DVCam recording to mini dv tape, Quality issue ?

Discussion in 'Video Cameras' started by Brad Gerrard, Jul 7, 2003.

  1. Brad Gerrard

    Brad Gerrard Guest

    Hi,

    If I use a sony dcr vx9000e camera that uses DVcam tape to record something,
    then edit on pc, and print to mini dv tape, is the quality reduced by going
    to mini tape, rather than dvcam tape?

    In general is there a difference in quality between dvcam tape and mini dv
    tape?

    Thanks,

    Brad
     
    Brad Gerrard, Jul 7, 2003
    #1
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  2. 'In general', none at all. DVCAM has a 50% wider track width and as a
    consequence runs for only 2/3 the time. It should therefore offer
    greater resilience against various gremlins like tape drop out, minor
    head alignment issues etc.

    There is also a minor variation in the way audio is recorded which most
    people aren't concerned about.

    If you mean the tape stock rather than the recording format, then Sony
    claim that their DVCAM tape is a step up in quality from their Premium
    and Excellence ranges - so it should be given the price differential.
    Much nicer boxes though.
     
    Malcolm Knight, Jul 7, 2003
    #2
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  3. Brad Gerrard

    Hughy Guest

    Interesting. Time for me to get with it!

    I understood that the VX9000 used "Full size" DV tape ie. the big cassettes.
    I also thought that DVCAM was just miniDV tape running at an increased tape
    speed with locked audio.

    So you can have a full size DV tape running in "DVCAM" mode OR standard DV
    mode??

    Can someone confirm/enlighten me (I've never owned a camera with a full size
    DV mechanism).

    Regards,
    Hughy.
     
    Hughy, Jul 7, 2003
    #3
  4. Brad Gerrard

    RGBaker Guest

    Full size and mini cassettes for both DV & DVCam are identical, barring
    claims from manufacturers that 'better' stock is put in shells labelled
    DVCam. You can use either DVCam cassettes in a DV device or vice versa.

    DVCam is a modest refinement of DV; both use the same DV25 codec, both use
    the same 4:1:1 chroma sampling (NTSC), both the same 5:1 compression (so too
    does DVCPro share all these commonalities). DVCam moves the tape through
    the device at a higher speed, so a tape doesn't last as long, and the 25Mb/s
    signal is 'spread' over a greater tape area. DVCam devices may also use a
    wider head ... but they don't have to, as confirmed by the PD150 for
    instance, which can record either DV or DVCam and uses DV standard heads.
    There is a minor change in how audio is handled in DVCam devices to make
    linear deck to deck editing easier -- audio frames are timed to sync with
    video frames so that boundaries are always physically aligned; a cut on a
    video frame will not truncate an audio frame and cause a blip. This audio
    handling is not important to NLE usage, and neither is it very significant
    to deck to deck editing as most capable decks perform an audio cross
    dissolve automatically at a video cut point to mask any audio errors -- this
    audio/video frame boundary alignment is known as 'locked' audio, and
    contrary to popular wisdom has nothing to do with audio sync ... which is of
    course always perfect in any tape based recording format.

    So yes, you can run either large or mine cassettes in either DV or DVCam
    mode, with a corresponding adjustment in the tape run time.

    GB
     
    RGBaker, Jul 7, 2003
    #4
  5. There are two sizes of cassette. Big and small. Both may be marked
    either DV or DVCAM. The golden rule is; if it will be accepted by the
    tape slot it will work. You will get a DV recording or a DVCAM recording
    dependent on the machine - many recent ones are switchable.

    All DVCAM machines will play back SP DV as well as DV. All Sony DV units
    will play back DVCAM (apart from first generation DV, VX700/VX1000) and
    a few JVC devices will also play back DVCAM.

    IIRC the VX9000 (and maybe the DSR200) were the only units which didn't
    accept small size cassettes. All others that take a big tape will also
    take small. There were also (IIRC) some sort of incompatibility with
    tapes recorded on the VX9000, something to do with audio. Sony used to
    put a 'qualifier' in the manuals of some of the later VCRs to cover it.
    All a bit of a hazy memory now.
     
    Malcolm Knight, Jul 7, 2003
    #5
  6. Ahem... 'as well as DVCAM'.
     
    Malcolm Knight, Jul 7, 2003
    #6
  7. Brad Gerrard

    John Guest

    I'm interested in the difference between locked audio and not locked
    audio. My understanding of an audio "frame" is that it is one sample,
    which in the case of DV usually represents a timespan of 1/48000
    second. If I am correct (which I suspect I am not), the worst case
    scenario that could occur when using a not locked audio system is that
    an audio cut could be made 1/48000 second later or earlier than a
    video cut, which doesn't seem like too much to worry about. Would you
    (or anyone else) be so kind as to elucidate?
     
    John, Jul 7, 2003
    #7
  8. Brad Gerrard

    John Guest

    Thanks for the explanation (here it is again in case anyone missed it!)...
     
    John, Jul 8, 2003
    #8
  9. AFAIR a DVCAM recording can only be played back in a DVCAM device, whereas a
    DV recording can be played back in either (assuming the ability to take the
    size of cassette!)

    At work I use a DSR-200 camera (large cassettes only) and a DSR-30 vcr
    (either size), edit using Premiere on a Mac - and sometimes run off a miniDV
    tape to take home to watch on my GV-D300.

    Bizarrely, before I can get the DSR-30 to accept a FireWire signal from the
    Mac (for recording back to tape) I have to force it into Unlocked Audio mode
    (which involves switching it on whilst holding down record and pause).

    Hamish
     
    Hamish Walker, Jul 12, 2003
    #9
  10. Brad Gerrard

    RGBaker Guest

    All Sony DV devices except the two that predate DVCam (vx1000, vx700) can
    play DVCam. Some non-Sony devices too.

    GB
     
    RGBaker, Jul 12, 2003
    #10
  11. Brad Gerrard

    David Marks Guest

    Panasonic AG-DV2500 in the States will playback all size DVCAM tapes as
    well as record mini DV on a DVCAM tape..
    It will play and record all size Mini DV tapes. Just bought one this week.
    JVC has an identical model.

    Dave Marks
     
    David Marks, Jul 12, 2003
    #11
  12. As addition to what others already wrote, the DVCAM decks do not play
    back LP mini-DV.

    -m-
     
    Martin Heffels, Jul 13, 2003
    #12
  13. That's very true :) Well, the original cam-co should
    at least be able to play LP back again.

    -m-
     
    Martin Heffels, Jul 13, 2003
    #13
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