Appendix J. File Metadata

Appendix J. File Metadata
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J.1. Introduction

The existing schemes for encoding metadata into audio files are extremely diverse. There are formally designed ones; some explicitly intended for use in professional broadcast settings (--e.g. CartChunk), others for general purpose "consumer" use (--e.g. ID3). Still others fall into a broad class that one may term "informal", based not on any recognized public standard but typically designed around a specific product or group of products. These informal schemes tend to be closely bound to the overall design and organization their native environment (--e.g. Rivendell's RDXL).

This appendix is an attempt to document the various file metadata schemes that are recognized by Rivendell, taking note of how each scheme maps to Rivendell's foundational RDXL schema while also describing any known quirks or limitations in Rivendell's implementation thereof. It's worth noting that, especially with regard to the informal schemes, Rivendell's implementation can be a moving target; one that is updated and extended as more information is gleaned about a given scheme by Rivendell's developers. One basic rule with regard to such informal schemes in Rivendell is that, in keeping with Postel's Prescription, support is generally read-only.

J.2. Supported Metadata Schemes

Table J.1. Supported Metadata Schemes

Type	File Type	Import	Export	Notes
RDXL	.mp2, .mp3, *.wav	Yes	Yes	Native Rivendell schema
CartChunk	*.wav	Yes	Yes	Formally defined
ID3	.mp2, .mp3	Yes	Yes	Formally defined
Scot Chunk	*.wav	Yes	No	Informal
Av10 Chunk	*.wav	Yes	No	Informal

J.2.1. RDXL

RDXL is Rivendell's native audio schema. It uses UTF-8 character encoding. Two levels of records are supported: "cart" data (exactly one record per cart) and "cut" data (zero or more records per cart).

Table J.2. RDXL Cart Fields

Field Name	Data Type	Max Width	Notes
Agency	String	64
Album	String	191
Artist	String	191
Asynchronous	Boolean	n/a	Valid values are 'true' or 'false'
Average Hook Length	Integer	191	milliseconds
Average Length	Integer	n/a	milliseconds
Average Segue Length	Integer	n/a	milliseconds
Client	String	64
Composer	String	64
Conductor	String	64
Cut Quantity	Integer	n/a
Enforce Length	Boolean	n/a	Valid values are 'true' or 'false'
Forced Length	Integer	n/a	milliseconds
Group Name	String	10
Label	String	64
Last Cut Played	Integer	n/a
Length Deviation	Integer	n/a	milliseconds
Macros	String	unlimited
Minimum Talk Length	Integer	n/a	milliseconds
Maximum Talk Length	Integer	n/a	milliseconds
Metadata Datetime	DateTime	n/a
Number	Integer	n/a
Owner	String	64
Publisher	String	64
Song ID	String	32
Title	String	191
Type	String	n/a	Valid values are 'audio' or 'macro'
Year	Integer	n/a
Usage Code	integer	n/a	0=Feature, 1=Open, 2=Close, 3=Theme
User Defined	String	191

Table J.3. RDXL Cut Fields

Field Name	Data Type	Max Width	Notes
Cut Name	String	12
Evergreen	Booleans	n/a	Valid values are 'true' or 'false'
Description	String	64
Outcue	String	64
Isrc	String	12
Isci	String	32
MusicBrainz Recording ID	String	40
MusicBrainz Release ID	String	40
Origin Date Time	DateTime	n/a
Start Date Time	DateTime	n/a
End Date Time	DateTime	n/a
Sunday	Boolean	n/a	Valid values are 'true' or 'false'
Monday	Boolean	n/a	Valid values are 'true' or 'false'
Tuesday	Boolean	n/a	Valid values are 'true' or 'false'
Wednesday	Boolean	n/a	Valid values are 'true' or 'false'
Thursday	Boolean	n/a	Valid values are 'true' or 'false'
Friday	Boolean	n/a	Valid values are 'true' or 'false'
Saturday	Boolean	n/a	Valid values are 'true' or 'false'
Start Daypart	Time	n/a
End Daypart	Time	n/a
Origin Name	String	64
Origin Login Name	String	191
Source Hostname	String	191
Origin Name	String	191
Weight	Integer	n/a
Last Play Datetime	DateTime	n/a
Play Counter	Integer	n/a
Coding Format	Integer	n/a	0=PCM16, 2=MPEG Layer II, 3=MPEG Layer III, 4=PCM24
Sample Rate	Integer	n/a	samples/second
Bit Rate	Integer	n/a	bits/second
Channels	Integer	n/a
Start Point	Integer	n/a	milliseconds
End Point	Integer	n/a	milliseconds
Fadeup Point	Integer	n/a	milliseconds
Fadedown Point	Integer	n/a	milliseconds
Segue Start Point	Integer	n/a	milliseconds
Segue End Point	Integer	n/a	milliseconds
Segue Gain	Integer	n/a	1/100 dBFS
Hook Start Point	Integer	n/a	milliseconds
Hook End Point	Integer	n/a	milliseconds
Talk Start Point	Integer	n/a	milliseconds
Talk End Point	Integer	n/a	milliseconds

