What's the best way to move forward from DV tape?

Discussion in 'Professional Video Production' started by Peter, Jul 9, 2011.

  1. Peter

    Peter Guest

    I have about 50 DV tapes, dating back to 1991.

    The earliest of those are actually ex Hi-8 tapes which I copied to DV
    tapes, by linking a now-gone Hi-8 camcorder to a Sony PC-100.

    Now I use a Sony HDR-HC1E which is great but is big and heavy.

    Nowadays, DV tape is dead.

    I am happy to keep the DV tapes in a safe because I know that high
    coercivity magnetic media lasts for many years. Tape is still used for
    serious data archiving in businesses. I use DDS4 at work and DLT at
    home.

    But no new camcorders record to DV, and anyway DV is a hassle for many
    purposes where you want unattended recording because the tape fills up
    after 1 hour, and the only way round that is to use the camera in a
    "webcam" mode (or shop demo mode if you like) whereby one feeds its
    composite audio output to e.g. a laptop where the data is recorded to
    some piece of software which writes it to a hard disk. And for this to
    work, mains power needs to be provided; if one uses the battery then
    the camera shuts down after some minutes.

    The best replacement for the HC1E appears to be one of these
    http://www.parkcameras.com/18746/Sony-HDR-CX700-HD-Flash-Camcorder.html

    but obviously it requires the data to be transferred out periodically,
    and stored somewhere safe.

    Then I need to transfer all those DV tapes to some new format, because
    the HC1E will be sold on Ebay.

    1) What is the simplest way to transfer the DV tapes to a PC,
    losslessly, to some standard format? For PAL DV tapes it will be the
    MJPEG DV format, and for the HD DV tapes it will be MPEG.

    2) What is the best way to store the data afterwards? I do not believe
    DVDs are the long term answer (20-30 years). Some may be OK but they
    are unproven.

    I store videos as they were taken, with no editing. To produce short
    movies I have usee Pinnacle (buggy crap), P/Elements (buggy crap), and
    now have Vegas 11 which seems to work. But it is the long term storage
    I am interested in.

    Maybe the best way will be to transfer (losslessly) the stuff to a PC
    and back it up to my DLT tape and take that offsite.

    Any suggestions appreciated :)

    (I need to check that CX700 has MANUAL audio level control for the
    external mike input, which I need for some applications like filming
    in a light aircraft. The HC1E has this, and it is very rare in
    consumer cams)
     
    Peter, Jul 9, 2011
    #1
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  2. My solution to this is to keep two low-use Sony Mini-DV
    camcorders (I have about 300 tapes). Alternatives are
    to buy a couple of low-use cheap camcorders to use as
    decks (I prefer Sony for their generally excellent head
    alignment) or to transfer the material to the computer
    by FireWire and copy the results to multiple hard-drives.
    I also would not store the material on DVDs, nor would I
    transcode the files to anything else until after editing.
    --DR
     
    David Ruether, Jul 9, 2011
    #2
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  3. Peter

    Frank Guest

    I know people with hundreds, if not thousands, although they're DVCAM
    format and not regular DV.
    Big and heavy? You've never used a professional grade
    over-the-shoulder camcorder, I presume?
    Well, standard definition is dead, or almost dead, at least in some
    parts of the world. Tape is still the standard programme interchange
    format, however, especially Sony's HDCAM and HDCAM SR formats.
    That's an excellent idea, and was recently discussed in one of these
    groups.
    Absolutely, as it's the lowest cost and most reliable means of long
    term data archival storage.
    Years ago, I used DDS at home, but have never used DLT (or LTO).
    A much better method is to use the camcorder's IEEE 1394a (FireWire /
    i.LINK) output, thus avoiding needless digital-to-analog and
    analog-to-digital conversions.
    Or the Canon HF G10.
    Are you answering your own question here?

    DV footage will have been lossy compressed with the DV codec. If you
    want to store this footage and maintain maximum possible quality, keep
    it in DV format. DO NOT transcode to Motion-JPEG or any other lossy
    codec!

