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  1. Hello.
    What I know is that the same rotation speed of a disc allows 2.4 for 12cm (1.6 for 8cm diameter) faster data reading at the outer edge.

    Because I am extremely knowledge thirsty and inquisitive, I thought that the community on VideoHelp can help me with my endless knowledge hunger. I keep a list of many questions I will maybe ask and topics (for example: calculating lossless digital zoom and loss value)

    I would like to know the relationships of the following parameters of CD, DVD, HD-DVD and BD (and HVD?).
    • Rotation speed at CAV (unchanging rotation speed) 1 or 1.6 or 2.4 = how many rotations per minute (RPM) or per second?
    • 1 CLV (same reading speed, varying rotation speed) speed = How many sectors per second?
    • Are the values slightly different for DVD+, DVD-, DVD-DL and DVD-RAM?
    • Is 1 on a CD 150 or 176.4 KiB/s? [2352(1500/1764)=2000!].

    This can also be useful for calculating the rotation speed acoustically.
    SCSi is partially crippled. The PC only knows the disc rotation speed by the data rate, not by the disc drive rotation engine.

    I hope that the community can provide useful information, and I would appreciate it.
    Last edited by TechLord; 16th Nov 2017 at 18:45. Reason: This can be useful for acoustic measurement.
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  2. Member Cornucopia's Avatar
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    CD, DVD, HD-DVD, SACD, and BD use CLV.
    LV/LD used both CLV and CAV.

    For 1x CD, that means 500rpm at innermost slowing constantly down to 200rpm at outermost. 8x would 4000 to 1600.
    For 1x DVD, I believe it's 1600rpm to 570. 8x would then be 4560 at the outermost. Note it doesn't, nor does any other optical disc format, achieve its full multiple of the rotational speed at the innermost tracks because it is already travelling at its max safe speed, which is about 10000rpm. That's why with burn data plots you see it ramp up to full level later on in the disc. If it travelled faster, it could wobble out of its tolerance and shatter (and there have been known cases of 48x or 52x explosions). Btw, the dvd disc format variations all work the same way rotationally.

    Don't know the other formats, but they are probably not much higher. BD gets its data throughput gains more due to data density than physical velocity. Aka more bits packed into each read pass as well as a fatter pipe.

    In fact, you shouldn't even care about read velocity at all because it is deterministic with feedback: it will speed up or slow down as much as needed to give the proper expected buffered data rate(s).

    Scott
    Last edited by Cornucopia; 16th Nov 2017 at 19:53.
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  3. Originally Posted by Cornucopia View Post
    CD, DVD, HD-DVD, SACD, and BD use CLV.
    LV/LD used both CLV and CAV.

    For 1x CD, that means 500rpm at innermost slowing constantly down to 200rpm at outermost. 8x would 4000 to 1600.
    For 1x DVD, I believe it's 1600rpm to 570. 8x would then be 4560 at the outermost. Note it doesn't, nor does any other optical disc format, achieve its full multiple of the rotational speed at the innermost tracks because it is already travelling at its max safe speed, which is about 10000rpm. That's why with burn data plots you see it ramp up to full level later on in the disc. If it travelled faster, it could wobble out of its tolerance and shatter (and there have been known cases of 48x or 52x explosions). Btw, the dvd disc format variations all work the same way rotationally.

    Don't know the other formats, but they are probably not much higher. BD gets its data throughput gains more due to data density than physical velocity. Aka more bits packed into each read pass as well as a fatter pipe.

    In fact, you shouldn't even care about read velocity at all because it is deterministic with feedback: it will speed up or slow down as much as needed to give the proper expected buffered data rate(s).

    Scott
    Excellent. Thank you for clarifying.
    I would just like to know, how the rotation speed for each format was specified.

    I know, that 1 on a CD is the CDDA bitrate. 75 sectors per second.
    How many sectors per second is 1 on DVD, HD-DVD and BD?.
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