J.2.2. CartChunk

CartChunk is a WAV file chunk format designed to allow the communication of basic radio traffic and continuity data between systems from diverse manufacturers and operating systems. It is explicitly specified by the Audio Engineering Society as standard AES46-2002 .

CartChunk is defined as an extension to the Broadcast Wave File format, and as such is usable only with WAV files. When importing metadata from a file containing valid CartChunk, CartChunk fields will be mapped to Rivendell RDXL fields as follows:

Table J.4. CartChunk to RDXL Field Mappings

CartChunk Field Name	RDXL Field Name	Data Type	Notes
Title	Title	String	ASCII title of cart audio sequence
Artist	Artist	String	ASCII artist or creator name
CutID	Cart Number	String	ASCII cut number identification
ClientID	Client	String	ASCII client identification
Category	Group Name	String	ASCII category ID, PSA, NEWS, etc
Classification	[none]	String	ASCII classification or auxiliary key
OutCue	Outcue	String	ASCII outcue text
StartDate	Start Date Time	Date	Applied to the Date field of Start Date Time, interpreted as the local system time zone
StartTime	Start Date Time	Time	Applied to the Time field of Start Date Time, interpreted as the local system time zone
EndDate	End Date Time	Date	Applied to the Date field of End Date Time, interpreted as the local system time zone
EndTime	End Date Time	Time	Applied to the Time field End Date Time, interpreted as the local system time zone
AUDs	Start Point	CartChunk PostTimer	See AES46-2002 Table A.2
AUDe	End Point	CartChunk PostTimer	See AES46-2002 Table A.2
SEGs	Segue Start Point	CartChunk PostTimer	See AES46-2002 Table A.2
SEGe	Segue End Point	CartChunk PostTimer	See AES46-2002 Table A.2
INTs	Talk Start Point	CartChunk PostTimer	See AES46-2002 Table A.2
INTe	Talk End Point	CartChunk PostTimer	See AES46-2002 Table A.2
INT	Talk End Point	CartChunk PostTimer	Variant form. When importing, also sets Talk Start Point to be equal to Start Point. Rivendell does not write this form. Point

J.2.3. ID3

ID3 is a metadata scheme intended for use with raw MPEG files. While not backed by a formal standards organization, ID3 is defined in a set of standards documents originally promulgated at http://id3.org/.

Rivendell supports both reading and writing ID3v2.3 tags. Each tag consists of a series of frames, each of which contains a field of metadata.

Table J.5. ID3v2.3 Frame to RDXL Field Mappings

ID3v2.3 Frame Name	RDXL Field Name	Data Type	Notes
TIT2	Title	String	Title/songname/content description
ARTIST	Artist	String	Non-standard frame
TALB	Artist	String	Album/Movie/Show title
ALBUM	Artist	String	Non-standard frame
TCOM	Composer	String	Composer
COMPOSER	Composer	String	Non-standard frame
TPUB	Label	String	Publisher
LABEL	Label	String	Non-standard frame
TPE3	Conductor	String	Conductor/performer refinement
CONDUCTOR	Conductor	String	Non-standard frame
TYER	Year	Integer	Year
DATE	Year	Integer	Non-standard frame
YEAR	Year	Integer	Non-standard frame
ISRC	Isrc	String	Non-standard frame
TBPM	Beats Per Minute	String	BPM (beats per minute)
BPM	Beats Per Minute	String	Non-standard frame
PUBLISHER	Publisher	String	Non-standard frame

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