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  1. Member yoda313's Avatar
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    Ok I know that you have to use 48khz when authoring a dvd. What I want to know is why it was developed in the first place.

    I understand 44.1khz was originally the cd standard. That is what vcd and svcd use since they are on that platform.

    Is 48khz needed for digital surround sound to work? Is that what was necessary? I guess what I'm getting at is was 48khz developed just so you needed a new platform to work on? Is there any true nuts and bolts reason for it or was it simply plopped out of thin air to make it different from previous formats?

    I'm just curious because I guess I never knew why the audio rate increase was neccessary, only that it was required.
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  2. Member edDV's Avatar
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    44KHz was used for uncompressed CD-Audio and MPeg1 audio but was found wanting in pro ranks.

    48k/96k came from the pro audio community, 48k was the base sample frequency for DAT recording and then was adopted for MPeg2/DV/DVD/Digital Broadcasting.

    DVD-Audio disc standard is 24bit/96KHz.

    The HD/BD DVD standards favor 96KHz sampling for audio although 48KHz can be used.

    ref.
    http://en.wikipedia.org/wiki/Sampling_rate
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  3. Member yoda313's Avatar
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    So it was easier for the movie studios to use the 48khz since that was the accepted standard for the professionals?

    I guess that makes sense - thanks eddv I wasn't too suprised to see you were the first to post a reply to this
    Donatello - The Shredder? Michelangelo - Maybe all that hardware is for making coleslaw?
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  4. Member edDV's Avatar
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    44KHz was a compromise to fit a 74 minute symphony or opera on an uncompressed 650MB CD.

    When CD was developed, studios were mostly using analog paths with some digital processing. Pro digital audio standardized later on 48KHz sampling.

    44KHz has a Nyquist cutoff of 22KHz but requires a more expensive analog low pass filter before A/D. This isn't much of a problem for CD Mastering labs but the little digital guy wanted more sampling headroom so that less sharp, less expensive low pass filters could be used.
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