Which DVD recorder is best for recording 3hour shows?

Discussion in 'Amateur Video Production' started by Worrier, May 11, 2005.

  1. Worrier

    Worrier Guest

    Most the DVD recorder record blocky video after 2hours on single disk.
    Is there a particular brand which offer accepatble recording for 3 hour
    shows?
     
    Worrier, May 11, 2005
    #1
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  2. I can't imagine so. It's kind of hard to fit 3 hrs. of video onto a DVD.

    You can do it but it has to be heavily processed, not just converted to
    MPEG2 and burned. A box would have to hold the entire 3+hour show and then
    burn it afterwards.

    Tom P.
     
    Henry Padilla, May 11, 2005
    #2
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  3. Worrier

    DanR Guest

    How is it that a DVR manages to squeeze almost one hour of video / audio per
    gigabyte of hard drive space. I have a DirecTivo and it records the digital
    stream directly and the playback looks exactly like live DirecTv. So the picture
    is acceptable but there must be some heavy duty compression going on before the
    signal hits my dish.
    Is it wrong to think that 3 hours of similar video will fit on a single layer
    DVD?
     
    DanR, May 11, 2005
    #3
  4. The very popular Liteon DVD recorder (available in many big-box
    stores like Costco, etc.) has a downloadable firmware update which
    disables Macrovision and enables "long-play" mode(s). I have not
    tried the LP modes myself.
     
    Richard Crowley, May 11, 2005
    #4
  5. I'm not sure what format TiVo saves it's data files in but I don't think
    it's MPEG2.

    Sure there are other formats that have better compression and so forth but
    they are not the DVD standard and will not play on DVD set-tops.

    Of course, if you are just trying to get the video files onto DVD media then
    you should be able to fit 5-8 hours depending on the compression and quality
    you are looking for.

    But, unless I miss my guess, yeah - [email protected] is all that really fits on a
    single-layer DVD in standard MPEG2 format (most compatible).

    Tom P.
     
    Henry Padilla, May 11, 2005
    #5
  6. That is the reason. The digital feed is recorded directly, no
    conversion done by the DVR. The source starts out more compressed
    than standard (8Mb/s) mpeg2 on a DVD. The recorder doesn't need to do
    anything in order to process it, but it must have access to the
    original signal *and* have a playback system for that. The digital TV
    signals may not be DVD compatible mpeg2. Quite likely not, because
    while mpeg2 is pretty good for higher data rate, higher quality
    output, it isn't optimal for lower data rate streaming.

    If you have to capture an analog source and compress it in real
    time, there are serious compromises in quality to get the speed.
    If you can access the highly processed digital source *and* have a
    player which can handle the format, sure. A PC with the right
    software could play it, but most set top DVD players won't.

    Same would apply if you captured it in analog (at a high data rate)
    and used a non-mpeg2 compressor, to get more recording time.

    Matching the digital TV results, though, won't be easy. You don't
    have access to the original uncompressed, high quality video. Without
    that, it isn't easy to get such good results from higher compression
    of lower quality signals, especially less than ideal off-air analog
    video (or worse, VHS tapes).
     
    Jeffery S. Jones, May 11, 2005
    #6
  7. Worrier

    Mike S. Guest

    The 3-hour mode is modeled on the 4-hour mode; half resolution, low bit
    rate (but 50% higher bit rate than the 4-hour speed). So you will lose
    resolution but potentially have fewer MPEG artifacts.
     
    Mike S., May 11, 2005
    #7
  8. Worrier

    Ken Maltby Guest


    How did "Matching the digital TV results" become the objective?

    At this time, DirecTV video is a modification of MPEG2. There are
    those who extract and transcode the DirecTiVo recorded "TY" files,
    to produce their own DVDs. The plan for HD looks to be a form of
    MPEG4 through the new satellites.

    Remember the whole process is an optimization of a closed system.
    The high power encoding that goes into the uplink stream, will be
    processed by proprietary receiving equipment; of strictly known
    parameters. The end result is a system made to output a high quality
    * analog * signal to drive the user's TV/video equipment.

