Latest post Tue, Apr 10 2018 9:27 PM by Krishius. 3 replies.
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  • Mon, Apr 9 2018 8:41 PM

    • Krishius
    • Top 500 Contributor
    • Joined on Wed, Oct 10 2007
    • Riga, Latvia
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    Analog Betacam playback quality: BetaSP VTR vs DigiBeta VTR

    Hi all!

     

    For a long time I was absolutely convinced that Digibeta VTR with analog playback capability is the best possible machine for playing analog Betacam tapes. But today by accident I had a chance to compare two captures of the same BetaSP tapes: the first captures were made with PVW-2800P some 5 or 6 years ago and second ones were made with DVW-M2000P few days ago. Both times tapes were captured to 1:1 10-bit and this codec/resolution is what I used to compare both.

    When PVW-2800P was used, it was connected to Nitris DX YPbPr input. DVW-M2000P is connected to the same Nitris DX box via SDI.

    The DVW-M2000P BetaSP playback seems to be slightly noisier than that of PVW-2800P. If observed on a CRT monitor, there seems to be no noticable difference between the two, also waveform monitor seems to show no problems (there is a small difference in overall signal levels between both VTRs, but nothing serious). But when watched on Avid software UI monitor and compared between the two (I put both clips in one sequence, one in V1 and second in V2, and then just switched the monitor icon between both), it is pretty obvious that DigiBeta has played the tapes with some sort of uneven random noise that mostly gathers in horizontally expanded portions that move in vertical axis. Also, it looks more like a luma noise to me.

    All in all (when not compared side by side with PVW-2800P capture) clips captured with DigiBeta look decent and up until now I didn't even notice anything wrong with how our Digibeta plays SP tapes. Only the side by side comparion made me wondering is everything OK and is really DigiBeta VTR the best choice for archive capture.

    Our M2000P was serviced recently and only regular cleaning and maintenace had to be done. If something else would be wrong with the deck, I'm sure service would tell us.

     

    Anyone else here has compared different analog/digital Betacam decks for analog playback quality? Conclusions?

     

    Thanks!

  • Mon, Apr 9 2018 10:00 PM In reply to

    Re: Analog Betacam playback quality: BetaSP VTR vs DigiBeta VTR

    I have always seen better results from BetaSP tapes using SDI from DigiBeta and HDCAM decks than I have from my 2800's Component output.
    The 2800 offers the advantage of easy tracking adjustment to optimise playback of older tapes.

    From your description. and non technical background, I would suspect that the DVW-M2000P's playback of the older analog BetaSP tapes could benefit from a tracking adjustment.  I have not used the DVW-M2000P but suspect it is like the 500 series and the tracking adjustment setup is from the Menu's.  (from the DVW-A500/1's manual   F13 TRACKING 0 off Select whether the tracking control operation with search dial is enabled or not CONTROL VIA 1 on during DT head playback.)

    Are you using reference video with both the Deck and Nitris DX box?

  • Mon, Apr 9 2018 10:22 PM In reply to

    • Krishius
    • Top 500 Contributor
    • Joined on Wed, Oct 10 2007
    • Riga, Latvia
    • Posts 248
    • Points 3,575

    Re: Analog Betacam playback quality: BetaSP VTR vs DigiBeta VTR

    Thanks, I will experiment with tracking.

    Yes, VTR and Nitris are both connected to BMD sync generator and are both set to sync to external reference.

  • Tue, Apr 10 2018 9:27 PM In reply to

    • Krishius
    • Top 500 Contributor
    • Joined on Wed, Oct 10 2007
    • Riga, Latvia
    • Posts 248
    • Points 3,575

    Re: Analog Betacam playback quality: BetaSP VTR vs DigiBeta VTR

    Anyone know something about what Sony calls "simple playback mode"? Maybe noisy playback can be explained with it?

    I'm studying our DigiBeta VTR and there seems to be missing any indications about its model and even S/N. There is nothing written on front panel (where model name usually is) and also there is no model name and S/N sticker on the rear panel.

    I suspect to have DVW-M2000 (without P) which is 525/60 model that has been swithed to 625/50 mode.

    We bought the VTR on eBay from Greece and up until now we had no doubt that machine is PAL.

    Although there is nothing mendioned about it in DVW-M2000 operation manual, MSW-M2000 (MPEG IMX) and HDW-M2000 (HDCAM) manuals state that when native PAL VTR is switched to NTSC and vice versa, analog Betacam of VTR's non-native system is played in simple playback mode, which I assume might mean that there is very basic signal processing used for decoding analog tapes, which might also mean that some extra noise is present on analog playback.

    And since MSW/HDW-M2000 models are from the same era as DVW-M2000 and they share many common things, I believe that this "simple playback mode" might also be true for DVW series, despite lack of information about it in manual.

     

    Any thoughts?

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