Objective

Playback of compressed sound format in Q3VM bytecode.

Intended Niches

• Playback of player's own choice of music in background.
• Large sound files (WAV size > 100KB) used in maps.
• Broadcasting of custom sound packs.

Candidates

• OggVorbis
  • Pros:
    • Lossy compression, from 10:1 and onwards.
    • Lossiness not noticeable in the heat of battle.
    • Streamable! (write out decompressed form in lots of small chunks, instead of one large file)
  • Cons:
    • Lots and lots of floating point (slow).
    • Still evolving (entails frequent import of upstream source).
• FLAC (Free Lossless Audio Codec)
  • Pros:
    • Decoding uses integer arithmetic (goes fast).
    • Lossless compression (1.3:1 to 3:1) - perfect reconstruction of sound.
    • Streamable!
  • Cons:
    • LGPL may cause licensing conflict wrt distribution of mod (until all Q3A code goes GPL).
    • Compression not as good as Ogg Vorbis.
• MP3 (MPEG-1 Layer 3)
  • Pros:
    • Very common format.
    • Lossy compression, from 6:1 to 15:1 or thereabouts.
    • Known decoder in QVM form exists.
    • Streamable?
  • Cons:
    • Format is encumbered by patents.
    • Practically impossible to create (encode to) MP3 legally and freely.
    • Therefore, most extant MP3s may be illegal just by existing.
    • Wasn't designed for scalability the way Ogg Vorbis is.
    • Encoders probably suck (i.e. resulting MP3 file sucks).
    • Decoder implementations also probably suck, legal issues notwithstanding.
    • Doesn't compress and preserve quality as well as Ogg Vorbis.
• TwinVQ (Transform-domain Weighted Interleave Vector Quantization), VQF, MPEG-4
  • Pros:
    • Extreme compression, around 40:1?
  • Cons:
    • "It's dead, Jim."
• MPEG-2 AAC (Advanced Audio Coding)
  • Pros:
    • Lossy compression, from 20:1?
  • Cons:
    • Weird licensing (not getting a player easily).
    • Based on the developers involved (companies), expect much encumberance with copyrights, patents, and trade secrets. (unfriendly to Q3 mod)