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NTSC to PAL conversion audio length question

Discussion in 'DVD±R for advanced users' started by Konran, Sep 2, 2004.

  1. Konran

    Konran Member

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    Hello all,

    when I converted NTSC 29.97fps MPEG-2 video to PAL 25fps with TMPGEnc Plus 2.5 I used inverse telecine 24fps and DVD PAL template. The result is a PAL 25fps video which is approx. 5.5sec longer than the original NTSC video file (1:32.21 hrs => 1:32.26 hrs). I assume that TMPGEnc internally converts 30fps in place of 29.97fps which makes a calculated difference of 5.5sec

    I expected that I have to time stretch the original audio file so that it is also 5.5sec longer. In fact only the unstretched original audio file is in sync with the PAL file. The time stretched longer audio is out of sync the longer it plays up to the end.

    What's the reason for that? What is my mistake in calculation?

    Regards, Konran
     
  2. Minion

    Minion Senior member

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    Well the Problem is that Tmpgenc does Not do Proper NTSC/Pal Conversions...It is Bad at most any Frame rate conversion and the Result is allmost allways a sync Problem and/Or Jumpy Playback when watched on TV....

    If the NTSC Mpeg2 file is From a Film Source (It would Have to be if you tried to used IVTC on it) then you Should load the Mpeg2 File into "DVD2AVI 1.77" and Make a D2V project File useing the "Forced Film" option....

    Now you will have a Audio File and a D2V project file that is used to Frameserve your Mpeg2 file to Tmpgenc, and with the "Forced Film" option enabled Tmpgenc will read your File as a 23.976fps NTSC film File....

    Now load the D2V file into Tmpgenc and set it up like you were going to encode it to Pal but this time select the "Do Not Frame Rate Convertion" setting in the "Advanced Settings" and encode the File to Pal...

    What this Does is speed up the 23.976fps video to 25fps but now the audio will be 4.024% shorter than the Video ,So you find out the exact length of the Pal Video file and then use the Time Stretch on the audio to that new Length and it should then Sync up perfectly....

    This will only work if your source NTSC Mpeg2 File is From a Film Source ,Meaning if it was Teliclined from 23.976fps to 29.976fps or had 2:3 pulldown flags....

    I use a Simular Method of Converting Pal to NTSC and it works every time..I did have a Problem with the audio before because when I shrunk/Stretched it I allways selected the Option that Keeps the Audio Pitch, appearantly that Time Stretch method isn"t very good so I use the Method that speeds up/Slows down the Audio and it works now every time and with only a 4% speed up /slow Down it isn"t noticeable and it is the Exact same method Studios use when makeing Pal DVD"s from NTSC Film sources....

    Cheers


    _X_X_X_X_X_[small]It"s better to be Pissed Off than Pissed On!!![/small]
     
    Last edited: Sep 2, 2004
  3. Konran

    Konran Member

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    Minion, thanks for your explanation. This is very useful for me because it is a very rare case that I have NTSC video sources.

    I'll do as you suggest with my next conversion run ... when that one is done that is currently running since last night.

    My NTSC source is from SVCD, MPEG-2, 29.97fps, 480x480 with 2:3 pulldown flags. When I found DVD2AVI last night I've set up a project frameserving 50 interlaced frames with smooth deinterlacer filter into MainConcept MPEG encoder. The result will be almost same length as the original. I expect that it'll be jumpy.

    Next attempt will be using your frameserving method with 23.976fps into 25fps and then see the difference.

    BTW: I often see frame rates of 29.97fps for NTSC and 29.976fps. Are these both valid rates (3rd decimal place)?

    Cheers
     
  4. Minion

    Minion Senior member

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    Yes 29.97 is basicly the same as 29.976 ,They are all Valid NTSC frame rates....

    Just make sure in DVD2AVI you go to "Video" to "Field Operations" and select "Forced Film" then the .D2V project file will be read as a 23.976fps Progressive Film File in Tmpgenc...And also remember to select the "Do Not Frame rate Convertion" option in Tmpgenc"s "Advanced Settings".....

    Good Luck
     
  5. Konran

    Konran Member

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    Thanks, that works excellent for the video part.

    Remaining problem is the audio part of the movie. The calculation factor I'm using is 0.95904 (23.976 divided by 25), so I get the estimated length of the PAL video and it is same as the frame length of the PAL video. I tried BeSweet and AC3machine to convert the file (AC3 from WAV). This one has kind of "needles" when playing back the file, very bad sound. Next was Sound Forge and Time Stretch (as you said you had prob's with stretching) - this function is inaccurate achieving the proper length. It differs of about 1 sec which is asynchronous in the last third of the movie.

