Converting PAL to NTSC without re-encodeing ??

Discussion in 'MPEG-1 and MPEG-2 encoding (AVI to DVD)' started by ink_sling, Jun 9, 2004.

  1. ink_sling

    ink_sling Guest

    Ok I remeber seeing a post awhile back here about doing this. I Want to convert PAL 23fps to NTSC 23.97/27 ? without reencoding. I have been searching and keep finding the same question posted. Can someone link me to some info about changing or patching a PAL movie so itll play on NTSC tv ? thanks all
     
    ink_sling, Jun 9, 2004
    #1
  2. shiroh

    shiroh Guest

    from PAL 25fps to NTSC film 23.96fps ?
    not much differences isn't it. unless you want it on your player. without reencoding i'm not sure, maybe discarding the frames.....i'll look into it.
     
    shiroh, Jun 10, 2004
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  3. sunyam0

    sunyam0 Guest

    Re-encoding is not simply a metter of changing the bit rates. There are other things involved.

    I’ve converted between NTSC/PAL and PAL/NTSC any number of times. I can tell you software based conversions are always bad: flickery, loss of color, paleness of image, loss of sharpness, etc. Hardware-based conversions are far superior, yet not quite the same as the original.

    I culled the following info from my notes. Hope you find it of some value.

    PAL format is 352 x 288 pixels @ 25 frames per second (fps) while NTSC is 352 x 240 @ 30 fps. The ratio of height to width for PAL is 1.22 whereas for NTSC it is 1.46. There is a 20% increase in resolution for a PAL (DVD) as compared to an NTSC (DVD). However, this does not necessarily translate into a superior image.

    PAL is higher in resolution (576 horizontal lines) than NTSC (480 horizontal lines), but NTSC updates the on-screen image more frequently than PAL (30 times per second versus 25 times per second). Thus, NTSC video is lower in resolution than PAL video, but because the screen updates more frequently, motion is rendered better in NTSC video than it is in PAL video. There is less jerkiness visible.

    Converting PAL to NTSC: 576 lines of resolution are reduced to 480 lines of resolution, and frames need to be inserted to go from the 25 frames per second of PAL to the 30 frames per second of NTSC. Once again, the resultant image is of less actual resolution than the original image, as information is discarded spatially and made up temporally.
     
    sunyam0, Jun 10, 2004
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  4. vurbal

    vurbal Administrator Staff Member

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    Actually, it might be possible, but it wouldn't play correctly on some (most?) DVD players. If you change the MPEG header information contained in a VOB you can trick many players into thinking the video has different properties than it does. I haven't heard of changing framerates, but I know you can change the resolution. The downside is that some players will insist on playing the video at the correct resolution, which obviously won't give you the same picture. That's how programs like DVD-Lab can make DVDs from SVCD (not DVD compliant) video that will play fine on many standalones.
     
    vurbal, Jun 10, 2004
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  5. ink_sling

    ink_sling Guest

    interesting. I am looking into changing the VOB header now. I have one dvd player that will play them all but my other one wont. Might be easier to just buy another cheap dvd player that plays everything hehe

    thanx for the replys
     
    ink_sling, Jun 10, 2004
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  6. Minion

    Minion Senior member

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    Yes this Is Possible, I have done it But it will Not play on your DVD Player because of the Pal Resolution Pluss you will have to Stretch the audio...

    What you do first is Demux the VOB file into a seperate M2V and AC3 audio file and then use a Tool called "DVD Patcher" to Patch "All of the Headers" in the File to 23.976fps but this will make the Video Longer than it was Before, so you have to decode the AC3 audio to a Wav file and use "Goldwave" to stretch the Wav audio file to the exact length of the Video file and then encode the Stretched Audio file to AC3 or Mp2 , Now you have to add the 3:2 Pulldown Flags to the Video file to make it 29.976fps, after doing this just Mux it back with the Audio file and now you will have a Pal resolution File with a NTSC Frame rate that you will Not be able to watch in your DVD Player/TV set.......

    The only Program I know of that Does Really Good Pal/NTSC Conversions becides High end Editing Programs is "Canopus Procoder" ...

    If you are trying to Convert a Pal DVD to a NTSC DVD I don"t see why you are afraid to Re-encode the file, If you use a High Quality mpeg encoder Like CCE SP the Quality Differance is Minimal and Probably not noticeable as Long as you use a decent Bitrate....
    Pluss you can Use AVISynth to do the 25fps to 23.976fps slowdown and it will also slow down the Audio also, ........

     
    Minion, Jun 10, 2004
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  7. vurbal

    vurbal Administrator Staff Member

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    Thanks for the input Minion. I thought that would probably be an issue, but I never assume anything. Do you have any suggestions for an AviSynth script to do the conversion. I've read a fair amount about it, but never tried myself and if you've tried it before I'd love to see what you used.
     
    vurbal, Jun 10, 2004
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  8. Minion

    Minion Senior member

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    Well I actually use Goldwave to do the Audio stretching and use AVISynth to do the Frame rate conversion.....

    What I do is Rip the Pal DVD to your Hard drive, and then use DVD2AVI 1.76/1.77 to make a D2V project file, and then I write an AVISynth Script that converts the Frame rate, a Little something like this:

    LoadPlugin("C:\PROGRA~1\GORDIA~1\mpeg2dec3.dll")
    LoadPlugin("C:\PROGRA~1\GORDIA~1\undot.dll")
    mpeg2source("C:\test.d2v")
    AssumeFPS(23.976,True)
    LanczosResize(720,480)
    Undot()

    Accept the Resizeing will be different depending on if your Pal DVD is Widescreen or Full screen, If it is Widescreen then use DVD2AVI to cut off the Black Bars on the Top and Bottom and then see what the Resolution is and then Convert the resolution to a 4:3 or 16:9 aspect ratio in a DVD Compliant NTSC resolution...
    If your movie is Widescreen and don"t know how to figure out the Proper resizeing without distorting the Image then Post back what the resolution of the File is after Cropping off the Black Boarders and then I will tell you....Cheers
     
    Minion, Jun 10, 2004
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  9. vurbal

    vurbal Administrator Staff Member

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    Okay. That's pretty much what I was thinking, but I figured I'd see if you had something different in mind.
     
    vurbal, Jun 10, 2004
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  10. shiroh

    shiroh Guest

    i'm grateful for my multi region player for playing PAL and NTSC. rarely i have a PAL source, as all my videos are anime and game extract :p
     
    shiroh, Jun 11, 2004
    #10

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