    You've posted your message using Forte Agent, so I'll assume that
    you're a Windows user, in which case you want to losslessly transfer
    the footage to your computer over FireWire and store it as DV-AVI
    files (about 13 GB per hour of footage).
    Right, forget DVD - they lack long-term reliability. Use a couple of
    large external hard disk drives, but also keep the original tapes.
    Camcorders and VCRs capable of reading DV tapes will still be
    available (on the used market) 20 years from now in case you ever want
    to go back to the original tapes for some reason. But note that HDDs
    aren't reliable for the long-term either. Flash memory cards are
    probably a better choice, but more expensive on a cost-per-byte basis.
    You can also do that, backing up the DV-AVI files that I mentioned
    above to DLT.
    Well, I hope that this has helped.
    A quick look at the specs for the U.S. model, known as the HDR-CX700V,
    I see "Mic Level Control : Yes (2steps)".

    OTOH, if you really care about audio quality (and I don't mean to
    offend you by this; I'm just stating my opinion), you wouldn't be
    using the camcorder's unbalanced microphone inputs anyway. You would
    either be using a prosumer-grade camcorder that has balanced three-pin
    XLR microphone inputs or, at the very least, a consumer-grade
    camcorder with unbalanced plugin-power microphone inputs but in
    conjunction with an interface such as the juicedLink CX231 that would
    allow you to use good quality balanced microphones.
     
    Frank, Jul 9, 2011
    #3
  4. Peter

    Peter Guest

    I was not aware the HC1E output anything out of its 1394 connector,
    until you pressed the Start Recording button, which in turn means
    having a tape in there, which means the thing will stop 1hr later.
    Indeed; I am looking at that one instead. It looks a lot better. I
    don't need 50P and I don't need 12 MP stills especially as their
    quality is not going to be better than a $100 12MP mini camera.
    I thought that HD cams like the HC1E store MPEG on the tape, not DV
    like all the SD ones did.

    Incidentally, I always wondered how the HC1E manages to get exactly
    1hr's recording onto a "1hr" tape, when Mpeg compressibility is so
    dependent on the subject matter.
    What program should I use?

    Also, surely, the HC1E tapes compain Mpeg so one would not end up with
    DV, would one?

    What would be the two file formats? IIRC, DV output from Elements is
    saved as an AVI file (which I realise is a wrapper for whatever
    format) and the HD output ought to be stored as MPG, no? I would need
    something futureproof, and of course playable directly with e.g. VLC.
    That would be my preferred method, as a DLT tape can hold ~ 160GB
    which would be around 10-15 DV tapes.
    Only 2 steps? The HC1E was fully variable. But anyway I am looking at
    the Canon G10.
    No offence, and a good point. Actually I don't care much for audio
    quality. The recordings are mostly amateur stuff like somebody cutting
    up a birthday cake :)

    The more serious use is out of a light aircraft, where I have a
    miniature mike, tucked up into the headset, going to a Sound
    Professionals mike preamp, whose 3.5mm output lead goes into the
    camcorder. A better method is to connect directly into the aircraft
    intercom but that has other issues which I won't go into (e.g. with 4
    people flying there are no spare headset connectors, so one would have
    to make up a splitter...

    I have been playing with different setups for these flying movies over
    the years and still don't have a great solution. My last one is here
    http://peter2000.gotdns.com/locarno-dep-26/locarno-dep-26.mp4

    You can see the audio quality there varies a great deal, and the best
    of it is not bad considering it is coming from a noise cancelling mike
    in a noisy cockpit.

    Another thing I played with was recording 1 still image per second and
    making a movie out of it. This gives a 25x speedup which is actually
    pretty good for flying movies which would otherwise be unwatchable.
    There were software issues combining these however, and of course
    there is no sound track unless one produces one afterwards. I cannot
    tell whether the G10 can do 1fps; I used a webcam for such movies and
    stored the stills with a little free prop which kept crashing...
     
    Peter, Jul 10, 2011
    #4
  5. Peter

    Frank Guest

    Most camcorders, if you insert a recordable tape (check the write
    protect slider/tab thingie to ensure that it's not write protected)
    and select Record/Pause mode, will output a signal. Give it a try.
    You were asking about DV, sir, not HDV (even your subject line says
    "DV tape"). I addressed the situation where you have DV footage that
    you want to preserve.

