libaaruformat/docs/spec/blocks/metadata.adoc

=== Metadata Block (`META`)

The metadata block contains descriptive information related to the media source, which is not part of the original media data itself.
Typical fields may include the manufacturer name, device model, acquisition sequence identifiers, and other contextual attributes.

All string values within this block are encoded as little-endian UTF-16 and terminated with a null character.

[source,c]
#define META_MAGIC 0x4154454D
/**Metadata block, contains metadata */
typedef struct MetadataBlockHeader
{
    uint32_t identifier;         ///< Block identifier, must be BlockType::MetadataBlock.
    uint32_t blockSize;          ///< Total size in bytes of the entire metadata block (header + strings).
    int32_t  mediaSequence;      ///< Sequence number within a multi-disc / multi-volume set (0-based or 1-based as
                                 ///< producer defines).
    int32_t  lastMediaSequence;  ///< Total number of media in the set; 0 or 1 if single item.
    uint32_t creatorOffset;      ///< Offset to UTF-16LE creator string (or undefined if creatorLength==0).
    uint32_t creatorLength;      ///< Length in bytes (including null) of creator string (0 if absent).
    uint32_t commentsOffset;     ///< Offset to UTF-16LE comments string.
    uint32_t commentsLength;     ///< Length in bytes (including null) of comments string.
    uint32_t mediaTitleOffset;   ///< Offset to UTF-16LE media title string.
    uint32_t mediaTitleLength;   ///< Length in bytes (including null) of media title string.
    uint32_t mediaManufacturerOffset;      ///< Offset to UTF-16LE media manufacturer string.
    uint32_t mediaManufacturerLength;      ///< Length in bytes (including null) of media manufacturer string.
    uint32_t mediaModelOffset;             ///< Offset to UTF-16LE media model string.
    uint32_t mediaModelLength;             ///< Length in bytes (including null) of media model string.
    uint32_t mediaSerialNumberOffset;      ///< Offset to UTF-16LE media serial number string.
    uint32_t mediaSerialNumberLength;      ///< Length in bytes (including null) of media serial number string.
    uint32_t mediaBarcodeOffset;           ///< Offset to UTF-16LE media barcode string.
    uint32_t mediaBarcodeLength;           ///< Length in bytes (including null) of media barcode string.
    uint32_t mediaPartNumberOffset;        ///< Offset to UTF-16LE media part number string.
    uint32_t mediaPartNumberLength;        ///< Length in bytes (including null) of media part number string.
    uint32_t driveManufacturerOffset;      ///< Offset to UTF-16LE drive manufacturer string.
    uint32_t driveManufacturerLength;      ///< Length in bytes (including null) of drive manufacturer string.
    uint32_t driveModelOffset;             ///< Offset to UTF-16LE drive model string.
    uint32_t driveModelLength;             ///< Length in bytes (including null) of drive model string.
    uint32_t driveSerialNumberOffset;      ///< Offset to UTF-16LE drive serial number string.
    uint32_t driveSerialNumberLength;      ///< Length in bytes (including null) of drive serial number string.
    uint32_t driveFirmwareRevisionOffset;  ///< Offset to UTF-16LE drive firmware revision string.
    uint32_t driveFirmwareRevisionLength;  ///< Length in bytes (including null) of drive firmware revision string.
} MetadataBlockHeader;

==== Field Descriptions

[cols="2,2,2,6",options="header"]
|===
|Type
|Size
|Name
|Description

|uint32_t
|4 bytes
|identifier
|The metadata table identifier, always `META`

|uint32_t
|4 bytes
|blockSize
|The size of this block including all of its data.

|int32_t
|4 bytes
|mediaSequence
|The number of heads.

|int32_t
|4 bytes
|lastMediaSequence
|The number of sectors per track.

|uint32_t
|4 bytes
|creatorOffset
|Offset to start of creator string from start of this block.

|uint32_t
|4 bytes
|creatorLength
|Length in bytes of the creator string.

|uint32_t
|4 bytes
|commentsOffset
|Offset to start of comments string from start of this block.

|uint32_t
|4 bytes
|commentsLength
|Length in bytes of the comments string.

|uint32_t
|4 bytes
|mediaTitleOffset
|Offset to start of media title string from start of this block.

|uint32_t
|4 bytes
|mediaTitleLength
|Length in bytes of the media title string.

|uint32_t
|4 bytes
|mediaManufacturerOffset
|Offset to start of media manufacturer string from start of this block.

|uint32_t
|4 bytes
|mediaManufacturerLength
|Length in bytes of the media manufacturer string.

|uint32_t
|4 bytes
|mediaModelOffset
|Offset to start of media model string from start of this block.

|uint32_t
|4 bytes
|mediaModelLength
|Length in bytes of the media model string.

|uint32_t
|4 bytes
|mediaSerialNumberOffset
|Offset to start of media serial number string from start of this block.

|uint32_t
|4 bytes
|mediaSerialNumberLength
|Length in bytes of the media serial number string.

|uint32_t
|4 bytes
|mediaBarcodeOffset
|Offset to start of media barcode string from start of this block.

|uint32_t
|4 bytes
|mediaBarcodeLength
|Length in bytes of the media barcode string.

|uint32_t
|4 bytes
|mediaPartNumberOffset
|Offset to start of media part number string from start of this block.

|uint32_t
|4 bytes
|mediaPartNumberLength
|Length in bytes of the media part number string.

|uint32_t
|4 bytes
|driveManufacturerOffset
|Offset to start of drive manufacturer string from start of this block.

|uint32_t
|4 bytes
|driveManufacturerLength
|Length in bytes of the drive manufacturer string.

|uint32_t
|4 bytes
|driveModelOffset
|Offset to start of drive model string from start of this block.

|uint32_t
|4 bytes
|driveModelLength
|Length in bytes of the drive model string.

|uint32_t
|4 bytes
|driveSerialNumberOffset
|Offset to start of drive serial number string from start of this block.

|uint32_t
|4 bytes
|driveSerialNumberLength
|Length in bytes of the drive serial number string.

|uint32_t
|4 bytes
|driveFirmwareRevisionOffset
|Offset to start of drive firmware revision string from start of this block.

|uint32_t
|4 bytes
|driveFirmwareRevisionLength
|Length in bytes of the drive firmware revision string.
|===