Discussion in 'Archived Threads 2001-2004' started by DavidBelis, Mar 16, 2003.

  1. DavidBelis

    DavidBelis Agent

    Jan 15, 2003
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    I know this might be an very ignorant question, but do mp4s exist?

    Because I've heard this name mentioned before. I know that there are MP2 and MP3s (obviously), but I had never heard of MP4s.

    If so, then how's their sound quality? How do they differe from MP3s? Also, are there any MP4 players in existence (software or hardware).

    I'd appreciate some information regarding MP4 files (assuming they're not just some sort of hoax)

  2. John-Miles

    John-Miles Screenwriter

    Nov 29, 2001
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    you might be thinking of MPEG4 which is a video compression format
  3. GaryEW

    GaryEW Auditioning

    Jan 7, 2003
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    Also,IIRC MP3 is actually short for MPEG 2 Audio Layer 3.
  4. Ken Chan

    Ken Chan Producer

    Apr 11, 1999
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    MPEG-1 uses the same three Layers, so it's probably safer to call it just "MPEG Layer-3 audio". The MPEG-2 flavors add really low bitrate and multi-channel support, but that's not what most people are using. So:

    MPEG-1: video and audio, VCDs. VCDs use Layer-2 audio, not Layer-3.
    MPEG-2: video and audio, DVDs, SVCDs, and HDTV. Note that DVDs are HDTV do not use MPEG audio! DVDs use PCM, Dolby Digital, and DTS, HDTV uses DD. (And SVCD uses Layer-2.)
    MPEG-3: originally MPEG for HD, but turned out to be unnecessary, folded into MPEG-2; no such thing
    MPEG-4: video and audio, even better compression, but requires more horsepower to encode/decode. DivX (the codec, not the Circuit City thing; the guys that come up with these names should be slapped around) is a variant.

    Next is... MPEG-7 (dunno what happened to 5 and 6).

    MP1: no such thing
    MP2: no such thing
    MP3: MPEG Layer-3 audio
    AAC: Advanced Audio Coding, different and better than MP3; used by satellite radio, and can be used with MPEG-2 and MPEG-4.
    MP4: There is an MPEG-4 Audio standard, a progression from AAC, but I dunno if people have started calling it "MP4" -- or whether they should. Don't you think it's confusing enough? [​IMG]


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