    If it were high definition 1080i50 HDV footage, instead of standard
    definition 576i50 footage, I would make the same recommendations
    except that the copy on your computer would be an .m2t file containing
    MPEG-2 video and MPEG-1 Layer II audio instead of a DV-AVI file
    containing DV video and LPCM audio.
    While the MPEG-2 video compression standard specifies the use of both
    CBR (Constant Bit Rate) and VBR (Variable Bit Rate) encoding, HDV, in
    both its 720 (JVC) and 1080 (Sony and Canon) forms, is always
    CBR-encoded.

    And the two-channel stereo MPEG-1 Layer II audio normally used in the
    HDV format is encoded at a constant bitrate of 384 kbps (192 kbps per
    channel). And if it's four-channel, as supported by a few HDV
    camcorders and VCRs, then the per-channel datarate is halved to 96
    kbps, thus keeping the total audio datarate at the same 384 kbps.
    Good question, and one that I can't really answer in any specific way.
    The best answer that I can give to you is to use whatever works most
    reliably on your given system.
    VLC is an excellent choice - and as mentioned above, for DV it would
    be a DV-AVI file (.avi) and for HDV it would be an .m2t file.
    I know. It pained me to write "2steps" (even with the missing blank
    space, which happened because I did a copy-and-paste from the Sony Web
    site and I wanted to quote it accurately, errors and all).
    I'm not sure about the 1 frame per second capability, but I'll view
    your video as soon as I get back - must run out on an errand right
    now or else it will be too late and tomorrow's schedule is already
    filled.

    Regards, and good luck!
     
    Frank, Jul 10, 2011
    #5
  6. Peter

    Peter Guest

    I recall this works, but the camera shuts down after some tens of
    seconds - unless mains power is connected up.
    OK; The HC1E records HD MPEG to DV tapes, hence my mixed up
    terminology.
    That's correct; Pinnacle and Elements both produce an M2T file. Only
    VLC manages to play it.
    I know this is a tangent but surely the data rate of the mpeg
    compressed video varies according to the subject, so I can't see how
    even CBR fits exactly on the tape. But I won't worry about it.
    Obviously, I can use any of the video editing programs, but that seems
    an overkill. I wondered if there are simple programs which will just
    get the video off the tape (interfacing to a camcorder) and write out
    the AVI or M2T file. But it's no big deal.
    VLC can also transcode i.e. convert formats, but I have rarely managed
    to get this to work usefully because there are so many combinations of
    formats and bit rates that without knowing the right ones one ends up
    with an unplayable video. They need a few "presets" in there.
     
    Peter, Jul 10, 2011
    #6
  7. Peter

    Frank Guest

    Correct; basically, you'll need an AC power source - or maybe a motor
    generator or a very big battery with an inverter that can drive an AC
    adapter.

    I've run Webcams for days at a time, but the camcorder used (DV in
    this case, not HDV) was always being powered via its AC adapter. This
    wasn't a problem for me as it was an "indoor" application, not out in
    the field where the nearest AC power (mains) outlet might be two miles
    away.

    Have you considered wind and/or solar power?
    Okay, no problem.
    Pretty much all contemporary NLEs support HDV. Are you sure that you
    aren't running into limitations of the speed of your computer
    hardware?

    In fact, if you have the appropriate DirectShow filters installed on
    your system, any DirectShow-based playback application, such as good
    old Windows Media Player, should play your HDV .m2t files just fine.

    Of course, Pinnacle software is often noted for having problems doing
    even simple things. :)
    I wouldn't call it a tangent, or even slightly OT (off-topic), as it
    directly relates to the subject at hand (which has now been changed
    from DV to HDV).

    Firstly, in HDV, both the video compression and the audio compression
    are CBR, just like DV/DVCAM/DVCPRO in that respect.

    Because of that, if one knows the linear recording density (and I
    stress linear, since we're talking about helical recording here), the
    tape speed (about 18.812 millimeters per second as I recall), and the
    physical length of a given cassette tape, then it's just a matter of
    simple arithmetic to compute the recording time per tape.

