Overview
IEC 62447-2:2007 specifies the compression format for the D‑12 helical‑scan compressed digital video cassette system using 6.35 mm magnetic tape. The standard defines the DV‑based data structure and decoding processes for a 100 Mb/s interface carrying compressed video, DV‑based digital audio and subcode/auxiliary data. Decode targets include eight channels of AES‑3 digital audio at 48 kHz, subcode, and high‑definition video formats 1080/60i, 1080/50i and 720/60p. This part (Part 2) focuses on how data is organized, compressed, quantized and packed for reliable storage and playback on D‑12 recorders.
Key Topics
- Data structure and DIF sequencing: layout of header, subcode, VAUX, audio and video sections; DIF block and sequence mapping for 50/60 Hz systems.
- Header and subcode formats: ID fields, SSYB and packs, timecode and binary group mapping.
- Audio packing and AES‑3 conversion: mapping of audio samples into AAUX packs and conversion to eight AES‑3 channels at 48 kHz.
- Video sampling and compression structure: input sampling for 1080/60i, 1080/50i and 720/60p; DCT block, macroblock and super‑block organization.
- DCT processing and quantization: DCT modes, weighting matrices and quantizer step definitions tailored to D‑12 video formats.
- Variable length coding (VLC) and bitstream arrangement: codeword tables, bit assignment and compressed macroblock arrangement to achieve 100 Mb/s stream.
- Error handling and auxiliary data: video error codes, VAUX packs and sampling‑rate conversion (Annex B).
- Normative and informative annexes: block diagram of a D‑12 recorder and digital filter parameters.
Applications
- Broadcast and production archive systems using D‑12 cassette recorders for HD master and ingest workflows.
- Equipment manufacturers implementing helical‑scan tape transports, encoders/decoders and media players compliant with the D‑12 format.
- Systems integrators and post‑production facilities requiring assured interoperability of DV‑based compressed video and multichannel AES‑3 audio over a 100 Mb/s interface.
- Digital preservation and media migration projects that need exact data mapping and error handling specifications for legacy 6.35 mm tape media.
Who should use this standard
- Broadcast equipment designers, firmware/software developers for D‑12 recorders, quality assurance engineers, archivists and standards bodies responsible for tape‑based HD video workflows.
Related Standards
- See Annex C for the relation to IEC 61834‑3 (document provides cross‑references and compatibility notes).
Keywords: IEC 62447-2, D-12, helical‑scan compressed digital video cassette, 6.35 mm tape, DV-based, compression format, 100 Mb/s, AES‑3, 48 kHz, 1080/60i, 1080/50i, 720/60p.