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lib_um_crypto_rust/um_crypto/ncm/Readme.MD

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NCM Decoder

Glossary

  • LV: Length-Value Encoding, length is u32 in Little-Endian.

File Format

  • Magic: CTENFDAM
  • NCM Version: 01 (u8)
  • App version: ?? (u8)
  • ContentKey (LV)
  • Metadata (LV)
  • CRC32 (of all previous data)
  • Cover Block
  • Encrypted Audio

Cover Block

  • Length: u32: frame_len = len(image1 + image2)
  • Length: u32: img1_len = len(image1)
  • Data: u8[img1_len]: image1
  • Data: u8[frame_len - img1_len]: image2 - unknown format