Pal to NTSC conversion: does this work?

[lapaz]

I want to convert a PAL DV avi into an NTSC avi and am thinking of buying a piece of software called DVfilm Atlantis for this (http://www.dvfilm.com/atlantis/).

However, as i use Adobe Premiere Pro i read about a method of converting PAL - NTSC using Premiere Pro and Virtual Dub on the Adobe board (i have copied the text below).
http://www.adobeforums.com/cgi-bin/webx?50@220.6YoXbcBvWsj.2@.2ccf2f96

What do the people with experience with PAL/NTSC conversion on this board think of this method? Does it make sense? Can i expect decent quality with it?
Thanks.


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Taken from Adobe board:
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High quality converting from PAL-NTSC or vice versa

Jorgen Bjerke - 12:59pm Jan 4, 2004 Pacific


At last, I have found a perfect way to convert between PAL and NTSC, and believe me, I have struggled a lot to make a non-jerking NTSC footage out of PAL. This guide is for converting both ways, using PPro and VirtualDub (freeware).

There are three things that differ between PAL and NTSC:
1) Frame rate: PAL is 25 frames per second (fps), NTSC is 29.97
2) Number of horisontal lines: PAL is 576 lines, NTSC is 480
3) How color is implemented into the black and white picture, but that's an analogue thing, and we don't have to think about it here.

The problem:
It's 1) that is the problem, frame rate. That means NTSC has to add some frames here and there from the PAL original, and that makes the footage jerky, especially when you have fields (normal video). To just export a PAL project as NTSC in PPro makes a horrible quality clip, so just forget that. This is how I do it (from now on):

The solution:
You could of course just play back your 25 fps PAL-footage with 29.97 fps - just speed it up a bit, but the difference is big enough to be noticed. So why not SLOW DOWN the PAL footage first? And thanks to PPro (and not v6.x) slowing and speeding is now true field based with blending so the rendered footage isn't jerky.

The difference between 25 and 29.97 is 25/29.97 = 83.4168% (rounded) from PAL to NTSC and 29.97/25 = 119.88% (exactly) from NTSC to PAL. So just change the speed of the video (and not the audio) to 83.4168 or 119.88% and export both video and audio as an AVI-file (or frame serve if you know what that is). Yes, the video and audio will now be out of sync.

Open the exported AVI in VirtualDub (a must have freeware found here: http://www.virtualdub.org). If that doesn't work, it's probably because you don't have any DV-codec installed. Download this free codec from Panasonic: http://users.tpg.com.au/mtam/install_panvfwdv.htm.

Open Video-Filters window and add a Resize node. Use width: 720 and height: 480 (if you convert to NTSC) or 576 (if you convert to PAL). Filter mode: Bicubic for PAL to NTSC or Precise bilinear for NTSC to PAL. Click Interlaced if your footage is normal interlaced video (VERY important).

Open Video-Frame Rate window and click "Change to" in "Source rate adjustment" and type in 29.97 (for conversion to NTSC) or 25 (for conversion to PAL). This will not render anything, just set a flag in the AVI-file telling the frame rate for playback. Since audio was out of sync in PPro, it will now be ALMOST 100% in sync again.

Open Video-Compression and select your DV-codec (f.ex. the Panasonic DV CODEC).

File-Save as AVI.

Create a new project in PPro (NTSC if you convertet to NTSC or PAL if you converted to PAL), import the new AVI-file and place it in the timeline. Check audio sync. I haven't tried with 1 hour clips, but I guess the audio will slip a little bit. Correct this and save as a new AVI, or export to DVD.

You're done...

Why not do everything in PPro? Because PPro can't squeeze or stretch the FRAME, just the video INSIDE the frame. The frame will always be 720x576 (PAL) or 720x480 (NTSC) inside your project. And PPro can't alter the frame rate without also alter the video itself (I think...).

[FOO]

The standard method is to slow the video down to 23.96
(only 4%) and resample the audio to match.
Then you resize and re-ecode to MPEG2 and telecine it
to make it 29.97

[lapaz]

Thanks for replying, but i must admit i am now even more confused than i already was.
Is there a guide somewhere for the 'standard method' you mention for going from PAL DV to NTSC DV?
(why and how slow down 4%, how to resample sound, which software to resize and what's telecine it?)

What is exactly the idea behind first slowing down and than speeding up? I have problems understanding this.

Maybe it's better for me to buy a commercial product like DVfilm Atlantis. Or do the methods mentioned above give better quality?

[FOO]

It may sound insane , but movies are shot at 24 fps
To show them on a PAL system , they just speed them up
to 25 fps. So the slowdown from PAL is just to get it back to
FILM speed.

Film to NTSC (24 to 30 fps) is done by inserting 2 extra fields
every 8. That's Telecine

So first you make it film speed and then you Telecine to 30

Slowing down doesn't really do anything. You just tell the video it's
24 instead of 25. Since the audio will be played at 48000 sample/sec
either way, it has to be resampled to play slower. Besweet will do that.

Unfortunately the number of vertical lines has to change from 576
to 480 and this requires a resize and a re-encode. That's the worst part of
the whole thing.

[bugster]

FOO is absolutley right, IF your final destination format is mpeg.

If forr some reason you must maintain your video in DV format and still convert from PAL to NTSC (or vice versa) then your method looks like it should work.