    Secondly, it's exactly because it's CBR that scenes of very high
    motion will sometimes break apart in HDV. What's happening is that the
    codec is constrained by the constant bit rate limitation of the format
    and can't devote more bits to complex scenes with high degrees of
    motion. This where VBR encoding can be useful, but both DV and HDV are
    CBR formats and don't use VBR encoding for either the audio stream or
    the video stream.

    A big difference between the video encoding in the DV25 formats (DV,
    DVCAM, and DVCPRO) is that DV25 is intraframe encoded whereas HDV is
    interframe encoded.

    In 1080i59.94 HDV there are 15 frames per GOP, or Group Of Pictures.
    In 1080i50 HDV, it's 12 frames per GOP.

    This is why a tape dropout in HDV will often result in a half-second
    disruption in the playback whereas a dropout in one of the DV25
    formats may affect only one or two frames.

    The bottom line, however, is that both DV and HDV are completely and
    totally CBR formats, thus recording time is a constant for a given
    tape speed and length of tape stock.

    If you have an application that requires greater recording time, then
    it's necessary to switch from the Mini-sized tapes and start using the
    Standard-sized tapes, which will give you about 276 minutes instead of
    about 60 minutes.

    I should probably also mention that virtually all tape-based video
    formats use CBR recording techniques for the simple reason that the
    tape itself moves at a constant, not variable, rate.

    This is where media such as flash memory cards, hard disk drives, and
    solid state drives come in handy. As long as they're fast enough to
    handle the maximum datarate, they don't care if the data is CBR or VBR
    encoded.
    For HDV ingest via an IEEE 1394a link to a computer, either use
    whatever your favorite NLE offers or else try Paviko's free HDVSplit
    program.

    HDVSplit utility for HDV capturing with scene split - HDV capture
    utility
    http://strony.aster.pl/paviko/hdvsplit.htm

    For DV ingest via an IEEE 1394a link to a computer, you've got many
    choices. If you need a list, just let me know (via e-mail). Many of
    them are freeware.

    Keep in mind that for DV, you need to make a choice as to whether you
    want to create DV Type 1 .avi files or DV Type 2 .avi files.

    I assume that you know the difference between the two, as well as the
    pros and cons of each type.

    HDV, whether 720 or 1080, has no such consideration, by the way.
    Yes, and I think that the transcoding capability was sort of an
    after-thought type of add-on. At least in my experience, it sometimes
    produces the expected results and sometimes it doesn't, but there are
    so many ways to transcode a file that it really doesn't bother me too
    much. I still feel that VLC media player is a great program and
    frequently recommend it to people.
     
    Frank, Jul 11, 2011
    #7
  8. Peter

    Justin Guest

    Hi Pete, I skimmed over everyone's response and I think they covered
    everything to level far beyond me. But I thought I would add my small
    bit of paranoia to the pile of knowledge.
    I had a similar problem but some of my tapes were Video8 going back to
    1986. I bought a TRV480 Digital 8, and converted everything via
    Firewire to my Sony HC96. Now they are all on MiniDV. Then I
    transferred all the footage from the MiniDVs to my PC (Windows at the
    time) in uncompressed DV video. Then I copied them to *two* external
    2.5" Western Digital hard drives. I keep one at home, and one in my
    safety deposit box.
    Some my background is Information Tech, both drives were formatted to
    NTFS to avoid the 4GB filesize limit of FAT32. Then I switched to Mac,
    and accessing NTFS using a free utility called NTFS-3g was super slow,
    but I still wanted to avoid the filesize limit. Now OS X supports exFAT
    - basically FAT64, and there is no real filesize limit that I will
    encounter. Both drives were reformatted and I can access them on
    Windows, Mac and my Linux machine. (whew)
    I use the same strategy for AVCHD footage. I make a DMG file which is
    basically an ISO file. If I have 2.5GB of space used on my SD card I
    make a 2.6GB DMG file, copy the entire folder/directory structure to
    that DMG file. This way iMovie sees the DMG file as a drive and I can
    import the footage while preserving the date/timecodes.
    The problem is that DMG is Mac only - ISO is a standard. Maybe I'll
    convert to ISO, but if I ever need to open a DMG on a PC or linux, there
    are utilities to do exactly that.

    Sorry for the long winded post...
     
    Justin, Aug 2, 2011
    #8
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