Video on a projector

Discussion in 'Digital Video' started by irishgrizzly, Nov 3, 2009.

  1. irishgrizzly macrumors 65816

    irishgrizzly

    Joined:
    May 15, 2006
    #1
    What's the smallest video resolution in pixels that you could get away with if displaying to screen is 12 x 9 feet?

    Thanks
     
  2. jampat macrumors 6502a

    Joined:
    Mar 17, 2008
    #2
    How far away are the viewers? What are you trying to display?
     
  3. irishgrizzly thread starter macrumors 65816

    irishgrizzly

    Joined:
    May 15, 2006
    #3
    The original file I was given was only 320X240. I guessed it was far to small so I asked for a better version. They sent me one tonight – huge file for what is only 2 minutes of footage – over 400mb (the original was 8mb).

    The only trouble with this new file is I get this error in VLC;

    Code:
    main: no suitable decoder module for fourcc `hdv3'.
    VLC probably does not support this sound or video format.
    Does anyone recognise this error? I get sound but no video.

    I tried using VisualHub to convert this .mov file to .swf as I'm going to be placing it in a flash pretension. But it still had no video after converting.

    I've no idea of the area of the place it being played – but judging from the screen size I'm thinking a large hall to about 150 people.
     
  4. spinnerlys Guest

    spinnerlys

    Joined:
    Sep 7, 2008
    Location:
    forlod bygningen
    #4
    400 MB for 2 minutes of video is almost DV quality, as in miniDV (camera), and that is a "low" quality.

    The VLC report says "HDV 3", which I don't know personally, but I might give you some information nonetheless.

    HDV is an HD recording format for DV tapes. It is recorded as an MPEG-2 stream on a DV cassette. But the stream is normally re-encoded during capture to something far less compressed than MPEG-2 to being properly editable.

    So it might be, that you have got an HDV stream, using the MPEG-2 codec and for which you need the Quick Time MPEG-2 Playback Component, which can be bought online at Apple Online Store.

    Contact the supplier of the video and let them tell you, what editing system, what codecs and settings they used to encode that file.



    PS: When you have no image before the conversion of a video, you will almost always never have an image after the conversion, as in order to do the conversion, the software doing the conversion must be able to read the video file and its contents, which is normally video + audio.

    .mov and .swf are only containers and no indicators (in the case of having the appropriate software for playing .mov and .swf files in general), if you can read a file 100% or not. It's the codecs inside them, that determine the working of a file.
     
  5. irishgrizzly thread starter macrumors 65816

    irishgrizzly

    Joined:
    May 15, 2006
    #5
    Thanks for the (detailed) info. I'm green to video formats, but the reason I thought I might get the video working was, I hoped Visual Hub may have extra – codecs(?), that VLC/Quicktime wouldn't have.

    If I get a better version of this file but need to downsize it. Which would be a good app to use? iMovie? Visual Hub or something else?
     
  6. spinnerlys Guest

    spinnerlys

    Joined:
    Sep 7, 2008
    Location:
    forlod bygningen
    #6
    I don't know Visual Hub that well, and if indeed is able to read files, VLC can't, because it has access to codec libraries, VLC doesn't, Visual Hub is able to view the file, therefore the "no image before, no image after" speech.

    I normally use MPEG Streamclip, and the times I recommended it multiplied by a tree, I would have had a forest by now.

    And yes, MPEG Streamclip is able of downsizing (making the resolution smaller) any video.

    But if you have that much of a "projection space" I would go with the highest possible, that you will get from your client and the highest the projector can manage.

    When the video is an HDV encoded file, then the resolution should be about 1440x1080 pixel.
     

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