has since split the standard into SCTE 35-1 (the message) and SCTE 35-2 (XML/binary mappings); the binary splice_info_section syntax implemented here is unchanged.

What is SCTE 35?

SCTE 35 is the cueing standard used across the cable / OTT industry to signal ad-insertion (avail) and content-segmentation opportunities in an MPEG transport stream. A splice_info_section (table_id 0xFC) carries one splice command (e.g. splice_insert, time_signal) plus a loop of splice descriptors (e.g. segmentation_descriptor), trailed by an MPEG CRC-32.

Quick start

use scte35_splice::{SpliceInfoSection, commands::{AnyCommand, TimeSignal}};
use scte35_splice::time::SpliceTime;
use dvb_common::{Parse, Serialize};

// Build a time_signal() section and emit it.
let ts = TimeSignal { splice_time: SpliceTime::with_pts(0x0_0012_3456) };
let section = SpliceInfoSection::new_clear(AnyCommand::TimeSignal(ts), &[]);
let bytes = section.to_bytes();
assert_eq!(bytes[0], 0xFC); // table_id

// ...and parse it straight back (CRC verified on parse).
let parsed = SpliceInfoSection::parse(&bytes).unwrap();
assert!(matches!(parsed.clear.unwrap().command, AnyCommand::TimeSignal(_)));

What's implemented

splice_info_section

Full §9.6 header: table_id (0xFC), section_length, protocol_version, encrypted_packet flag + encryption_algorithm (encrypted region kept raw), 33-bit pts_adjustment, 12-bit tier, splice_command_length, splice_command_type, descriptor_loop_length, CRC-32 (verified on parse). Decoded accessor: pts_adjustment_duration() → core::time::Duration.

Splice commands — 6 (§9.6.1 Table 7)

All 6 are in the declare_commands! list in commands/any.rs; each has Parse

Serialize impl and round-trip tests. Unknown/reserved command types fall through to AnyCommand::Unknown with raw bytes preserved.

Type	Command	Notes
0x00	`splice_null`	Empty; CRC-only keep-alive
0x04	`splice_schedule`	One or more timed splice events
0x05	`splice_insert`	Immediate or timed insert with `break_duration`
0x06	`time_signal`	`splice_time` with optional PTS
0x07	`bandwidth_reservation`	Empty payload
0xFF	`private_command`	`identifier` (32-bit) + opaque body

Splice descriptors — 5 (§10.1 Table 16)

All 5 are in the declare_splice_descriptors! list in descriptors/any.rs; unknown tags fall through to AnySpliceDescriptor::Unknown with raw body (lossless).

Tag	Descriptor	Notes
0x00	`avail_descriptor`	`provider_avail_id`
0x01	`DTMF_descriptor`	preroll + DTMF chars
0x02	`segmentation_descriptor`	`segmentation_upid`, typed `SegmentationTypeId`, `DeviceRestrictions`, `component_list`
0x03	`time_descriptor`	TAI seconds + nanoseconds + UTC offset
0x04	`audio_descriptor`	Multi-component audio coding info

Segmentation assignment tables

Typed enums so callers never re-implement the spec lookup tables (§10.3.3.1):

Enum	Table	Values
`DeviceRestrictions`	Table 21	4 variants (2-bit field)
`SegmentationUpidType`	Table 22	18 named variants (0x00–0x11) + `Reserved(u8)`
`SegmentationTypeId`	Table 23	48 named variants (0x00–0x51) + `Reserved(u8)`

All three enums round-trip via from_* / to_u8; unrecognised values are carried through Reserved(raw) without data loss.

Decoded time accessors

90 kHz SpliceTime and BreakDuration fields expose pts() / duration() accessors returning core::time::Duration. The 33-bit pts_adjustment field likewise has a pts_adjustment_duration() accessor (carry-ignored wrap per the spec).

Dispatch and drift tests

AnyCommand and AnySpliceDescriptor are each generated from a single declare_*! macro invocation that is the single source of truth for the dispatcher and a compile-time drift test. Adding a new command or descriptor requires one line in the macro list.

dvb-si integration

SCTE 35 sections ride on a PID the PMT labels with a registration descriptor carrying the "CUEI" format_identifier — which dvb-si already parses. Once you have the 0xFC section bytes (e.g. from a dvb-si demux), route them into SpliceInfoSection::parse.

Feature flags

Feature	Default	Description
`std`	on	Link the standard library. Without it the crate is `#![no_std]` + `alloc`.
`serde`	on	Serialize-only (`serde::Serialize`) on all types; no Deserialize.

MSRV

Rust 1.81.

Spec grounding

The syntax tables and the assignment tables are hand-transcribed in scte35-splice/docs/scte_35.md; every module doc cites the SCTE 35 section, table and tag/command_type it implements. SCTE 35 is published by SCTE at no cost.

Examples

Run with cargo run -p scte35-splice --example <name>:

parse_splice_insert — parse a real splice_info_section carrying a splice_insert().
round_trip_and_descriptors — walk the splice descriptor loop and prove the serializer is byte-exact.

License

Licensed under either of MIT or Apache-2.0 at your option.

scte35-splice 1.0.0