Introduction

Metadata or "data about data" is information about an object and collected as specified in a schema. There are several schema in use for audio-visual work each specifying many different elements.

Metadata elements collected need to be selected to suit the eventual users and be manageable. The broadcaster requires different data to the academic or library administrator.

Automation greatly assists with some tasks

What to collect?

When tapes and discs are digitised metadata comes from several sources eg.

1. handwritten notes, labels etc with the object
2. notes of playback problems or remedial steps
3. equipment used to digitise the object
4. automatically generated data in BWF creation
5. external sources

The BWF allows embedding of data eg. ISRC, Originator details, encoding history etc but this is not standardised and data may be ignored or even deleted by other software applications.

Preparation

Before work commences we will arrange what data we should collect and how it is to be submitted.

If you prefer we can supply a default list of elements from the AES, EBU or LOC schema.

Standards at LOC

Standards at AES

Standards at EBU

MP3 Metadata

MP3 metadata frames are defined in ID3v2, an informal standard. Users can define their own frames, if needed. The present list of frames is here.

AAC or MP3?

AAC

• More sample frequencies (from 8 kHz to 96 kHz) than MP3 (16 kHz to 48 kHz)
• Up to 48 channels (MP3 supports up to two channels in MPEG-1 mode and up to 5.1 channels in MPEG-2 mode)

MP3

• Compatible with all players
• AAC (Apple's choice) fewer players.
• CBR used for max compatibility, VBR more efficient.

MP3, CBR, 48kHz, bitrate to suit