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Restrictions when copying from Panasonic recorder's HDD to DVD in High Speed mode

Discussion in 'Blu-ray & DVD Recorders' started by im_spartacus, Oct 2, 2009.

  1. im_spartacus

    im_spartacus Member

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    I've copied video recordings of my old band's gigs from VHS cassettes to the hard drive of my Panasonic DMR-EX768EB, with a view to then transferring the material to DVDs for posterity. Once on the hard drive, I've chapter-ised each title to enable skipping from song to song, and created playlists for copying to DVD. So far, so good.

    However, the various restrictions and limitations specified in the user manual with regard to maintaining chapter-isation are a major brain-bender. Having got to grips with them (or so I thought), the key issue seems to be that chapters are only maintained on the DVD copy if the playlist is copied across in high speed mode; if not, default chapters are created on finalisation at intervals of about five minutes, if you're using DVD-RWs (as I am).

    When the recording mode is set to one of the non-high speed modes, the display shows the DVD capacity in hours, and the percentage of the 4.7 GB 120 min disk that will be taken up by a 1 hr 55 min title is consistent with the non-high speed mode currently selected (e.g. 95% of 2 hrs available at SP, 47% of 4 hrs available at LP, etc.)

    Fair enough, but when I set the recording mode to high speed, the on-screen display changes to denote the capacity of the DVD being written to in MB rather than hours (i.e. capacity rather than time), and says that the 1 hr 55 min title I want to copy would take up 176% of the space available on the DVD.

    I'm as sure as I can be that I'm not breaking any of the rules regarding use of FR recording mode, mixed audio types, an excessive number of deleted segments, etc. I don't understand (and the manual doesn't explain, so far as I can see) why use of the high speed mode should cause a title of less than two hours in length to exceed the capacity of a two-hour DVD. I can appreciate that having an index to enable the chapterisation would occupy some space, but not that it should appear to practically double the size of the source material! How come use of high speed mode doesn't just alter the time it takes to make the copy? More importantly, any ideas for a workaround that would enable keeping the chapters?:lease:
  2. Gavtech

    Gavtech Administrator

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    Evidently when you first recorded the material to the hard drive you must have used XP mode .. which equates to 1 hour per disc [ approx].

    High Speed mode is simple digital cloning so if it occupies 1 hour at XP quality on the HDD it will also occupy 1 hour on a removable DVD.

    On a separate note since you say your objective is to save these recordings for posterity, it is recommend that you use DVD-R rather than DVD-RW. [ ..plus a RAM back up would be good - Can be bounced losslessly to and from the hard disc to make refresh copies further down the line]

    At this stage, if you wish to maintain your existing chapters, you will have to split the material in two and put each 'half' onto a separate disc at high speed.

    Another alternative would be to split the title at every existing chapter point. This gives every song an accessible title in the finished product.

    You still would not be able to get all the songs onto a single disc, but could collect / select which go where.

    At present it is not possible to get all the material onto a single standard disc without real time copying... which means encoding and thus incurring quality loss and also losing all existing chapter points - as you have already surmised.

    Another alternative is using double layer discs... but generally I recommend against that. It can be problematic and unreliable.
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  3. bonzobanana

    bonzobanana Active Member

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    I remember making exactly the same mistake myself in the past when I first got a Panasonic dvd recorder. As gavtech would say 'SP' is the recommended quality setting for almost all uses. A good compromise between quality and recording time. That would have given you the two hours. Its worth remembering that only high speed dubbing avoids re-encoding the mpeg video data as its written to dvd. So you did everything right except for setting the wrong quality setting at the very beginning.
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  4. im_spartacus

    im_spartacus Member

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    Gavtech and bonzobanana,

    Many thanks for your useful and speedy replies. It did occur to me that the mode under which I recorded the VHS material to the hard drive might be an issue, and here's where I should mention something I didn't in the first place (I'm a great believer in giving too much information rather than too little, but have a tendency to go on a bit, in case you hadn't noticed;)).