    The analog (S-Video) output of this process is very clean and is a
    great source for A/D conversion and compression.

    The objective is to digitally store that analog signal so that when the
    digitally stored data is eventually converted back to an Analog output,
    for TV display, - or- serves as source data for a digital display : it
    matches ( as far as is noticeable to a normally critical watcher ) the
    quality of display that would have resulted from playing the original
    analog output of the satellite receiver.

    To address the # of Hours per DVD issue, using a DirecTiVo
    S-Video source and a storage size of Half D1, I have met that
    objective with bitrates low enough to provide for a little over Four
    hours of audio and video. Which equates to ~ six hours of TV,
    with commercials & credits removed.

    What "fits" on a DVD is solely a matter of bitrate. What it takes
    to meet the objective I mentioned, at the lower bitrates, is a more
    complex subject. There are also, more than one set of approaches
    that can achieve such results. (Some take longer than others.)

    There are some who disagree with my position, and believe there
    must be something wrong with my perception of quality video. But
    what I have described is based on my personal experience over the
    course of hundreds of captures.

    Luck;
    Ken
     
    Ken Maltby, May 11, 2005
    #8
  9. Worrier

    Ken Maltby Guest

    Well there -is- someone here who has some practical understanding.

    Luck;
    Ken
     
    Ken Maltby, May 11, 2005
    #9
  10. Worrier

    marks542004 Guest

    If you need unattended capture I would go with one of the new 'Tivo'
    type boxes.

    I saw one recently that was supposed to capture to a hard disk
    internally and then let you select recordings to write to DVD.
    (at least according to the sales guy)
     
    marks542004, May 11, 2005
    #10
  11. Worrier

    David Chien Guest

    Pioneer. In particular, the latest lineup in Japan with the updated Diga
    (?) chips which provide even better quality at lower bitrates than their
    older models, which are among the best already. ( eg. see
    www.videohelp.com for their forum talk on the Pioneer DVR-220-S vs. iLo
    at Walmart video recording quality comparison thread - lots of pics
    there) They're nice because you've got fine control over the multi-step
    compression setting so you can hopefully get a better recording than
    other decks.

    The latest AV magazines in Japan this month had a review of the various
    recorders just out in Japan and the Pioneer won.

    Of course, when the latest models with latest CPUs will hit the USA?....

    But anyways, by year-end, hopefully, HD DVD recorder decks will be out
    and that'll be the end of this Q.

    Or, even w/o HD DVD recorders, Pioneer also released their DL recorders
    in japan, so you can now record 4 hours in SP mode (Vs. 2 hours on a SL
    disc) onto a DL disc.
     
    David Chien, May 12, 2005
    #11
  12. Worrier

    David Chien Guest

    Pioneer. In particular, the latest lineup in Japan with the updated Diga

    Correction. Double-checked the magazine, and it's the Panasonic Diga
    series in Japan.
    http://www.diga.jp/

    eg. the Latest Pansonic DMR-EH50
    They say, in their charts, that you can get SP-like resolution (500
    lines or so) in LP mode (which in prior models, only got around 250 lines).

    http://panasonic.jp/dvd/products/eh60_eh50/spec/06.html
    http://panasonic.jp/dvd/products/eh60_eh50/spec/subwin_01.html
    http://panasonic.jp/dvd/products/eh60_eh50/img/spec_06_h01.gif
     
    David Chien, May 12, 2005
    #12
  13. I've seen TiVo boxes (made by a company that starts with "H". Sorry, I
    can't remember.) that has a DVD burner built right into the TiVo box!

    $400 Last I saw.
    Tom P.
     
    Henry Padilla, May 13, 2005
    #13
  14. Worrier

    Bob Moore Guest

    Not with my "ilo"DVDR4. Records 3 or 4 hours in real time.

    Bob
     
    Bob Moore, May 13, 2005
    #14
  15. Worrier

    Harry Kiri Guest

    For DV, you can record approx 4.5 *minutes* of video/audio per
    gigabyte - not one hour!

