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Black Bars missing when encoding

Discussion in 'DivX / XviD' started by buraku, Jan 13, 2005.

  1. buraku

    buraku Member

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    This is the first time i've encountered this problem and i can't think of any reason why this is happening.

    After I rip the 16:9 dvd (i've tried both dvd shrink and decrypter) and view the rip with media player or windvd, the movie looks just like the dvd would on my tv, with black bars at the bottom and top.

    but when i prepare it to encode with xvid, whatever app i use to encode with stretches the image vertically to cover the top and bottom black bars. it does it in dvdx, dvd2avi, whatever. and the stats always still show the vid as being 720 x 480, which it is, but with bars missing for some reason so that the image stretches to fit 720 x 480.

    the majority of the time i either use dvdx and set crop to custom/selection so that i can crop the black bars and still keep the original aspect ratio. or i prepare to frameserve to another app with dvd2avi. but in both apps, the file is shown without the bars for some reason.

    i've tried everything. why is this happening?
     
  2. buraku

    buraku Member

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    the only way i found to do this was a resize filter in vdub or avisynth. which option would be best to resize? bilinear, bicubic, precise bicubic, lanszos?
     
  3. shiroh

    shiroh Guest

    regarding first post.
    maybe its auto cropping ?
    or maybe its encoded anamorphically without those letterbox in the first place. the ones you see on the tv is generated on playback.
    try to see the mpeg 2 with virtualdubmod...or anything.

    regarding the seconf post.
    i do all my filtering on avisynth now. its faster than vdub's, mainly cause it doesn't convert the colourspace to rgb32. and doing that might compromise the video quality.
    which algo to resize.
    lanczos4 is the latest. it is a sharp resizer. so that will kill compressibility to unnecessary scenes (those motion blur scenes)
    lanczos is older but less sharp.
    bicubic is neutral. but it will be a little blurry than lanczos.

    bicubicresize(x,y,-0.2,0.6)

    a sharper bicubicresize, add those coefficient.

    try bicublinresize (its a plugin)

    see what best for your eyes.

    capture the same fram with png (use vdubmod) and see the filesize.
     
  4. buraku

    buraku Member

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    yeah, it was an anamorphic file. for some reason that just didn't click in my head, even though i said i hadn't seen them before, i had, lots of times. i don't know what i was thinking.

    yeah, i've just jumped the wagon over to avisynth here lately and i'm pleased with the results. it takes a little longer for me to set up, but i think it looks better than vdub.

    i'll try that bicublinresize.

    another question. if you aren't filtering with vdub but just encoding straight to avi, will it change color spaces also? or does this just refer to filtering?
     

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