Re: Stream or download of files

From: Neil Smith [MVP Digital Media] (neil_at_nospam.com)
Date: 12/03/04

  • Next message: MikeR: "Re: WMA Lossless at 48kHz, 16-bit, 2 Channel?" 
    Date: Fri, 03 Dec 2004 21:22:12 GMT

    On Fri, 3 Dec 2004 00:15:04 -0800, "Sopwith"
    <Sopwith@discussions.microsoft.com> wrote:

    >I have a somewhat similar question - when using the New Session Wizard and
    >you come to the Content Distribution screen, which selection do you use which
    >will create a file that if a user clicks a link on a web page the file will
    >buffer and begin playing while it downloads? After the download completes,
    >the user needs to be able to click "save as" and save the file to their hard
    >drive for later viewing.

    It's saved in IE's temporary internet files if you're downloading from
    a web server. Media servers allow you to turn off the save function,
    and web servers allow you to send no-cache headers to simulate this by
    limiting how IE can stor it in the cache (** Of course you may not be
    using IE so all bets are effectively off ;-)

    Probably, if you play a file then fight-click the link and pick
    "Save-As" it won't go to download the whole file, it'll just load it
    from the cache. Some providers do a lot of obfuscation and rotation to
    the URLs to prevent this happening to them, often using short-duration
    sessions to pass the URL to the browser.

    >I don't fully understand the difference between Web Server (progressive
    >download), Windows Media Server (streaming), and File Download (computer
    >playback)?

    Well, with a streaming server, you can package the encoded file with
    multiple bitrates. The streaming server then negotiates with the users
    media player for the best stream it can 'keep-up with', based on their
    network settings. It can also do 'fallback' if the client isn't
    keeping up with the bitrate (and ad-insertion and other neat stuff)

    A web server stream is more like a long-term file download, which the
    player begins to buffer when it thinks it has enough of the file to
    play end to end (this all depends on the clients buffering settings,
    which can be adjusted with scripting).

    You can only have a single stream rate in a web server download (well
    maybe you can offer several, but the wen server has no way to
    negotiate with the client which bitrate to deliver so you'd get sent
    *all* the streams which is obviously worse than picking even the
    fastest stream ;-p)

    File download is mostly used for very high bitrate files eg encoded
    DVDs and VCD. I think really it's just down to the combinations of
    codecs and data rates you get offered in the wizard.

    If you use the full interface from the "Properties" button, you'll get
    a better feel for how many options there are.

    HTH
    Cheers - Neil

  • Next message: MikeR: "Re: WMA Lossless at 48kHz, 16-bit, 2 Channel?"