NTSC (29.97) to PAL - Problems with video/audio sync

[kevinm]

Hi,
I have been battling for some weeks trying to convert NTSC video from my camcorder to PAL. With the help from many informative articles on this website I have managed to get the video side of the conversion working really well. I am using avisynth 2.5 to frameserve to TMPGec Plus.
My original posts were to the Audio forum and Bugster has been helping me with the audio side but now I am wondering if I have done something wrong with the video conversion, hence the post to this forum.

Here is my avisynth script ..

LoadPlugin("D:\Applications\Mpeg2Decoder\MPEGDecod er.dll")
LoadPlugin("D:\Applications\SmoothDeinterlacer\Smo othDeinterlacer.dll")
MPEGSource("D:\pdwork\ntsc.mpg", -2, "raw")
SeparateFields()
ConvertToYUY2(interlaced=true)
Weave()
SmoothDeinterlace(doublerate=true)
#ConvertFPS(50)
ChangeFPS(50)
LanczosResize(720,576)
SeparateFields()
SelectEvery(4,1,2)
Weave()
ConvertToRGB()


The resulting video stream is very smooth, way better than any NTSC to PAL conversion I have been able to do before.

The problem I am having is with syncing the audio to the video stream. I have tried BeSweet and Goldwave to change the length of the audio but whatever I try nothing ends up synced up. The closest I can get is if I multiplex the original (ntsc.mp2) audio stream to the converted video stream (.m2v). The multiplexing is being done using TMPGEnc.

I can't figure out why I need to change the speed of audio. The converted video ends up exactly the same length as the original so why do I have to stretch the audio?

Here are some details on the various files I have managed to created so far:

1) Original NTSC source (filename: ntsc.mpg)
(info from preview in TMPGEnc)
720x480, 29.97fps, 112323 frames, total length 01:02:27 (1hour 02 mins)

2) video converted to PAL using avisynth/TMPGenc (filename: ntsc2pal.m2v)
(info from preview in TMPGEnc)
720x576, 25fps, 93695 frames, total length 01:02:27

3) Original audio stream, extracted as MP2 from ntsc.mpg using TMPGenc (filename: ntsc.mp2)
(info from Goldwave)
total length = 01:02:27.912

4) Modified audio in WAV format (using 'warp' feature in Goldwave) (filename: ntsc2pal.wav)
(info from Goldwave)
total length = 01:14:12.150

5) Above WAV file encoded to MP2 using TMPGenc (filename: ntsc2pal.mp2)
(info from Goldwave)
total length = 01:14:12.168

Can someone please tell me which audio stream I should be muxing with the converted video? I cannot see how any of the stretched audio will work as the length is completely wrong, but all the articles I have read in this and the Audio forum say that I need to go through some stage to change the length of the audio.

Also, has anyone been successful in using avisynth to simultaneously convert the video and audio streams? I have read that there is a plugin for avisynth that will allow the audio stream to be imported,

thanks,

Kevin

[nkuperw]

I don't know what you did with audio stuff, but I haven't seen anywhere about your chanign the framerate of the audio as well. If you're audio is still at ntsc, you'll need to change it to 25 fps (PAL). I usually use Besweet and it works fine. Once your audio as been "re-framed" you should be able to mux the video and audio in sync.

[kevinm]

thanks for your reply.

Yes I have done the frame rate conversion for the audio for NTSC to PAL. The two files I created are described in my original post (files 4) and 5) )

These both end up with a different length to the original and also the converted video stream. Is this right?

Maybe there is sonething that is missing from the step I am doing in Goldwave. Maybe I have to do some sort of frame rate convert whilst maintaining the original length?

I previously tried BeSweet to do the audio frame rate convert but had the same problems, i.e. converted audio length much too long.

I have followed the proceedures gigevin in the Besweet conversion guides found on this web site, I guess I must still be missing a step somewhere.

Can you help answer the fundamental question:

Should the converted audio be the same length as the original audio stream from the NTSC mpg?

thanks,

Kevin

[nkuperw]

How come in you framerate change your specifiying 50 fps?

[kevinm]

To be honest I don't know why it is there, I just copied it from a conversion tutorial I found on this site. All I really changed was the file import as I am importing MPEG for my run.

My problem is that most of these tutorials deal with NTSC film, DV conversion. None that I found cover conversion from NTSC video (29.97) to PAL. Also the audio steps usually deal with conversion from AC3. I have really struggled with this (I'm fairly new to this conversion stuff incase you hadn't already guessed).

Anyway, as the converted video looked good (played in WINDVD) I assumed all was well.

Do you think I should re-run the video conversion without the ChangeFPS(50) ?

Kevin