dvb-bbframe

ETSI DVB-S2 / S2X / T2 Base-Band Frame (BBFRAME) parser and builder, supporting both Normal Mode (NM) and High Efficiency Mode (HEM).

A BBFRAME is the unit of payload carried in a DVB-S2/S2X/T2 baseband stream: a 10-byte BBHEADER followed by a data field of user packets (a Transport Stream or Generic Stream). This crate parses and rebuilds the header and walks the data field; it does not implement the physical layer (LDPC/BCH coding, modulation). GSE payloads (Generic Stream Encapsulation) are out of scope — hand the data field to the third-party dvb-gse crate.

Quick start

use dvb_bbframe::header::{Bbheader, Mode};
use dvb_bbframe::pump::BbframePump;

// Parse a 10-byte BBHEADER directly:
let hdr = Bbheader::parse(frame)?;
assert_eq!(hdr.mode, Mode::Normal);
println!("UPL={} DFL={} SYNC=0x{:02X}", hdr.upl, hdr.dfl, hdr.sync);

// Or use the pump for per-PLP BBFrame→inner-TS extraction:
let mut pump = BbframePump::new();
let inner_ts_packets = pump.feed(5 /* plp_id */, &df_bytes);
for pkt in inner_ts_packets {
    // 188-byte inner TS packets, sync byte restored
}

What's implemented

BBHEADER (10 bytes, EN 302 307-1 / EN 302 755)

All fields from the Bbheader struct:

Field	Width	Notes
`matype.ts_gs`	2 bits	`TsGs` enum: `Ts`, `Gfps`, `Gcs`, `Gse`
`matype.sis`	1 bit	Single/Multi input stream
`matype.ccm`	1 bit	CCM/ACM flag
`matype.issyi`	1 bit	Input Stream Synchronization Indicator active
`matype.npd`	1 bit	Null Packet Deletion active
`matype.ext`	2 bits	Roll-off / reserved (`RollOff` accessor for S2/S2X)
`matype.isi`	8 bits	Input Stream Identifier (MIS only)
`upl`	16 bits	User Packet Length in bits (NM only; 0 in HEM)
`sync`	8 bits	UP sync byte copy (NM only)
`dfl`	16 bits	Data Field Length in bits
`syncd`	16 bits	Bit offset to first complete UP in data field
`mode`	CRC-8	`Mode` enum: `Normal` (0) or `HighEfficiency` (1), recovered via `crc8(hdr[0..9]) ^ hdr[9]`
`issy_in_header`	3 bytes	ISSY bytes (HEM only; `None` in NM)

Bbheader::issy() decodes issy_in_header into an Issy enum.

ISSY decoding (EN 302 755 Annex C / EN 302 307-1 Annex D)

Issy, SignallingKind, and BufsUnit cover all three ISSY forms:

Form	Prefix	Result
ISCR short	`bit[7]=0`	`Issy::IscrShort(u16)` — 15-bit ISCR
ISCR long	`bit[7:6]=10`	`Issy::IscrLong(u32)` — 22-bit ISCR
Signalling	`bit[7:6]=11`	`Issy::Signalling(SignallingKind)`

SignallingKind variants: Bufs { bufs, units }, Tto { tto_e, tto_m, tto_l }, BufStat { bufstat, units } (DVB-S2 Annex D), Reserved(u32). Decoded accessors: bufs_bits(), bufs_bytes(), bufstat_bits(), bufstat_bytes(), tto_t_over_256().

User-packet extraction (EN 302 755 §5.1.8)

Type	Description
`NmTsIter`	Iterator over NM UPs (188-byte stride; CRC-8 byte replaced with sync 0x47)
`HemTsIter`	Iterator over HEM UPs (187-byte stride; sync byte prepended; DNP skipped when NPD active)
`UpIter`	Runtime-dispatched enum wrapping either iterator
`up_iter(data, bbheader)`	Constructs the right iterator from the parsed header
`CarryOverExtractor`	Stateful cross-boundary reassembler; `feed_nm` / `feed_hem` (allocating) and `feed_nm_into` / `feed_hem_into` (buffer-reuse)

SYNCD = 0xFFFF (no UP starts in this data field) is handled correctly.

BbframePump

BbframePump packages the whole BBHEADER-parse → mode-detect → CarryOverExtractor chain for multi-PLP streams. Feed (plp_id, df_bytes) pairs; the pump keeps independent per-PLP carry-over state and returns completed 188-byte inner TS packets.

Feature flags

Feature	Default	Description
`std`	on	Link the standard library. Without it the crate is `#![no_std]` + `alloc`.
`serde`	off	Serialize-only (`serde::Serialize`) on `Bbheader`, `Matype`, `TsGs`, `Mode`, `Issy`, `SignallingKind`, `BufsUnit`, `RollOff`.
`yoke`	off	`yoke::Yokeable` on `NmTsIter` and `HemTsIter`.

MSRV

Rust 1.86.

Authoritative references

ETSI EN 302 307-1 (DVB-S2) / EN 302 307-2 (DVB-S2X)
ETSI EN 302 755 (DVB-T2) — §5.1.7 (BBHEADER/HEM), §5.1.8 (UP carriage), Annex C (ISSY), Annex F (CRC-8)

The structured spec reference is under docs/; the canonical PDFs are vendored in the workspace specs/ directory.

Examples

Run with cargo run -p dvb-bbframe --example <name>:

parse_bbheader — parse a single DVB-S2 BBHEADER (with a valid Normal-Mode CRC-8).
walk_capture — reassemble BBFrames from a real DVB-S2 capture and parse every header.

License

Licensed under either of MIT (LICENSE-MIT) or Apache-2.0 (LICENSE-APACHE), at your option.

dvb-bbframe 8.6.0