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Converting problems - Jerky screen

Discussion in 'MPEG-1 and MPEG-2 encoding (AVI to DVD)' started by born1974, Jan 13, 2005.

  1. born1974

    born1974 Member

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    I got a question. When i try to convert basicly any file type to dvd i get a consistant screen jerk just enough to make me eyes flake out. all the original files don't do that. It's only after i convert them. they jerk both on my computer and on dvd player. some of the files i've converted to dvd are avi,mpeg,svcd,divx,ect. and some were pal some were ntsc. some were 25 fps,29.97 fps,and some were 23 or something like that. I always convert to mpeg2 29.97 ntsc, but every file does the exact same thing. a slight screen jerk. even during the converting proscess you can see it jerk but only slower. Is this a video card or memory problem. maybe i need a faster processor. please help me. this is the only problem i ever come across.
     
  2. aldaco12

    aldaco12 Active member

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    Sorry, I'm not able to help you. Im a fundamentalist. I NEVER conver AVIs to DVDs. I prefer VCD (even to SVCD): garbage in = garbage out.
    A DVD movie is 4.5 GB and an AVI id 700-900 MB.
    Tha result is proportional to the size saving.
    Making a VCD is more serious (1 800 MB AVI = 2h movie = 1300 MB mpeg-1).
     
  3. born1974

    born1974 Member

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    actually i should have mentioned than before i got a dvd burner i used to make vcd's and that had the same problem too with jerky screen. and to boot i think avi at the same bitrate as a vcd is 3 times better only you can't play avi's on a dvd player or any componet that i know of. vcd's have big pixle problems i converted a dvd with a bitrate of 8.5 Mps to vcd to the most that it would let me put on a cd and distoryed the file 3 times worse that vhs. so vcd sucks to no end i think.
     
  4. Minion

    Minion Senior member

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    Your Problem Most Likely Lies in the Frame rates you are Useing...

    If you have a Pal 25FPS AVI file you Can"t just Load it into a Mpeg encoder and Encode it to 29.976fps NTSC and expect it to Play Normally because you will get Jumpy Playback...
    Most Mpeg encoders can not do Proper Frame Rate conversions as they use a Method of Frame Duplication and Decimation to convert Frame Rates which results in Jumpy Playback...This is Because the Encoder Just Duplicates Frames to Make up the New Frame Rate and the Jumpyness is caused from seeing Duplicated Frames....

    So what you Have to do is either learn how to convert Frame rates properly yourself or use a Mpeg encoder that can do Proper Frame rate Conversions Like "Canopus Procoder" ......

    Also when you get a 23.976fps File you have to encode it with 2:3 Pulldown enabled which will make it 29.976fps...Or you can encode it to a 23.976fps Mpeg-2 file and use a program like "DoPulldown" to add the 2:3 Pulldown flags and make it 29.976fps...
    Most All Retail NTSC DVD"s are Made from 23.976fps Film Material with 2:3 Pulldown....

    And this Statement makes no sence if I understand it correctly:

    You can Not compare the Bitrates and File sizes of One Format to the file Size and Bitrates of a Different Format, so it can Not be said that encodeing a 700mb AVI file to a 1.3gb VCD file will produce better quality than encodeing a 700mb AVI file to a 4gb Mpeg-2 file....
    What Matters is the Resolution and the Overall Quality of the source File and the Bitrate and resolution that you encode the File to, and also the Quality of the Mpeg encoder has a Big effect on the Output Quality as when useing a High quality encoder you can achieve much better quality and at a Much Lower Bitrate than when useing a Low Quality mpeg encoder....

    Cheers
     
  5. born1974

    born1974 Member

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    what i meant by comparing file formats is. if you were to take the highest of video qualities that has never been compressed ever. and make and vcd then with the original file make an avi both of witch would just fit on a cd. the avi would be better. anyways the part about fps and that stuff i was told that whatever the file contains that your trying to convert is what you should make the converted file. but i don't understand the part because i usally go for ntsc because i have to. 29.97 if that is what the original is, or 23.97 if that is what the original file is. and if it's 25 well i just convert to 29.97 anyways. the resolution i make whatever a dvd is. 720x480 or somthing like that i could be wrong. now the part about progressive or interlaced or pulldown and top field first and gop and other boxes that need to checked or unchecked i don't know about that stuff i usually go with whatever the original is. if those are the more important things i guess i need to know what they mean and do. i now have the avi codec that tells what stuff is and that's half the battle. the programs i currently have is TMPEGenc, nero vision3, adobe premiere. and a couple of other things. i do know that once a file has been converted to a lossy format you will never get it back. the damage has been done. i work a lot with wav files for my music and the sme thing aplies 1=wave 2=convert to mp3. 3= convert mp3 back to wav 4= 2 and 3 will sound the same.
     
  6. Minion

    Minion Senior member

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