I would be interested to see exactly what Premier Pro is doing when you slow down/speed up the video though. If it does anything more complex than change the fps (which it must as you can do this on sections within the video I believe) it must add or remove fromes or fields somewhere along the line.

[ronnylov]

A PAL DV avi is mostly interlaced from a camcorder. The method of slowing down to 23.976 fps and telecine it to 29.97 fps will not work unless you deinterlace the PAL DV avi first.

[FOO]

I guess that would look bad
Atop - Abottom -Atop - Bbottom....
Atop is earlier in time than Abottom so Abottom-Atop would look jerky
I was thinking Film

[lapaz]

Thanks all for the comments.
Well, i decided to try out the method for DV-pal to DV-ntsc conversion (and making a DVD from the converted footage) mentioned in my first post, and it works!
And the result is actually quite good, compared to some commercial products i tested with the same footage:

- DVfilm atlantis, $150, seems to use the 'film' method you guys describe: first deinterlace, than telecine it

- Focus/Firestore converter, $300, uses a method for 'time resampling' called Blend Fields: displays the three nearest fields (upper-lower-upper or lower-upper-lower) and blends only two (upper-upper or lower-lower).

The results with the commercial conversion products are a bit sharper than with Premiere Pro (in combination with Virtual dub) but not worth the extra money in my opinion.
The trick with Premiere Pro seems to be in a feature called 'frame blend speed changes', which maybe does the same as the Focus converter.

Concluding: Premiere Pro 7 does in my opinion a much better job (using the method described) then what i expected based upon most reports i read. So i stick to Premiere for my conversions!

[bmiller]

One question.Getting the original video onto your computer.Living in ntsc territory,do i need the pal dv camera to capture the video,or can i use an ntsc camera to capture from,and use pro to convert.
Thanks for any help.

[lapaz]

i am not sure if i understand your question, but you first simply transfer the original DV footage from your camcorder to your PC (no need for a capture card, best way is transfering via a firewire port). This footage will be PAL or NTSC, depending on your equipment. Next you do the PAL-NTSC or NTSC-PAL conversion with Premiere Pro and Virtual dub, as described.

[bmiller]

I have some footage recorded in Australia on a Pal camcorder.I live in Canada.Do i need the Pal camcorder to transfer the video to my computer,or can i use a north american ntsc camera to transfer the video to my pc before i convert.I'm not sure if it makes any difference.It would be easier if i could use an ntsc camera,as the pal one has gone home.
My brother in law wanted them converted,and commercially they cost about $150 a 2hour tape.Thanks

[Dragonsf]

AFAIK standard NTSC DCR can't playback PAL footage - my PAL DCR can playback NTSC.At least the color information will be lost.

[lapaz]

yes, i think you need a PAL camcorder to transfer it to your PC

[gazzella]

I recently read the how to convert from PAL to NTSC. That's exactly what I want to do. the instructions said after installing virtual dub & Panasonic CODEC, I did all that, got to the part where you go to 'File', then Save AS AVI, but that was not highlighted, so I could not click on it.... also, what is PPro ?
I'm a beginner at this, but everything else I was able to follow.
What do I need to do next?
Thanks, Joe P.

[lapaz]

PPro is Adobe Premiere Pro. Do you have this software? And have you first changed the speed (slowed it to 83.4168%) of your PAL material in PPro and exported it as DV Avi? This is the file you need to import in Virtual dub.
No idea why you can't choose 'save as' in Virtual dub.

[DVO]

You can try FireStore DV Standards Converter. It can convert between NTSC-PAL both ways using 3 different methods. I haven't tried it, but the program got elected as best video utility or something by Computer Video magazine last year.

Edit:
For more info:
http://www.computervideo.net/mar03-4.html

[gazzella]

Thanks for getting back to me.... I missed a step... I don't have Adobe Premier Pro, after seeing the price... I can see why... but I do see that I can download a 30 day trial version. I can follow instructions although I have a very limited experience in this stuff. I just wanted to be able to convert from PAL to NTSC without the major headache invlolved because of my limited experience. I only have one DVD that is PAL, I don't know if I will need to do this again in the future, but because I'm an entertainer, I wanted my backup singers to be able to learn from this DVD after I burned it to a DVD-R because they don't have dvd rom's on their computers. They just have home dvd players that can only view NTSC (region 1). If you can help me get through this.. that would be great.
Thanks,
Joe P.

[lapaz]

I am afraid converting a PAL DVD to NTSC DVD is different than converting PAL DV footage to NTSC DV footage. I am no expert but i think some extra steps are needed for this (please search the site).
This is because DVDs are encoded in MPEG which is different from the DV (Digital Video) footage you record with a camcorder.
And the software/methods described in this thread are about converting DV material.

If they have a CD-rom drive, maybe it's easier to copy the DVD to a CD-R (in DiVX format), with for example software like Fairuse

[gazzella]

Thanks, but they don't have a DVD ROM drive, I guess I have to do more research.

[bode]

I've read that Canopus Procoder does a good conversion and it's easy!

I'm about to try this out, but won't be able to get feedback on the results for a while.

Check the Canopus forums for more info.

http://forum.canopus.com/

Demo:
http://www.canopus.us/US/products/ProCoder/pm_procoder.asp