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71 lines
3.1 KiB
Plaintext
71 lines
3.1 KiB
Plaintext
=== Tracks Block (`TRKS`)
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The tracks block holds a structured list of track entries, typically aligned with the layout specified in the table of contents or a similar indexing schema.
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This format is common in optical media such as CDs, DVDs, and related disc-based formats.
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==== Structure Definition
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[source,c]
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#define TRACKS_MAGIC 0x534B5254
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/**Contains list of optical disc tracks */
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typedef struct TracksHeader
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{
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uint32_t identifier; ///< Block identifier (must be BlockType::TracksBlock).
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uint16_t entries; ///< Number of TrackEntry records following this header.
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uint64_t crc64; ///< CRC64-ECMA of the TrackEntry array (header excluded, legacy byte-swap for early versions).
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} TracksHeader;
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==== Field Descriptions
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[cols="2,2,2,6",options="header"]
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|===
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|Type|Size|Name|Description
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|uint32_t|4 bytes|identifier|The tracks block identifier, always `TRKS`
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|uint16_t|2 bytes|entries|The number of entries following this header
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|uint64_t|8 bytes|crc64|CRC64-ECMA checksum of the entries following this header
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|===
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==== Track entries
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[source,c]
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/**Optical disc track */
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typedef struct TrackEntry
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{
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uint8_t sequence; ///< Track number (1..99 typical for CD audio/data). 0 may indicate placeholder/non-standard.
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uint8_t type; ///< Track type (value from \ref TrackType).
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int64_t start; ///< Inclusive starting LBA of the track.
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int64_t end; ///< Inclusive ending LBA of the track.
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int64_t pregap; ///< Pre-gap length in sectors preceding track start (0 if none).
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uint8_t session; ///< Session number (1-based). 1 for single-session discs.
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uint8_t isrc[13]; ///< ISRC raw 13-byte code (no null terminator). All zeros if not present.
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uint8_t flags; ///< Control / attribute bitfield (see file documentation for suggested bit mapping).
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} TrackEntry;
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==== Field Descriptions
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[cols="2,2,2,6",options="header"]
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|===
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|Type|Size|Name|Description
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|uint8|1 byte|sequence|Track number.
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|uint8|1 byte|type|Track type (see table below).
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|int64|8 bytes|start|Track starting LBA (including pregap).
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|int64|8 bytes|end|Track ending LBA.
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|int64|8 bytes|pregap|Size of track’s pregap in sectors.
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|uint8|1 byte|session|Session the track belongs to.
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|StringA|13 bytes|isrc|Track’s ISRC in ASCIIZ.
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|uint8|1 byte|flags|Track flags as indicated in TOC if applicable.
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|===
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==== Track Types
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[cols="2,1,8",options="header"]
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|===
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|Type|Value|Description
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|Audio|0|All sectors in the track contain audio as defined by the Red Book.
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|Data|1|All sectors in the track contain user data that is not defined by any of the following types.
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|CdMode1|2|All sectors in the track contain user data according to MODE 1 as defined by the Yellow Book.
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|CdMode2Formless|3|All sectors in the track contain user data according to MODE 2 as defined by the Yellow and Green Books. Not all sectors belong to the same Form.
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|CdMode2Form1|4|All sectors in the track contain user data according to MODE 2 Form 1 as defined by the Yellow and Green Books. All sectors belong to the same Form.
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|CdMode2Form2|5|All sectors in the track contain user data according to MODE 2 Form 2 as defined by the Yellow and Green Books. All sectors belong to the same Form.
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|===
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