Snd0.at9

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Adaptive Transform Acoustic Coding (ATRAC) is a family of proprietary audio compression algorithms developed by Sony.

Audio middleware such as FMOD and Audiokinetic Wwise support it.

Background Music[edit]

  • Sampling Frequency: 48kHz
  • Number of channels: 1 or 2 (even when ATRAC9 itself supports mono, stereo, 4.0, 5.1 and 7.1)
  • Limitations: maximum 2MB filesize (similar to PS Vita).

Format ATRAC9[edit]

Offset Size Example Value (conversion) Notes
RIFF chunk descriptor
0x00 0x04 52 49 46 46 "RIFF" Magic
0x04 0x04 20 B3 18 00 00 18 B3 20 File Size
0x08 0x04 57 41 56 45 "WAVE" ID
fmt sub-chunk
0x0C 0x04 66 6D 74 20 "fmt " chunk specifying the data format
0x10 0x04 34 00 00 00 52 bytes fmt chunk size
0x14 0x02 FE FF FF FE format tag
0x16 0x02 02 00 2 Number of channels
0x18 0x04 80 BB 00 00 48000 (0xBB80) 48 kHz Sample Frequency
Supported (kHz)
12 24 48 kHz
0x1A 0x04 00 00 50 46 18000 Byte rate: 144 kbps (18000/125 bytes per second)
  • Block Align (384) * Sampling Frequency (48000) / Samples per block (1024) = 18000
Supported (kilobits per second)
PS4 48 60 72 84 96 120 144 168 192 240 288 300 336 360 420 504
PSVITA 48 60 72 84 96 120 144 168 192
0x20 0x02 80 01 384 Audio block align
0x22 0x02 00 00 0 Quantifying bit number
0x24 0x02 22 00 34 Extension number
0x26 0x02 00 04 1024 Samples per block
0x28 0x04 03 00 00 00 0x03 (00000011) Channel Mask (position of the speakers)
0x2C 0x10 - - Codec identifier: GUID
0x3C 0x04 01 00 00 00 - Version


References
References: