st337

SMPTE ST 337:2015 ("Format for Non-PCM Audio and Data in an AES3 Serial Digital Audio Interface") burst-preamble/burst-payload framing — spec-complete parse/serialize, no_std.

ST 337 defines how compressed/non-PCM audio (AC-3, E-AC-3, DTS, etc.) and other data is carried inside the AES3 professional digital audio interface's sample words, via a repeating burst-preamble structure (Pa/Pb sync words, a Pc info word, a Pd length word, and — for the "extended" data-type escape code — Pe/Pf) followed by the opaque compressed-audio (or other) payload.

[Burst] — one complete data burst: [BurstPreamble] + the opaque burst_payload bytes (§7.1/§7.2).
[BurstPreamble] — data_type, data_mode, error_flag, data_type_dependent, data_stream_number, length_code, and (when the six-word "extended" form is used) Pe/Pf (§7.2.4).
[DataMode] — the data_mode field (§7.2.4.3 Table 8). Only DataMode::Mode16 is supported for parse/build — see docs/st337.md's "Scope decisions" for why.

See docs/st337.md for the curated SMPTE ST 337:2015 §7 transcription this crate implements field-for-field (fetched directly from pub.smpte.org/latest/st337/st0337-2015.pdf), and docs/st337-PROVENANCE.md for a real-fixture + independent-oracle (ffmpeg -f spdif) cross-check of the sync-word constants and Pc bit layout — including a genuine, documented discrepancy it surfaced between ST 337's own length_code semantics (bits) and IEC 61937's for the same nominal data type (bytes).

What this crate is not: an AES3 physical-layer (biphase-mark line code, subframe/timeslot bit placement) codec, and not a data_type -> codec registry (that mapping is SMPTE ST 338, not independently verified here — data_type is a plain validated u8, not an enum with invented codec names). It parses/builds the logical burst word sequence as a plain byte stream (&[u8], 2 bytes per 16-bit preamble word) — the same "container-not-codec" scope this workspace's transmux crate uses for media containers.

#![no_std] + alloc; depends only on broadcast-common.

Quick start

use broadcast_common::{Parse, Serialize};
use st337::{Burst, DataMode};

let payload = [0xDE, 0xAD, 0xBE, 0xEF];
let burst = Burst::new(1, DataMode::Mode16, false, 0, 0, None, &payload).unwrap();

let mut bytes = vec![0u8; burst.serialized_len()];
burst.serialize_into(&mut bytes).unwrap();
assert_eq!(Burst::parse(&bytes).unwrap(), burst);

Examples

cargo run -p st337 --example build_burst
cargo run -p st337 --example parse_burst

Features

Feature	Default	Description
`std`	yes	Link the standard library. Without it the crate is `#![no_std]` + `alloc`.
`serde`	no	`serde::Serialize`/`Deserialize` derives on public types.

Minimum Supported Rust Version

1.95.0

License