Why 640 x 272?

Discussion in 'Other video questions' started by slss, Dec 1, 2008.

  1. slss

    slss Member

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    Hi guys,

    I have noticed that alot of AVIs i recieve are 640 x 272.

    Why is this particular size chosen?

    It dosen't allow for full screen on a wide screen and i am concerned about image burn whilst watching a movie with such large black bars at the top and bottom of the screen.
    i have fiqured i rough way of using Virtualdub to resize it to 640 x 480 which gives me the full screen view albiet a slight reduction of picture quality.

    but why this particular size, wouldnt it just be better to have a full screen movie. it sure looks better when the screen is full.

    anyways. thanks in advance for you patience.
     
    slss, Dec 1, 2008
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  2. davexnet

    davexnet Active member

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    This size is picked in order to maintain the original aspect ratio
    of the movie (2.35:1). There are too many permutations in the way the
    TV and/or DVD player resize and compensate for the A/R to really do any
    thing else. Secondly, for those of us who watch of the PC,
    this gives the proper A/R.

    Thirdly whether you're using a 4:3 or 16:9 TV, the question of
    accurate A/R is relevant. If you stretch the picture too much
    vertically, every thing starts to look tall and thin - but some prefer
    this to the black bars. Each to his own.

     
    davexnet, Dec 1, 2008
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  3. jony218

    jony218 Guest

    do what I do, open your avi in avidemux use the crop filter to crop out the blackbars (make sure the parts you cutout are an even number) and resave as a xvid. With my amd quadcore 9750 it takes 25 minutes to reencode a 2 hour movie with minimal loss of quality. The finished AVI will play in fullscreen on your TV. I prefer the fullscreen everytime, I never see any blackbars on my 27 inch flatscreen LCD.

    http://fixounet.free.fr/avidemux/screenshots.html
     
    jony218, Dec 1, 2008
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  4. slss

    slss Member

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    thanks davexnet, i get your point but as you said 'each to their own', but thanks for clearing it up.

    jony218, thanks also. problem is, when i open it in AVIdemux there are no black lines to crop, neither when i open it in Virtualdub. the only time the black bars are visible is when i play it through my DVD player onto my plasma.

    my video editing vocabulary is very limited, sorry. but i hope this explains my situation.

    also, would resizing in Virtualdub to 640x480 give me the full screen on the widescreen plasma or am i missing something? I did resize a file and it looked stretched out like Davxnet said but if thats the best i can get to fill the screen then im happy.

    thanks guys.
     
    Last edited: Dec 2, 2008
    slss, Dec 2, 2008
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  5. davexnet

    davexnet Active member

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    This is what I meant when I said TV's have different resizing
    capabilities with certain signals - I'm don't know what *your* TV wil
    do. Some wide screens stretch a 4:3 picture sideways, so that things
    to the edges look to fat. Some pillar box the picture, giving
    wide black bars to the left and right.

    Are you converting the avi to a proper DVD? Or are you playing
    the avi itself in the DVD player? If you're converting, make sure
    you encode the DVD with 16:9 set in the encoder - this will reduce
    the top and bottom bars but maintain the proper aspect ratio.



     
    davexnet, Dec 2, 2008
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  6. slss

    slss Member

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    hi, im not resizing to a dvd but i have done this, to 16:9, and it worked perfectly. no bars. but what i am doing is playing an AVI direct from a USB slot in the DVD player and that is what is giving mme the black bars.

    my tv will play 4:3 with black bars either side.

    thanks again
     
    slss, Dec 3, 2008
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  7. Xiaofeng6

    Xiaofeng6 Guest

    Xiaofeng6, Dec 17, 2008
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