    Now I'm trying it with Sound Forge and Pitch Shift which also makes a small inaccuracy in the length I get with it. The difference is only 200 ms which surely is much better than time shifting and it is quite OK during playback.

    What are you using to pitch shift your audio files?

    Cheers
     
  6. Minion

    Minion Senior member

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    I used to use Vegas Video and Sound Forge to do it but I allways had problems with the Stretched Audio files still not Syncing up....
    I now use "GoldWave" which has a "Time Warp" feature were you Just put in the Length you want the file to be Stretched/Shrunk to and in a couple of Minutes it is Done and then you just render the New File to Wav....
    To Find out the Length of the Mpeg2 file I usually use "Virtual-Dub-Mpeg2" to load the Mpeg file and go to "File" to "File Information" and it shows the length of the Mpeg2 file and I use that Length to Stretch/Shrink the audio to...
    I noticed that If I used Tmpgenc to find out the Length that it would Report a different length than Virtual-Dub-Mpeg2 did.....

    You can download V-Dub-Mpeg2 here:
    Virtual-Dub-Mpeg2
    http://fcchandler.home.comcast.net/stable/VirtualDub-MPEG2.zip

    I now use AVISynth to do my Pal/NTSC conversions because it can slow down the Video and Audio at the same time while Frameserveing to the Encoder which is a Lot easier than the other method, The only problem with useing AVISynth is Learning how to use it properly because it is a fairly complex video processing Tool....

    Cheers
     
  7. Konran

    Konran Member

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    Superb, GoldWave's time warp function works absolutely perfectly for these conversions. It really produces an exactly time length specified file. Very good.

    I already used VirtualDubMod in conjunction with AVISynth, but it didn't now about the realiability of these file info feature. Now while trying it I had more than 80% crashes of the program when i step into the file information dialog (mostly memory access errors, MPEG-2 parsing OK) with 1.9GB MPEG-2 files.

    So I rely on TMPGEnc DVD Author's frame count which often is 1 frame beneath reality or I recalculate the time code of DVDlab's bitrate viewer and frame rate back to no. of frames.

    I'm definitly interested to try out AVISynth more specific. Are there any links to get more into the difficult conversion techniques?

    Cheers
     
  8. fugitive2

    fugitive2 Regular member

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    I would like to know, if it's not to much asked,
    what the reason was for converting, since most players play both PAL and NTSC, when i have NTSC material, i leave it that way, because my player converts it to PAL60, and on my tv i get an extra color adjust option; tint, wich i can adjust to my like-ings, it has no effect on PAL colors on my tv,
    when watching PAL again.
     
  9. Konran

    Konran Member

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    The standalone player(s) no problem but my friend's TV can't playback NTSC (colorless and rough picture). That's why I put an additional PAL version of the movie onto the DVD. I myself keep on watching the NTSC version of this DVD.

    Cheers
     
  10. Minion

    Minion Senior member

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    The Same with my TV set ..My DVD Player can Play Pal and NTSC but my TV will not display Pal Video properly, It is in Black and white when I try to play Pal video on my NTSC TV set....
     
  11. fugitive2

    fugitive2 Regular member

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    Most of the tv sets here in the Netherlands (Europe)
    can display PAL60 (converted NTSC) with color, normaly, (maybe it's a legal issue in US/NTSC countries ?)
    These tv's even aren't called multi-system or so,
    One can only guess why things are this way...
    In the past i thought they skipped the PAL/NTSC
    boundaries with satellite transmission and digital media, but they did not...
    btw. the Plextor 402U capture unit can capture
    non standard signals like PAL60 i noticed..
    But is there realy a good software util. that can convert different tv systems ? i know of TMPGEnc, but is this the best there is ?
     
  12. Minion

    Minion Senior member

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    I have a Great Method for Converting Pal/NTSC Formats which Involves useing AVISynth...

    Tmpgenc and most other encoders suck at converting Pal/NTSC cuz they use Frame Duplication and decimation to convert Frame rates which can cause Jumpy Playback in high Motion scenes...The best Methods for converting Pal/NTSC is useing Frame and Field Interpolation or Simply Speeding up and Slowing down the Video which is the best way for converting 23.976fps NTSC film to Pal 25fps or converting Progressive Pal to NTSC film with 2:3 Pulldown...

    Canopus Procoder is probably the best for Converting Interlaced Pal/NTSC but AVISynth is best for Progressive Sources....

