poka.sh

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M2TS

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Blu-ray BDAV Transport Stream.

At a glance
Original creator Blu-ray Disc Association
First published 2006
Purpose The transport stream of Blu-ray (BDAV) and AVCHD video: MPEG-2 transport packets with a four-byte arrival timestamp in front of each.
Extensions .m2ts
Poka parser poka-m2ts
Viewer poka-metadata-card-viewer
Depth tier Metadata card (see Depth tiers)
Breadth tier B4 Summary (see Breadth tiers)

How much Poka reads

B4 Summary. The container and metadata are read and summarised (counts, properties, structure), but the main content is not rendered.

Confidence: high (the reviewer read the code and a test that proves the claim). Basis: Reviewed 2026-10-16: parsers/poka-m2ts/src/lib.rs (stride detection, PAT and multi-packet PMT reassembly, PID census, arrival timestamps), tests/timing.rs and tests/samples.rs over 3 corpus clips (first 2 MB of Atmos, AVCHD and Dolby Vision discs) plus a plain .ts reference. Metadata card of structure and codec line-up only; no video or audio decoded. Covers BDAV 192-byte and plain 188-byte transport streams.

What Poka does not read

  • No video or audio is decoded
  • Resolution, frame rate, aspect ratio, audio channel layout and language are not read (PMT descriptors are skipped)
  • Duration is only the arrival-timestamp span: a lower bound for a file large enough to contain a wrap (about 99 MB at 20 Mbit/s), since the number of wraps is not counted (PCR is not used)
  • Only the first 200000 packets are walked
  • Other service tables (SIT, EIT, SDT) are not read
  • Blu-ray playlist and clip info files (MPLS, CLPI) are separate files and not read
  • Stream types outside a 21-entry table show as a hex number
  • Subtitle and graphics streams are counted, not decoded
  • Corpus clips are cut at 2 MB so large real discs are untested

Background

The Library of Congress describes M2TS as a modification of the MPEG-2 transport stream used by BDAV on Blu-ray discs and by AVCHD camcorders. The Blu-ray Disc Association released the first version of the Blu-ray format in 2006; AVCHD, from Sony and Panasonic, was announced the same year. Poka measures the packet stride (192 bytes, or 188 for a plain transport stream) instead of assuming it, counts packets per PID, and reassembles the program tables across packets to name each stream's codec. A Blu-ray PMT often spans two packets, and reading one packet only would find no programmes at all. The duration comes from the first and last arrival timestamps. The 30-bit clock wraps about every 40 seconds, which at the 20 Mbit/s a Blu-ray is authored for is roughly 99 MB of file, so only a file at least that large is reported as a lower bound; a shorter one cannot have wrapped. Timestamps that go backwards inside a file are reported as giving no duration at all. No video is decoded.

Versions

Version Identifier Poka Note
BDAV / AVCHD transport stream 192-byte packets, sync byte 0x47 at offset 4 Read Stream structure and codecs only.

Libraries

Libraries Poka uses or has assessed for this format, with the status, licence and language the registry records.

  • oxideav-bluray (candidate; MIT; Rust; https://github.com/OxideAV/oxideav-bluray) — Reads .m2ts 192-byte BDAV packets, strips header to 188-byte TS; also BDMV/UDF/playlists; v0.0.4 Sep 2026, very young.
  • oxideav-mpegts (candidate; MIT; Rust; https://github.com/OxideAV/oxideav-mpegts) — Pure Rust MPEG-TS demuxer (188-byte packets, PAT/PMT, PES), intended for Blu-ray m2ts pipelines; v0.0.3.
  • bdinfo-rs-core (candidate; LGPL-2.1-or-later; Rust; https://github.com/agentjp/bdinfo-rs) — Blu-ray analyser with its own M2TS demuxer and codec scanners; has a WebAssembly build; v4.0.0.
  • mpeg2ts-reader (candidate; MIT OR Apache-2.0; Rust; https://github.com/dholroyd/mpeg2ts-reader) — Mature TS parser (v0.18.2) but 188-byte packets only; README says m2ts 192-byte framing is not handled, so strip the 4-byte prefix first.

Sources