Driver 3 XA

XA

Format type: Audio
Endianness: Little-endian

Format Specifications

char {4} - identifier ("e4x" 92)

uint32 {4}   - Unknown
uint32 {4}   - sampling rate
uint32 {4}   - format type (possibly only compression flag)
uint32 {4}   - track 0 data offset
uint32 {4}   - track 1 data offset
uint32 {4}   - track 0 data size
uint32 {4}   - track 1 data size
uint32 {4}   - Unknown
// if format tag is 1

uint32 {4} - block size

// for each track

byte {x} - padding until track offset

// if format tag is 0

int16 {x} - raw stereo PCM data

// if format tag is 1

// until track has finished (IMA ADPCM variant blocks)

int16 {2} - initial sample (left channel)

byte {1} - initial index (left channel)

byte {1} - unused (0x00)

int16 {2} - initial sample (right channel)

byte {1} - initial index (right channel)

byte {1} - unused (0x00)

byte {x} - sample codes (left channel) (first half of block)

byte {x} - sample codes (right channel) (second half of block)

Notes and Comments

The track data can theoretically be stored in different formats: Format type 0 specifies raw uncompressed 16 bit PCM data, while format type 1 tags the data as being compressed by an IMA ADPCM variant. Since only those two types are currently known to exist, the format type field might actually be just a boolean value.
If the offset and/or size value for a particular track are 0, then this track does not exist within the file.
This format also applies to Driver: Parallel Lines with a minor modification: The header identifier is "XA30".