    Regards,
    Hughy
     
    Harry Kiri, May 14, 2005
    #15
  16. An interesting statement of fact, but how does it address the
    question?

    Not sure what "DanR" means by an hour per gigabyte since
    single-layer DVRs are 4.7 GB and typically hold ~2 hours in
    "standard play".

    Of course, the generic answer is: compression.
     
    Richard Crowley, May 14, 2005
    #16
  17. Worrier

    David McCall Guest

    The generic answer is probably correct.

    I think you usually cut the horizontal resolution in half
    to squeeze 4 hours onto a DVD. Otherwise the artifacts
    would likely be pretty awful, unless your video is a locked
    off shot of someone talking in front of a static background.

    I think the number I've seen is 13 gigs an hour for DV. So
    you would only get about 20 minutes of raw DV data onto
    a DVD without further compressing it.

    I'm not much of mathematician, but DV is about 5 to 1
    compression so you would have to up the compression
    to 15 to 1 to put an hour of DV material onto a DVD, and
    that would work out to 30 to 1 to fit 2 hours, and even more
    to put 3 hours on a single layer DVD. Is that about right?

    David
     
    David McCall, May 14, 2005
    #17
  18. Worrier

    DanR Guest

    The point of my question is that DirecTV manages to squeeze an hour of TV
    programming into 1 GB and the image is acceptable to most viewers. What is
    special about their methods that can't be replicated by DVD encoders. And this
    encoding / decoding happens in real time.
     
    DanR, May 14, 2005
    #18
  19. Worrier

    Ken Maltby Guest

    A very good summation of, perhaps, a third of the issue.
    What you have described is right on, to the point and
    certainly correct. If all of the data initially digitized were
    of the same value, to the human eye/mind, then what
    your last paragraph implies would also be correct.

    It's not just a matter of squishing the same data into a
    smaller space somehow, it includes removing unneeded/
    unused or unusable data first. Then there is the matter
    of the removal of data the repeats itself, but keeping a
    reference to how it is repeated. Then the compression
    we are all familiar with (like that used for "zip" files) is
    performed on any unused space/nondata elements.

    MPEG1 was a good first try. MPEG2 was a Giant
    step forward on the video side, and still is a great match
    to a standard TV's requirements/capabilities. And now
    various MPEG4 options provide even more effective
    "compression"/unneeded data removal, than earlier
    methods.

    So it's not correct to view MPEG compression at
    50:1 as 10 times DV's 5:1, in terms of resulting video
    quality, when viewed.

    It certainly has an impact when you wish to make
    modifications to the video data though, in that case,
    the less the data, you are trying to alter, has been
    manipulated, the better. ( But even that is changing,
    as Editors are becoming available that do an excellent
    job of rendering each frame, of any compressed
    format, into their own native format [YUV space, for
    now] before they do their Editing)

    It becomes not only a matter of "how much"
    compression but of "how" the compression was done.

    There are more factors involved, mostly related to
    what you feed the encoding/compression process,
    that have a major impact on any individual's results
    using MPEG compression. There are less effective
    encoding programs, they are not all the same. It is
    often possible to have dramatically differing results
    using different settings, in the same encoder. Then
    there is the fact that each original video source will
    have characteristics that define it's "compressibility",
    for any particular compression scheme.

    To repeat:
    " The objective is to digitally store an analog signal so
    that when the digitally stored data is eventually converted
    back to an Analog output, for TV display, - or- serves as
    source data for a digital display : it matches ( as far as is
    noticeable to a normally critical watcher ) the quality of
    display that would have resulted from playing the original
    analog signal."

    It is quite possible to meet that objective with MPEG2
    ( the compression method for DVDs) at Half D1 and
    variable bitrates that will normally allow close to 4.5 hrs
    per DVD.

    Luck;
    Ken
     
    Ken Maltby, May 14, 2005
    #19
  20. Worrier

    David McCall Guest

    Thanks for picking up the ball and carrying it further than I could.

    David
     
    David McCall, May 14, 2005
    #20
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