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Another newbie "help me please" thread

Discussion in 'Camcorders, Action Cams & Video Editing Forum' started by scrumhalf, Aug 12, 2003.

  1. scrumhalf

    scrumhalf
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    First of all, greetings to all from sunny Cardiff.

    :)

    Ive never owned a camcorder before, but with my second nipper being born i think now its a must. I dont want to spend anymore than £500 really, and obviously want the best that the money can buy. Ive found a review site on the net, but there are not a lot of cams reported on there really. I dont want to end up with something with crappy sound and picture, as im sure you can appreciate. So as well as your opinions on what cam, can you please tell me of as many review sites, UK or US that you know of?

    Also, I understand that a DV cam captures in AVI, which is approx 13GB for 1 hour of footage. If that 13GB AVI is encoded into DVD (.VOB`s) how big would that 13GB be then? Would it fit onto a DVD5?

    Many thanks in advance for the help.

    Cheers!
     
  2. vonhosen

    vonhosen
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    I'm not up to date on mid range models...... but with regards to your 2nd question about how big is 13Gb going to be on a DVD, that will depend on what rate you encode at.

    VOBs are Video Object files which is the data stream containing MPEG video & whatever audio you have encoded. The maximum data rate for DVD is about 9.8Mbs and you will comfortably be able to get an hour (13Gb) of AVI encoded to MPEG-2 & on a DVD-5.

    Your 4.7Gb DVD-5 disc actually only has 4.37Gb of disc space (as far as your computer is concerned) How much video you can get on that disc is going to be down to how you manage available bitrate. This is going to be influenced by what you are willing to drop the bitrate to in order to fit more onto the disc & what audio you are using on your disc during authoring.

    As a simple example
    To fit 90 mins of video on a DVD-5 disc you have an available bitrate (allowing for authoring overheads such as menus) of 6.66Mbs. This is what rate is available for all your video & audio combined. Now if you are using Dolby Stereo audio at say 192Kbs you can see that you are looking at just under 6.5Mbs available for your average video bitrate but if you were having to use PCM audio at about 1600kbs you would only have just over 5.0Mbs available for your video.

    It's a bit simplified I know but generally the more bitrate for your video encode the higher the quality. The difference between 8 & 9 Mbs will not be as marked as the difference between 4 & 5 Mbs.
     
  3. scrumhalf

    scrumhalf
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    Thanks for the reply mate. I get the jist of it, i think :)

    So to get the best possible picture, and max bitrate for encoding to DVD, id be looking at about 60 mins of video with Dolby stero sound?
    How would the picture then, on the DVD compare to the origonal DV tape? Ive never even seen a digital camcorder recording, so ive no idea what its like.
    I know a re-encode of a file is only as good as the source, but with theese cams converted to DVD, would the picture have as much clarity as a DVD film purchased in the shops for example?

    Also, im quite tempted to go for the JVC GR-D70 at £436.18 online at comet. Had any experience with this cam?

    Thanks again.
     
  4. vonhosen

    vonhosen
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    No experience of the camera you are looking at .

    Will it look as good as a commercial DVD ?

    In general no (remember how much money Hollywood are spending on lighting, cameras etc compared to you. Not to mention their film treatment & encoders). You should find the quality that a good mid range DV camera records at very good. After that the quality of your MPEG encoder is going to have a large impact. These can vary as much in price as camcorders. TMPGEnc & CCE Basic are two very good quality encoders at about £40 mark and using these with a decent bitrate the quality of your MPEG should be similar to your AVI original despite the compression & I would expect you to be pleased with the results.

    Whether you can get Dolby audio on your DVD will depend on your authoring software (Dolby licenses are not cheap so programs that include a Dolby encoder tend to be a bit more pricey)
     
  5. scrumhalf

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    Once again, thanks for taking time to edcuate a prune.
    :clown:

    With regards to the Dolby license you spoke of. Earlier on when explaining about the bit rates, you mentioned the variation between encoding the audio in Dolby stereo at 192Kbps and PCM at 1600Kbps. Now, as far as im aware the only difference between the D.stereo and PCM is that the PCM is uncompressed, and therefore SHOULD offer better sound. But is the difference that much? Because if it isnt, surely id be better off encoding in D.Stereo and upping the bit rate on the video.

    Doesent TMpeg come with the option of encoding in either audio format?

    Cheers.
     
  6. vonhosen

    vonhosen
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    Yes to the audiophile PCM should offer more detail than Dolby audio but as you have said at the expense of video quality/space.

    Most video you are going to shoot isn't going to require audiophile audio quality and compressed audio offered by Dolby or MPEG audio is going to be fine.

    The difficulty comes in authoring as per DVD spec. When the DVD video specs were originally drwan up PAL players had to support a minimum of PCM & MPEG audio (MPEG audio having similar compression rate to Dolby) while NTSC players had to support a minimum of PCM & Dolby stereo. There wasn't much take up with the MPEG decoders so the specs were revised in that PAL players also had to support a minimum including Dolby stereo.

    For maximum compatability you should use Dolby (compressed) or PCM (uncompressed) audio. In PAL land though you can get away with MPEG a lot of the time.

    TMPGEnc does allow you to ouput PCM or MPEG audio but not Dolby. As I said official Dolby AC3 encoders have an expensive licence attached (A Dolby standalone software 5.1 encoder can cost about $1000). Most Dolby software encoders will come as part of the authoring software (Programs like Sonic's DVDit PE & ReelDVD have built in Dolby stereo encoders but this pushses the cost of the programs up). I myself have a Dolby 5.1 mixing & encoding pacakge as part of my editing software (Sonic Foundry's Vegas)

    Cheaper authoring programs tend not to offer Dolby but will allow you to output MPEG audio.

    In short if you can you are best using compressed audio & saving bitrate for video.

    Of course you could always get someone with a Dolby encoder to encode your PCM to Dolby for you if your authoring package will accept dolby but doesn't have an encoder included.;)
     

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