    This was my second attempt at copying; the first didn't involve a playlist (I hadn't read that bit of the manual at the time!), and ended up with me accidentally reformatting the HDD instead of the DVD-RW in the tray (stupid [-]me [/-]'DRIVE SELECT' button!; downside - loss of hours of movies saved since January:thumbsdow: upside - loss of hours of gardening programs the wife never gets around to watching:smashin:).

    As a result, I had to copy the tapes to the HDD again, and it was only on this occasion that I actively set the mode to XP, it having occurred to me belatedly that I should try to get the highest resolution possible before burning to DVD.

    The point is, I could swear that I didn't set the mode to XP before the first tape to HDD copies were made, and so am assuming that the mode would have defaulted to SP, the mode I invariably use when recording broadcasts to the HDD (this whole operation is the first time I've ever copied anything to DVD, from any source).

    Assuming that was the case, I could also swear that when I tried to copy the title in question (which had been chapterised but not playlisted) in high speed mode, I got the same 176%-of-disk-space-so-no-can-do result, and once again had to copy in SP mode.

    As a result, when it occurred to me to copy the tapes in XP, I didn't think it would make any difference to how much space on the DVD would be required. I suppose I was thinking of it in terms of taking a photocopy of a sharper photographic print than of a blurrier one (and I kidded myself that I could see a difference between the quality of the second copy on the HDD made in XP and the first in SP).

    There's some tortuous analogy I'm trying to work out involving pouring liquid from one container to another, but it involves the volume/density of the liquid and the volume of the containers changing in the process, and I can't get it straight in my head. I'm going to copy the tape again tonight in SP mode and see what the options are after that.

    Thanks again for taking the time, gents - Gavtech's tips about taking RAM backups and not using DL discs would never have occurred to me. Great forum!:thumbsup:
  5. Gavtech

    Gavtech Administrator

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    I've tried to run with the analogy ... but it's problematic and I suspect is just serving to confuse rather than illuminate.

    Quality and storage [Time length] are inversely proportional.... and it is difficult to fit that into into a fluid volumetric analogy given that fluids are not compressible.

    A part of the analogy may be made to work by introducing the concept of quality.

    eg... A DVD container may have a capacity of 1 pint.
    You can pour 1 pint of beer from the hard disc into that DVD.

    If you water the beer down and have a pint of 'beer' that is 50% water 50% beer you can still pour it into the DVD and fill it. The problem with the analogy is how to equate that the same pint now has twice as much in it as it did before!

    [Chuckle ] I don't like this analogy at all.

    Try this - without analogy:
    A DVD is a fixed capacity storage container.
    You can cram more [ longer time length ] video material into that container by discarding some data from the original video [ thus degrading it and losing quality] in order to make it fit the container.


    In practice, there are some simple rules to follow when dealing with video on disc.

    The most important of all, and the basic golden rule is:-
    Keep encodings to a minimum... and preferably to no more than one.

    The first encoding happens when you record material to the hard disc.

    High speed copying is the only form of copying that does not involve re-encoding, so should always be aimed at as the preferred choice.

    That means planning from the start how much time you wish to get on a disc and setting the quality accordingly.
    XP for 1 hour nominal. SP for two hours nominal.

    Just in case you are not aware, you could also record your original material in FR mode.
    That would stretch out the material so that it would optimally fit onto a DVD using as little compression as possible to make best use of the available disc space. .. [Albeit in practice there is not likely to be a great deal of difference between the 1 hr 55 mins of material here and the 2 hours 8 minutes that can typically be squeezed onto a disc at SP quality.]
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  6. im_spartacus

    im_spartacus Member

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    Gavtech,

    Thanks again - your watered-down beer analogy works very well with regard to the issue of quality and volume. You've got a real knack for explaining things in clear terms, a rare thing these days, I find.

    I've now re-recorded from the VHS in SP and, sure enough, after chapterising and playlisting, the title fits on a DVD when copied in high-speed mode. (I can add my recollection that this wasn't possible the first time to the long list of things I could have sworn were the case that subsequently turned out not to be!) The chapters are where they should be, and having been finalised it plays on my PC and another DVD player. Job done! :thumbsup:

    The fundamentals you've made me aware of with regard to encoding and so forth will prove invaluable from hereon. Many thanks to you, and more power to you and the forum! :smashin:
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