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Activity Forums Compression Techniques horizontal lines apperaring after compression

  • horizontal lines apperaring after compression

    Posted by Vid Osredkar on April 16, 2010 at 5:38 pm

    Hi everybody, have a problem thats been bothering me for a long time, and your help would be very welcome.
    (original is uncompressed from AE, when played, no artifacts appear)When i export this file from Sorensen Squezze as a flash flv, I get strange lines across certain parts when there is camera movement.I have tried a bunch of different settings, and cant seem to find what the problem is.
    I use on2vp6 codec, and have tried cbr and vbr (2 -pass) with different bit rates.
    here is an example of my problem

    https://www.flotaskydive.com/

    the first video on top
    the footage is made out of jpgs with some basic camera movmement.
    any suggestions?
    i thank you in advance
    best regards
    Vid

    Vid Osredkar replied 16 years, 4 months ago 3 Members · 5 Replies
  • 5 Replies
  • Chris Blair

    April 18, 2010 at 5:07 pm

    Looks like interlace artifacts to me. We need to know how the original uncompressed file was created. Pixel resolution (1920×1080; 1280×720; 720×486 etc.), frame rate, pulldown or no pulldown; was it rendered with fields or frames etc.

    My guess is you rendered fields. With such a simple animation and such slow movement, and considering your final output is displayed on a computer, I’d render using frames and turn on motion blur. It’ll take a little longer to render, but that should eliminate what you’re seeing. I don’t know of anything in compressing to an flv that would cause what you’re seeing.

    Chris Blair
    Magnetic Image, Inc.
    Evansville, IN
    http://www.videomi.com

  • Vid Osredkar

    April 20, 2010 at 9:48 am

    Hi Chris, first of all, thank you for your reply.
    Here is a link to the video in question
    https://www.flotaskydive.com/content/view/15/17/
    the video i posted above is an old project but with the same problem. Original cello is rendered from AE:
    uncompressed
    pixel resolution is 650×260 (requested flv size is the same),
    25fps,
    no fields rendered and
    no pull down.
    sample videos are a bit smaller cause they dont fit on my test page.
    have in mind that its work in progress and color correction and other fixes have not yet been done.
    any comments are welcome
    vid

  • Daniel Low

    April 20, 2010 at 2:41 pm

    [vid osredkar] “pixel resolution is 650×260”

    Your encoded frame size needs to be equally divisible by 16 or 8:
    https://www.adobe.com/devnet/flash/apps/flv_bitrate_calculator/video_sizes.html

    The player on the webpage needs to have exactly those dimensions, do not let the player rescale the video.

    __________________________________________________________________
    Sent from my iPad Nano.

  • Vid Osredkar

    April 21, 2010 at 9:27 am

    Thanks Daniel!
    I followed the tip, made a new test comp in AE, size 448×336, exported it without compressing(picture looks great no lines),i put it in sorenson,encoded the same size to flv,what i ended up with, is on the site
    https://www.flotaskydive.com/content/view/15/17/
    video on top
    no rescaling was done by the player, neither now or in the previous examples.
    as you can see my problem did not go away.
    i have the same resolution from the start in AE comp till the end encoded as flv (and it is divisible by 16).
    I must be doing something wrong i guess
    this compression thing is amazing
    vid

  • Vid Osredkar

    April 24, 2010 at 9:42 am

    Hi
    i finally came to an end with my problem.The flv player on our sight its the one to blame, because when i put the same flv file on youtube the picture is good, and no lines appear.
    thanks again for all the help
    best regards
    vid

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