    Cheers
     
  13. fugitive2

    fugitive2 Regular member

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    So i guess AviSynth is good to
    convert extracted NTSC dvd's ?
    I did some experimenting with AviSynth,
    (fades and whipes) could you recomend some AviSynth
    scripts ?
    I like to play with these sort of things, but are
    not a hero in scripting myself, changing bits only...
     
  14. Minion

    Minion Senior member

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    Well Most of the Scripts I write are pretty Basic, Usually just resizeing and Noise filtering and sharpening and sometimes de-interlaceing and frame rate conversions......

    The Script that you write totally depends on the source files you are working with and what you want to do with them...Like this is the Typical Script i use:

    LoadPlugin("C:\Filters\undot.dll")
    LoadPlugin("C:\Filters\FluxSmooth.dll")
    avisource("C:\Documents and Settings\Chris\Desktop\taking.lives.avi")
    LanczosResize(704,304)
    Undot()
    FluxSmooth(7,7)
    Sharpen(0.85)
    AddBorders(08,88,08,88)


     
  15. fugitive2

    fugitive2 Regular member

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    Okay, so i guess you're doing most of the time -
    clean up "actions" with the AviSynth util,
    and i'm glad i can skip that with my setup,
    i guess i need some re-adjusting "things" when i
    transfer LaserDiscs, well, i will "Google"
    some things up, or check the videohelp site out,
    when i realy need some things, i already did some
    experimenting with whipe and title scripts...
    and i liked the results, and you get good results,
    for free ! i thought this was not possible within
    the MS OS .
     
  16. sking1001

    sking1001 Member

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    Here's my AviSynth script for PAL to NTSC (Progressive Sources):

    MPEG2Source("movie.d2v", idct=7)

    ## PAL to NTSC
    GripCrop(720, 480, overscan=2, source_anamorphic=true, dest_anamorphic=true)

    ## Use this for NTSC to PAL
    #GripCrop(720, 576, overscan=2, source_anamorphic=true, dest_anamorphic=true)

    GripSize(resizer="BicubicResize")
    GripBorders()

    ## PAL to NTSC
    AssumeFPS(23.976) # output will have to be telecined to 29.970

    ## Use this for NTSC to PAL
    #AssumeFPS(25)

    ## I like this for CCE encoding
    ConvertToYUY2()


    The plug-in for GripCrop(), etc is here:
    http://www.incredible.de.tf/Downloads/GripFit_YV12.rar

    Now, the audio will need to be stretched seperately. (I came across this thread looking for a better tool for converting AC3 audio...guess I'll try GoldWave??)

     
  17. Minion

    Minion Senior member

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    If you use this command you will not need to Stretch/Shrink the audio....

    AssumeFPS(23.976,True)

    If the audio is in a seperate File or it is in Dolby AC3 you can use the AC3Source.dll to load it and it should still get Stretched/Shrunk allong with the Video....

    Cheers
     
  18. sking1001

    sking1001 Member

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    Minion, thanks so much for the reply.

    AC3Source.dll...sounds very cool! It actually never occured to me to serve the audio with AviSynth as well.

    However, if I do that, I still have the problem of finding a good AC3 Encoder.

    If I bring an .AVS file into my MPEG Encoder my only option will be MP2 or LPCM.

    My goal is to preserve the quality/amplitude of a demuxed AC3 file and only change the frame rate.

    ...now, suppose my authoring/mux tool could read an .AVS file...well no...I suppose it would appear as LPCM when frame-served anyway, right?

    btw, it appears GoldWave does not support .AC3 files. I'm still looking for a better solution.

    Have I stated anything incorrectly above?

    tia,
    sking
     
  19. Minion

    Minion Senior member

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    Yes the audio would get decoded and served as Uncompressed WAV or LPCM when useing the AC3Source.dll....

    There are Quite a Few AC3 encoders out there these days that you can use..The one I usually use is the One that Comes with the Vegas 5/DVD Architect 2 Package, There is also a AC3 encoder plugin for Tmpgenc Xpress that you can use to encode to AC3...
    There are also a Number of DVD audio Creation Programs available...

    No matter what you do the audio will have to be decoded to Uncompressed before Stretching/Shrinking the Audio Cuz you can not Stretch it when it is Compressed so either whatever encodeing software you use will decode it before stretching or you will have to do it before Stretching it, Either way the audio gets re-encoded back to AC3 or to whatever format you choose to use on your DVD.....

    Cheers
     
  20. sking1001

    sking1001 Member

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    Excellent clarification.

    Thanks!
    :)
     

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